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pyparsing-pyparsing/pyparsing/core.py
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dualfroz 286b7d7b78 fix: skip leading whitespace before parse-action loc on Or and MatchFirst 
Parse actions attached directly to an Or ('^') or MatchFirst ('|')
expression received the raw, un-whitespace-skipped loc instead of the
whitespace-skipped location of the matched tokens. And ('+') already
handled this correctly by setting callPreparse = True in its __init__;
Or and MatchFirst never did the equivalent correction, so they always
fell through to the callPreparse = False default set by the shared
ParseExpression base class.

Set callPreparse on Or and MatchFirst using the same "do all
alternatives pre-skip whitespace" condition Or.parseImpl already uses
internally, so tokens_start is corrected only when it is safe to do so
without changing which alternative matches (e.g. alternatives such as
White() or AtStringStart() that intentionally disable callPreparse
still prevent the pre-skip, exactly as before).

Fixes #557
2026-09-04 03:38:24 +02:00

7006 lines
249 KiB
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#
# core.py
#
from __future__ import annotations
import collections.abc
from collections import deque
import os
import typing
from typing import (
Any,
Callable,
Generator,
NamedTuple,
Sequence,
TextIO,
Union,
cast,
)
from abc import ABC, abstractmethod
from enum import Enum
import string
import copy
import warnings
import re
import sys
from collections.abc import Iterable
import traceback
import types
from operator import itemgetter
from functools import wraps
from threading import RLock
from pathlib import Path
from .warnings import PyparsingDeprecationWarning, PyparsingDiagnosticWarning
from .util import (
_FifoCache,
_UnboundedCache,
__config_flags,
_collapse_string_to_ranges,
_convert_escaped_numerics_to_char,
_escape_regex_range_chars,
_flatten,
LRUMemo as _LRUMemo,
UnboundedMemo as _UnboundedMemo,
deprecate_argument,
replaced_by_pep8,
)
from .exceptions import *
from .actions import *
from .results import ParseResults, _ParseResultsWithOffset
from .unicode import pyparsing_unicode
_MAX_INT = sys.maxsize
str_type: tuple[type, ...] = (str, bytes)
#
# Copyright (c) 2003-2022 Paul T. McGuire
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
from functools import cached_property
class __compat__(__config_flags):
"""
A cross-version compatibility configuration for pyparsing features that will be
released in a future version. By setting values in this configuration to True,
those features can be enabled in prior versions for compatibility development
and testing.
- ``collect_all_And_tokens`` - flag to enable fix for Issue #63 that fixes erroneous grouping
of results names when an :class:`And` expression is nested within an :class:`Or` or :class:`MatchFirst`;
maintained for compatibility, but setting to ``False`` no longer restores pre-2.3.1
behavior
"""
_type_desc = "compatibility"
collect_all_And_tokens = True
_all_names = [__ for __ in locals() if not __.startswith("_")]
_fixed_names = """
collect_all_And_tokens
""".split()
class __diag__(__config_flags):
_type_desc = "diagnostic"
warn_multiple_tokens_in_named_alternation = False
warn_ungrouped_named_tokens_in_collection = False
warn_name_set_on_empty_Forward = False
warn_on_parse_using_empty_Forward = False
warn_on_assignment_to_Forward = False
warn_on_multiple_string_args_to_oneof = False
warn_on_match_first_with_lshift_operator = False
enable_debug_on_named_expressions = False
_all_names = [__ for __ in locals() if not __.startswith("_")]
_warning_names = [name for name in _all_names if name.startswith("warn")]
_debug_names = [name for name in _all_names if name.startswith("enable_debug")]
@classmethod
def enable_all_warnings(cls) -> None:
for name in cls._warning_names:
cls.enable(name)
class Diagnostics(Enum):
"""
Diagnostic configuration (all default to disabled)
- ``warn_multiple_tokens_in_named_alternation`` - flag to enable warnings when a results
name is defined on a :class:`MatchFirst` or :class:`Or` expression with one or more :class:`And` subexpressions
- ``warn_ungrouped_named_tokens_in_collection`` - flag to enable warnings when a results
name is defined on a containing expression with ungrouped subexpressions that also
have results names
- ``warn_name_set_on_empty_Forward`` - flag to enable warnings when a :class:`Forward` is defined
with a results name, but has no contents defined
- ``warn_on_parse_using_empty_Forward`` - flag to enable warnings when a :class:`Forward` is
defined in a grammar but has never had an expression attached to it
- ``warn_on_assignment_to_Forward`` - flag to enable warnings when a :class:`Forward` is defined
but is overwritten by assigning using ``'='`` instead of ``'<<='`` or ``'<<'``
- ``warn_on_multiple_string_args_to_oneof`` - flag to enable warnings when :class:`one_of` is
incorrectly called with multiple str arguments
- ``enable_debug_on_named_expressions`` - flag to auto-enable debug on all subsequent
calls to :class:`ParserElement.set_name`
Diagnostics are enabled/disabled by calling :class:`enable_diag` and :class:`disable_diag`.
All warnings can be enabled by calling :class:`enable_all_warnings`.
"""
warn_multiple_tokens_in_named_alternation = 0
warn_ungrouped_named_tokens_in_collection = 1
warn_name_set_on_empty_Forward = 2
warn_on_parse_using_empty_Forward = 3
warn_on_assignment_to_Forward = 4
warn_on_multiple_string_args_to_oneof = 5
warn_on_match_first_with_lshift_operator = 6
enable_debug_on_named_expressions = 7
def enable_diag(diag_enum: Diagnostics) -> None:
"""
Enable a global pyparsing diagnostic flag (see :class:`Diagnostics`).
"""
__diag__.enable(diag_enum.name)
def disable_diag(diag_enum: Diagnostics) -> None:
"""
Disable a global pyparsing diagnostic flag (see :class:`Diagnostics`).
"""
__diag__.disable(diag_enum.name)
def enable_all_warnings() -> None:
"""
Enable all global pyparsing diagnostic warnings (see :class:`Diagnostics`).
"""
__diag__.enable_all_warnings()
# hide abstract class
del __config_flags
def _should_enable_warnings(
cmd_line_warn_options: typing.Iterable[str], warn_env_var: typing.Optional[str]
) -> bool:
enable = bool(warn_env_var)
for warn_opt in cmd_line_warn_options:
w_action, w_message, w_category, w_module, w_line = (warn_opt + "::::").split(
":"
)[:5]
if not w_action.lower().startswith("i") and (
not (w_message or w_category or w_module) or w_module == "pyparsing"
):
enable = True
elif w_action.lower().startswith("i") and w_module in ("pyparsing", ""):
enable = False
return enable
if _should_enable_warnings(
sys.warnoptions, os.environ.get("PYPARSINGENABLEALLWARNINGS")
):
enable_all_warnings()
# build list of single arg builtins, that can be used as parse actions
# fmt: off
_single_arg_builtins = {
sum, len, sorted, reversed, list, tuple, set, any, all, min, max
}
# fmt: on
_generatorType = types.GeneratorType
ParseImplReturnType = tuple[int, Any]
PostParseReturnType = Union[ParseResults, Sequence[ParseResults]]
ParseCondition = Union[
Callable[[], bool],
Callable[[ParseResults], bool],
Callable[[int, ParseResults], bool],
Callable[[str, int, ParseResults], bool],
]
ParseFailAction = Callable[[str, int, "ParserElement", Exception], None]
DebugStartAction = Callable[[str, int, "ParserElement", bool], None]
DebugSuccessAction = Callable[
[str, int, int, "ParserElement", ParseResults, bool], None
]
DebugExceptionAction = Callable[[str, int, "ParserElement", Exception, bool], None]
alphas: str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
identchars: str = pyparsing_unicode.Latin1.identchars
identbodychars: str = pyparsing_unicode.Latin1.identbodychars
nums: str = "0123456789"
hexnums: str = "0123456789ABCDEFabcdef"
alphanums: str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
printables: str = (
'!"'
"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~"
)
class _ParseActionIndexError(Exception):
"""
Internal wrapper around IndexError so that IndexErrors raised inside
parse actions aren't misinterpreted as IndexErrors raised inside
ParserElement parseImpl methods.
"""
def __init__(self, msg: str, exc: BaseException) -> None:
self.msg: str = msg
self.exc: BaseException = exc
_trim_arity_call_line: traceback.StackSummary = None # type: ignore[assignment]
pa_call_line_synth = ()
def _trim_arity(func, max_limit=3):
"""decorator to trim function calls to match the arity of the target"""
global _trim_arity_call_line, pa_call_line_synth
if func in _single_arg_builtins:
return lambda s, l, t: func(t)
limit = 0
found_arity = False
# synthesize what would be returned by traceback.extract_stack at the call to
# user's parse action 'func', so that we don't incur call penalty at parse time
# fmt: off
LINE_DIFF = 9
# IF ANY CODE CHANGES, EVEN JUST COMMENTS OR BLANK LINES, BETWEEN THE NEXT LINE AND
# THE CALL TO FUNC INSIDE WRAPPER, LINE_DIFF MUST BE MODIFIED!!!!
_trim_arity_call_line = _trim_arity_call_line or traceback.extract_stack(limit=2)[-1]
pa_call_line_synth = pa_call_line_synth or (_trim_arity_call_line[0], _trim_arity_call_line[1] + LINE_DIFF)
def wrapper(*args):
nonlocal found_arity, limit
if found_arity:
return func(*args[limit:])
while 1:
try:
ret = func(*args[limit:])
found_arity = True
return ret
except TypeError as te:
# re-raise TypeErrors if they did not come from our arity testing
if found_arity:
raise
else:
tb = te.__traceback__
frames = traceback.extract_tb(tb, limit=2)
frame_summary = frames[-1]
trim_arity_type_error = (
[frame_summary[:2]][-1][:2] == pa_call_line_synth
)
del tb
if trim_arity_type_error:
if limit < max_limit:
limit += 1
continue
raise
except IndexError as ie:
# wrap IndexErrors inside a _ParseActionIndexError
raise _ParseActionIndexError(
"IndexError raised in parse action", ie
).with_traceback(None)
# fmt: on
# copy func name to wrapper for sensible debug output
# (can't use functools.wraps, since that messes with function signature)
func_name = getattr(func, "__name__", getattr(func, "__class__").__name__)
wrapper.__name__ = func_name
wrapper.__doc__ = func.__doc__
return wrapper
def condition_as_parse_action(
fn: ParseCondition, message: typing.Optional[str] = None, fatal: bool = False
) -> ParseAction:
"""
Function to convert a simple predicate function that returns ``True`` or ``False``
into a parse action. Can be used in places when a parse action is required
and :meth:`ParserElement.add_condition` cannot be used (such as when adding a condition
to an operator level in :class:`infix_notation`).
Optional keyword arguments:
:param message: define a custom message to be used in the raised exception
:param fatal: if ``True``, will raise :class:`ParseFatalException`
to stop parsing immediately;
otherwise will raise :class:`ParseException`
"""
msg = message if message is not None else "failed user-defined condition"
exc_type = ParseFatalException if fatal else ParseException
fn = _trim_arity(fn)
@wraps(fn)
def pa(s, l, t):
if not bool(fn(s, l, t)):
raise exc_type(s, l, msg)
return pa
# control characters escaped so they can't corrupt the printed debug line
# (for example a stray '\r' would otherwise return the cursor to column 0)
_debug_control_char_map = {c: repr(chr(c))[1:-1] for c in (*range(0x20), 0x7F)}
def _default_start_debug_action(
instring: str, loc: int, expr: ParserElement, cache_hit: bool = False
):
cache_hit_str = "*" if cache_hit else ""
current_col = col(loc, instring)
current_line = line(loc, instring)
escaped_line = current_line.translate(_debug_control_char_map)
# keep the caret under the match location after escaping widens the line
caret_col = (
len(current_line[: current_col - 1].translate(_debug_control_char_map)) + 1
)
print(
(
f"{cache_hit_str}Match {expr} at loc {loc}({lineno(loc, instring)},{current_col})\n"
f" {escaped_line}\n"
f" {'^':>{caret_col}}"
)
)
def _default_success_debug_action(
instring: str,
startloc: int,
endloc: int,
expr: ParserElement,
toks: ParseResults,
cache_hit: bool = False,
):
cache_hit_str = "*" if cache_hit else ""
print(f"{cache_hit_str}Matched {expr} -> {toks.as_list()}")
def _default_exception_debug_action(
instring: str,
loc: int,
expr: ParserElement,
exc: Exception,
cache_hit: bool = False,
):
cache_hit_str = "*" if cache_hit else ""
print(f"{cache_hit_str}Match {expr} failed, {type(exc).__name__} raised: {exc}")
def null_debug_action(*args):
"""'Do-nothing' debug action, to suppress debugging output during parsing."""
class ParserElement(ABC):
"""Abstract base level parser element class."""
DEFAULT_WHITE_CHARS: str = " \n\t\r"
verbose_stacktrace: bool = False
_literalStringClass: type = None # type: ignore[assignment]
@staticmethod
def set_default_whitespace_chars(chars: str) -> None:
r"""
Overrides the default whitespace chars
Example:
.. doctest::
# default whitespace chars are space, <TAB> and newline
>>> Word(alphas)[1, ...].parse_string("abc def\nghi jkl")
ParseResults(['abc', 'def', 'ghi', 'jkl'], {})
# change to just treat newline as significant
>>> ParserElement.set_default_whitespace_chars(" \t")
>>> Word(alphas)[1, ...].parse_string("abc def\nghi jkl")
ParseResults(['abc', 'def'], {})
# Reset to default
>>> ParserElement.set_default_whitespace_chars(" \n\t\r")
"""
ParserElement.DEFAULT_WHITE_CHARS = chars
# update whitespace all parse expressions defined in this module
for expr in _builtin_exprs:
if expr.copyDefaultWhiteChars:
expr.whiteChars = set(chars)
@staticmethod
def inline_literals_using(cls: type) -> None:
"""
Set class to be used for inclusion of string literals into a parser.
Example:
.. doctest::
:options: +NORMALIZE_WHITESPACE
# default literal class used is Literal
>>> integer = Word(nums)
>>> date_str = (
... integer("year") + '/'
... + integer("month") + '/'
... + integer("day")
... )
>>> date_str.parse_string("1999/12/31")
ParseResults(['1999', '/', '12', '/', '31'],
{'year': '1999', 'month': '12', 'day': '31'})
# change to Suppress
>>> ParserElement.inline_literals_using(Suppress)
>>> date_str = (
... integer("year") + '/'
... + integer("month") + '/'
... + integer("day")
... )
>>> date_str.parse_string("1999/12/31")
ParseResults(['1999', '12', '31'],
{'year': '1999', 'month': '12', 'day': '31'})
# Reset
>>> ParserElement.inline_literals_using(Literal)
"""
ParserElement._literalStringClass = cls
@classmethod
def using_each(cls, seq, **class_kwargs):
"""
Yields a sequence of ``class(obj, **class_kwargs)`` for obj in seq.
Example:
.. testcode::
LPAR, RPAR, LBRACE, RBRACE, SEMI = Suppress.using_each("(){};")
.. versionadded:: 3.1.0
"""
yield from (cls(obj, **class_kwargs) for obj in seq)
class DebugActions(NamedTuple):
debug_try: typing.Optional[DebugStartAction]
debug_match: typing.Optional[DebugSuccessAction]
debug_fail: typing.Optional[DebugExceptionAction]
def __init__(self, savelist: bool = False) -> None:
self.parseAction: list[ParseAction] = list()
self.failAction: typing.Optional[ParseFailAction] = None
self.customName: str = None # type: ignore[assignment]
self._defaultName: typing.Optional[str] = None
self.resultsName: str = None # type: ignore[assignment]
self.saveAsList: bool = savelist
self.skipWhitespace: bool = True
self.whiteChars: set[str] = set(ParserElement.DEFAULT_WHITE_CHARS)
self.copyDefaultWhiteChars: bool = True
# used when checking for left-recursion
self._may_return_empty: bool = False
self.keepTabs: bool = False
self.ignoreExprs: list[ParserElement] = list()
self.debug: bool = False
self.streamlined: bool = False
# optimize exception handling for subclasses that don't advance parse index
self.mayIndexError: bool = True
self.errmsg: Union[str, None] = ""
# mark results names as modal (report only last) or cumulative (list all)
self.modalResults: bool = True
# custom debug actions
self.debugActions = self.DebugActions(None, None, None)
# avoid redundant calls to preParse
self.callPreparse: bool = True
self.callDuringTry: bool = False
self.suppress_warnings_: list[Diagnostics] = []
self.show_in_diagram: bool = True
@property
def mayReturnEmpty(self) -> bool:
"""
.. deprecated:: 3.3.0
use _may_return_empty instead.
"""
return self._may_return_empty
@mayReturnEmpty.setter
def mayReturnEmpty(self, value) -> None:
"""
.. deprecated:: 3.3.0
use _may_return_empty instead.
"""
self._may_return_empty = value
def suppress_warning(self, warning_type: Diagnostics) -> ParserElement:
"""
Suppress warnings emitted for a particular diagnostic on this expression.
Example:
.. doctest::
>>> label = pp.Word(pp.alphas)
# Normally using an empty Forward in a grammar
# would print a warning, but we can suppress that
>>> base = pp.Forward().suppress_warning(
... pp.Diagnostics.warn_on_parse_using_empty_Forward)
>>> grammar = base | label
>>> print(grammar.parse_string("x"))
['x']
"""
self.suppress_warnings_.append(warning_type)
return self
def visit_all(self):
"""General-purpose method to yield all expressions and sub-expressions
in a grammar. Typically just for internal use.
"""
to_visit = deque([self])
seen = set()
while to_visit:
cur = to_visit.popleft()
# guard against looping forever through recursive grammars
if cur in seen:
continue
seen.add(cur)
to_visit.extend(cur.recurse())
yield cur
def copy(self) -> ParserElement:
"""
Make a copy of this :class:`ParserElement`. Useful for defining
different parse actions for the same parsing pattern, using copies of
the original parse element.
Example:
.. testcode::
integer = Word(nums).set_parse_action(
lambda toks: int(toks[0]))
integerK = integer.copy().add_parse_action(
lambda toks: toks[0] * 1024) + Suppress("K")
integerM = integer.copy().add_parse_action(
lambda toks: toks[0] * 1024 * 1024) + Suppress("M")
print(
(integerK | integerM | integer)[1, ...].parse_string(
"5K 100 640K 256M")
)
prints:
.. testoutput::
[5120, 100, 655360, 268435456]
Equivalent form of ``expr.copy()`` is just ``expr()``:
.. testcode::
integerM = integer().add_parse_action(
lambda toks: toks[0] * 1024 * 1024) + Suppress("M")
"""
cpy = copy.copy(self)
cpy.parseAction = self.parseAction[:]
cpy.ignoreExprs = self.ignoreExprs[:]
if self.copyDefaultWhiteChars:
cpy.whiteChars = set(ParserElement.DEFAULT_WHITE_CHARS)
return cpy
def set_results_name(
self, name: str, list_all_matches: bool = False, **kwargs
) -> ParserElement:
"""
Define name for referencing matching tokens as a nested attribute
of the returned parse results.
Normally, results names are assigned as you would assign keys in a dict:
any existing value is overwritten by later values. If it is necessary to
keep all values captured for a particular results name, call ``set_results_name``
with ``list_all_matches`` = True.
NOTE: ``set_results_name`` returns a *copy* of the original :class:`ParserElement` object;
this is so that the client can define a basic element, such as an
integer, and reference it in multiple places with different names.
You can also set results names using the abbreviated syntax,
``expr("name")`` in place of ``expr.set_results_name("name")``
- see :meth:`__call__`. If ``list_all_matches`` is required, use
``expr("name*")``.
Example:
.. testcode::
integer = Word(nums)
date_str = (integer.set_results_name("year") + '/'
+ integer.set_results_name("month") + '/'
+ integer.set_results_name("day"))
# equivalent form:
date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
"""
listAllMatches: bool = deprecate_argument(kwargs, "listAllMatches", False)
list_all_matches = listAllMatches or list_all_matches
return self._setResultsName(name, list_all_matches)
def _setResultsName(self, name, list_all_matches=False) -> ParserElement:
if name is None:
return self
newself = self.copy()
if name.endswith("*"):
name = name[:-1]
list_all_matches = True
newself.resultsName = name
newself.modalResults = not list_all_matches
return newself
def set_break(self, break_flag: bool = True) -> ParserElement:
"""
Method to invoke the Python pdb debugger when this element is
about to be parsed. Set ``break_flag`` to ``True`` to enable, ``False`` to
disable.
"""
if break_flag:
_parseMethod = self._parse
def breaker(instring, loc, do_actions=True, callPreParse=True):
# this call to breakpoint() is intentional, not a checkin error
breakpoint()
return _parseMethod(instring, loc, do_actions, callPreParse)
breaker._originalParseMethod = _parseMethod # type: ignore [attr-defined]
self._parse = breaker # type: ignore [method-assign]
elif hasattr(self._parse, "_originalParseMethod"):
self._parse = self._parse._originalParseMethod # type: ignore [method-assign]
return self
def set_parse_action(
self, *fns: ParseAction, call_during_try: bool = False, **kwargs: Any
) -> ParserElement:
"""
Define one or more actions to perform when successfully matching parse element definition.
Parse actions can be called to perform data conversions, do extra validation,
update external data structures, or enhance or replace the parsed tokens.
Each parse action ``fn`` is a callable method with 0-3 arguments, called as
``fn(s, loc, toks)`` , ``fn(loc, toks)`` , ``fn(toks)`` , or just ``fn()`` , where:
- ``s`` = the original string being parsed (see note below)
- ``loc`` = the location of the matching substring
- ``toks`` = a list of the matched tokens, packaged as a :class:`ParseResults` object
The parsed tokens are passed to the parse action as ParseResults. They can be
modified in place using list-style append, extend, and pop operations to update
the parsed list elements; and with dictionary-style item set and del operations
to add, update, or remove any named results. If the tokens are modified in place,
it is not necessary to return them with a return statement.
Parse actions can also completely replace the given tokens, with another ``ParseResults``
object, or with some entirely different object (common for parse actions that perform data
conversions). A convenient way to build a new parse result is to define the values
using a dict, and then create the return value using :class:`ParseResults.from_dict`.
If None is passed as the ``fn`` parse action, all previously added parse actions for this
expression are cleared.
Optional keyword arguments:
:param call_during_try: (default= ``False``) indicate if parse action
should be run during lookaheads and alternate
testing. For parse actions that have side
effects, it is important to only call the parse
action once it is determined that it is being
called as part of a successful parse.
For parse actions that perform additional
validation, then ``call_during_try`` should
be passed as True, so that the validation code
is included in the preliminary "try" parses.
.. Note::
The default parsing behavior is to expand tabs in the input string
before starting the parsing process.
See :meth:`parse_string` for more information on parsing strings
containing ``<TAB>`` s, and suggested methods to maintain a
consistent view of the parsed string, the parse location, and
line and column positions within the parsed string.
Example: Parse dates in the form ``YYYY/MM/DD``
-----------------------------------------------
Setup code:
.. testcode::
def convert_to_int(toks):
'''a parse action to convert toks from str to int
at parse time'''
return int(toks[0])
def is_valid_date(instring, loc, toks):
'''a parse action to verify that the date is a valid date'''
from datetime import date
year, month, day = toks[::2]
try:
date(year, month, day)
except ValueError:
raise ParseException(instring, loc, "invalid date given")
integer = Word(nums)
date_str = integer + '/' + integer + '/' + integer
# add parse actions
integer.set_parse_action(convert_to_int)
date_str.set_parse_action(is_valid_date)
Successful parse - note that integer fields are converted to ints:
.. testcode::
print(date_str.parse_string("1999/12/31"))
prints:
.. testoutput::
[1999, '/', 12, '/', 31]
Failure - invalid date:
.. testcode::
date_str.parse_string("1999/13/31")
prints:
.. testoutput::
Traceback (most recent call last):
ParseException: invalid date given, found '1999' ...
"""
callDuringTry: bool = deprecate_argument(kwargs, "callDuringTry", False)
if list(fns) == [None]:
self.parseAction.clear()
return self
if not all(callable(fn) for fn in fns):
raise TypeError("parse actions must be callable")
self.parseAction[:] = [_trim_arity(fn) for fn in fns]
self.callDuringTry = self.callDuringTry or call_during_try or callDuringTry
return self
def add_parse_action(
self, *fns: ParseAction, call_during_try: bool = False, **kwargs: Any
) -> ParserElement:
"""
Add one or more parse actions to expression's list of parse actions. See :class:`set_parse_action`.
See examples in :class:`copy`.
"""
callDuringTry: bool = deprecate_argument(kwargs, "callDuringTry", False)
self.parseAction += [_trim_arity(fn) for fn in fns]
self.callDuringTry = self.callDuringTry or callDuringTry or call_during_try
return self
def add_condition(
self, *fns: ParseCondition, call_during_try: bool = False, **kwargs: Any
) -> ParserElement:
"""Add a boolean predicate function to expression's list of parse actions. See
:class:`set_parse_action` for function call signatures. Unlike ``set_parse_action``,
functions passed to ``add_condition`` need to return boolean success/fail of the condition.
Optional keyword arguments:
- ``message`` = define a custom message to be used in the raised exception
- ``fatal`` = if True, will raise ParseFatalException to stop parsing immediately; otherwise will raise
ParseException
- ``call_during_try`` = boolean to indicate if this method should be called during internal tryParse calls,
default=False
Example:
.. doctest::
:options: +NORMALIZE_WHITESPACE
>>> integer = Word(nums).set_parse_action(lambda toks: int(toks[0]))
>>> year_int = integer.copy().add_condition(
... lambda toks: toks[0] >= 2000,
... message="Only support years 2000 and later")
>>> date_str = year_int + '/' + integer + '/' + integer
>>> result = date_str.parse_string("1999/12/31")
Traceback (most recent call last):
ParseException: Only support years 2000 and later...
"""
callDuringTry: bool = deprecate_argument(kwargs, "callDuringTry", False)
for fn in fns:
self.parseAction.append(
condition_as_parse_action(
fn,
message=str(kwargs.get("message")),
fatal=bool(kwargs.get("fatal", False)),
)
)
self.callDuringTry = self.callDuringTry or call_during_try or callDuringTry
return self
def set_fail_action(self, fn: ParseFailAction) -> ParserElement:
"""
Define action to perform if parsing fails at this expression.
Fail acton fn is a callable function that takes the arguments
``fn(s, loc, expr, err)`` where:
- ``s`` = string being parsed
- ``loc`` = location where expression match was attempted and failed
- ``expr`` = the parse expression that failed
- ``err`` = the exception thrown
The function returns no value. It may throw :class:`ParseFatalException`
if it is desired to stop parsing immediately."""
self.failAction = fn
return self
def _skipIgnorables(self, instring: str, loc: int) -> int:
if not self.ignoreExprs:
return loc
exprsFound = True
ignore_expr_fns = [e._parse for e in self.ignoreExprs]
last_loc = loc
while exprsFound:
exprsFound = False
for ignore_fn in ignore_expr_fns:
try:
while 1:
loc, dummy = ignore_fn(instring, loc)
exprsFound = True
except ParseException:
pass
# check if all ignore exprs matched but didn't actually advance the parse location
if loc == last_loc:
break
last_loc = loc
return loc
def preParse(self, instring: str, loc: int) -> int:
if self.ignoreExprs:
loc = self._skipIgnorables(instring, loc)
if self.skipWhitespace:
instrlen = len(instring)
white_chars = self.whiteChars
while loc < instrlen and instring[loc] in white_chars:
loc += 1
return loc
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
return loc, []
def postParse(self, instring, loc, tokenlist):
return tokenlist
# @profile
def _parseNoCache(
self, instring, loc, do_actions=True, callPreParse=True
) -> tuple[int, ParseResults]:
debugging = self.debug # and do_actions)
len_instring = len(instring)
if debugging or self.failAction:
# print("Match {} at loc {}({}, {})".format(self, loc, lineno(loc, instring), col(loc, instring)))
try:
if callPreParse and self.callPreparse:
pre_loc = self.preParse(instring, loc)
else:
pre_loc = loc
tokens_start = pre_loc
if self.debugActions.debug_try:
self.debugActions.debug_try(instring, tokens_start, self, False)
if self.mayIndexError or pre_loc >= len_instring:
try:
loc, tokens = self.parseImpl(instring, pre_loc, do_actions)
except IndexError:
raise ParseException(instring, len_instring, self.errmsg, self)
else:
loc, tokens = self.parseImpl(instring, pre_loc, do_actions)
except Exception as err:
# print("Exception raised:", err)
if self.debugActions.debug_fail:
self.debugActions.debug_fail(
instring, tokens_start, self, err, False
)
if self.failAction:
self.failAction(instring, tokens_start, self, err)
raise
else:
if callPreParse and self.callPreparse:
pre_loc = self.preParse(instring, loc)
else:
pre_loc = loc
tokens_start = pre_loc
if self.mayIndexError or pre_loc >= len_instring:
try:
loc, tokens = self.parseImpl(instring, pre_loc, do_actions)
except IndexError:
raise ParseException(instring, len_instring, self.errmsg, self)
else:
loc, tokens = self.parseImpl(instring, pre_loc, do_actions)
tokens = self.postParse(instring, loc, tokens)
ret_tokens = ParseResults(
tokens, self.resultsName, aslist=self.saveAsList, modal=self.modalResults
)
if self.parseAction and (do_actions or self.callDuringTry):
if debugging:
try:
for fn in self.parseAction:
try:
tokens = fn(instring, tokens_start, ret_tokens) # type: ignore [call-arg, arg-type]
except IndexError as parse_action_exc:
exc = ParseException("exception raised in parse action")
raise exc from parse_action_exc
if tokens is not None and tokens is not ret_tokens:
ret_tokens = ParseResults(
tokens,
self.resultsName,
aslist=self.saveAsList
and isinstance(tokens, (ParseResults, list)),
modal=self.modalResults,
)
except Exception as err:
# print "Exception raised in user parse action:", err
if self.debugActions.debug_fail:
self.debugActions.debug_fail(
instring, tokens_start, self, err, False
)
raise
else:
for fn in self.parseAction:
try:
tokens = fn(instring, tokens_start, ret_tokens) # type: ignore [call-arg, arg-type]
except IndexError as parse_action_exc:
exc = ParseException("exception raised in parse action")
raise exc from parse_action_exc
if tokens is not None and tokens is not ret_tokens:
ret_tokens = ParseResults(
tokens,
self.resultsName,
aslist=self.saveAsList
and isinstance(tokens, (ParseResults, list)),
modal=self.modalResults,
)
if debugging:
# print("Matched", self, "->", ret_tokens.as_list())
if self.debugActions.debug_match:
self.debugActions.debug_match(
instring, tokens_start, loc, self, ret_tokens, False
)
return loc, ret_tokens
def try_parse(
self,
instring: str,
loc: int,
*,
raise_fatal: bool = False,
do_actions: bool = False,
) -> int:
try:
return self._parse(instring, loc, do_actions=do_actions)[0]
except ParseFatalException:
if raise_fatal:
raise
raise ParseException(instring, loc, self.errmsg, self)
def can_parse_next(self, instring: str, loc: int, do_actions: bool = False) -> bool:
try:
self.try_parse(instring, loc, do_actions=do_actions)
except (ParseException, IndexError):
return False
else:
return True
# cache for left-recursion in Forward references
recursion_lock = RLock()
recursion_memos: collections.abc.MutableMapping[
tuple[int, Forward, bool], tuple[int, Union[ParseResults, Exception]]
] = {}
class _CacheType(typing.Protocol):
"""
Class to be used for packrat and left-recursion cacheing of results
and exceptions.
"""
not_in_cache: bool
def get(self, *args) -> typing.Any: ...
def set(self, *args) -> None: ...
def clear(self) -> None: ...
class NullCache(dict):
"""
A null cache type for initialization of the packrat_cache class variable.
If/when enable_packrat() is called, this null cache will be replaced by a
proper _CacheType class instance.
"""
not_in_cache: bool = True
def get(self, *args) -> typing.Any: ...
def set(self, *args) -> None: ...
def clear(self) -> None: ...
# class-level argument cache for optimizing repeated calls when backtracking
# through recursive expressions
packrat_cache: _CacheType = NullCache()
packrat_cache_lock = RLock()
packrat_cache_stats = [0, 0]
# this method gets repeatedly called during backtracking with the same arguments -
# we can cache these arguments and save ourselves the trouble of re-parsing the contained expression
def _parseCache(
self, instring, loc, do_actions=True, callPreParse=True
) -> tuple[int, ParseResults]:
HIT, MISS = 0, 1
lookup = (self, instring, loc, callPreParse, do_actions)
with ParserElement.packrat_cache_lock:
cache = ParserElement.packrat_cache
value = cache.get(lookup)
if value is cache.not_in_cache:
ParserElement.packrat_cache_stats[MISS] += 1
try:
value = self._parseNoCache(instring, loc, do_actions, callPreParse)
except ParseBaseException as pe:
# cache a copy of the exception, without the traceback
cache.set(lookup, pe.__class__(*pe.args))
raise
else:
cache.set(lookup, (value[0], value[1].copy(), loc))
return value
else:
ParserElement.packrat_cache_stats[HIT] += 1
if self.debug and self.debugActions.debug_try:
try:
self.debugActions.debug_try(instring, loc, self, cache_hit=True) # type: ignore [call-arg]
except TypeError:
pass
if isinstance(value, Exception):
if self.debug and self.debugActions.debug_fail:
try:
self.debugActions.debug_fail(
instring, loc, self, value, cache_hit=True # type: ignore [call-arg]
)
except TypeError:
pass
raise value
value = cast(tuple[int, ParseResults, int], value)
loc_, result, endloc = value[0], value[1].copy(), value[2]
if self.debug and self.debugActions.debug_match:
try:
self.debugActions.debug_match(
instring, loc_, endloc, self, result, cache_hit=True # type: ignore [call-arg]
)
except TypeError:
pass
return loc_, result
_parse = _parseNoCache
@staticmethod
def reset_cache() -> None:
"""
Clears caches used by packrat and left-recursion.
"""
with ParserElement.packrat_cache_lock:
ParserElement.packrat_cache.clear()
ParserElement.packrat_cache_stats[:] = [0] * len(
ParserElement.packrat_cache_stats
)
ParserElement.recursion_memos.clear()
# class attributes to keep caching status
_packratEnabled = False
_left_recursion_enabled = False
@staticmethod
def disable_memoization() -> None:
"""
Disables active Packrat or Left Recursion parsing and their memoization
This method also works if neither Packrat nor Left Recursion are enabled.
This makes it safe to call before activating Packrat nor Left Recursion
to clear any previous settings.
"""
with ParserElement.packrat_cache_lock:
ParserElement.reset_cache()
ParserElement._left_recursion_enabled = False
ParserElement._packratEnabled = False
ParserElement._parse = ParserElement._parseNoCache
@staticmethod
def enable_left_recursion(
cache_size_limit: typing.Optional[int] = None, *, force=False
) -> None:
"""
Enables "bounded recursion" parsing, which allows for both direct and indirect
left-recursion. During parsing, left-recursive :class:`Forward` elements are
repeatedly matched with a fixed recursion depth that is gradually increased
until finding the longest match.
Example:
.. testcode::
import pyparsing as pp
pp.ParserElement.enable_left_recursion()
E = pp.Forward("E")
num = pp.Word(pp.nums)
# match `num`, or `num '+' num`, or `num '+' num '+' num`, ...
E <<= E + '+' - num | num
print(E.parse_string("1+2+3+4"))
prints:
.. testoutput::
['1', '+', '2', '+', '3', '+', '4']
Recursion search naturally memoizes matches of ``Forward`` elements and may
thus skip reevaluation of parse actions during backtracking. This may break
programs with parse actions which rely on strict ordering of side-effects.
Parameters:
- ``cache_size_limit`` - (default=``None``) - memoize at most this many
``Forward`` elements during matching; if ``None`` (the default),
memoize all ``Forward`` elements.
Bounded Recursion parsing works similar but not identical to Packrat parsing,
thus the two cannot be used together. Use ``force=True`` to disable any
previous, conflicting settings.
"""
with ParserElement.packrat_cache_lock:
if force:
ParserElement.disable_memoization()
elif ParserElement._packratEnabled:
raise RuntimeError("Packrat and Bounded Recursion are not compatible")
if cache_size_limit is None:
ParserElement.recursion_memos = _UnboundedMemo()
elif cache_size_limit > 0:
ParserElement.recursion_memos = _LRUMemo(capacity=cache_size_limit) # type: ignore[assignment]
else:
raise NotImplementedError(f"Memo size of {cache_size_limit}")
ParserElement._left_recursion_enabled = True
@staticmethod
def enable_packrat(
cache_size_limit: Union[int, None] = 128, *, force: bool = False
) -> None:
"""
Enables "packrat" parsing, which adds memoizing to the parsing logic.
Repeated parse attempts at the same string location (which happens
often in many complex grammars) can immediately return a cached value,
instead of re-executing parsing/validating code. Memoizing is done of
both valid results and parsing exceptions.
Parameters:
- ``cache_size_limit`` - (default= ``128``) - if an integer value is provided
will limit the size of the packrat cache; if None is passed, then
the cache size will be unbounded; if 0 is passed, the cache will
be effectively disabled.
This speedup may break existing programs that use parse actions that
have side-effects. For this reason, packrat parsing is disabled when
you first import pyparsing. To activate the packrat feature, your
program must call the class method :class:`ParserElement.enable_packrat`.
For best results, call ``enable_packrat()`` immediately after
importing pyparsing.
.. Can't really be doctested, alas
Example::
import pyparsing
pyparsing.ParserElement.enable_packrat()
Packrat parsing works similar but not identical to Bounded Recursion parsing,
thus the two cannot be used together. Use ``force=True`` to disable any
previous, conflicting settings.
"""
with ParserElement.packrat_cache_lock:
if force:
ParserElement.disable_memoization()
elif ParserElement._left_recursion_enabled:
raise RuntimeError("Packrat and Bounded Recursion are not compatible")
if ParserElement._packratEnabled:
return
ParserElement._packratEnabled = True
if cache_size_limit is None:
ParserElement.packrat_cache = _UnboundedCache()
else:
ParserElement.packrat_cache = _FifoCache(cache_size_limit)
ParserElement._parse = ParserElement._parseCache
def parse_string(
self, instring: str, parse_all: bool = False, **kwargs
) -> ParseResults:
"""
Parse a string with respect to the parser definition. This function is intended as the primary interface to the
client code.
:param instring: The input string to be parsed.
:param parse_all: If set, the entire input string must match the grammar.
:param parseAll: retained for pre-PEP8 compatibility, will be removed in a future release.
:raises ParseException: Raised if ``parse_all`` is set and the input string does not match the whole grammar.
:returns: the parsed data as a :class:`ParseResults` object, which may be accessed as a `list`, a `dict`, or
an object with attributes if the given parser includes results names.
If the input string is required to match the entire grammar, ``parse_all`` flag must be set to ``True``. This
is also equivalent to ending the grammar with :class:`StringEnd`\\ ().
To report proper column numbers, ``parse_string`` operates on a copy of the input string where all tabs are
converted to spaces (8 spaces per tab, as per the default in ``string.expandtabs``). If the input string
contains tabs and the grammar uses parse actions that use the ``loc`` argument to index into the string
being parsed, one can ensure a consistent view of the input string by doing one of the following:
- calling ``parse_with_tabs`` on your grammar before calling ``parse_string`` (see :class:`parse_with_tabs`),
- define your parse action using the full ``(s,loc,toks)`` signature, and reference the input string using the
parse action's ``s`` argument, or
- explicitly expand the tabs in your input string before calling ``parse_string``.
Examples:
By default, partial matches are OK.
.. doctest::
>>> res = Word('a').parse_string('aaaaabaaa')
>>> print(res)
['aaaaa']
The parsing behavior varies by the inheriting class of this abstract class. Please refer to the children
directly to see more examples.
It raises an exception if parse_all flag is set and instring does not match the whole grammar.
.. doctest::
>>> res = Word('a').parse_string('aaaaabaaa', parse_all=True)
Traceback (most recent call last):
ParseException: Expected end of text, found 'b' ...
"""
parseAll: bool = deprecate_argument(kwargs, "parseAll", False)
parse_all = parse_all or parseAll
ParserElement.reset_cache()
if not self.streamlined:
self.streamline()
for e in self.ignoreExprs:
e.streamline()
if not self.keepTabs:
instring = instring.expandtabs()
try:
loc, tokens = self._parse(instring, 0)
if parse_all:
loc = self.preParse(instring, loc)
se = Empty() + StringEnd().set_debug(False)
se._parse(instring, loc)
except _ParseActionIndexError as pa_exc:
raise pa_exc.exc
except ParseBaseException as exc:
if ParserElement.verbose_stacktrace:
raise
# catch and re-raise exception from here, clearing out pyparsing internal stack trace
raise exc.with_traceback(None)
else:
return tokens
def scan_string(
self,
instring: str,
max_matches: int = _MAX_INT,
overlap: bool = False,
always_skip_whitespace=True,
*,
debug: bool = False,
**kwargs,
) -> Generator[tuple[ParseResults, int, int], None, None]:
"""
Scan the input string for expression matches. Each match will return the
matching tokens, start location, and end location. May be called with optional
``max_matches`` argument, to clip scanning after 'n' matches are found. If
``overlap`` is specified, then overlapping matches will be reported.
Note that the start and end locations are reported relative to the string
being parsed. See :class:`parse_string` for more information on parsing
strings with embedded tabs.
Example:
.. testcode::
source = "sldjf123lsdjjkf345sldkjf879lkjsfd987"
print(source)
for tokens, start, end in Word(alphas).scan_string(source):
print(' '*start + '^'*(end-start))
print(' '*start + tokens[0])
prints:
.. testoutput::
sldjf123lsdjjkf345sldkjf879lkjsfd987
^^^^^
sldjf
^^^^^^^
lsdjjkf
^^^^^^
sldkjf
^^^^^^
lkjsfd
"""
maxMatches: int = deprecate_argument(kwargs, "maxMatches", _MAX_INT)
max_matches = min(maxMatches, max_matches)
if not self.streamlined:
self.streamline()
for e in self.ignoreExprs:
e.streamline()
if not self.keepTabs:
instring = str(instring).expandtabs()
instrlen = len(instring)
loc = 0
if always_skip_whitespace:
preparser = Empty()
preparser.ignoreExprs = self.ignoreExprs
preparser.whiteChars = self.whiteChars
preparseFn = preparser.preParse
else:
preparseFn = self.preParse
parseFn = self._parse
ParserElement.reset_cache()
matches = 0
try:
while loc <= instrlen and matches < max_matches:
try:
preloc: int = preparseFn(instring, loc)
nextLoc: int
tokens: ParseResults
nextLoc, tokens = parseFn(instring, preloc, callPreParse=False)
except ParseException:
loc = preloc + 1
else:
if nextLoc > loc:
matches += 1
if debug:
print(
{
"tokens": tokens.as_list(),
"start": preloc,
"end": nextLoc,
}
)
yield tokens, preloc, nextLoc
if overlap:
nextloc = preparseFn(instring, loc)
if nextloc > loc:
loc = nextLoc
else:
loc += 1
else:
loc = nextLoc
else:
loc = preloc + 1
except ParseBaseException as exc:
if ParserElement.verbose_stacktrace:
raise
# catch and re-raise exception from here, clears out pyparsing internal stack trace
raise exc.with_traceback(None)
def transform_string(self, instring: str, *, debug: bool = False) -> str:
"""
Extension to :class:`scan_string`, to modify matching text with modified tokens that may
be returned from a parse action. To use ``transform_string``, define a grammar and
attach a parse action to it that modifies the returned token list.
Invoking ``transform_string()`` on a target string will then scan for matches,
and replace the matched text patterns according to the logic in the parse
action. ``transform_string()`` returns the resulting transformed string.
Example:
.. testcode::
quote = '''now is the winter of our discontent,
made glorious summer by this sun of york.'''
wd = Word(alphas)
wd.set_parse_action(lambda toks: toks[0].title())
print(wd.transform_string(quote))
prints:
.. testoutput::
Now Is The Winter Of Our Discontent,
Made Glorious Summer By This Sun Of York.
"""
out: list[str] = []
lastE = 0
# force preservation of <TAB>s, to minimize unwanted transformation of string, and to
# keep string locs straight between transform_string and scan_string
self.keepTabs = True
try:
for t, s, e in self.scan_string(instring, debug=debug):
if s > lastE:
out.append(instring[lastE:s])
lastE = e
if not t:
continue
if isinstance(t, ParseResults):
out += t.as_list()
elif isinstance(t, Iterable) and not isinstance(t, str_type):
out.extend(t)
else:
out.append(t)
out.append(instring[lastE:])
out = [o for o in out if o]
return "".join([str(s) for s in _flatten(out)])
except ParseBaseException as exc:
if ParserElement.verbose_stacktrace:
raise
# catch and re-raise exception from here, clears out pyparsing internal stack trace
raise exc.with_traceback(None)
def search_string(
self,
instring: str,
max_matches: int = _MAX_INT,
*,
debug: bool = False,
**kwargs,
) -> ParseResults:
"""
Another extension to :class:`scan_string`, simplifying the access to the tokens found
to match the given parse expression. May be called with optional
``max_matches`` argument, to clip searching after 'n' matches are found.
Example:
.. testcode::
quote = '''More than Iron, more than Lead,
more than Gold I need Electricity'''
# a capitalized word starts with an uppercase letter,
# followed by zero or more lowercase letters
cap_word = Word(alphas.upper(), alphas.lower())
print(cap_word.search_string(quote))
# the sum() builtin can be used to merge results
# into a single ParseResults object
print(sum(cap_word.search_string(quote)))
prints:
.. testoutput::
[['More'], ['Iron'], ['Lead'], ['Gold'], ['I'], ['Electricity']]
['More', 'Iron', 'Lead', 'Gold', 'I', 'Electricity']
"""
maxMatches: int = deprecate_argument(kwargs, "maxMatches", _MAX_INT)
max_matches = min(maxMatches, max_matches)
try:
return ParseResults(
[
t
for t, s, e in self.scan_string(
instring,
max_matches=max_matches,
always_skip_whitespace=False,
debug=debug,
)
]
)
except ParseBaseException as exc:
if ParserElement.verbose_stacktrace:
raise
# catch and re-raise exception from here, clears out pyparsing internal stack trace
raise exc.with_traceback(None)
def split(
self,
instring: str,
maxsplit: int = _MAX_INT,
include_separators: bool = False,
**kwargs,
) -> Generator[str, None, None]:
"""
Generator method to split a string using the given expression as a separator.
May be called with optional ``maxsplit`` argument, to limit the number of splits;
and the optional ``include_separators`` argument (default= ``False``), if the separating
matching text should be included in the split results.
Example:
.. testcode::
punc = one_of(list(".,;:/-!?"))
print(list(punc.split(
"This, this?, this sentence, is badly punctuated!")))
prints:
.. testoutput::
['This', ' this', '', ' this sentence', ' is badly punctuated', '']
"""
includeSeparators: bool = deprecate_argument(kwargs, "includeSeparators", False)
include_separators = includeSeparators or include_separators
last = 0
for t, s, e in self.scan_string(instring, max_matches=maxsplit):
yield instring[last:s]
if include_separators:
yield t[0]
last = e
yield instring[last:]
def __add__(self, other) -> ParserElement:
"""
Implementation of ``+`` operator - returns :class:`And`. Adding strings to a :class:`ParserElement`
converts them to :class:`Literal`\\ s by default.
Example:
.. testcode::
greet = Word(alphas) + "," + Word(alphas) + "!"
hello = "Hello, World!"
print(hello, "->", greet.parse_string(hello))
prints:
.. testoutput::
Hello, World! -> ['Hello', ',', 'World', '!']
``...`` may be used as a parse expression as a short form of :class:`SkipTo`:
.. testcode::
Literal('start') + ... + Literal('end')
is equivalent to:
.. testcode::
Literal('start') + SkipTo('end')("_skipped*") + Literal('end')
Note that the skipped text is returned with '_skipped' as a results name,
and to support having multiple skips in the same parser, the value returned is
a list of all skipped text.
"""
if other is Ellipsis:
return _PendingSkip(self)
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return And([self, other])
def __radd__(self, other) -> ParserElement:
"""
Implementation of ``+`` operator when left operand is not a :class:`ParserElement`
"""
if other is Ellipsis:
return SkipTo(self)("_skipped*") + self
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return other + self
def __sub__(self, other) -> ParserElement:
"""
Implementation of ``-`` operator, returns :class:`And` with error stop
"""
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return self + And._ErrorStop() + other
def __rsub__(self, other) -> ParserElement:
"""
Implementation of ``-`` operator when left operand is not a :class:`ParserElement`
"""
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return other - self
def __mul__(self, other) -> ParserElement:
"""
Implementation of ``*`` operator, allows use of ``expr * 3`` in place of
``expr + expr + expr``. Expressions may also be multiplied by a 2-integer
tuple, similar to ``{min, max}`` multipliers in regular expressions. Tuples
may also include ``None`` as in:
- ``expr*(n, None)`` or ``expr*(n, )`` is equivalent
to ``expr*n + ZeroOrMore(expr)``
(read as "at least n instances of ``expr``")
- ``expr*(None, n)`` is equivalent to ``expr*(0, n)``
(read as "0 to n instances of ``expr``")
- ``expr*(None, None)`` is equivalent to ``ZeroOrMore(expr)``
- ``expr*(1, None)`` is equivalent to ``OneOrMore(expr)``
Note that ``expr*(None, n)`` does not raise an exception if
more than n exprs exist in the input stream; that is,
``expr*(None, n)`` does not enforce a maximum number of expr
occurrences. If this behavior is desired, then write
``expr*(None, n) + ~expr``
"""
if other is Ellipsis:
other = (0, None)
elif isinstance(other, tuple) and other[:1] == (Ellipsis,):
other = (0, *other[1:2], None)[:2]
if not isinstance(other, (int, tuple)):
return NotImplemented
if isinstance(other, int):
minElements, optElements = other, 0
else:
other = tuple(o if o is not Ellipsis else None for o in other)
other = (*other, None, None)[:2]
if other[0] is None:
other = (0, other[1])
if isinstance(other[0], int) and other[1] is None:
if other[0] == 0:
return ZeroOrMore(self)
if other[0] == 1:
return OneOrMore(self)
else:
return self * other[0] + ZeroOrMore(self)
elif isinstance(other[0], int) and isinstance(other[1], int):
minElements, optElements = other
optElements -= minElements
else:
return NotImplemented
if minElements < 0:
raise ValueError("cannot multiply ParserElement by negative value")
if optElements < 0:
raise ValueError(
"second tuple value must be greater or equal to first tuple value"
)
if minElements == optElements == 0:
return And([])
if optElements:
# Build the optional tail as a bounded ``ZeroOrMore`` instead of a
# deeply nested ``Opt(self + Opt(self + ...))`` chain. The nested
# form recursed ``optElements`` levels deep, which raised
# RecursionError for large upper bounds (e.g. ``expr[..., 1000]``)
# -- see issue #332. ``ZeroOrMore(..., max=optElements)`` is a flat
# loop that still *exits early* (it stops at the first non-match,
# just like the recursive form), so it preserves the original
# early-exit behavior while no longer scaling the call stack with
# the upper bound.
optionalTail = ZeroOrMore(self, max=optElements)
if minElements:
if minElements == 1:
ret = self + optionalTail
else:
ret = And([self] * minElements) + optionalTail
else:
ret = optionalTail
else:
if minElements == 1:
ret = self
else:
ret = And([self] * minElements)
return ret
def __rmul__(self, other) -> ParserElement:
return self.__mul__(other)
def __or__(self, other) -> ParserElement:
"""
Implementation of ``|`` operator - returns :class:`MatchFirst`
.. versionchanged:: 3.1.0
Support ``expr | ""`` as a synonym for ``Optional(expr)``.
"""
if other is Ellipsis:
return _PendingSkip(self, must_skip=True)
if isinstance(other, str_type):
# `expr | ""` is equivalent to `Opt(expr)`
if other == "":
return Opt(self)
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return MatchFirst([self, other])
def __ror__(self, other) -> ParserElement:
"""
Implementation of ``|`` operator when left operand is not a :class:`ParserElement`
"""
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return other | self
def __xor__(self, other) -> ParserElement:
"""
Implementation of ``^`` operator - returns :class:`Or`
"""
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return Or([self, other])
def __rxor__(self, other) -> ParserElement:
"""
Implementation of ``^`` operator when left operand is not a :class:`ParserElement`
"""
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return other ^ self
def __and__(self, other) -> ParserElement:
"""
Implementation of ``&`` operator - returns :class:`Each`
"""
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return Each([self, other])
def __rand__(self, other) -> ParserElement:
"""
Implementation of ``&`` operator when left operand is not a :class:`ParserElement`
"""
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return other & self
def __invert__(self) -> ParserElement:
"""
Implementation of ``~`` operator - returns :class:`NotAny`
"""
return NotAny(self)
# disable __iter__ to override legacy use of sequential access to __getitem__ to
# iterate over a sequence
__iter__ = None
def __getitem__(self, key):
"""
use ``[]`` indexing notation as a short form for expression repetition:
- ``expr[n]`` is equivalent to ``expr*n``
- ``expr[m, n]`` is equivalent to ``expr*(m, n)``
- ``expr[n, ...]`` or ``expr[n,]`` is equivalent
to ``expr*n + ZeroOrMore(expr)``
(read as "at least n instances of ``expr``")
- ``expr[..., n]`` is equivalent to ``expr*(0, n)``
(read as "0 to n instances of ``expr``")
- ``expr[...]`` and ``expr[0, ...]`` are equivalent to ``ZeroOrMore(expr)``
- ``expr[1, ...]`` is equivalent to ``OneOrMore(expr)``
``None`` may be used in place of ``...``.
Note that ``expr[..., n]`` and ``expr[m, n]`` do not raise an exception
if more than ``n`` ``expr``\\ s exist in the input stream. If this behavior is
desired, then write ``expr[..., n] + ~expr``.
For repetition with a stop_on expression, use slice notation:
- ``expr[...: end_expr]`` and ``expr[0, ...: end_expr]`` are equivalent to ``ZeroOrMore(expr, stop_on=end_expr)``
- ``expr[1, ...: end_expr]`` is equivalent to ``OneOrMore(expr, stop_on=end_expr)``
.. versionchanged:: 3.1.0
Support for slice notation.
"""
stop_on_defined = False
stop_on = NoMatch()
if isinstance(key, slice):
key, stop_on = key.start, key.stop
if key is None:
key = ...
stop_on_defined = True
elif isinstance(key, tuple) and isinstance(key[-1], slice):
key, stop_on = (key[0], key[1].start), key[1].stop
stop_on_defined = True
# convert single arg keys to tuples
if isinstance(key, str_type):
key = (key,)
try:
iter(key)
except TypeError:
key = (key, key)
if len(key) > 2:
raise TypeError(
f"only 1 or 2 index arguments supported ({key[:5]}{f'... [{len(key)}]' if len(key) > 5 else ''})"
)
# clip to 2 elements
ret = self * tuple(key[:2])
ret = typing.cast(_MultipleMatch, ret)
if stop_on_defined:
ret.stopOn(stop_on)
return ret
def __call__(self, name: typing.Optional[str] = None) -> ParserElement:
"""
Shortcut for :class:`set_results_name`, with ``list_all_matches=False``.
If ``name`` is given with a trailing ``'*'`` character, then ``list_all_matches`` will be
passed as ``True``.
If ``name`` is omitted, same as calling :class:`copy`.
Example:
.. testcode::
# these are equivalent
userdata = (
Word(alphas).set_results_name("name")
+ Word(nums + "-").set_results_name("socsecno")
)
userdata = Word(alphas)("name") + Word(nums + "-")("socsecno")
"""
if name is not None:
return self._setResultsName(name)
return self.copy()
def suppress(self) -> ParserElement:
"""
Suppresses the output of this :class:`ParserElement`; useful to keep punctuation from
cluttering up returned output.
"""
return Suppress(self)
def ignore_whitespace(self, recursive: bool = True) -> ParserElement:
"""
Enables the skipping of whitespace before matching the characters in the
:class:`ParserElement`'s defined pattern.
:param recursive: If ``True`` (the default), also enable whitespace skipping in child elements (if any)
"""
self.skipWhitespace = True
return self
def leave_whitespace(self, recursive: bool = True) -> ParserElement:
"""
Disables the skipping of whitespace before matching the characters in the
:class:`ParserElement`'s defined pattern. This is normally only used internally by
the pyparsing module, but may be needed in some whitespace-sensitive grammars.
:param recursive: If true (the default), also disable whitespace skipping in child elements (if any)
"""
self.skipWhitespace = False
return self
def set_whitespace_chars(
self, chars: Union[set[str], str], copy_defaults: bool = False
) -> ParserElement:
"""
Overrides the default whitespace chars
"""
self.skipWhitespace = True
self.whiteChars = set(chars)
self.copyDefaultWhiteChars = copy_defaults
return self
def parse_with_tabs(self) -> ParserElement:
"""
Overrides default behavior to expand ``<TAB>`` s to spaces before parsing the input string.
Must be called before ``parse_string`` when the input grammar contains elements that
match ``<TAB>`` characters.
"""
self.keepTabs = True
return self
def ignore(self, other: ParserElement) -> ParserElement:
"""
Define expression to be ignored (e.g., comments) while doing pattern
matching; may be called repeatedly, to define multiple comment or other
ignorable patterns.
Example:
.. doctest::
>>> patt = Word(alphas)[...]
>>> print(patt.parse_string('ablaj /* comment */ lskjd'))
['ablaj']
>>> patt = Word(alphas)[...].ignore(c_style_comment)
>>> print(patt.parse_string('ablaj /* comment */ lskjd'))
['ablaj', 'lskjd']
"""
if isinstance(other, str_type):
other = Suppress(other)
if isinstance(other, Suppress):
if other not in self.ignoreExprs:
self.ignoreExprs.append(other)
else:
self.ignoreExprs.append(Suppress(other.copy()))
return self
def set_debug_actions(
self,
start_action: DebugStartAction,
success_action: DebugSuccessAction,
exception_action: DebugExceptionAction,
) -> ParserElement:
"""
Customize display of debugging messages while doing pattern matching:
:param start_action: method to be called when an expression is about to be parsed;
should have the signature::
fn(input_string: str,
location: int,
expression: ParserElement,
cache_hit: bool)
:param success_action: method to be called when an expression has successfully parsed;
should have the signature::
fn(input_string: str,
start_location: int,
end_location: int,
expression: ParserELement,
parsed_tokens: ParseResults,
cache_hit: bool)
:param exception_action: method to be called when expression fails to parse;
should have the signature::
fn(input_string: str,
location: int,
expression: ParserElement,
exception: Exception,
cache_hit: bool)
"""
self.debugActions = self.DebugActions(
start_action or _default_start_debug_action, # type: ignore[truthy-function]
success_action or _default_success_debug_action, # type: ignore[truthy-function]
exception_action or _default_exception_debug_action, # type: ignore[truthy-function]
)
self.debug = any(self.debugActions)
return self
def set_debug(self, flag: bool = True, recurse: bool = False) -> ParserElement:
"""
Enable display of debugging messages while doing pattern matching.
Set ``flag`` to ``True`` to enable, ``False`` to disable.
Set ``recurse`` to ``True`` to set the debug flag on this expression and all sub-expressions.
Example:
.. testcode::
wd = Word(alphas).set_name("alphaword")
integer = Word(nums).set_name("numword")
term = wd | integer
# turn on debugging for wd
wd.set_debug()
term[1, ...].parse_string("abc 123 xyz 890")
prints:
.. testoutput::
:options: +NORMALIZE_WHITESPACE
Match alphaword at loc 0(1,1)
abc 123 xyz 890
^
Matched alphaword -> ['abc']
Match alphaword at loc 4(1,5)
abc 123 xyz 890
^
Match alphaword failed, ParseException raised: Expected alphaword, ...
Match alphaword at loc 8(1,9)
abc 123 xyz 890
^
Matched alphaword -> ['xyz']
Match alphaword at loc 12(1,13)
abc 123 xyz 890
^
Match alphaword failed, ParseException raised: Expected alphaword, ...
abc 123 xyz 890
^
Match alphaword failed, ParseException raised: Expected alphaword, found end of text ...
The output shown is that produced by the default debug actions - custom debug actions can be
specified using :meth:`set_debug_actions`. Prior to attempting
to match the ``wd`` expression, the debugging message ``"Match <exprname> at loc <n>(<line>,<col>)"``
is shown. Then if the parse succeeds, a ``"Matched"`` message is shown, or an ``"Exception raised"``
message is shown. Also note the use of :meth:`set_name` to assign a human-readable name to the expression,
which makes debugging and exception messages easier to understand - for instance, the default
name created for the :class:`Word` expression without calling :meth:`set_name` is ``"W:(A-Za-z)"``.
.. versionchanged:: 3.1.0
``recurse`` argument added.
"""
if recurse:
for expr in self.visit_all():
expr.set_debug(flag, recurse=False)
return self
if flag:
self.set_debug_actions(
_default_start_debug_action,
_default_success_debug_action,
_default_exception_debug_action,
)
else:
self.debug = False
return self
@property
def default_name(self) -> str:
if self._defaultName is None:
self._defaultName = self._generateDefaultName()
return self._defaultName
@abstractmethod
def _generateDefaultName(self) -> str:
"""
Child classes must define this method, which defines how the ``default_name`` is set.
"""
def set_name(self, name: typing.Optional[str]) -> ParserElement:
"""
Define name for this expression, makes debugging and exception messages clearer. If
`__diag__.enable_debug_on_named_expressions` is set to True, setting a name will also
enable debug for this expression.
If `name` is None, clears any custom name for this expression, and clears the
debug flag is it was enabled via `__diag__.enable_debug_on_named_expressions`.
Example:
.. doctest::
>>> integer = Word(nums)
>>> integer.parse_string("ABC")
Traceback (most recent call last):
ParseException: Expected W:(0-9) (at char 0), (line:1, col:1)
>>> integer.set_name("integer")
integer
>>> integer.parse_string("ABC")
Traceback (most recent call last):
ParseException: Expected integer (at char 0), (line:1, col:1)
.. versionchanged:: 3.1.0
Accept ``None`` as the ``name`` argument.
"""
self.customName = name # type: ignore[assignment]
self.errmsg = f"Expected {str(self)}"
if __diag__.enable_debug_on_named_expressions:
self.set_debug(name is not None)
return self
@property
def name(self) -> str:
"""
Returns a user-defined name if available, but otherwise defaults back to the auto-generated name
"""
return self.customName if self.customName is not None else self.default_name
@name.setter
def name(self, new_name) -> None:
self.set_name(new_name)
def __str__(self) -> str:
return self.name
def __repr__(self) -> str:
return str(self)
def streamline(self) -> ParserElement:
self.streamlined = True
self._defaultName = None
return self
def recurse(self) -> list[ParserElement]:
return []
def _checkRecursion(self, parseElementList):
subRecCheckList = parseElementList[:] + [self]
for e in self.recurse():
e._checkRecursion(subRecCheckList)
def validate(self, validateTrace=None) -> None:
"""
.. deprecated:: 3.0.0
Do not use to check for left recursion.
Check defined expressions for valid structure, check for infinite recursive definitions.
"""
warnings.warn(
"ParserElement.validate() is deprecated, and should not be used to check for left recursion",
PyparsingDeprecationWarning,
stacklevel=2,
)
self._checkRecursion([])
def parse_file(
self,
file_or_filename: Union[str, Path, TextIO],
encoding: str = "utf-8",
parse_all: bool = False,
**kwargs,
) -> ParseResults:
"""
Execute the parse expression on the given file or filename.
If a filename is specified (instead of a file object),
the entire file is opened, read, and closed before parsing.
"""
parseAll: bool = deprecate_argument(kwargs, "parseAll", False)
parse_all = parse_all or parseAll
try:
file_or_filename = typing.cast(TextIO, file_or_filename)
file_contents = file_or_filename.read()
except AttributeError:
file_or_filename = typing.cast(str, file_or_filename)
with open(file_or_filename, "r", encoding=encoding) as f:
file_contents = f.read()
try:
return self.parse_string(file_contents, parse_all)
except ParseBaseException as exc:
if ParserElement.verbose_stacktrace:
raise
# catch and re-raise exception from here, clears out pyparsing internal stack trace
raise exc.with_traceback(None)
def __eq__(self, other):
if self is other:
return True
elif isinstance(other, str_type):
return self.matches(other, parse_all=True)
elif isinstance(other, ParserElement):
return vars(self) == vars(other)
return False
def __hash__(self):
return id(self)
def matches(self, test_string: str, parse_all: bool = True, **kwargs) -> bool:
"""
Method for quick testing of a parser against a test string. Good for simple
inline microtests of sub expressions while building up larger parser.
:param test_string: to test against this expression for a match
:param parse_all: flag to pass to :meth:`parse_string` when running tests
Example:
.. doctest::
>>> expr = Word(nums)
>>> expr.matches("100")
True
"""
parseAll: bool = deprecate_argument(kwargs, "parseAll", True)
parse_all = parse_all and parseAll
try:
self.parse_string(str(test_string), parse_all=parse_all)
return True
except ParseBaseException:
return False
def run_tests(
self,
tests: Union[str, list[str]],
parse_all: bool = True,
comment: typing.Optional[Union[ParserElement, str]] = "#",
full_dump: bool = True,
print_results: bool = True,
failure_tests: bool = False,
post_parse: typing.Optional[
Callable[[str, ParseResults], typing.Optional[str]]
] = None,
file: typing.Optional[TextIO] = None,
with_line_numbers: bool = False,
*,
parseAll: bool = True,
fullDump: bool = True,
printResults: bool = True,
failureTests: bool = False,
postParse: typing.Optional[
Callable[[str, ParseResults], typing.Optional[str]]
] = None,
) -> tuple[bool, list[tuple[str, Union[ParseResults, Exception]]]]:
"""
Execute the parse expression on a series of test strings, showing each
test, the parsed results or where the parse failed. Quick and easy way to
run a parse expression against a list of sample strings.
Parameters:
- ``tests`` - a list of separate test strings, or a multiline string of test strings
- ``parse_all`` - (default= ``True``) - flag to pass to :class:`parse_string` when running tests
- ``comment`` - (default= ``'#'``) - expression for indicating embedded comments in the test
string; pass None to disable comment filtering
- ``full_dump`` - (default= ``True``) - dump results as list followed by results names in nested outline;
if False, only dump nested list
- ``print_results`` - (default= ``True``) prints test output to stdout
- ``failure_tests`` - (default= ``False``) indicates if these tests are expected to fail parsing
- ``post_parse`` - (default= ``None``) optional callback for successful parse results; called as
`fn(test_string, parse_results)` and returns a string to be added to the test output
- ``file`` - (default= ``None``) optional file-like object to which test output will be written;
if None, will default to ``sys.stdout``
- ``with_line_numbers`` - default= ``False``) show test strings with line and column numbers
Returns: a (success, results) tuple, where success indicates that all tests succeeded
(or failed if ``failure_tests`` is True), and the results contain a list of lines of each
test's output
Passing example:
.. testcode::
number_expr = pyparsing_common.number.copy()
result = number_expr.run_tests('''
# unsigned integer
100
# negative integer
-100
# float with scientific notation
6.02e23
# integer with scientific notation
1e-12
# negative decimal number without leading digit
-.100
''')
print("Success" if result[0] else "Failed!")
prints:
.. testoutput::
:options: +NORMALIZE_WHITESPACE
# unsigned integer
100
[100]
# negative integer
-100
[-100]
# float with scientific notation
6.02e23
[6.02e+23]
# integer with scientific notation
1e-12
[1e-12]
# negative decimal number without leading digit
-.100
[-0.1]
Success
Failure-test example:
.. testcode::
result = number_expr.run_tests('''
# stray character
100Z
# too many '.'
3.14.159
''', failure_tests=True)
print("Success" if result[0] else "Failed!")
prints:
.. testoutput::
:options: +NORMALIZE_WHITESPACE
# stray character
100Z
100Z
^
ParseException: Expected end of text, found 'Z' ...
# too many '.'
3.14.159
3.14.159
^
ParseException: Expected end of text, found '.' ...
FAIL: Expected end of text, found '.' ...
Success
Each test string must be on a single line. If you want to test a string that spans multiple
lines, create a test like this:
.. testcode::
expr = Word(alphanums)[1,...]
expr.run_tests(r"this is a test\\n of strings that spans \\n 3 lines")
.. testoutput::
:options: +NORMALIZE_WHITESPACE
:hide:
this is a test\\n of strings that spans \\n 3 lines
['this', 'is', 'a', 'test', 'of', 'strings', 'that', 'spans', '3', 'lines']
(Note that this is a raw string literal, you must include the leading ``'r'``.)
"""
from .testing import pyparsing_test
parseAll = parseAll and parse_all
fullDump = fullDump and full_dump
printResults = printResults and print_results
failureTests = failureTests or failure_tests
postParse = postParse or post_parse
if isinstance(tests, str_type):
tests = typing.cast(str, tests)
line_strip = type(tests).strip
tests = [line_strip(test_line) for test_line in tests.rstrip().splitlines()]
comment_specified = comment is not None
if comment_specified:
if isinstance(comment, str_type):
comment = typing.cast(str, comment)
comment = Literal(comment)
comment = typing.cast(ParserElement, comment)
if file is None:
file = sys.stdout
print_ = file.write
result: Union[ParseResults, Exception]
allResults: list[tuple[str, Union[ParseResults, Exception]]] = []
comments: list[str] = []
success = True
NL = Literal(r"\n").add_parse_action(replace_with("\n")).ignore(quoted_string)
BOM = "\ufeff"
nlstr = "\n"
for t in tests:
if comment_specified and comment.matches(t, False) or comments and not t:
comments.append(
pyparsing_test.with_line_numbers(t) if with_line_numbers else t
)
continue
if not t:
continue
out = [
f"{nlstr}{nlstr.join(comments) if comments else ''}",
pyparsing_test.with_line_numbers(t) if with_line_numbers else t,
]
comments.clear()
try:
# convert newline marks to actual newlines, and strip leading BOM if present
t = NL.transform_string(t.lstrip(BOM))
result = self.parse_string(t, parse_all=parse_all)
except ParseBaseException as pe:
fatal = "(FATAL) " if isinstance(pe, ParseFatalException) else ""
out.append(pe.explain())
out.append(f"FAIL: {fatal}{pe}")
if ParserElement.verbose_stacktrace:
out.extend(traceback.format_tb(pe.__traceback__))
success = success and failureTests
result = pe
except Exception as exc:
tag = "FAIL-EXCEPTION"
# see if this exception was raised in a parse action
tb = exc.__traceback__
it = iter(traceback.walk_tb(tb))
for f, line in it:
if (f.f_code.co_filename, line) == pa_call_line_synth:
next_f = next(it)[0]
tag += f" (raised in parse action {next_f.f_code.co_name!r})"
break
out.append(f"{tag}: {type(exc).__name__}: {exc}")
if ParserElement.verbose_stacktrace:
out.extend(traceback.format_tb(exc.__traceback__))
success = success and failureTests
result = exc
else:
success = success and not failureTests
if postParse is not None:
try:
pp_value = postParse(t, result)
if pp_value is not None:
if isinstance(pp_value, ParseResults):
out.append(pp_value.dump())
else:
out.append(str(pp_value))
else:
out.append(result.dump())
except Exception as e:
out.append(result.dump(full=fullDump))
out.append(
f"{postParse.__name__} failed: {type(e).__name__}: {e}"
)
else:
out.append(result.dump(full=fullDump))
out.append("")
if printResults:
print_("\n".join(out))
allResults.append((t, result))
return success, allResults
def create_diagram(
self,
output_html: Union[TextIO, Path, str],
vertical: int = 3,
show_results_names: bool = False,
show_groups: bool = False,
embed: bool = False,
show_hidden: bool = False,
**kwargs,
) -> None:
"""
Create a railroad diagram for the parser.
Parameters:
- ``output_html`` (str or file-like object) - output target for generated
diagram HTML
- ``vertical`` (int) - threshold for formatting multiple alternatives vertically
instead of horizontally (default=3)
- ``show_results_names`` - bool flag whether diagram should show annotations for
defined results names
- ``show_groups`` - bool flag whether groups should be highlighted with an unlabeled surrounding box
- ``show_hidden`` - bool flag to show diagram elements for internal elements that are usually hidden
- ``embed`` - bool flag whether generated HTML should omit <HEAD>, <BODY>, and <DOCTYPE> tags to embed
the resulting HTML in an enclosing HTML source
- ``head`` - str containing additional HTML to insert into the <HEAD> section of the generated code;
can be used to insert custom CSS styling
- ``body`` - str containing additional HTML to insert at the beginning of the <BODY> section of the
generated code
Additional diagram-formatting keyword arguments can also be included;
see railroad.Diagram class.
.. versionchanged:: 3.1.0
``embed`` argument added.
"""
try:
from .diagram import to_railroad, railroad_to_html
except ImportError as ie:
raise Exception(
"must ``pip install pyparsing[diagrams]`` to generate parser railroad diagrams"
) from ie
self.streamline()
railroad = to_railroad(
self,
vertical=vertical,
show_results_names=show_results_names,
show_groups=show_groups,
show_hidden=show_hidden,
diagram_kwargs=kwargs,
)
if not isinstance(output_html, (str, Path)):
# we were passed a file-like object, just write to it
output_html.write(railroad_to_html(railroad, embed=embed, **kwargs))
return
with open(output_html, "w", encoding="utf-8") as diag_file:
diag_file.write(railroad_to_html(railroad, embed=embed, **kwargs))
# Compatibility synonyms
# fmt: off
inlineLiteralsUsing = staticmethod(replaced_by_pep8("inlineLiteralsUsing", inline_literals_using))
setDefaultWhitespaceChars = staticmethod(replaced_by_pep8(
"setDefaultWhitespaceChars", set_default_whitespace_chars
))
disableMemoization = staticmethod(replaced_by_pep8("disableMemoization", disable_memoization))
enableLeftRecursion = staticmethod(replaced_by_pep8("enableLeftRecursion", enable_left_recursion))
enablePackrat = staticmethod(replaced_by_pep8("enablePackrat", enable_packrat))
resetCache = staticmethod(replaced_by_pep8("resetCache", reset_cache))
setResultsName = replaced_by_pep8("setResultsName", set_results_name)
setBreak = replaced_by_pep8("setBreak", set_break)
setParseAction = replaced_by_pep8("setParseAction", set_parse_action)
addParseAction = replaced_by_pep8("addParseAction", add_parse_action)
addCondition = replaced_by_pep8("addCondition", add_condition)
setFailAction = replaced_by_pep8("setFailAction", set_fail_action)
tryParse = replaced_by_pep8("tryParse", try_parse)
parseString = replaced_by_pep8("parseString", parse_string)
scanString = replaced_by_pep8("scanString", scan_string)
transformString = replaced_by_pep8("transformString", transform_string)
searchString = replaced_by_pep8("searchString", search_string)
ignoreWhitespace = replaced_by_pep8("ignoreWhitespace", ignore_whitespace)
leaveWhitespace = replaced_by_pep8("leaveWhitespace", leave_whitespace)
setWhitespaceChars = replaced_by_pep8("setWhitespaceChars", set_whitespace_chars)
parseWithTabs = replaced_by_pep8("parseWithTabs", parse_with_tabs)
setDebugActions = replaced_by_pep8("setDebugActions", set_debug_actions)
setDebug = replaced_by_pep8("setDebug", set_debug)
setName = replaced_by_pep8("setName", set_name)
parseFile = replaced_by_pep8("parseFile", parse_file)
runTests = replaced_by_pep8("runTests", run_tests)
canParseNext = replaced_by_pep8("canParseNext", can_parse_next)
defaultName = default_name
# fmt: on
class _PendingSkip(ParserElement):
# internal placeholder class to hold a place were '...' is added to a parser element,
# once another ParserElement is added, this placeholder will be replaced with a SkipTo
def __init__(self, expr: ParserElement, must_skip: bool = False) -> None:
super().__init__()
self.anchor = expr
self.must_skip = must_skip
def _generateDefaultName(self) -> str:
return str(self.anchor + Empty()).replace("Empty", "...")
def __add__(self, other) -> ParserElement:
skipper = SkipTo(other).set_name("...")("_skipped*")
if self.must_skip:
def must_skip(t):
if not t._skipped or t._skipped.as_list() == [""]:
del t[0]
t.pop("_skipped", None)
def show_skip(t):
if t._skipped.as_list()[-1:] == [""]:
t.pop("_skipped")
t["_skipped"] = f"missing <{self.anchor!r}>"
return (
self.anchor + skipper().add_parse_action(must_skip)
| skipper().add_parse_action(show_skip)
) + other
return self.anchor + skipper + other
def __repr__(self):
return self.defaultName
def parseImpl(self, *args) -> ParseImplReturnType:
raise Exception(
"use of `...` expression without following SkipTo target expression"
)
class Token(ParserElement):
"""Abstract :class:`ParserElement` subclass, for defining atomic
matching patterns.
"""
def __init__(self) -> None:
super().__init__(savelist=False)
def _generateDefaultName(self) -> str:
return type(self).__name__
class NoMatch(Token):
"""
A token that will never match.
"""
def __init__(self) -> None:
super().__init__()
self._may_return_empty = True
self.mayIndexError = False
self.errmsg = "Unmatchable token"
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
raise ParseException(instring, loc, self.errmsg, self)
class Literal(Token):
"""
Token to exactly match a specified string.
Example:
.. doctest::
>>> Literal('abc').parse_string('abc')
ParseResults(['abc'], {})
>>> Literal('abc').parse_string('abcdef')
ParseResults(['abc'], {})
>>> Literal('abc').parse_string('ab')
Traceback (most recent call last):
ParseException: Expected 'abc', found 'ab' (at char 0), (line: 1, col: 1)
For case-insensitive matching, use :class:`CaselessLiteral`.
For keyword matching (force word break before and after the matched string),
use :class:`Keyword` or :class:`CaselessKeyword`.
"""
def __new__(cls, match_string: str = "", **kwargs):
# Performance tuning: select a subclass with optimized parseImpl
if cls is Literal:
matchString: str = deprecate_argument(kwargs, "matchString", "")
match_string = matchString or match_string
if not match_string:
return super().__new__(Empty)
if len(match_string) == 1:
return super().__new__(_SingleCharLiteral)
# Default behavior
return super().__new__(cls)
# Needed to make copy.copy() work correctly if we customize __new__
def __getnewargs__(self):
return (self.match,)
def __init__(self, match_string: str = "", **kwargs) -> None:
matchString: str = deprecate_argument(kwargs, "matchString", "")
super().__init__()
match_string = matchString or match_string
self.match = match_string
self.matchLen = len(match_string)
self.firstMatchChar = match_string[:1]
self.errmsg = f"Expected {self.name}"
self._may_return_empty = False
self.mayIndexError = False
def _generateDefaultName(self) -> str:
return repr(self.match)
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if instring[loc] == self.firstMatchChar and instring.startswith(
self.match, loc
):
return loc + self.matchLen, self.match
raise ParseException(instring, loc, self.errmsg, self)
class Empty(Literal):
"""
An empty token, will always match.
"""
def __init__(self, match_string="", *, matchString="") -> None:
super().__init__("")
self._may_return_empty = True
self.mayIndexError = False
def _generateDefaultName(self) -> str:
return "Empty"
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
return loc, []
class _SingleCharLiteral(Literal):
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if instring[loc] == self.firstMatchChar:
return loc + 1, self.match
raise ParseException(instring, loc, self.errmsg, self)
ParserElement._literalStringClass = Literal
class Keyword(Token):
"""
Token to exactly match a specified string as a keyword, that is,
it must be immediately preceded and followed by whitespace or
non-keyword characters. Compare with :class:`Literal`:
- ``Literal("if")`` will match the leading ``'if'`` in
``'ifAndOnlyIf'``.
- ``Keyword("if")`` will not; it will only match the leading
``'if'`` in ``'if x=1'``, or ``'if(y==2)'``
Accepts two optional constructor arguments in addition to the
keyword string:
- ``ident_chars`` is a string of characters that would be valid
identifier characters, defaulting to all alphanumerics + "_" and
"$"
- ``caseless`` allows case-insensitive matching, default is ``False``.
Example:
.. doctest::
:options: +NORMALIZE_WHITESPACE
>>> Keyword("start").parse_string("start")
ParseResults(['start'], {})
>>> Keyword("start").parse_string("starting")
Traceback (most recent call last):
ParseException: Expected Keyword 'start', keyword was immediately
followed by keyword character, found 'ing' (at char 5), (line:1, col:6)
.. doctest::
:options: +NORMALIZE_WHITESPACE
>>> Keyword("start").parse_string("starting").debug()
Traceback (most recent call last):
ParseException: Expected Keyword "start", keyword was immediately
followed by keyword character, found 'ing' ...
For case-insensitive matching, use :class:`CaselessKeyword`.
"""
DEFAULT_KEYWORD_CHARS = f"{alphanums}_$"
def __init__(
self,
match_string: str = "",
ident_chars: typing.Optional[str] = None,
caseless: bool = False,
**kwargs,
) -> None:
matchString = deprecate_argument(kwargs, "matchString", "")
identChars = deprecate_argument(kwargs, "identChars", None)
super().__init__()
identChars = identChars or ident_chars
if identChars is None:
identChars = Keyword.DEFAULT_KEYWORD_CHARS
match_string = matchString or match_string
self.match = match_string
self.matchLen = len(match_string)
self.firstMatchChar = match_string[:1]
if not self.firstMatchChar:
raise ValueError("null string passed to Keyword; use Empty() instead")
self.errmsg = f"Expected {type(self).__name__} {self.name}"
self._may_return_empty = False
self.mayIndexError = False
self.caseless = caseless
if caseless:
self.caselessmatch = match_string.upper()
identChars = identChars.upper()
self.ident_chars = set(identChars)
@property
def identChars(self) -> set[str]:
"""
.. deprecated:: 3.3.0
use ident_chars instead.
Property returning the characters being used as keyword characters for this expression.
"""
return self.ident_chars
def _generateDefaultName(self) -> str:
return repr(self.match)
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
errmsg = self.errmsg or ""
errloc = loc
if self.caseless:
if instring[loc : loc + self.matchLen].upper() == self.caselessmatch:
if loc == 0 or instring[loc - 1].upper() not in self.identChars:
if (
loc >= len(instring) - self.matchLen
or instring[loc + self.matchLen].upper() not in self.identChars
):
return loc + self.matchLen, self.match
# followed by keyword char
errmsg += ", was immediately followed by keyword character"
errloc = loc + self.matchLen
else:
# preceded by keyword char
errmsg += ", keyword was immediately preceded by keyword character"
errloc = loc - 1
# else no match just raise plain exception
elif (
instring[loc] == self.firstMatchChar
and self.matchLen == 1
or instring.startswith(self.match, loc)
):
if loc == 0 or instring[loc - 1] not in self.identChars:
if (
loc >= len(instring) - self.matchLen
or instring[loc + self.matchLen] not in self.identChars
):
return loc + self.matchLen, self.match
# followed by keyword char
errmsg += ", keyword was immediately followed by keyword character"
errloc = loc + self.matchLen
else:
# preceded by keyword char
errmsg += ", keyword was immediately preceded by keyword character"
errloc = loc - 1
# else no match just raise plain exception
raise ParseException(instring, errloc, errmsg, self)
@staticmethod
def set_default_keyword_chars(chars) -> None:
"""
Overrides the default characters used by :class:`Keyword` expressions.
"""
Keyword.DEFAULT_KEYWORD_CHARS = chars
# Compatibility synonyms
setDefaultKeywordChars = staticmethod(
replaced_by_pep8("setDefaultKeywordChars", set_default_keyword_chars)
)
class CaselessLiteral(Literal):
"""
Token to match a specified string, ignoring case of letters.
Note: the matched results will always be in the case of the given
match string, NOT the case of the input text.
Example:
.. doctest::
>>> CaselessLiteral("CMD")[1, ...].parse_string("cmd CMD Cmd10")
ParseResults(['CMD', 'CMD', 'CMD'], {})
(Contrast with example for :class:`CaselessKeyword`.)
"""
def __init__(self, match_string: str = "", **kwargs) -> None:
matchString: str = deprecate_argument(kwargs, "matchString", "")
match_string = matchString or match_string
super().__init__(match_string.upper())
# Preserve the defining literal.
self.returnString = match_string
self.errmsg = f"Expected {self.name}"
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if instring[loc : loc + self.matchLen].upper() == self.match:
return loc + self.matchLen, self.returnString
raise ParseException(instring, loc, self.errmsg, self)
class CaselessKeyword(Keyword):
"""
Caseless version of :class:`Keyword`.
Example:
.. doctest::
>>> CaselessKeyword("CMD")[1, ...].parse_string("cmd CMD Cmd10")
ParseResults(['CMD', 'CMD'], {})
(Contrast with example for :class:`CaselessLiteral`.)
"""
def __init__(
self, match_string: str = "", ident_chars: typing.Optional[str] = None, **kwargs
) -> None:
matchString: str = deprecate_argument(kwargs, "matchString", "")
identChars: typing.Optional[str] = deprecate_argument(
kwargs, "identChars", None
)
identChars = identChars or ident_chars
match_string = matchString or match_string
super().__init__(match_string, identChars, caseless=True)
class CloseMatch(Token):
"""A variation on :class:`Literal` which matches "close" matches,
that is, strings with at most 'n' mismatching characters.
:class:`CloseMatch` takes parameters:
- ``match_string`` - string to be matched
- ``caseless`` - a boolean indicating whether to ignore casing when comparing characters
- ``max_mismatches`` - (``default=1``) maximum number of
mismatches allowed to count as a match
The results from a successful parse will contain the matched text
from the input string and the following named results:
- ``mismatches`` - a list of the positions within the
match_string where mismatches were found
- ``original`` - the original match_string used to compare
against the input string
If ``mismatches`` is an empty list, then the match was an exact
match.
Example:
.. doctest::
:options: +NORMALIZE_WHITESPACE
>>> patt = CloseMatch("ATCATCGAATGGA")
>>> patt.parse_string("ATCATCGAAXGGA")
ParseResults(['ATCATCGAAXGGA'],
{'original': 'ATCATCGAATGGA', 'mismatches': [9]})
>>> patt.parse_string("ATCAXCGAAXGGA")
Traceback (most recent call last):
ParseException: Expected 'ATCATCGAATGGA' (with up to 1 mismatches),
found 'ATCAXCGAAXGGA' (at char 0), (line:1, col:1)
# exact match
>>> patt.parse_string("ATCATCGAATGGA")
ParseResults(['ATCATCGAATGGA'],
{'original': 'ATCATCGAATGGA', 'mismatches': []})
# close match allowing up to 2 mismatches
>>> patt = CloseMatch("ATCATCGAATGGA", max_mismatches=2)
>>> patt.parse_string("ATCAXCGAAXGGA")
ParseResults(['ATCAXCGAAXGGA'],
{'original': 'ATCATCGAATGGA', 'mismatches': [4, 9]})
"""
def __init__(
self,
match_string: str,
max_mismatches: typing.Optional[int] = None,
*,
caseless=False,
**kwargs,
) -> None:
maxMismatches: int = deprecate_argument(kwargs, "maxMismatches", 1)
maxMismatches = max_mismatches if max_mismatches is not None else maxMismatches
super().__init__()
self.match_string = match_string
self.maxMismatches = maxMismatches
self.errmsg = f"Expected {self.match_string!r} (with up to {self.maxMismatches} mismatches)"
self.caseless = caseless
self.mayIndexError = False
self._may_return_empty = False
def _generateDefaultName(self) -> str:
return f"{type(self).__name__}:{self.match_string!r}"
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
start = loc
instrlen = len(instring)
maxloc = start + len(self.match_string)
if maxloc <= instrlen:
match_string = self.match_string
match_stringloc = 0
mismatches = []
maxMismatches = self.maxMismatches
for match_stringloc, s_m in enumerate(
zip(instring[loc:maxloc], match_string)
):
src, mat = s_m
if self.caseless:
src, mat = src.lower(), mat.lower()
if src != mat:
mismatches.append(match_stringloc)
if len(mismatches) > maxMismatches:
break
else:
loc = start + match_stringloc + 1
results = ParseResults([instring[start:loc]])
results["original"] = match_string
results["mismatches"] = mismatches
return loc, results
raise ParseException(instring, loc, self.errmsg, self)
class Word(Token):
"""Token for matching words composed of allowed character sets.
Parameters:
- ``init_chars`` - string of all characters that should be used to
match as a word; "ABC" will match "AAA", "ABAB", "CBAC", etc.;
if ``body_chars`` is also specified, then this is the string of
initial characters
- ``body_chars`` - string of characters that
can be used for matching after a matched initial character as
given in ``init_chars``; if omitted, same as the initial characters
(default=``None``)
- ``min`` - minimum number of characters to match (default=1)
- ``max`` - maximum number of characters to match (default=0)
- ``exact`` - exact number of characters to match (default=0)
- ``as_keyword`` - match as a keyword (default=``False``)
- ``exclude_chars`` - characters that might be
found in the input ``body_chars`` string but which should not be
accepted for matching ;useful to define a word of all
printables except for one or two characters, for instance
(default=``None``)
:class:`srange` is useful for defining custom character set strings
for defining :class:`Word` expressions, using range notation from
regular expression character sets.
A common mistake is to use :class:`Word` to match a specific literal
string, as in ``Word("Address")``. Remember that :class:`Word`
uses the string argument to define *sets* of matchable characters.
This expression would match "Add", "AAA", "dAred", or any other word
made up of the characters 'A', 'd', 'r', 'e', and 's'. To match an
exact literal string, use :class:`Literal` or :class:`Keyword`.
pyparsing includes helper strings for building Words:
- :attr:`alphas`
- :attr:`nums`
- :attr:`alphanums`
- :attr:`hexnums`
- :attr:`alphas8bit` (alphabetic characters in ASCII range 128-255
- accented, tilded, umlauted, etc.)
- :attr:`punc8bit` (non-alphabetic characters in ASCII range
128-255 - currency, symbols, superscripts, diacriticals, etc.)
- :attr:`printables` (any non-whitespace character)
``alphas``, ``nums``, and ``printables`` are also defined in several
Unicode sets - see :class:`pyparsing_unicode`.
Example:
.. testcode::
# a word composed of digits
integer = Word(nums)
# Two equivalent alternate forms:
Word("0123456789")
Word(srange("[0-9]"))
# a word with a leading capital, and zero or more lowercase
capitalized_word = Word(alphas.upper(), alphas.lower())
# hostnames are alphanumeric, with leading alpha, and '-'
hostname = Word(alphas, alphanums + '-')
# roman numeral
# (not a strict parser, accepts invalid mix of characters)
roman = Word("IVXLCDM")
# any string of non-whitespace characters, except for ','
csv_value = Word(printables, exclude_chars=",")
:raises ValueError: If ``min`` and ``max`` are both specified
and the test ``min <= max`` fails.
.. versionchanged:: 3.1.0
Raises :exc:`ValueError` if ``min`` > ``max``.
"""
def __init__(
self,
init_chars: str = "",
body_chars: typing.Optional[str] = None,
min: int = 1,
max: int = 0,
exact: int = 0,
as_keyword: bool = False,
exclude_chars: typing.Optional[str] = None,
**kwargs,
) -> None:
initChars: typing.Optional[str] = deprecate_argument(kwargs, "initChars", None)
bodyChars: typing.Optional[str] = deprecate_argument(kwargs, "bodyChars", None)
asKeyword: bool = deprecate_argument(kwargs, "asKeyword", False)
excludeChars: typing.Optional[str] = deprecate_argument(
kwargs, "excludeChars", None
)
initChars = initChars or init_chars
bodyChars = bodyChars or body_chars
asKeyword = asKeyword or as_keyword
excludeChars = excludeChars or exclude_chars
super().__init__()
if not initChars:
raise ValueError(
f"invalid {type(self).__name__}, initChars cannot be empty string"
)
initChars_set = set(initChars)
if excludeChars:
excludeChars_set = set(excludeChars)
initChars_set -= excludeChars_set
if bodyChars:
bodyChars = "".join(set(bodyChars) - excludeChars_set)
self.init_chars = initChars_set
self.initCharsOrig = "".join(sorted(initChars_set))
if bodyChars:
self.bodyChars = set(bodyChars)
self.bodyCharsOrig = "".join(sorted(bodyChars))
else:
self.bodyChars = initChars_set
self.bodyCharsOrig = self.initCharsOrig
self.maxSpecified = max > 0
if min < 1:
raise ValueError(
"cannot specify a minimum length < 1; use Opt(Word()) if zero-length word is permitted"
)
if self.maxSpecified and min > max:
raise ValueError(
f"invalid args, if min and max both specified min must be <= max (min={min}, max={max})"
)
self.minLen = min
if max > 0:
self.maxLen = max
else:
self.maxLen = _MAX_INT
if exact > 0:
min = max = exact
self.maxLen = exact
self.minLen = exact
self.errmsg = f"Expected {self.name}"
self.mayIndexError = False
self.asKeyword = asKeyword
if self.asKeyword:
self.errmsg += " as a keyword"
# see if we can make a regex for this Word
if " " not in (self.initChars | self.bodyChars):
if len(self.initChars) == 1:
re_leading_fragment = re.escape(self.initCharsOrig)
else:
re_leading_fragment = f"[{_collapse_string_to_ranges(self.initChars)}]"
if self.bodyChars == self.initChars:
if max == 0 and self.minLen == 1:
repeat = "+"
elif max == 1:
repeat = ""
else:
if self.minLen != self.maxLen:
repeat = f"{{{self.minLen},{'' if self.maxLen == _MAX_INT else self.maxLen}}}"
else:
repeat = f"{{{self.minLen}}}"
self.reString = f"{re_leading_fragment}{repeat}"
else:
if max == 1:
re_body_fragment = ""
repeat = ""
else:
re_body_fragment = f"[{_collapse_string_to_ranges(self.bodyChars)}]"
if max == 0 and self.minLen == 1:
repeat = "*"
elif max == 2:
repeat = "?" if min <= 1 else ""
else:
if min != max:
repeat = f"{{{min - 1 if min > 0 else ''},{max - 1 if max > 0 else ''}}}"
else:
repeat = f"{{{min - 1 if min > 0 else ''}}}"
self.reString = f"{re_leading_fragment}{re_body_fragment}{repeat}"
if self.asKeyword:
self.reString = rf"\b{self.reString}\b"
try:
self.re = re.compile(self.reString)
except re.error:
self.re = None # type: ignore[assignment]
else:
self.re_match = self.re.match
self.parseImpl = self.parseImpl_regex # type: ignore[method-assign]
@property
def initChars(self) -> set[str]:
"""
.. deprecated:: 3.3.0
use `init_chars` instead.
Property returning the initial chars to be used when matching this
Word expression. If no body chars were specified, the initial characters
will also be the body characters.
"""
return set(self.init_chars)
def copy(self) -> Word:
"""
Returns a copy of this expression.
Generally only used internally by pyparsing.
"""
ret: Word = cast(Word, super().copy())
if hasattr(self, "re_match"):
ret.re_match = self.re_match
ret.parseImpl = ret.parseImpl_regex # type: ignore[method-assign]
return ret
def _generateDefaultName(self) -> str:
def charsAsStr(s):
max_repr_len = 16
s = _collapse_string_to_ranges(s, re_escape=False)
if len(s) > max_repr_len:
return f"{s[:max_repr_len - 3]}..."
return s
if self.initChars != self.bodyChars:
base = f"W:({charsAsStr(self.initChars)}, {charsAsStr(self.bodyChars)})"
else:
base = f"W:({charsAsStr(self.initChars)})"
# add length specification
if self.minLen > 1 or self.maxLen != _MAX_INT:
if self.minLen == self.maxLen:
if self.minLen == 1:
return base[2:]
else:
return base + f"{{{self.minLen}}}"
elif self.maxLen == _MAX_INT:
return base + f"{{{self.minLen},...}}"
else:
return base + f"{{{self.minLen},{self.maxLen}}}"
return base
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if instring[loc] not in self.initChars:
raise ParseException(instring, loc, self.errmsg, self)
start = loc
loc += 1
instrlen = len(instring)
body_chars: set[str] = self.bodyChars
maxloc = start + self.maxLen
maxloc = min(maxloc, instrlen)
while loc < maxloc and instring[loc] in body_chars:
loc += 1
throw_exception = False
if loc - start < self.minLen:
throw_exception = True
elif self.asKeyword and (
(start > 0 and instring[start - 1] in body_chars)
or (loc < instrlen and instring[loc] in body_chars)
):
throw_exception = True
if throw_exception:
raise ParseException(instring, loc, self.errmsg, self)
return loc, instring[start:loc]
def parseImpl_regex(self, instring, loc, do_actions=True) -> ParseImplReturnType:
result = self.re_match(instring, loc)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
return loc, result[0]
class Char(Word):
"""A short-cut class for defining :class:`Word` ``(characters, exact=1)``,
when defining a match of any single character in a string of
characters.
"""
def __init__(
self,
charset: str,
as_keyword: bool = False,
exclude_chars: typing.Optional[str] = None,
**kwargs,
) -> None:
asKeyword: bool = deprecate_argument(kwargs, "asKeyword", False)
excludeChars: typing.Optional[str] = deprecate_argument(
kwargs, "excludeChars", None
)
asKeyword = asKeyword or as_keyword
excludeChars = excludeChars or exclude_chars
super().__init__(
charset, exact=1, as_keyword=asKeyword, exclude_chars=excludeChars
)
class Regex(Token):
r"""Token for matching strings that match a given regular
expression. Defined with string specifying the regular expression in
a form recognized by the stdlib Python `re module <https://docs.python.org/3/library/re.html>`_.
If the given regex contains named groups (defined using ``(?P<name>...)``),
these will be preserved as named :class:`ParseResults`.
If instead of the Python stdlib ``re`` module you wish to use a different RE module
(such as the ``regex`` module), you can do so by building your ``Regex`` object with
a compiled RE that was compiled using ``regex``.
The parameters ``pattern`` and ``flags`` are passed
to the ``re.compile()`` function as-is. See the Python
`re module <https://docs.python.org/3/library/re.html>`_ module for an
explanation of the acceptable patterns and flags.
Example:
.. testcode::
realnum = Regex(r"[+-]?\d+\.\d*")
# ref: https://stackoverflow.com/questions/267399/how-do-you-match-only-valid-roman-numerals-with-a-regular-expression
roman = Regex(r"M{0,4}(CM|CD|D?{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})")
# named fields in a regex will be returned as named results
date = Regex(r'(?P<year>\d{4})-(?P<month>\d\d?)-(?P<day>\d\d?)')
# the Regex class will accept regular expressions compiled using the
# re module
import re
parser = pp.Regex(re.compile(r'[0-9]'))
"""
def __init__(
self,
pattern: Any,
flags: Union[re.RegexFlag, int] = 0,
as_group_list: bool = False,
as_match: bool = False,
**kwargs,
) -> None:
super().__init__()
asGroupList: bool = deprecate_argument(kwargs, "asGroupList", False)
asMatch: bool = deprecate_argument(kwargs, "asMatch", False)
asGroupList = asGroupList or as_group_list
asMatch = asMatch or as_match
if isinstance(pattern, str_type):
if not pattern:
raise ValueError("null string passed to Regex; use Empty() instead")
self._re = None
self._may_return_empty = None # type: ignore [assignment]
self.reString = self.pattern = pattern
elif hasattr(pattern, "pattern") and hasattr(pattern, "match"):
self._re = pattern
self._may_return_empty = None # type: ignore [assignment]
self.pattern = self.reString = pattern.pattern
elif callable(pattern):
# defer creating this pattern until we really need it
self.pattern = pattern
self._may_return_empty = None # type: ignore [assignment]
self._re = None
else:
raise TypeError(
"Regex may only be constructed with a string or a compiled RE object,"
" or a callable that takes no arguments and returns a string or a"
" compiled RE object"
)
self.flags = flags
self.errmsg = f"Expected {self.name}"
self.mayIndexError = False
self.asGroupList = asGroupList
self.asMatch = asMatch
if self.asGroupList:
self.parseImpl = self.parseImplAsGroupList # type: ignore [method-assign]
if self.asMatch:
self.parseImpl = self.parseImplAsMatch # type: ignore [method-assign]
def copy(self) -> Regex:
"""
Returns a copy of this expression.
Generally only used internally by pyparsing.
"""
ret: Regex = cast(Regex, super().copy())
if self.asGroupList:
ret.parseImpl = ret.parseImplAsGroupList # type: ignore [method-assign]
if self.asMatch:
ret.parseImpl = ret.parseImplAsMatch # type: ignore [method-assign]
return ret
@cached_property
def re(self) -> re.Pattern:
"""
Property returning the compiled regular expression for this Regex.
Generally only used internally by pyparsing.
"""
if self._re:
return self._re
if callable(self.pattern):
# replace self.pattern with the string returned by calling self.pattern()
self.pattern = cast(Callable[[], str], self.pattern)()
# see if we got a compiled RE back instead of a str - if so, we're done
if hasattr(self.pattern, "pattern") and hasattr(self.pattern, "match"):
self._re = cast(re.Pattern[str], self.pattern)
self.pattern = self.reString = self._re.pattern
return self._re
try:
self._re = re.compile(self.pattern, self.flags)
except re.error:
raise ValueError(f"invalid pattern ({self.pattern!r}) passed to Regex")
else:
self._may_return_empty = self.re.match("", pos=0) is not None
return self._re
@cached_property
def re_match(self) -> Callable[[str, int], Any]:
return self.re.match
@property
def mayReturnEmpty(self):
if self._may_return_empty is None:
# force compile of regex pattern, to set may_return_empty flag
self.re # noqa
return self._may_return_empty
@mayReturnEmpty.setter
def mayReturnEmpty(self, value):
self._may_return_empty = value
def _generateDefaultName(self) -> str:
unescaped = repr(self.pattern).replace("\\\\", "\\")
return f"Re:({unescaped})"
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
# explicit check for matching past the length of the string;
# this is done because the re module will not complain about
# a match with `pos > len(instring)`, it will just return ""
if loc > len(instring) and self.mayReturnEmpty:
raise ParseException(instring, loc, self.errmsg, self)
result = self.re_match(instring, loc)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
ret = ParseResults(result[0])
d = result.groupdict()
for k, v in d.items():
ret[k] = v
return loc, ret
def parseImplAsGroupList(self, instring, loc, do_actions=True):
if loc > len(instring) and self.mayReturnEmpty:
raise ParseException(instring, loc, self.errmsg, self)
result = self.re_match(instring, loc)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
ret = result.groups()
return loc, ret
def parseImplAsMatch(self, instring, loc, do_actions=True):
if loc > len(instring) and self.mayReturnEmpty:
raise ParseException(instring, loc, self.errmsg, self)
result = self.re_match(instring, loc)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
ret = result
return loc, ret
def sub(self, repl: str) -> ParserElement:
r"""
Return :class:`Regex` with an attached parse action to transform the parsed
result as if called using `re.sub(expr, repl, string) <https://docs.python.org/3/library/re.html#re.sub>`_.
Example:
.. testcode::
make_html = Regex(r"(\w+):(.*?):").sub(r"<\1>\2</\1>")
print(make_html.transform_string("h1:main title:"))
.. testoutput::
<h1>main title</h1>
"""
if self.asGroupList:
raise TypeError("cannot use sub() with Regex(as_group_list=True)")
if self.asMatch and callable(repl):
raise TypeError(
"cannot use sub() with a callable with Regex(as_match=True)"
)
if self.asMatch:
def pa(tokens):
return tokens[0].expand(repl)
else:
def pa(tokens):
return self.re.sub(repl, tokens[0])
return self.add_parse_action(pa)
class QuotedString(Token):
r"""
Token for matching strings that are delimited by quoting characters.
Defined with the following parameters:
- ``quote_char`` - string of one or more characters defining the
quote delimiting string
- ``esc_char`` - character to re_escape quotes, typically backslash
(default= ``None``)
- ``esc_quote`` - special quote sequence to re_escape an embedded quote
string (such as SQL's ``""`` to re_escape an embedded ``"``)
(default= ``None``)
- ``multiline`` - boolean indicating whether quotes can span
multiple lines (default= ``False``)
- ``unquote_results`` - boolean indicating whether the matched text
should be unquoted (default= ``True``)
- ``end_quote_char`` - string of one or more characters defining the
end of the quote delimited string (default= ``None`` => same as
quote_char)
- ``convert_whitespace_escapes`` - convert escaped whitespace
(``'\t'``, ``'\n'``, etc.) to actual whitespace
(default= ``True``)
.. caution:: ``convert_whitespace_escapes`` has no effect if
``unquote_results`` is ``False``.
Example:
.. doctest::
>>> qs = QuotedString('"')
>>> print(qs.search_string('lsjdf "This is the quote" sldjf'))
[['This is the quote']]
>>> complex_qs = QuotedString('{{', end_quote_char='}}')
>>> print(complex_qs.search_string(
... 'lsjdf {{This is the "quote"}} sldjf'))
[['This is the "quote"']]
>>> sql_qs = QuotedString('"', esc_quote='""')
>>> print(sql_qs.search_string(
... 'lsjdf "This is the quote with ""embedded"" quotes" sldjf'))
[['This is the quote with "embedded" quotes']]
"""
ws_map = dict(((r"\t", "\t"), (r"\n", "\n"), (r"\f", "\f"), (r"\r", "\r")))
def __init__(
self,
quote_char: str = "",
esc_char: typing.Optional[str] = None,
esc_quote: typing.Optional[str] = None,
multiline: bool = False,
unquote_results: bool = True,
end_quote_char: typing.Optional[str] = None,
convert_whitespace_escapes: bool = True,
**kwargs,
) -> None:
super().__init__()
quoteChar: str = deprecate_argument(kwargs, "quoteChar", "")
escChar: str = deprecate_argument(kwargs, "escChar", None)
escQuote: str = deprecate_argument(kwargs, "escQuote", None)
unquoteResults: bool = deprecate_argument(kwargs, "unquoteResults", True)
endQuoteChar: typing.Optional[str] = deprecate_argument(
kwargs, "endQuoteChar", None
)
convertWhitespaceEscapes: bool = deprecate_argument(
kwargs, "convertWhitespaceEscapes", True
)
esc_char = escChar or esc_char
esc_quote = escQuote or esc_quote
unquote_results = unquoteResults and unquote_results
end_quote_char = endQuoteChar or end_quote_char
convert_whitespace_escapes = (
convertWhitespaceEscapes and convert_whitespace_escapes
)
quote_char = quoteChar or quote_char
# reject empty or whitespace-only quote chars, but preserve any
# whitespace that is part of a valid quote delimiter (e.g. a leading
# newline in a multiline quote such as "\n;")
if not quote_char.strip():
raise ValueError("quote_char cannot be the empty string")
if end_quote_char is None:
end_quote_char = quote_char
elif not end_quote_char.strip():
raise ValueError("end_quote_char cannot be the empty string")
self.quote_char: str = quote_char
self.quote_char_len: int = len(quote_char)
self.first_quote_char: str = quote_char[0]
self.end_quote_char: str = end_quote_char
self.end_quote_char_len: int = len(end_quote_char)
self.esc_char: str = esc_char or ""
self.has_esc_char: bool = esc_char is not None
self.esc_quote: str = esc_quote or ""
self.unquote_results: bool = unquote_results
self.convert_whitespace_escapes: bool = convert_whitespace_escapes
self.multiline = multiline
self.re_flags = re.RegexFlag(0)
# fmt: off
# build up re pattern for the content between the quote delimiters
inner_pattern: list[str] = []
if esc_quote:
inner_pattern.append(rf"(?:{re.escape(esc_quote)})")
if esc_char:
inner_pattern.append(rf"(?:{re.escape(esc_char)}.)")
if len(self.end_quote_char) > 1:
inner_pattern.append(
"(?:"
+ "|".join(
f"(?:{re.escape(self.end_quote_char[:i])}(?!{re.escape(self.end_quote_char[i:])}))"
for i in range(len(self.end_quote_char) - 1, 0, -1)
)
+ ")"
)
if self.multiline:
self.re_flags |= re.MULTILINE | re.DOTALL
inner_pattern.append(
rf"(?:[^{_escape_regex_range_chars(self.end_quote_char[0])}"
rf"{(_escape_regex_range_chars(self.esc_char) if self.has_esc_char else '')}])"
)
else:
inner_pattern.append(
rf"(?:[^{_escape_regex_range_chars(self.end_quote_char[0])}\n\r"
rf"{(_escape_regex_range_chars(self.esc_char) if self.has_esc_char else '')}])"
)
self.pattern = "".join(
[
re.escape(self.quote_char),
"(?:",
'|'.join(inner_pattern),
")*",
re.escape(self.end_quote_char),
]
)
if self.unquote_results:
if self.convert_whitespace_escapes:
self.unquote_scan_re = re.compile(
rf"({'|'.join(re.escape(k) for k in self.ws_map)})"
rf"|(\\[0-7]{3}|\\0|\\x[0-9a-fA-F]{2}|\\u[0-9a-fA-F]{4})"
rf"|({re.escape(self.esc_char)}.)"
rf"|(\n|.)",
flags=self.re_flags,
)
else:
self.unquote_scan_re = re.compile(
rf"({re.escape(self.esc_char)}.)"
rf"|(\n|.)",
flags=self.re_flags
)
# fmt: on
try:
self.re = re.compile(self.pattern, self.re_flags)
self.reString = self.pattern
self.re_match = self.re.match
except re.error:
raise ValueError(f"invalid pattern {self.pattern!r} passed to Regex")
self.errmsg = f"Expected {self.name}"
self.mayIndexError = False
self._may_return_empty = True
def _generateDefaultName(self) -> str:
if self.quote_char == self.end_quote_char and isinstance(
self.quote_char, str_type
):
return f"string enclosed in {self.quote_char!r}"
return f"quoted string, starting with {self.quote_char} ending with {self.end_quote_char}"
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
# check first character of opening quote to see if that is a match
# before doing the more complicated regex match
result = (
instring[loc] == self.first_quote_char
and self.re_match(instring, loc)
or None
)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
# get ending loc and matched string from regex matching result
loc = result.end()
ret = result[0]
if self.unquote_results:
# strip off quotes
ret = ret[self.quote_char_len : -self.end_quote_char_len]
if isinstance(ret, str_type):
# fmt: off
if self.convert_whitespace_escapes:
# as we iterate over matches in the input string,
# collect from whichever match group of the unquote_scan_re
# regex matches (only 1 group will match at any given time)
ret = "".join(
# match group 1 matches \t, \n, etc.
self.ws_map[g] if (g := match[1])
# match group 2 matches escaped octal, null, hex, and Unicode
# sequences
else _convert_escaped_numerics_to_char(g[1:]) if (g := match[2])
# match group 3 matches escaped characters
else g[-1] if (g := match[3])
# match group 4 matches any character
else match[4]
for match in self.unquote_scan_re.finditer(ret)
)
else:
ret = "".join(
# match group 1 matches escaped characters
g[-1] if (g := match[1])
# match group 2 matches any character
else match[2]
for match in self.unquote_scan_re.finditer(ret)
)
# fmt: on
# replace escaped quotes
if self.esc_quote:
ret = ret.replace(self.esc_quote, self.end_quote_char)
return loc, ret
class CharsNotIn(Token):
"""Token for matching words composed of characters *not* in a given
set (will include whitespace in matched characters if not listed in
the provided exclusion set - see example). Defined with string
containing all disallowed characters, and an optional minimum,
maximum, and/or exact length. The default value for ``min`` is
1 (a minimum value < 1 is not valid); the default values for
``max`` and ``exact`` are 0, meaning no maximum or exact
length restriction.
Example:
.. testcode::
# define a comma-separated-value as anything that is not a ','
csv_value = CharsNotIn(',')
print(
DelimitedList(csv_value).parse_string(
"dkls,lsdkjf,s12 34,@!#,213"
)
)
prints:
.. testoutput::
['dkls', 'lsdkjf', 's12 34', '@!#', '213']
"""
def __init__(
self, not_chars: str = "", min: int = 1, max: int = 0, exact: int = 0, **kwargs
) -> None:
super().__init__()
notChars: str = deprecate_argument(kwargs, "notChars", "")
self.skipWhitespace = False
self.notChars = not_chars or notChars
self.notCharsSet = set(self.notChars)
if min < 1:
raise ValueError(
"cannot specify a minimum length < 1; use"
" Opt(CharsNotIn()) if zero-length char group is permitted"
)
self.minLen = min
if max > 0:
self.maxLen = max
else:
self.maxLen = _MAX_INT
if exact > 0:
self.maxLen = exact
self.minLen = exact
self.errmsg = f"Expected {self.name}"
self._may_return_empty = self.minLen == 0
self.mayIndexError = False
def _generateDefaultName(self) -> str:
not_chars_str = _collapse_string_to_ranges(self.notChars)
if len(not_chars_str) > 16:
return f"!W:({self.notChars[: 16 - 3]}...)"
else:
return f"!W:({self.notChars})"
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
notchars = self.notCharsSet
if instring[loc] in notchars:
raise ParseException(instring, loc, self.errmsg, self)
start = loc
loc += 1
maxlen = min(start + self.maxLen, len(instring))
while loc < maxlen and instring[loc] not in notchars:
loc += 1
if loc - start < self.minLen:
raise ParseException(instring, loc, self.errmsg, self)
return loc, instring[start:loc]
class White(Token):
"""Special matching class for matching whitespace. Normally,
whitespace is ignored by pyparsing grammars. This class is included
when some whitespace structures are significant. Define with
a string containing the whitespace characters to be matched; default
is ``" \\t\\r\\n"``. Also takes optional ``min``,
``max``, and ``exact`` arguments, as defined for the
:class:`Word` class.
"""
whiteStrs = {
" ": "<SP>",
"\t": "<TAB>",
"\n": "<LF>",
"\r": "<CR>",
"\f": "<FF>",
"\u00a0": "<NBSP>",
"\u1680": "<OGHAM_SPACE_MARK>",
"\u180e": "<MONGOLIAN_VOWEL_SEPARATOR>",
"\u2000": "<EN_QUAD>",
"\u2001": "<EM_QUAD>",
"\u2002": "<EN_SPACE>",
"\u2003": "<EM_SPACE>",
"\u2004": "<THREE-PER-EM_SPACE>",
"\u2005": "<FOUR-PER-EM_SPACE>",
"\u2006": "<SIX-PER-EM_SPACE>",
"\u2007": "<FIGURE_SPACE>",
"\u2008": "<PUNCTUATION_SPACE>",
"\u2009": "<THIN_SPACE>",
"\u200a": "<HAIR_SPACE>",
"\u200b": "<ZERO_WIDTH_SPACE>",
"\u202f": "<NNBSP>",
"\u205f": "<MMSP>",
"\u3000": "<IDEOGRAPHIC_SPACE>",
}
def __init__(
self, ws: str = " \t\r\n", min: int = 1, max: int = 0, exact: int = 0
) -> None:
super().__init__()
self.matchWhite = ws
self.set_whitespace_chars(
"".join(c for c in self.whiteStrs if c not in self.matchWhite),
copy_defaults=True,
)
# self.leave_whitespace()
self._may_return_empty = True
self.errmsg = f"Expected {self.name}"
self.minLen = min
if max > 0:
self.maxLen = max
else:
self.maxLen = _MAX_INT
if exact > 0:
self.maxLen = exact
self.minLen = exact
def _generateDefaultName(self) -> str:
return "".join(White.whiteStrs[c] for c in self.matchWhite)
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if instring[loc] not in self.matchWhite:
raise ParseException(instring, loc, self.errmsg, self)
start = loc
loc += 1
maxloc = start + self.maxLen
maxloc = min(maxloc, len(instring))
while loc < maxloc and instring[loc] in self.matchWhite:
loc += 1
if loc - start < self.minLen:
raise ParseException(instring, loc, self.errmsg, self)
return loc, instring[start:loc]
class PositionToken(Token):
def __init__(self) -> None:
super().__init__()
self._may_return_empty = True
self.mayIndexError = False
class GoToColumn(PositionToken):
"""Token to advance to a specific column of input text; useful for
tabular report scraping.
"""
def __init__(self, colno: int) -> None:
super().__init__()
self.col = colno
def preParse(self, instring: str, loc: int) -> int:
if col(loc, instring) == self.col:
return loc
instrlen = len(instring)
if self.ignoreExprs:
loc = self._skipIgnorables(instring, loc)
while (
loc < instrlen
and instring[loc].isspace()
and col(loc, instring) != self.col
):
loc += 1
return loc
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
thiscol = col(loc, instring)
if thiscol > self.col:
raise ParseException(instring, loc, "Text not in expected column", self)
newloc = loc + self.col - thiscol
ret = instring[loc:newloc]
return newloc, ret
class LineStart(PositionToken):
r"""Matches if current position is at the logical beginning of a line (after skipping whitespace)
within the parse string
Example:
.. testcode::
test = '''\
AAA this line
AAA and this line
AAA and even this line
B AAA but definitely not this line
'''
for t in (LineStart() + 'AAA' + rest_of_line).search_string(test):
print(t)
prints:
.. testoutput::
['AAA', ' this line']
['AAA', ' and this line']
['AAA', ' and even this line']
"""
def __init__(self) -> None:
super().__init__()
self.leave_whitespace()
self.orig_whiteChars = set() | self.whiteChars
self.whiteChars.discard("\n")
self.skipper = Empty().set_whitespace_chars(self.whiteChars)
self.set_name("start of line")
def preParse(self, instring: str, loc: int) -> int:
if loc == 0:
return loc
ret = self.skipper.preParse(instring, loc)
if "\n" in self.orig_whiteChars:
while instring[ret : ret + 1] == "\n":
ret = self.skipper.preParse(instring, ret + 1)
return ret
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if col(loc, instring) == 1:
return loc, []
raise ParseException(instring, loc, self.errmsg, self)
class LineEnd(PositionToken):
"""Matches if current position is at the end of a line within the
parse string
"""
def __init__(self) -> None:
super().__init__()
self.whiteChars.discard("\n")
self.set_whitespace_chars(self.whiteChars, copy_defaults=False)
self.set_name("end of line")
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if loc < len(instring):
if instring[loc] == "\n":
return loc + 1, "\n"
else:
raise ParseException(instring, loc, self.errmsg, self)
elif loc == len(instring):
return loc + 1, []
else:
raise ParseException(instring, loc, self.errmsg, self)
class StringStart(PositionToken):
"""Matches if current position is at the beginning of the parse
string
"""
def __init__(self) -> None:
super().__init__()
self.set_name("start of text")
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
# see if entire string up to here is just whitespace and ignoreables
if loc != 0 and loc != self.preParse(instring, 0):
raise ParseException(instring, loc, self.errmsg, self)
return loc, []
class StringEnd(PositionToken):
"""
Matches if current position is at the end of the parse string
"""
def __init__(self) -> None:
super().__init__()
self.set_name("end of text")
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if loc < len(instring):
raise ParseException(instring, loc, self.errmsg, self)
if loc == len(instring):
return loc + 1, []
if loc > len(instring):
return loc, []
raise ParseException(instring, loc, self.errmsg, self)
class WordStart(PositionToken):
"""Matches if the current position is at the beginning of a
:class:`Word`, and is not preceded by any character in a given
set of ``word_chars`` (default= ``printables``). To emulate the
``\b`` behavior of regular expressions, use
``WordStart(alphanums)``. ``WordStart`` will also match at
the beginning of the string being parsed, or at the beginning of
a line.
"""
def __init__(self, word_chars: str = printables, **kwargs) -> None:
wordChars: str = deprecate_argument(kwargs, "wordChars", printables)
wordChars = word_chars if wordChars == printables else wordChars
super().__init__()
self.wordChars = set(wordChars)
self.set_name("start of a word")
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if loc != 0:
if (
instring[loc - 1] in self.wordChars
or instring[loc] not in self.wordChars
):
raise ParseException(instring, loc, self.errmsg, self)
return loc, []
class WordEnd(PositionToken):
"""Matches if the current position is at the end of a :class:`Word`,
and is not followed by any character in a given set of ``word_chars``
(default= ``printables``). To emulate the ``\b`` behavior of
regular expressions, use ``WordEnd(alphanums)``. ``WordEnd``
will also match at the end of the string being parsed, or at the end
of a line.
"""
def __init__(self, word_chars: str = printables, **kwargs) -> None:
wordChars: str = deprecate_argument(kwargs, "wordChars", printables)
wordChars = word_chars if wordChars == printables else wordChars
super().__init__()
self.wordChars = set(wordChars)
self.skipWhitespace = False
self.set_name("end of a word")
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
instrlen = len(instring)
if instrlen > 0 and loc < instrlen:
if (
instring[loc] in self.wordChars
or instring[loc - 1] not in self.wordChars
):
raise ParseException(instring, loc, self.errmsg, self)
return loc, []
class Tag(Token):
"""
A meta-element for inserting a named result into the parsed
tokens that may be checked later in a parse action or while
processing the parsed results. Accepts an optional tag value,
defaulting to `True`.
Example:
.. doctest::
>>> end_punc = "." | ("!" + Tag("enthusiastic"))
>>> greeting = "Hello," + Word(alphas) + end_punc
>>> result = greeting.parse_string("Hello, World.")
>>> print(result.dump())
['Hello,', 'World', '.']
>>> result = greeting.parse_string("Hello, World!")
>>> print(result.dump())
['Hello,', 'World', '!']
- enthusiastic: True
.. versionadded:: 3.1.0
"""
def __init__(self, tag_name: str, value: Any = True) -> None:
super().__init__()
self._may_return_empty = True
self.mayIndexError = False
self.leave_whitespace()
self.tag_name = tag_name
self.tag_value = value
self.add_parse_action(self._add_tag)
self.show_in_diagram = False
def _add_tag(self, tokens: ParseResults):
tokens[self.tag_name] = self.tag_value
def _generateDefaultName(self) -> str:
return f"{type(self).__name__}:{self.tag_name}={self.tag_value!r}"
class ParseExpression(ParserElement):
"""Abstract subclass of ParserElement, for combining and
post-processing parsed tokens.
"""
def __init__(
self, exprs: typing.Iterable[ParserElement], savelist: bool = False
) -> None:
super().__init__(savelist)
self.exprs: list[ParserElement]
if isinstance(exprs, _generatorType):
exprs = list(exprs)
if isinstance(exprs, str_type):
self.exprs = [self._literalStringClass(exprs)]
elif isinstance(exprs, ParserElement):
self.exprs = [exprs]
elif isinstance(exprs, Iterable):
exprs = list(exprs)
# if sequence of strings provided, wrap with Literal
if any(isinstance(expr, str_type) for expr in exprs):
exprs = (
self._literalStringClass(e) if isinstance(e, str_type) else e
for e in exprs
)
self.exprs = list(exprs)
else:
try:
self.exprs = list(exprs)
except TypeError:
self.exprs = [exprs]
self.callPreparse = False
def recurse(self) -> list[ParserElement]:
return self.exprs[:]
def append(self, other) -> ParserElement:
"""
Add an expression to the list of expressions related to this ParseExpression instance.
"""
self.exprs.append(other)
self._defaultName = None
return self
def leave_whitespace(self, recursive: bool = True) -> ParserElement:
"""
Extends ``leave_whitespace`` defined in base class, and also invokes ``leave_whitespace`` on
all contained expressions.
"""
super().leave_whitespace(recursive)
if recursive:
self.exprs = [e.copy() for e in self.exprs]
for e in self.exprs:
e.leave_whitespace(recursive)
return self
def ignore_whitespace(self, recursive: bool = True) -> ParserElement:
"""
Extends ``ignore_whitespace`` defined in base class, and also invokes ``ignore_whitespace`` on
all contained expressions.
"""
super().ignore_whitespace(recursive)
if recursive:
self.exprs = [e.copy() for e in self.exprs]
for e in self.exprs:
e.ignore_whitespace(recursive)
return self
def ignore(self, other) -> ParserElement:
"""
Define expression to be ignored (e.g., comments) while doing pattern
matching; may be called repeatedly, to define multiple comment or other
ignorable patterns.
"""
if isinstance(other, Suppress):
if other not in self.ignoreExprs:
super().ignore(other)
for e in self.exprs:
e.ignore(self.ignoreExprs[-1])
else:
super().ignore(other)
for e in self.exprs:
e.ignore(self.ignoreExprs[-1])
return self
def _generateDefaultName(self) -> str:
return f"{type(self).__name__}:({self.exprs})"
def streamline(self) -> ParserElement:
if self.streamlined:
return self
super().streamline()
for e in self.exprs:
e.streamline()
# collapse nested :class:`And`'s of the form ``And(And(And(a, b), c), d)`` to ``And(a, b, c, d)``
# but only if there are no parse actions or resultsNames on the nested And's
# (likewise for :class:`Or`'s and :class:`MatchFirst`'s)
if len(self.exprs) == 2:
first, second = self.exprs
if (
isinstance(first, self.__class__)
and not first.parseAction
and first.resultsName is None
and not first.debug
):
self.exprs[:] = (*first.exprs, second)
self._defaultName = None
self._may_return_empty |= first.mayReturnEmpty
self.mayIndexError |= first.mayIndexError
last = self.exprs[-1]
if (
isinstance(last, self.__class__)
and not last.parseAction
and last.resultsName is None
and not last.debug
):
self.exprs[-1:] = last.exprs
self._defaultName = None
self._may_return_empty |= last.mayReturnEmpty
self.mayIndexError |= last.mayIndexError
self.errmsg = f"Expected {self}"
return self
def validate(self, validateTrace=None) -> None:
warnings.warn(
"ParserElement.validate() is deprecated, and should not be used to check for left recursion",
PyparsingDeprecationWarning,
stacklevel=2,
)
tmp = (validateTrace if validateTrace is not None else [])[:] + [self]
for e in self.exprs:
e.validate(tmp)
self._checkRecursion([])
def copy(self) -> ParserElement:
"""
Returns a copy of this expression.
Generally only used internally by pyparsing.
"""
ret = super().copy()
ret = typing.cast(ParseExpression, ret)
ret.exprs = [e.copy() for e in self.exprs]
return ret
def _setResultsName(self, name, list_all_matches=False) -> ParserElement:
if not (
__diag__.warn_ungrouped_named_tokens_in_collection
and Diagnostics.warn_ungrouped_named_tokens_in_collection
not in self.suppress_warnings_
):
return super()._setResultsName(name, list_all_matches)
for e in self.exprs:
if (
isinstance(e, ParserElement)
and e.resultsName
and (
Diagnostics.warn_ungrouped_named_tokens_in_collection
not in e.suppress_warnings_
)
):
warning = (
"warn_ungrouped_named_tokens_in_collection:"
f" setting results name {name!r} on {type(self).__name__} expression"
f" collides with {e.resultsName!r} on contained expression"
)
warnings.warn(warning, PyparsingDiagnosticWarning, stacklevel=3)
break
return super()._setResultsName(name, list_all_matches)
# Compatibility synonyms
# fmt: off
leaveWhitespace = replaced_by_pep8("leaveWhitespace", leave_whitespace)
ignoreWhitespace = replaced_by_pep8("ignoreWhitespace", ignore_whitespace)
# fmt: on
class And(ParseExpression):
"""
Requires all given :class:`ParserElement` s to be found in the given order.
Expressions may be separated by whitespace.
May be constructed using the ``'+'`` operator.
May also be constructed using the ``'-'`` operator, which will
suppress backtracking.
Example:
.. testcode::
integer = Word(nums)
name_expr = Word(alphas)[1, ...]
expr = And([integer("id"), name_expr("name"), integer("age")])
# more easily written as:
expr = integer("id") + name_expr("name") + integer("age")
"""
class _ErrorStop(Empty):
def __init__(self, *args, **kwargs) -> None:
super().__init__(*args, **kwargs)
self.leave_whitespace()
def _generateDefaultName(self) -> str:
return "-"
def __init__(
self,
exprs_arg: typing.Iterable[Union[ParserElement, str]],
savelist: bool = True,
) -> None:
# instantiate exprs as a list, converting strs to ParserElements
exprs: list[ParserElement] = [
self._literalStringClass(e) if isinstance(e, str) else e for e in exprs_arg
]
# convert any Ellipsis elements to SkipTo
if Ellipsis in exprs:
# Ellipsis cannot be the last element
if exprs[-1] is Ellipsis:
raise Exception("cannot construct And with sequence ending in ...")
tmp: list[ParserElement] = []
for cur_expr, next_expr in zip(exprs, exprs[1:]):
if cur_expr is Ellipsis:
tmp.append(SkipTo(next_expr)("_skipped*"))
else:
tmp.append(cur_expr)
exprs[:-1] = tmp
super().__init__(exprs, savelist)
if self.exprs:
self._may_return_empty = all(e.mayReturnEmpty for e in self.exprs)
if not isinstance(self.exprs[0], White):
self.set_whitespace_chars(
self.exprs[0].whiteChars,
copy_defaults=self.exprs[0].copyDefaultWhiteChars,
)
self.skipWhitespace = self.exprs[0].skipWhitespace
else:
self.skipWhitespace = False
else:
self._may_return_empty = True
self.callPreparse = True
def streamline(self) -> ParserElement:
"""
Collapse `And` expressions like `And(And(And(A, B), C), D)`
to `And(A, B, C, D)`.
.. doctest::
>>> expr = Word("A") + Word("B") + Word("C") + Word("D")
>>> # Using '+' operator creates nested And expression
>>> expr
{{{W:(A) W:(B)} W:(C)} W:(D)}
>>> # streamline simplifies to a single And with multiple expressions
>>> expr.streamline()
{W:(A) W:(B) W:(C) W:(D)}
Guards against collapsing out expressions that have special features,
such as results names or parse actions.
Resolves pending Skip commands defined using `...` terms.
"""
# collapse any _PendingSkip's
if self.exprs and any(
isinstance(e, ParseExpression)
and e.exprs
and isinstance(e.exprs[-1], _PendingSkip)
for e in self.exprs[:-1]
):
deleted_expr_marker = NoMatch()
for i, e in enumerate(self.exprs[:-1]):
if e is deleted_expr_marker:
continue
if (
isinstance(e, ParseExpression)
and e.exprs
and isinstance(e.exprs[-1], _PendingSkip)
):
e.exprs[-1] = e.exprs[-1] + self.exprs[i + 1]
self.exprs[i + 1] = deleted_expr_marker
self.exprs = [e for e in self.exprs if e is not deleted_expr_marker]
super().streamline()
# link any IndentedBlocks to the prior expression
prev: ParserElement
cur: ParserElement
for prev, cur in zip(self.exprs, self.exprs[1:]):
# traverse cur or any first embedded expr of cur looking for an IndentedBlock
# (but watch out for recursive grammar)
seen = set()
while True:
if id(cur) in seen:
break
seen.add(id(cur))
if isinstance(cur, IndentedBlock):
prev.add_parse_action(
lambda s, l, t, cur_=cur: setattr(
cur_, "parent_anchor", col(l, s)
)
)
break
subs = cur.recurse()
next_first = next(iter(subs), None)
if next_first is None:
break
cur = typing.cast(ParserElement, next_first)
self._may_return_empty = all(e.mayReturnEmpty for e in self.exprs)
return self
def parseImpl(self, instring, loc, do_actions=True):
# if no exprs defined, assume we contain a single Empty
# (consistent with behavior of `all([])` returning True)
exprs = iter(self.exprs or (Empty(),))
# pass False as callPreParse arg to _parse for first element, since we already
# pre-parsed the string as part of our And pre-parsing
loc, resultlist = next(exprs)._parse(
instring, loc, do_actions, callPreParse=False
)
# iterate over remaining expressions
raise_syntax_error_immediately = False
for e in exprs:
# if isinstance(e, And._ErrorStop):
if type(e) is And._ErrorStop:
raise_syntax_error_immediately = True
continue
if raise_syntax_error_immediately:
try:
loc, exprtokens = e._parse(instring, loc, do_actions)
except ParseSyntaxException:
raise
except ParseBaseException as pe:
pe.__traceback__ = None
raise ParseSyntaxException._from_exception(pe)
except IndexError:
raise ParseSyntaxException(
instring, len(instring), self.errmsg, self
)
else:
loc, exprtokens = e._parse(instring, loc, do_actions)
resultlist += exprtokens
return loc, resultlist
def __iadd__(self, other):
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return self.append(other) # And([self, other])
def _checkRecursion(self, parseElementList):
subRecCheckList = parseElementList[:] + [self]
for e in self.exprs:
e._checkRecursion(subRecCheckList)
if not e.mayReturnEmpty:
break
def _generateDefaultName(self) -> str:
inner = " ".join(str(e) for e in self.exprs)
# strip off redundant inner {}'s
while len(inner) > 1 and inner[0 :: len(inner) - 1] == "{}":
inner = inner[1:-1]
return f"{{{inner}}}"
class Or(ParseExpression):
"""Requires that at least one :class:`ParserElement` is found. If
two expressions match, the expression that matches the longest
string will be used. May be constructed using the ``'^'``
operator.
Example:
.. testcode::
# construct Or using '^' operator
number = Word(nums) ^ Combine(Word(nums) + '.' + Word(nums))
print(number.search_string("123 3.1416 789"))
prints:
.. testoutput::
[['123'], ['3.1416'], ['789']]
"""
def __init__(
self, exprs: typing.Iterable[ParserElement], savelist: bool = False
) -> None:
super().__init__(exprs, savelist)
if self.exprs:
self._may_return_empty = any(e.mayReturnEmpty for e in self.exprs)
self.skipWhitespace = all(e.skipWhitespace for e in self.exprs)
# only pre-skip whitespace here (so a parse action attached
# directly to this Or gets the whitespace-skipped loc) if every
# alternative would itself have pre-skipped it; otherwise leave
# this to each alternative, same condition already used in
# parseImpl below to decide whether to pre-skip before trying
# the alternatives
self.callPreparse = all(e.callPreparse for e in self.exprs)
else:
self._may_return_empty = True
def streamline(self) -> ParserElement:
super().streamline()
if self.exprs:
self._may_return_empty = any(e.mayReturnEmpty for e in self.exprs)
self.saveAsList = any(e.saveAsList for e in self.exprs)
self.skipWhitespace = all(
e.skipWhitespace and not isinstance(e, White) for e in self.exprs
)
else:
self.saveAsList = False
return self
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
maxExcLoc = -1
maxException = None
matches: list[tuple[int, ParserElement]] = []
fatals: list[ParseFatalException] = []
if all(e.callPreparse for e in self.exprs):
loc = self.preParse(instring, loc)
for e in self.exprs:
try:
loc2 = e.try_parse(instring, loc, raise_fatal=True)
except ParseFatalException as pfe:
pfe.__traceback__ = None
pfe.parser_element = e
fatals.append(pfe)
maxException = None
maxExcLoc = -1
except ParseException as err:
if not fatals:
err.__traceback__ = None
if err.loc > maxExcLoc:
maxException = err
maxExcLoc = err.loc
except IndexError:
if len(instring) > maxExcLoc:
maxException = ParseException(
instring, len(instring), e.errmsg, self
)
maxExcLoc = len(instring)
else:
# save match among all matches, to retry longest to shortest
matches.append((loc2, e))
if matches:
# re-evaluate all matches in descending order of length of match, in case attached actions
# might change whether or how much they match of the input.
matches.sort(key=itemgetter(0), reverse=True)
if not do_actions:
# no further conditions or parse actions to change the selection of
# alternative, so the first match will be the best match
best_expr = matches[0][1]
return best_expr._parse(instring, loc, do_actions)
longest: tuple[int, typing.Optional[ParseResults]] = -1, None
for loc1, expr1 in matches:
if loc1 <= longest[0]:
# already have a longer match than this one will deliver, we are done
return longest
try:
loc2, toks = expr1._parse(instring, loc, do_actions)
except ParseException as err:
err.__traceback__ = None
if err.loc > maxExcLoc:
maxException = err
maxExcLoc = err.loc
else:
if loc2 >= loc1:
return loc2, toks
# didn't match as much as before
elif loc2 > longest[0]:
longest = loc2, toks
if longest != (-1, None):
return longest
if fatals:
if len(fatals) > 1:
fatals.sort(key=lambda e: -e.loc)
if fatals[0].loc == fatals[1].loc:
fatals.sort(key=lambda e: (-e.loc, -len(str(e.parser_element))))
max_fatal = fatals[0]
raise max_fatal
if maxException is not None:
# infer from this check that all alternatives failed at the current position
# so emit this collective error message instead of any single error message
parse_start_loc = self.preParse(instring, loc)
if maxExcLoc == parse_start_loc:
maxException.msg = self.errmsg or ""
raise maxException
raise ParseException(instring, loc, "no defined alternatives to match", self)
def __ixor__(self, other):
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return self.append(other) # Or([self, other])
def _generateDefaultName(self) -> str:
return f"{{{' ^ '.join(str(e) for e in self.exprs)}}}"
def _setResultsName(self, name, list_all_matches=False) -> ParserElement:
if (
__diag__.warn_multiple_tokens_in_named_alternation
and Diagnostics.warn_multiple_tokens_in_named_alternation
not in self.suppress_warnings_
):
if any(
isinstance(e, And)
and Diagnostics.warn_multiple_tokens_in_named_alternation
not in e.suppress_warnings_
for e in self.exprs
):
warning = (
"warn_multiple_tokens_in_named_alternation:"
f" setting results name {name!r} on {type(self).__name__} expression"
" will return a list of all parsed tokens in an And alternative,"
" in prior versions only the first token was returned; enclose"
" contained argument in Group"
)
warnings.warn(warning, PyparsingDiagnosticWarning, stacklevel=3)
return super()._setResultsName(name, list_all_matches)
class MatchFirst(ParseExpression):
"""Requires that at least one :class:`ParserElement` is found. If
more than one expression matches, the first one listed is the one that will
match. May be constructed using the ``'|'`` operator.
Example: Construct MatchFirst using '|' operator
.. doctest::
# watch the order of expressions to match
>>> number = Word(nums) | Combine(Word(nums) + '.' + Word(nums))
>>> print(number.search_string("123 3.1416 789")) # Fail!
[['123'], ['3'], ['1416'], ['789']]
# put more selective expression first
>>> number = Combine(Word(nums) + '.' + Word(nums)) | Word(nums)
>>> print(number.search_string("123 3.1416 789")) # Better
[['123'], ['3.1416'], ['789']]
"""
def __init__(
self, exprs: typing.Iterable[ParserElement], savelist: bool = False
) -> None:
super().__init__(exprs, savelist)
if self.exprs:
self._may_return_empty = any(e.mayReturnEmpty for e in self.exprs)
self.skipWhitespace = all(e.skipWhitespace for e in self.exprs)
# only pre-skip whitespace here (so a parse action attached
# directly to this MatchFirst gets the whitespace-skipped loc)
# if every alternative would itself have pre-skipped it; when an
# alternative depends on seeing unskipped whitespace (e.g. a
# leading White()), leave preparse to that alternative instead
self.callPreparse = all(e.callPreparse for e in self.exprs)
else:
self._may_return_empty = True
def streamline(self) -> ParserElement:
if self.streamlined:
return self
super().streamline()
if self.exprs:
self.saveAsList = any(e.saveAsList for e in self.exprs)
self._may_return_empty = any(e.mayReturnEmpty for e in self.exprs)
self.skipWhitespace = all(
e.skipWhitespace and not isinstance(e, White) for e in self.exprs
)
else:
self.saveAsList = False
self._may_return_empty = True
return self
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
maxExcLoc = -1
maxException = None
for e in self.exprs:
try:
return e._parse(instring, loc, do_actions)
except ParseFatalException as pfe:
pfe.__traceback__ = None
pfe.parser_element = e
raise
except ParseException as err:
if err.loc > maxExcLoc:
maxException = err
maxExcLoc = err.loc
except IndexError:
if len(instring) > maxExcLoc:
maxException = ParseException(
instring, len(instring), e.errmsg, self
)
maxExcLoc = len(instring)
if maxException is not None:
# infer from this check that all alternatives failed at the current position
# so emit this collective error message instead of any individual error message
parse_start_loc = self.preParse(instring, loc)
if maxExcLoc == parse_start_loc:
maxException.msg = self.errmsg or ""
raise maxException
raise ParseException(instring, loc, "no defined alternatives to match", self)
def __ior__(self, other):
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return self.append(other) # MatchFirst([self, other])
def _generateDefaultName(self) -> str:
return f"{{{' | '.join(str(e) for e in self.exprs)}}}"
def _setResultsName(self, name, list_all_matches=False) -> ParserElement:
if (
__diag__.warn_multiple_tokens_in_named_alternation
and Diagnostics.warn_multiple_tokens_in_named_alternation
not in self.suppress_warnings_
):
if any(
isinstance(e, And)
and Diagnostics.warn_multiple_tokens_in_named_alternation
not in e.suppress_warnings_
for e in self.exprs
):
warning = (
"warn_multiple_tokens_in_named_alternation:"
f" setting results name {name!r} on {type(self).__name__} expression"
" will return a list of all parsed tokens in an And alternative,"
" in prior versions only the first token was returned; enclose"
" contained argument in Group"
)
warnings.warn(warning, PyparsingDiagnosticWarning, stacklevel=3)
return super()._setResultsName(name, list_all_matches)
class Each(ParseExpression):
"""Requires all given :class:`ParserElement` s to be found, but in
any order. Expressions may be separated by whitespace.
May be constructed using the ``'&'`` operator.
Example:
.. testcode::
color = one_of("RED ORANGE YELLOW GREEN BLUE PURPLE BLACK WHITE BROWN")
shape_type = one_of("SQUARE CIRCLE TRIANGLE STAR HEXAGON OCTAGON")
integer = Word(nums)
shape_attr = "shape:" + shape_type("shape")
posn_attr = "posn:" + Group(integer("x") + ',' + integer("y"))("posn")
color_attr = "color:" + color("color")
size_attr = "size:" + integer("size")
# use Each (using operator '&') to accept attributes in any order
# (shape and posn are required, color and size are optional)
shape_spec = shape_attr & posn_attr & Opt(color_attr) & Opt(size_attr)
shape_spec.run_tests('''
shape: SQUARE color: BLACK posn: 100, 120
shape: CIRCLE size: 50 color: BLUE posn: 50,80
color:GREEN size:20 shape:TRIANGLE posn:20,40
'''
)
prints:
.. testoutput::
:options: +NORMALIZE_WHITESPACE
shape: SQUARE color: BLACK posn: 100, 120
['shape:', 'SQUARE', 'color:', 'BLACK', 'posn:', ['100', ',', '120']]
- color: 'BLACK'
- posn: ['100', ',', '120']
- x: '100'
- y: '120'
- shape: 'SQUARE'
...
shape: CIRCLE size: 50 color: BLUE posn: 50,80
['shape:', 'CIRCLE', 'size:', '50', 'color:', 'BLUE',
'posn:', ['50', ',', '80']]
- color: 'BLUE'
- posn: ['50', ',', '80']
- x: '50'
- y: '80'
- shape: 'CIRCLE'
- size: '50'
...
color:GREEN size:20 shape:TRIANGLE posn:20,40
['color:', 'GREEN', 'size:', '20', 'shape:', 'TRIANGLE',
'posn:', ['20', ',', '40']]
- color: 'GREEN'
- posn: ['20', ',', '40']
- x: '20'
- y: '40'
- shape: 'TRIANGLE'
- size: '20'
...
"""
def __init__(
self, exprs: typing.Iterable[ParserElement], savelist: bool = True
) -> None:
super().__init__(exprs, savelist)
if self.exprs:
self._may_return_empty = all(e.mayReturnEmpty for e in self.exprs)
else:
self._may_return_empty = True
self.skipWhitespace = True
self.initExprGroups = True
self.saveAsList = True
def __iand__(self, other):
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
return self.append(other) # Each([self, other])
def streamline(self) -> ParserElement:
super().streamline()
if self.exprs:
self._may_return_empty = all(e.mayReturnEmpty for e in self.exprs)
else:
self._may_return_empty = True
return self
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if self.initExprGroups:
self.opt1map = dict(
(id(e.expr), e) for e in self.exprs if isinstance(e, Opt)
)
opt1 = [e.expr for e in self.exprs if isinstance(e, Opt)]
opt2 = [
e
for e in self.exprs
if e.mayReturnEmpty and not isinstance(e, (Opt, Regex, ZeroOrMore))
]
self.optionals = opt1 + opt2
self.multioptionals = [
e.expr.set_results_name(e.resultsName, list_all_matches=True)
for e in self.exprs
if isinstance(e, _MultipleMatch)
]
self.multirequired = [
e.expr.set_results_name(e.resultsName, list_all_matches=True)
for e in self.exprs
if isinstance(e, OneOrMore)
]
self.required = [
e for e in self.exprs if not isinstance(e, (Opt, ZeroOrMore, OneOrMore))
]
self.required += self.multirequired
self.initExprGroups = False
tmpLoc = loc
tmpReqd = self.required[:]
tmpOpt = self.optionals[:]
multis = self.multioptionals[:]
matchOrder: list[ParserElement] = []
keepMatching = True
failed: list[ParserElement] = []
fatals: list[ParseFatalException] = []
while keepMatching:
tmpExprs = tmpReqd + tmpOpt + multis
failed.clear()
fatals.clear()
for e in tmpExprs:
try:
tmpLoc = e.try_parse(instring, tmpLoc, raise_fatal=True)
except ParseFatalException as pfe:
pfe.__traceback__ = None
pfe.parser_element = e
fatals.append(pfe)
failed.append(e)
except ParseException:
failed.append(e)
else:
matchOrder.append(self.opt1map.get(id(e), e))
if e in tmpReqd:
tmpReqd.remove(e)
elif e in tmpOpt:
tmpOpt.remove(e)
if len(failed) == len(tmpExprs):
keepMatching = False
# look for any ParseFatalExceptions
if fatals:
if len(fatals) > 1:
fatals.sort(key=lambda e: -e.loc)
if fatals[0].loc == fatals[1].loc:
fatals.sort(key=lambda e: (-e.loc, -len(str(e.parser_element))))
max_fatal = fatals[0]
raise max_fatal
if tmpReqd:
missing = ", ".join([str(e) for e in tmpReqd])
raise ParseException(
instring,
loc,
f"Missing one or more required elements ({missing})",
)
# add any unmatched Opts, in case they have default values defined
matchOrder += [e for e in self.exprs if isinstance(e, Opt) and e.expr in tmpOpt]
total_results = ParseResults([])
for e in matchOrder:
loc, results = e._parse(instring, loc, do_actions)
total_results += results
return loc, total_results
def _generateDefaultName(self) -> str:
return f"{{{' & '.join(str(e) for e in self.exprs)}}}"
class ParseElementEnhance(ParserElement):
"""Abstract subclass of :class:`ParserElement`, for combining and
post-processing parsed tokens.
"""
def __init__(self, expr: Union[ParserElement, str], savelist: bool = False) -> None:
super().__init__(savelist)
if isinstance(expr, str_type):
expr_str = typing.cast(str, expr)
if issubclass(self._literalStringClass, Token):
expr = self._literalStringClass(expr_str) # type: ignore[call-arg]
elif issubclass(type(self), self._literalStringClass):
expr = Literal(expr_str)
else:
expr = self._literalStringClass(Literal(expr_str)) # type: ignore[assignment, call-arg]
expr = typing.cast(ParserElement, expr)
self.expr = expr
if expr is not None:
self.mayIndexError = expr.mayIndexError
self._may_return_empty = expr.mayReturnEmpty
self.set_whitespace_chars(
expr.whiteChars, copy_defaults=expr.copyDefaultWhiteChars
)
self.skipWhitespace = expr.skipWhitespace
self.saveAsList = expr.saveAsList
self.callPreparse = expr.callPreparse
self.ignoreExprs.extend(expr.ignoreExprs)
def recurse(self) -> list[ParserElement]:
return [self.expr] if self.expr is not None else []
def parseImpl(self, instring, loc, do_actions=True):
if self.expr is None:
raise ParseException(instring, loc, "No expression defined", self)
try:
return self.expr._parse(instring, loc, do_actions, callPreParse=False)
except ParseSyntaxException:
raise
except ParseBaseException as pbe:
pbe.pstr = pbe.pstr or instring
pbe.loc = pbe.loc or loc
pbe.parser_element = pbe.parser_element or self
if not isinstance(self, Forward) and self.customName is not None:
if self.errmsg:
pbe.msg = self.errmsg
raise
def leave_whitespace(self, recursive: bool = True) -> ParserElement:
"""
Extends ``leave_whitespace`` defined in base class, and also invokes ``leave_whitespace`` on
the contained expression.
"""
super().leave_whitespace(recursive)
if recursive:
if self.expr is not None:
self.expr = self.expr.copy()
self.expr.leave_whitespace(recursive)
return self
def ignore_whitespace(self, recursive: bool = True) -> ParserElement:
"""
Extends ``ignore_whitespace`` defined in base class, and also invokes ``ignore_whitespace`` on
the contained expression.
"""
super().ignore_whitespace(recursive)
if recursive:
if self.expr is not None:
self.expr = self.expr.copy()
self.expr.ignore_whitespace(recursive)
return self
def ignore(self, other) -> ParserElement:
"""
Define expression to be ignored (e.g., comments) while doing pattern
matching; may be called repeatedly, to define multiple comment or other
ignorable patterns.
"""
if not isinstance(other, Suppress) or other not in self.ignoreExprs:
super().ignore(other)
if self.expr is not None:
self.expr.ignore(self.ignoreExprs[-1])
return self
def streamline(self) -> ParserElement:
super().streamline()
if self.expr is not None:
self.expr.streamline()
return self
def _checkRecursion(self, parseElementList):
if self in parseElementList:
raise RecursiveGrammarException(parseElementList + [self])
subRecCheckList = parseElementList[:] + [self]
if self.expr is not None:
self.expr._checkRecursion(subRecCheckList)
def validate(self, validateTrace=None) -> None:
warnings.warn(
"ParserElement.validate() is deprecated, and should not be used to check for left recursion",
PyparsingDeprecationWarning,
stacklevel=2,
)
if validateTrace is None:
validateTrace = []
tmp = validateTrace[:] + [self]
if self.expr is not None:
self.expr.validate(tmp)
self._checkRecursion([])
def _generateDefaultName(self) -> str:
return f"{type(self).__name__}:({self.expr})"
# Compatibility synonyms
# fmt: off
leaveWhitespace = replaced_by_pep8("leaveWhitespace", leave_whitespace)
ignoreWhitespace = replaced_by_pep8("ignoreWhitespace", ignore_whitespace)
# fmt: on
class IndentedBlock(ParseElementEnhance):
"""
Expression to match one or more expressions at a given indentation level.
Useful for parsing text where structure is implied by indentation (like Python source code).
Example:
.. testcode::
'''
BNF:
statement ::= assignment_stmt | if_stmt
assignment_stmt ::= identifier '=' rvalue
rvalue ::= identifier | integer
if_stmt ::= 'if' bool_condition block
block ::= ([indent] statement)...
identifier ::= [A..Za..z]
integer ::= [0..9]...
bool_condition ::= 'TRUE' | 'FALSE'
'''
IF, TRUE, FALSE = Keyword.using_each("IF TRUE FALSE".split())
statement = Forward()
identifier = Char(alphas)
integer = Word(nums).add_parse_action(lambda t: int(t[0]))
rvalue = identifier | integer
assignment_stmt = identifier + "=" + rvalue
if_stmt = IF + (TRUE | FALSE) + IndentedBlock(statement)
statement <<= Group(assignment_stmt | if_stmt)
result = if_stmt.parse_string('''
IF TRUE
a = 1000
b = 2000
IF FALSE
z = 100
''')
print(result.dump())
.. testoutput::
['IF', 'TRUE', [['a', '=', 1000], ['b', '=', 2000], ['IF', 'FALSE', [['z', '=', 100]]]]]
[0]:
IF
[1]:
TRUE
[2]:
[['a', '=', 1000], ['b', '=', 2000], ['IF', 'FALSE', [['z', '=', 100]]]]
[0]:
['a', '=', 1000]
[1]:
['b', '=', 2000]
[2]:
['IF', 'FALSE', [['z', '=', 100]]]
[0]:
IF
[1]:
FALSE
[2]:
[['z', '=', 100]]
[0]:
['z', '=', 100]
"""
class _Indent(Empty):
def __init__(self, ref_col: int) -> None:
super().__init__()
self.errmsg = f"expected indent at column {ref_col}"
self.add_condition(lambda s, l, t: col(l, s) == ref_col)
class _IndentGreater(Empty):
def __init__(self, ref_col: int) -> None:
super().__init__()
self.errmsg = f"expected indent at column greater than {ref_col}"
self.add_condition(lambda s, l, t: col(l, s) > ref_col)
def __init__(
self, expr: ParserElement, *, recursive: bool = False, grouped: bool = True
) -> None:
super().__init__(expr, savelist=True)
# if recursive:
# raise NotImplementedError("IndentedBlock with recursive is not implemented")
self._recursive = recursive
self._grouped = grouped
self.parent_anchor = 1
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
# advance parse position to non-whitespace by using an Empty()
# this should be the column to be used for all subsequent indented lines
anchor_loc = Empty().preParse(instring, loc)
# see if self.expr matches at the current location - if not it will raise an exception
# and no further work is necessary
self.expr.try_parse(instring, anchor_loc, do_actions=do_actions)
indent_col = col(anchor_loc, instring)
peer_detect_expr = self._Indent(indent_col)
inner_expr = Empty() + peer_detect_expr + self.expr
if self._recursive:
sub_indent = self._IndentGreater(indent_col)
nested_block = IndentedBlock(
self.expr, recursive=self._recursive, grouped=self._grouped
)
nested_block.set_debug(self.debug)
nested_block.parent_anchor = indent_col
inner_expr += Opt(sub_indent + nested_block)
inner_expr.set_name(f"inner {hex(id(inner_expr))[-4:].upper()}@{indent_col}")
block = OneOrMore(inner_expr)
trailing_undent = self._Indent(self.parent_anchor) | StringEnd()
if self._grouped:
wrapper = Group
else:
wrapper = lambda expr: expr # type: ignore[misc, assignment]
return (wrapper(block) + Optional(trailing_undent)).parseImpl(
instring, anchor_loc, do_actions
)
class AtStringStart(ParseElementEnhance):
"""Matches if expression matches at the beginning of the parse
string::
AtStringStart(Word(nums)).parse_string("123")
# prints ["123"]
AtStringStart(Word(nums)).parse_string(" 123")
# raises ParseException
"""
def __init__(self, expr: Union[ParserElement, str]) -> None:
super().__init__(expr)
self.callPreparse = False
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if loc != 0:
raise ParseException(instring, loc, "not found at string start")
return super().parseImpl(instring, loc, do_actions)
class AtLineStart(ParseElementEnhance):
r"""Matches if an expression matches at the beginning of a line within
the parse string
Example:
.. testcode::
test = '''\
BBB this line
BBB and this line
BBB but not this one
A BBB and definitely not this one
'''
for t in (AtLineStart('BBB') + rest_of_line).search_string(test):
print(t)
prints:
.. testoutput::
['BBB', ' this line']
['BBB', ' and this line']
"""
def __init__(self, expr: Union[ParserElement, str]) -> None:
super().__init__(expr)
self.callPreparse = False
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if col(loc, instring) != 1:
raise ParseException(instring, loc, "not found at line start")
return super().parseImpl(instring, loc, do_actions)
class FollowedBy(ParseElementEnhance):
"""Lookahead matching of the given parse expression.
``FollowedBy`` does *not* advance the parsing position within
the input string, it only verifies that the specified parse
expression matches at the current position. ``FollowedBy``
always returns a null token list. If any results names are defined
in the lookahead expression, those *will* be returned for access by
name.
Example:
.. testcode::
# use FollowedBy to match a label only if it is followed by a ':'
data_word = Word(alphas)
label = data_word + FollowedBy(':')
attr_expr = Group(
label + Suppress(':')
+ OneOrMore(data_word, stop_on=label).set_parse_action(' '.join)
)
attr_expr[1, ...].parse_string(
"shape: SQUARE color: BLACK posn: upper left").pprint()
prints:
.. testoutput::
[['shape', 'SQUARE'], ['color', 'BLACK'], ['posn', 'upper left']]
"""
def __init__(self, expr: Union[ParserElement, str]) -> None:
super().__init__(expr)
self._may_return_empty = True
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
# by using self._expr.parse and deleting the contents of the returned ParseResults list
# we keep any named results that were defined in the FollowedBy expression
_, ret = self.expr._parse(instring, loc, do_actions=do_actions)
del ret[:]
return loc, ret
class PrecededBy(ParseElementEnhance):
"""Lookbehind matching of the given parse expression.
``PrecededBy`` does not advance the parsing position within the
input string, it only verifies that the specified parse expression
matches prior to the current position. ``PrecededBy`` always
returns a null token list, but if a results name is defined on the
given expression, it is returned.
Parameters:
- ``expr`` - expression that must match prior to the current parse
location
- ``retreat`` - (default= ``None``) - (int) maximum number of characters
to lookbehind prior to the current parse location
If the lookbehind expression is a string, :class:`Literal`,
:class:`Keyword`, or a :class:`Word` or :class:`CharsNotIn`
with a specified exact or maximum length, then the retreat
parameter is not required. Otherwise, retreat must be specified to
give a maximum number of characters to look back from
the current parse position for a lookbehind match.
Example:
.. testcode::
# VB-style variable names with type prefixes
int_var = PrecededBy("#") + pyparsing_common.identifier
str_var = PrecededBy("$") + pyparsing_common.identifier
"""
def __init__(self, expr: Union[ParserElement, str], retreat: int = 0) -> None:
super().__init__(expr)
self.expr = self.expr().leave_whitespace()
self._may_return_empty = True
self.mayIndexError = False
self.exact = False
if isinstance(expr, str_type):
expr = typing.cast(str, expr)
retreat = len(expr)
self.exact = True
elif isinstance(expr, (Literal, Keyword)):
retreat = expr.matchLen
self.exact = True
elif isinstance(expr, (Word, CharsNotIn)) and expr.maxLen != _MAX_INT:
retreat = expr.maxLen
self.exact = True
elif isinstance(expr, PositionToken):
retreat = 0
self.exact = True
self.retreat = retreat
self.errmsg = f"not preceded by {expr}"
self.skipWhitespace = False
self.parseAction.append(lambda s, l, t: t.__delitem__(slice(None, None)))
def parseImpl(self, instring, loc=0, do_actions=True) -> ParseImplReturnType:
if self.exact:
if loc < self.retreat:
raise ParseException(instring, loc, self.errmsg, self)
start = loc - self.retreat
_, ret = self.expr._parse(instring, start)
return loc, ret
# retreat specified a maximum lookbehind window, iterate
test_expr = self.expr + StringEnd()
instring_slice = instring[max(0, loc - self.retreat) : loc]
last_expr: ParseBaseException = ParseException(instring, loc, self.errmsg, self)
for offset in range(1, min(loc, self.retreat + 1) + 1):
try:
# print('trying', offset, instring_slice, repr(instring_slice[loc - offset:]))
_, ret = test_expr._parse(instring_slice, len(instring_slice) - offset)
except ParseBaseException as pbe:
last_expr = pbe
else:
break
else:
raise last_expr
return loc, ret
class Located(ParseElementEnhance):
"""
Decorates a returned token with its starting and ending
locations in the input string.
This helper adds the following results names:
- ``locn_start`` - location where matched expression begins
- ``locn_end`` - location where matched expression ends
- ``value`` - the actual parsed results
Be careful if the input text contains ``<TAB>`` characters, you
may want to call :class:`ParserElement.parse_with_tabs`
Example:
.. testcode::
wd = Word(alphas)
for match in Located(wd).search_string("ljsdf123lksdjjf123lkkjj1222"):
print(match)
prints:
.. testoutput::
[0, ['ljsdf'], 5]
[8, ['lksdjjf'], 15]
[18, ['lkkjj'], 23]
"""
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
# skip leading whitespace before capturing the start location, so
# locn_start marks the start of the match and not preceding whitespace,
# even when the wrapped expression delegates whitespace skipping to its
# sub-expressions (e.g. And/MatchFirst). Issue #621.
start = self.expr.preParse(instring, loc)
loc, tokens = self.expr._parse(instring, start, do_actions, callPreParse=False)
ret_tokens = ParseResults([start, tokens, loc])
ret_tokens["locn_start"] = start
ret_tokens["value"] = tokens
ret_tokens["locn_end"] = loc
if self.resultsName:
# must return as a list, so that the name will be attached to the complete group
return loc, [ret_tokens]
else:
return loc, ret_tokens
class NotAny(ParseElementEnhance):
"""
Lookahead to disallow matching with the given parse expression.
``NotAny`` does *not* advance the parsing position within the
input string, it only verifies that the specified parse expression
does *not* match at the current position. Also, ``NotAny`` does
*not* skip over leading whitespace. ``NotAny`` always returns
a null token list. May be constructed using the ``'~'`` operator.
Example:
.. testcode::
AND, OR, NOT = map(CaselessKeyword, "AND OR NOT".split())
# take care not to mistake keywords for identifiers
ident = ~(AND | OR | NOT) + Word(alphas)
boolean_term = Opt(NOT) + ident
# very crude boolean expression - to support parenthesis groups and
# operation hierarchy, use infix_notation
boolean_expr = boolean_term + ((AND | OR) + boolean_term)[...]
# integers that are followed by "." are actually floats
integer = Word(nums) + ~Char(".")
"""
def __init__(self, expr: Union[ParserElement, str]) -> None:
super().__init__(expr)
# do NOT use self.leave_whitespace(), don't want to propagate to exprs
# self.leave_whitespace()
self.skipWhitespace = False
self._may_return_empty = True
self.errmsg = f"Found unwanted token, {self.expr}"
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if self.expr.can_parse_next(instring, loc, do_actions=do_actions):
raise ParseException(instring, loc, self.errmsg, self)
return loc, []
def _generateDefaultName(self) -> str:
return f"~{{{self.expr}}}"
class _MultipleMatch(ParseElementEnhance):
def __init__(
self,
expr: Union[str, ParserElement],
stop_on: typing.Optional[Union[ParserElement, str]] = None,
max: typing.Optional[int] = None,
**kwargs,
) -> None:
stopOn: typing.Optional[Union[ParserElement, str]] = deprecate_argument(
kwargs, "stopOn", None
)
super().__init__(expr)
if max is not None and max <= 0:
raise ValueError("max must be greater than 0")
stopOn = stopOn or stop_on
self.saveAsList = True
self.max_count = max
ender = stopOn
if isinstance(ender, str_type):
ender = self._literalStringClass(ender)
self.stopOn(ender)
def stop_on(self, ender) -> ParserElement:
if isinstance(ender, str_type):
ender = self._literalStringClass(ender)
self.not_ender = ~ender if ender is not None else None
return self
stopOn = stop_on
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
self_expr_parse = self.expr._parse
self_skip_ignorables = self._skipIgnorables
check_ender = False
if self.not_ender is not None:
try_not_ender = self.not_ender.try_parse
check_ender = True
# must be at least one (but first see if we are the stopOn sentinel;
# if so, fail)
if check_ender:
try_not_ender(instring, loc)
loc, tokens = self_expr_parse(instring, loc, do_actions)
match_count = 1
try:
hasIgnoreExprs = not not self.ignoreExprs
while self.max_count is None or match_count < self.max_count:
if check_ender:
try_not_ender(instring, loc)
if hasIgnoreExprs:
preloc = self_skip_ignorables(instring, loc)
else:
preloc = loc
loc, tmptokens = self_expr_parse(instring, preloc, do_actions)
tokens += tmptokens
match_count += 1
except (ParseException, IndexError):
pass
return loc, tokens
def _setResultsName(self, name, list_all_matches=False) -> ParserElement:
if (
__diag__.warn_ungrouped_named_tokens_in_collection
and Diagnostics.warn_ungrouped_named_tokens_in_collection
not in self.suppress_warnings_
):
for e in [self.expr] + self.expr.recurse():
if (
isinstance(e, ParserElement)
and e.resultsName
and (
Diagnostics.warn_ungrouped_named_tokens_in_collection
not in e.suppress_warnings_
)
):
warning = (
"warn_ungrouped_named_tokens_in_collection:"
f" setting results name {name!r} on {type(self).__name__} expression"
f" collides with {e.resultsName!r} on contained expression"
)
warnings.warn(warning, PyparsingDiagnosticWarning, stacklevel=3)
break
return super()._setResultsName(name, list_all_matches)
class OneOrMore(_MultipleMatch):
"""
Repetition of one or more of the given expression.
Parameters:
- ``expr`` - expression that must match one or more times
- ``stop_on`` - (default= ``None``) - expression for a terminating sentinel
(only required if the sentinel would ordinarily match the repetition
expression)
Example:
.. doctest::
>>> data_word = Word(alphas)
>>> label = data_word + FollowedBy(':')
>>> attr_expr = Group(
... label + Suppress(':')
... + OneOrMore(data_word).set_parse_action(' '.join))
>>> text = "shape: SQUARE posn: upper left color: BLACK"
# Fail! read 'posn' as data instead of next label
>>> attr_expr[1, ...].parse_string(text).pprint()
[['shape', 'SQUARE posn']]
# use stop_on attribute for OneOrMore
# to avoid reading label string as part of the data
>>> attr_expr = Group(
... label + Suppress(':')
... + OneOrMore(
... data_word, stop_on=label).set_parse_action(' '.join))
>>> OneOrMore(attr_expr).parse_string(text).pprint() # Better
[['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'BLACK']]
# could also be written as
>>> (attr_expr * (1,)).parse_string(text).pprint()
[['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'BLACK']]
"""
def _generateDefaultName(self) -> str:
return f"{{{self.expr}}}..."
class ZeroOrMore(_MultipleMatch):
"""
Optional repetition of zero or more of the given expression.
Parameters:
- ``expr`` - expression that must match zero or more times
- ``stop_on`` - expression for a terminating sentinel
(only required if the sentinel would ordinarily match the repetition
expression) - (default= ``None``)
Example: similar to :class:`OneOrMore`
"""
def __init__(
self,
expr: Union[str, ParserElement],
stop_on: typing.Optional[Union[ParserElement, str]] = None,
max: typing.Optional[int] = None,
**kwargs,
) -> None:
stopOn: Union[ParserElement, str] = deprecate_argument(kwargs, "stopOn", None)
super().__init__(expr, stop_on=stopOn or stop_on, max=max)
self._may_return_empty = True
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
try:
return super().parseImpl(instring, loc, do_actions)
except (ParseException, IndexError):
return loc, ParseResults([], name=self.resultsName)
def _generateDefaultName(self) -> str:
return f"[{self.expr}]..."
class DelimitedList(ParseElementEnhance):
"""Helper to define a delimited list of expressions - the delimiter
defaults to ','. By default, the list elements and delimiters can
have intervening whitespace, and comments, but this can be
overridden by passing ``combine=True`` in the constructor. If
``combine`` is set to ``True``, the matching tokens are
returned as a single token string, with the delimiters included;
otherwise, the matching tokens are returned as a list of tokens,
with the delimiters suppressed.
If ``allow_trailing_delim`` is set to True, then the list may end with
a delimiter.
Example:
.. doctest::
>>> DelimitedList(Word(alphas)).parse_string("aa,bb,cc")
ParseResults(['aa', 'bb', 'cc'], {})
>>> DelimitedList(Word(hexnums), delim=':', combine=True
... ).parse_string("AA:BB:CC:DD:EE")
ParseResults(['AA:BB:CC:DD:EE'], {})
.. versionadded:: 3.1.0
"""
def __init__(
self,
expr: Union[str, ParserElement],
delim: Union[str, ParserElement] = ",",
combine: bool = False,
min: typing.Optional[int] = None,
max: typing.Optional[int] = None,
*,
allow_trailing_delim: bool = False,
) -> None:
if isinstance(expr, str_type):
expr = ParserElement._literalStringClass(expr)
expr = typing.cast(ParserElement, expr)
if min is not None and min < 1:
raise ValueError("min must be greater than 0")
if max is not None and min is not None and max < min:
raise ValueError("max must be greater than, or equal to min")
self.content = expr
self.raw_delim = str(delim)
self.delim = delim
self.combine = combine
if not combine:
self.delim = Suppress(delim) if not isinstance(delim, Suppress) else delim
self.min = min or 1
self.max = max
self.allow_trailing_delim = allow_trailing_delim
delim_list_expr = self.content + (self.delim + self.content) * (
self.min - 1,
None if self.max is None else self.max - 1,
)
if self.allow_trailing_delim:
delim_list_expr += Opt(self.delim)
if self.combine:
delim_list_expr = Combine(delim_list_expr)
super().__init__(delim_list_expr, savelist=True)
def _generateDefaultName(self) -> str:
content_expr = self.content.streamline()
return f"{content_expr} [{self.raw_delim} {content_expr}]..."
class _NullToken:
def __bool__(self):
return False
def __str__(self):
return ""
class Opt(ParseElementEnhance):
"""
Optional matching of the given expression.
:param expr: expression that must match zero or more times
:param default: (optional) - value to be returned
if the optional expression is not found.
Example:
.. testcode::
# US postal code can be a 5-digit zip, plus optional 4-digit qualifier
zip = Combine(Word(nums, exact=5) + Opt('-' + Word(nums, exact=4)))
zip.run_tests('''
# traditional ZIP code
12345
# ZIP+4 form
12101-0001
# invalid ZIP
98765-
''')
prints:
.. testoutput::
:options: +NORMALIZE_WHITESPACE
# traditional ZIP code
12345
['12345']
# ZIP+4 form
12101-0001
['12101-0001']
# invalid ZIP
98765-
98765-
^
ParseException: Expected end of text, found '-' (at char 5), (line:1, col:6)
FAIL: Expected end of text, found '-' (at char 5), (line:1, col:6)
"""
__optionalNotMatched = _NullToken()
def __init__(
self, expr: Union[ParserElement, str], default: Any = __optionalNotMatched
) -> None:
super().__init__(expr, savelist=False)
self.saveAsList = self.expr.saveAsList
self.defaultValue = default
self._may_return_empty = True
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
self_expr = self.expr
try:
loc, tokens = self_expr._parse(
instring, loc, do_actions, callPreParse=False
)
except (ParseException, IndexError):
default_value = self.defaultValue
if default_value is not self.__optionalNotMatched:
if self_expr.resultsName:
tokens = ParseResults([default_value])
tokens[self_expr.resultsName] = default_value
else:
tokens = [default_value] # type: ignore[assignment]
else:
tokens = [] # type: ignore[assignment]
return loc, tokens
def _generateDefaultName(self) -> str:
inner = str(self.expr)
# strip off redundant inner {}'s
while len(inner) > 1 and inner[0 :: len(inner) - 1] == "{}":
inner = inner[1:-1]
return f"[{inner}]"
Optional = Opt
class SkipTo(ParseElementEnhance):
"""
Token for skipping over all undefined text until the matched
expression is found.
:param expr: target expression marking the end of the data to be skipped
:param include: if ``True``, the target expression is also parsed
(the skipped text and target expression are returned
as a 2-element list) (default= ``False``).
:param ignore: (default= ``None``) used to define grammars
(typically quoted strings and comments)
that might contain false matches to the target expression
:param fail_on: (default= ``None``) define expressions that
are not allowed to be included in the skipped test;
if found before the target expression is found,
the :class:`SkipTo` is not a match
Example:
.. testcode::
report = '''
Outstanding Issues Report - 1 Jan 2000
# | Severity | Description | Days Open
-----+----------+-------------------------------------------+-----------
101 | Critical | Intermittent system crash | 6
94 | Cosmetic | Spelling error on Login ('log|n') | 14
79 | Minor | System slow when running too many reports | 47
'''
integer = Word(nums)
SEP = Suppress('|')
# use SkipTo to simply match everything up until the next SEP
# - ignore quoted strings, so that a '|' character inside a quoted string does not match
# - parse action will call token.strip() for each matched token, i.e., the description body
string_data = SkipTo(SEP, ignore=quoted_string)
string_data.set_parse_action(token_map(str.strip))
ticket_expr = (integer("issue_num") + SEP
+ string_data("sev") + SEP
+ string_data("desc") + SEP
+ integer("days_open"))
for tkt in ticket_expr.search_string(report):
print(tkt.dump())
prints:
.. testoutput::
['101', 'Critical', 'Intermittent system crash', '6']
- days_open: '6'
- desc: 'Intermittent system crash'
- issue_num: '101'
- sev: 'Critical'
['94', 'Cosmetic', "Spelling error on Login ('log|n')", '14']
- days_open: '14'
- desc: "Spelling error on Login ('log|n')"
- issue_num: '94'
- sev: 'Cosmetic'
['79', 'Minor', 'System slow when running too many reports', '47']
- days_open: '47'
- desc: 'System slow when running too many reports'
- issue_num: '79'
- sev: 'Minor'
"""
def __init__(
self,
other: Union[ParserElement, str],
include: bool = False,
ignore: typing.Optional[Union[ParserElement, str]] = None,
fail_on: typing.Optional[Union[ParserElement, str]] = None,
**kwargs,
) -> None:
failOn: typing.Optional[Union[ParserElement, str]] = deprecate_argument(
kwargs, "failOn", None
)
super().__init__(other)
failOn = failOn or fail_on
self.ignoreExpr = ignore
self._may_return_empty = True
self.mayIndexError = False
self.includeMatch = include
self.saveAsList = False
if isinstance(failOn, str_type):
self.failOn = self._literalStringClass(failOn)
else:
self.failOn = failOn
self.errmsg = f"No match found for {self.expr}"
self.ignorer = Empty().leave_whitespace()
self._update_ignorer()
def _update_ignorer(self):
# rebuild internal ignore expr from current ignore exprs and assigned ignoreExpr
self.ignorer.ignoreExprs.clear()
for e in self.expr.ignoreExprs:
self.ignorer.ignore(e)
if self.ignoreExpr:
self.ignorer.ignore(self.ignoreExpr)
def ignore(self, expr):
"""
Define expression to be ignored (e.g., comments) while doing pattern
matching; may be called repeatedly, to define multiple comment or other
ignorable patterns.
"""
super().ignore(expr)
self._update_ignorer()
def parseImpl(self, instring, loc, do_actions=True):
startloc = loc
instrlen = len(instring)
self_expr_parse = self.expr._parse
self_failOn_canParseNext = (
self.failOn.can_parse_next if self.failOn is not None else None
)
ignorer_try_parse = self.ignorer.try_parse if self.ignorer.ignoreExprs else None
tmploc = loc
while tmploc <= instrlen:
if self_failOn_canParseNext is not None:
# break if failOn expression matches
if self_failOn_canParseNext(instring, tmploc):
break
if ignorer_try_parse is not None:
# advance past ignore expressions
prev_tmploc = tmploc
while 1:
try:
tmploc = ignorer_try_parse(instring, tmploc)
except ParseBaseException:
break
# see if all ignorers matched, but didn't actually ignore anything
if tmploc == prev_tmploc:
break
prev_tmploc = tmploc
try:
self_expr_parse(instring, tmploc, do_actions=False, callPreParse=False)
except (ParseException, IndexError):
# no match, advance loc in string
tmploc += 1
else:
# matched skipto expr, done
break
else:
# ran off the end of the input string without matching skipto expr, fail
raise ParseException(instring, loc, self.errmsg, self)
# build up return values
loc = tmploc
skiptext = instring[startloc:loc]
skipresult = ParseResults(skiptext)
if self.includeMatch:
loc, mat = self_expr_parse(instring, loc, do_actions, callPreParse=False)
skipresult += mat
return loc, skipresult
class Forward(ParseElementEnhance):
"""
Forward declaration of an expression to be defined later -
used for recursive grammars, such as algebraic infix notation.
When the expression is known, it is assigned to the ``Forward``
instance using the ``'<<'`` operator.
.. Note::
Take care when assigning to ``Forward`` not to overlook
precedence of operators.
Specifically, ``'|'`` has a lower precedence than ``'<<'``, so that::
fwd_expr << a | b | c
will actually be evaluated as::
(fwd_expr << a) | b | c
thereby leaving b and c out as parseable alternatives.
It is recommended that you explicitly group the values
inserted into the :class:`Forward`::
fwd_expr << (a | b | c)
Converting to use the ``'<<='`` operator instead will avoid this problem.
See :meth:`ParseResults.pprint` for an example of a recursive
parser created using :class:`Forward`.
"""
def __init__(
self, other: typing.Optional[Union[ParserElement, str]] = None
) -> None:
self.caller_frame = traceback.extract_stack(limit=2)[0]
super().__init__(other, savelist=False) # type: ignore[arg-type]
self.lshift_line = None
def __lshift__(self, other) -> Forward:
if hasattr(self, "caller_frame"):
del self.caller_frame
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
return NotImplemented
self.expr = other
self.streamlined = other.streamlined
self.mayIndexError = self.expr.mayIndexError
self._may_return_empty = self.expr.mayReturnEmpty
self.set_whitespace_chars(
self.expr.whiteChars, copy_defaults=self.expr.copyDefaultWhiteChars
)
self.skipWhitespace = self.expr.skipWhitespace
self.saveAsList = self.expr.saveAsList
self.ignoreExprs.extend(self.expr.ignoreExprs)
self.lshift_line = traceback.extract_stack(limit=2)[-2] # type: ignore[assignment]
return self
def __ilshift__(self, other) -> Forward:
if not isinstance(other, ParserElement):
return NotImplemented
return self << other
def __or__(self, other) -> ParserElement:
caller_line = traceback.extract_stack(limit=2)[-2]
if (
__diag__.warn_on_match_first_with_lshift_operator
and caller_line == self.lshift_line
and Diagnostics.warn_on_match_first_with_lshift_operator
not in self.suppress_warnings_
):
warnings.warn(
"warn_on_match_first_with_lshift_operator:"
" using '<<' operator with '|' is probably an error, use '<<='",
PyparsingDiagnosticWarning,
stacklevel=2,
)
ret = super().__or__(other)
return ret
def __del__(self):
# see if we are getting dropped because of '=' reassignment of var instead of '<<=' or '<<'
if (
self.expr is None
and __diag__.warn_on_assignment_to_Forward
and Diagnostics.warn_on_assignment_to_Forward not in self.suppress_warnings_
):
warnings.warn_explicit(
"warn_on_assignment_to_Forward:"
" Forward defined here but no expression attached later using '<<=' or '<<'",
UserWarning,
filename=self.caller_frame.filename,
lineno=self.caller_frame.lineno,
)
def parseImpl(self, instring, loc, do_actions=True) -> ParseImplReturnType:
if (
self.expr is None
and __diag__.warn_on_parse_using_empty_Forward
and Diagnostics.warn_on_parse_using_empty_Forward
not in self.suppress_warnings_
):
# walk stack until parse_string, scan_string, search_string, or transform_string is found
parse_fns = (
"parse_string",
"scan_string",
"search_string",
"transform_string",
)
tb = traceback.extract_stack(limit=200)
for i, frm in enumerate(reversed(tb), start=1):
if frm.name in parse_fns:
stacklevel = i + 1
break
else:
stacklevel = 2
warnings.warn(
"warn_on_parse_using_empty_Forward:"
" Forward expression was never assigned a value, will not parse any input",
PyparsingDiagnosticWarning,
stacklevel=stacklevel,
)
if not ParserElement._left_recursion_enabled:
return super().parseImpl(instring, loc, do_actions)
# ## Bounded Recursion algorithm ##
# Recursion only needs to be processed at ``Forward`` elements, since they are
# the only ones that can actually refer to themselves. The general idea is
# to handle recursion stepwise: We start at no recursion, then recurse once,
# recurse twice, ..., until more recursion offers no benefit (we hit the bound).
#
# The "trick" here is that each ``Forward`` gets evaluated in two contexts
# - to *match* a specific recursion level, and
# - to *search* the bounded recursion level
# and the two run concurrently. The *search* must *match* each recursion level
# to find the best possible match. This is handled by a memo table, which
# provides the previous match to the next level match attempt.
#
# See also "Left Recursion in Parsing Expression Grammars", Medeiros et al.
#
# There is a complication since we not only *parse* but also *transform* via
# actions: We do not want to run the actions too often while expanding. Thus,
# we expand using `do_actions=False` and only run `do_actions=True` if the next
# recursion level is acceptable.
with ParserElement.recursion_lock:
memo = ParserElement.recursion_memos
try:
# we are parsing at a specific recursion expansion - use it as-is
prev_loc, prev_result = memo[loc, self, do_actions]
if isinstance(prev_result, Exception):
raise prev_result
return prev_loc, prev_result.copy()
except KeyError:
act_key = (loc, self, True)
peek_key = (loc, self, False)
# we are searching for the best recursion expansion - keep on improving
# both `do_actions` cases must be tracked separately here!
prev_loc, prev_peek = memo[peek_key] = (
loc - 1,
ParseException(
instring, loc, "Forward recursion without base case", self
),
)
if do_actions:
memo[act_key] = memo[peek_key]
while True:
try:
new_loc, new_peek = super().parseImpl(instring, loc, False)
except ParseException:
# we failed before getting any match - do not hide the error
if isinstance(prev_peek, Exception):
raise
new_loc, new_peek = prev_loc, prev_peek
# the match did not get better: we are done
if new_loc <= prev_loc:
if do_actions:
# replace the match for do_actions=False as well,
# in case the action did backtrack
prev_loc, prev_result = memo[peek_key] = memo[act_key]
del memo[peek_key], memo[act_key]
return prev_loc, copy.copy(prev_result)
del memo[peek_key]
return prev_loc, copy.copy(prev_peek)
# the match did get better: see if we can improve further
if do_actions:
try:
memo[act_key] = super().parseImpl(instring, loc, True)
except ParseException as e:
memo[peek_key] = memo[act_key] = (new_loc, e)
raise
prev_loc, prev_peek = memo[peek_key] = new_loc, new_peek
def leave_whitespace(self, recursive: bool = True) -> ParserElement:
"""
Extends ``leave_whitespace`` defined in base class.
"""
self.skipWhitespace = False
return self
def ignore_whitespace(self, recursive: bool = True) -> ParserElement:
"""
Extends ``ignore_whitespace`` defined in base class.
"""
self.skipWhitespace = True
return self
def streamline(self) -> ParserElement:
if not self.streamlined:
self.streamlined = True
if self.expr is not None:
self.expr.streamline()
return self
def validate(self, validateTrace=None) -> None:
warnings.warn(
"ParserElement.validate() is deprecated, and should not be used to check for left recursion",
PyparsingDeprecationWarning,
stacklevel=2,
)
if validateTrace is None:
validateTrace = []
if self not in validateTrace:
tmp = validateTrace[:] + [self]
if self.expr is not None:
self.expr.validate(tmp)
self._checkRecursion([])
def _generateDefaultName(self) -> str:
# Avoid infinite recursion by setting a temporary _defaultName
save_default_name = self._defaultName
self._defaultName = ": ..."
# Use the string representation of main expression.
try:
if self.expr is not None:
ret_string = str(self.expr)[:1000]
else:
ret_string = "None"
except Exception:
ret_string = "..."
self._defaultName = save_default_name
return f"{type(self).__name__}: {ret_string}"
def copy(self) -> ParserElement:
"""
Returns a copy of this expression.
Generally only used internally by pyparsing.
"""
if self.expr is not None:
return super().copy()
else:
ret = Forward()
ret <<= self
return ret
def _setResultsName(self, name, list_all_matches=False) -> ParserElement:
# fmt: off
if (
__diag__.warn_name_set_on_empty_Forward
and Diagnostics.warn_name_set_on_empty_Forward not in self.suppress_warnings_
and self.expr is None
):
warning = (
"warn_name_set_on_empty_Forward:"
f" setting results name {name!r} on {type(self).__name__} expression"
" that has no contained expression"
)
warnings.warn(warning, PyparsingDiagnosticWarning, stacklevel=3)
# fmt: on
return super()._setResultsName(name, list_all_matches)
# Compatibility synonyms
# fmt: off
leaveWhitespace = replaced_by_pep8("leaveWhitespace", leave_whitespace)
ignoreWhitespace = replaced_by_pep8("ignoreWhitespace", ignore_whitespace)
# fmt: on
class TokenConverter(ParseElementEnhance):
"""
Abstract subclass of :class:`ParseElementEnhance`, for converting parsed results.
"""
def __init__(self, expr: Union[ParserElement, str], savelist=False) -> None:
super().__init__(expr) # , savelist)
self.saveAsList = False
class Combine(TokenConverter):
"""Converter to concatenate all matching tokens to a single string.
By default, the matching patterns must also be contiguous in the
input string; this can be disabled by specifying
``'adjacent=False'`` in the constructor.
Example:
.. doctest::
>>> real = Word(nums) + '.' + Word(nums)
>>> print(real.parse_string('3.1416'))
['3', '.', '1416']
>>> # will also erroneously match the following
>>> print(real.parse_string('3. 1416'))
['3', '.', '1416']
>>> real = Combine(Word(nums) + '.' + Word(nums))
>>> print(real.parse_string('3.1416'))
['3.1416']
>>> # no match when there are internal spaces
>>> print(real.parse_string('3. 1416'))
Traceback (most recent call last):
ParseException: Expected W:(0123...)
"""
def __init__(
self,
expr: ParserElement,
join_string: str = "",
adjacent: bool = True,
*,
joinString: typing.Optional[str] = None,
) -> None:
super().__init__(expr)
joinString = joinString if joinString is not None else join_string
# suppress whitespace-stripping in contained parse expressions, but re-enable it on the Combine itself
if adjacent:
self.leave_whitespace()
self.adjacent = adjacent
self.skipWhitespace = True
self.joinString = joinString
self.callPreparse = True
def ignore(self, other) -> ParserElement:
"""
Define expression to be ignored (e.g., comments) while doing pattern
matching; may be called repeatedly, to define multiple comment or other
ignorable patterns.
"""
if self.adjacent:
ParserElement.ignore(self, other)
else:
super().ignore(other)
return self
def postParse(self, instring, loc, tokenlist):
retToks = tokenlist.copy()
del retToks[:]
retToks += ParseResults(
["".join(tokenlist._asStringList(self.joinString))], modal=self.modalResults
)
if self.resultsName and retToks.haskeys():
return [retToks]
else:
return retToks
class Group(TokenConverter):
"""Converter to return the matched tokens as a list - useful for
returning tokens of :class:`ZeroOrMore` and :class:`OneOrMore` expressions.
The optional ``aslist`` argument when set to True will return the
parsed tokens as a Python list instead of a pyparsing ParseResults.
Example:
.. doctest::
>>> ident = Word(alphas)
>>> num = Word(nums)
>>> term = ident | num
>>> func = ident + Opt(DelimitedList(term))
>>> print(func.parse_string("fn a, b, 100"))
['fn', 'a', 'b', '100']
>>> func = ident + Group(Opt(DelimitedList(term)))
>>> print(func.parse_string("fn a, b, 100"))
['fn', ['a', 'b', '100']]
"""
def __init__(self, expr: ParserElement, aslist: bool = False) -> None:
super().__init__(expr)
self.saveAsList = True
self._asPythonList = aslist
def postParse(self, instring, loc, tokenlist):
if self._asPythonList:
return ParseResults.List(
tokenlist.as_list()
if isinstance(tokenlist, ParseResults)
else list(tokenlist)
)
return [tokenlist]
class Dict(TokenConverter):
"""Converter to return a repetitive expression as a list, but also
as a dictionary. Each element can also be referenced using the first
token in the expression as its key. Useful for tabular report
scraping when the first column can be used as a item key.
The optional ``asdict`` argument when set to True will return the
parsed tokens as a Python dict instead of a pyparsing ParseResults.
Example:
.. doctest::
>>> data_word = Word(alphas)
>>> label = data_word + FollowedBy(':')
>>> attr_expr = (
... label + Suppress(':')
... + OneOrMore(data_word, stop_on=label)
... .set_parse_action(' '.join)
... )
>>> text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
>>> # print attributes as plain groups
>>> print(attr_expr[1, ...].parse_string(text).dump())
['shape', 'SQUARE', 'posn', 'upper left', 'color', 'light blue', 'texture', 'burlap']
# instead of OneOrMore(expr), parse using Dict(Group(expr)[1, ...])
# Dict will auto-assign names.
>>> result = Dict(Group(attr_expr)[1, ...]).parse_string(text)
>>> print(result.dump())
[['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'light blue'], ['texture', 'burlap']]
- color: 'light blue'
- posn: 'upper left'
- shape: 'SQUARE'
- texture: 'burlap'
[0]:
['shape', 'SQUARE']
[1]:
['posn', 'upper left']
[2]:
['color', 'light blue']
[3]:
['texture', 'burlap']
# access named fields as dict entries, or output as dict
>>> print(result['shape'])
SQUARE
>>> print(result.as_dict())
{'shape': 'SQUARE', 'posn': 'upper left', 'color': 'light blue', 'texture': 'burlap'}
See more examples at :class:`ParseResults` of accessing fields by results name.
"""
def __init__(self, expr: ParserElement, asdict: bool = False) -> None:
super().__init__(expr)
self.saveAsList = True
self._asPythonDict = asdict
def postParse(self, instring, loc, tokenlist):
for i, tok in enumerate(tokenlist):
if len(tok) == 0:
continue
ikey = tok[0]
if isinstance(ikey, int):
ikey = str(ikey).strip()
# ParseResults are not hashable, cannot be used as a dict key
if isinstance(ikey, ParseResults):
continue
if len(tok) == 1:
tokenlist[ikey] = _ParseResultsWithOffset("", i)
elif len(tok) == 2 and not isinstance(tok[1], ParseResults):
tokenlist[ikey] = _ParseResultsWithOffset(tok[1], i)
else:
try:
dictvalue = tok.copy() # ParseResults(i)
except Exception:
exc = TypeError(
"could not extract dict values from parsed results"
" - Dict expression must contain Grouped expressions"
)
raise exc from None
del dictvalue[0]
if len(dictvalue) != 1 or (
isinstance(dictvalue, ParseResults) and dictvalue.haskeys()
):
tokenlist[ikey] = _ParseResultsWithOffset(dictvalue, i)
else:
tokenlist[ikey] = _ParseResultsWithOffset(dictvalue[0], i)
# Mark the tokenlist so that as_dict() knows to serialize an empty
# result as {} rather than [], preserving dict semantics even when
# there are no matched entries.
tokenlist._is_dict_context = True
if self._asPythonDict:
return [tokenlist.as_dict()] if self.resultsName else tokenlist.as_dict()
return [tokenlist] if self.resultsName else tokenlist
class Suppress(TokenConverter):
"""Converter for ignoring the results of a parsed expression.
Example:
.. doctest::
>>> source = "a, b, c,d"
>>> wd = Word(alphas)
>>> wd_list1 = wd + (',' + wd)[...]
>>> print(wd_list1.parse_string(source))
['a', ',', 'b', ',', 'c', ',', 'd']
# often, delimiters that are useful during parsing are just in the
# way afterward - use Suppress to keep them out of the parsed output
>>> wd_list2 = wd + (Suppress(',') + wd)[...]
>>> print(wd_list2.parse_string(source))
['a', 'b', 'c', 'd']
# Skipped text (using '...') can be suppressed as well
>>> source = "lead in START relevant text END trailing text"
>>> start_marker = Keyword("START")
>>> end_marker = Keyword("END")
>>> find_body = Suppress(...) + start_marker + ... + end_marker
>>> print(find_body.parse_string(source))
['START', 'relevant text ', 'END']
(See also :class:`DelimitedList`.)
"""
def __init__(self, expr: Union[ParserElement, str], savelist: bool = False) -> None:
if expr is ...:
expr = _PendingSkip(NoMatch())
super().__init__(expr)
def __add__(self, other) -> ParserElement:
if isinstance(self.expr, _PendingSkip):
return Suppress(SkipTo(other)) + other
return super().__add__(other)
def __sub__(self, other) -> ParserElement:
if isinstance(self.expr, _PendingSkip):
return Suppress(SkipTo(other)) - other
return super().__sub__(other)
def postParse(self, instring, loc, tokenlist):
return []
def suppress(self) -> ParserElement:
return self
# XXX: Example needs to be re-done for updated output
def trace_parse_action(f: ParseAction) -> ParseAction:
"""Decorator for debugging parse actions.
When the parse action is called, this decorator will print
``">> entering method-name(line:<current_source_line>, <parse_location>, <matched_tokens>)"``.
When the parse action completes, the decorator will print
``"<<"`` followed by the returned value, or any exception that the parse action raised.
Example:
.. testsetup:: stderr
import sys
sys.stderr = sys.stdout
.. testcleanup:: stderr
sys.stderr = sys.__stderr__
.. testcode:: stderr
wd = Word(alphas)
@trace_parse_action
def remove_duplicate_chars(tokens):
return ''.join(sorted(set(''.join(tokens))))
wds = wd[1, ...].set_parse_action(remove_duplicate_chars)
print(wds.parse_string("slkdjs sld sldd sdlf sdljf"))
prints:
.. testoutput:: stderr
:options: +NORMALIZE_WHITESPACE
>>entering remove_duplicate_chars(line: 'slkdjs sld sldd sdlf sdljf',
0, ParseResults(['slkdjs', 'sld', 'sldd', 'sdlf', 'sdljf'], {}))
<<leaving remove_duplicate_chars (ret: 'dfjkls')
['dfjkls']
.. versionchanged:: 3.1.0
Exception type added to output
"""
f = _trim_arity(f)
def z(*paArgs):
thisFunc = f.__name__
s, l, t = paArgs[-3:]
if len(paArgs) > 3:
thisFunc = f"{type(paArgs[0]).__name__}.{thisFunc}"
sys.stderr.write(f">>entering {thisFunc}(line: {line(l, s)!r}, {l}, {t!r})\n")
try:
ret = f(*paArgs)
except Exception as exc:
sys.stderr.write(
f"<<leaving {thisFunc} (exception: {type(exc).__name__}: {exc})\n"
)
raise
sys.stderr.write(f"<<leaving {thisFunc} (ret: {ret!r})\n")
return ret
z.__name__ = f.__name__
return z
# convenience constants for positional expressions
empty = Empty().set_name("empty")
line_start = LineStart().set_name("line_start")
line_end = LineEnd().set_name("line_end")
string_start = StringStart().set_name("string_start")
string_end = StringEnd().set_name("string_end")
_escapedPunc = Regex(r"\\[\\[\]\/\-\*\.\$\+\^\?()~ ]").set_parse_action(
lambda s, l, t: t[0][1]
)
_escapedHexChar = Regex(r"\\0?[xX][0-9a-fA-F]+").set_parse_action(
lambda s, l, t: chr(int(t[0].lstrip(r"\0x"), 16))
)
_escapedOctChar = Regex(r"\\0[0-7]+").set_parse_action(
lambda s, l, t: chr(int(t[0][1:], 8))
)
_singleChar = (
_escapedPunc | _escapedHexChar | _escapedOctChar | CharsNotIn(r"\]", exact=1)
)
_charRange = Group(_singleChar + Suppress("-") + _singleChar)
_reBracketExpr = (
Literal("[")
+ Opt("^").set_results_name("negate")
+ Group(OneOrMore(_charRange | _singleChar)).set_results_name("body")
+ Literal("]")
)
def srange(s: str) -> str:
r"""Helper to easily define string ranges for use in :class:`Word`
construction. Borrows syntax from regexp ``'[]'`` string range
definitions::
srange("[0-9]") -> "0123456789"
srange("[a-z]") -> "abcdefghijklmnopqrstuvwxyz"
srange("[a-z$_]") -> "abcdefghijklmnopqrstuvwxyz$_"
The input string must be enclosed in []'s, and the returned string
is the expanded character set joined into a single string. The
values enclosed in the []'s may be:
- a single character
- an escaped character with a leading backslash (such as ``\-``
or ``\]``)
- an escaped hex character with a leading ``'\x'``
(``\x21``, which is a ``'!'`` character) (``\0x##``
is also supported for backwards compatibility)
- an escaped octal character with a leading ``'\0'``
(``\041``, which is a ``'!'`` character)
- a range of any of the above, separated by a dash (``'a-z'``,
etc.)
- any combination of the above (``'aeiouy'``,
``'a-zA-Z0-9_$'``, etc.)
"""
def _expanded(p):
if isinstance(p, ParseResults):
yield from (chr(c) for c in range(ord(p[0]), ord(p[1]) + 1))
else:
yield p
try:
return "".join(
[c for part in _reBracketExpr.parse_string(s).body for c in _expanded(part)]
)
except Exception as e:
return ""
def token_map(func, *args) -> ParseAction:
"""Helper to define a parse action by mapping a function to all
elements of a :class:`ParseResults` list. If any additional args are passed,
they are forwarded to the given function as additional arguments
after the token, as in
``hex_integer = Word(hexnums).set_parse_action(token_map(int, 16))``,
which will convert the parsed data to an integer using base 16.
Example (compare the last to example in :class:`ParserElement.transform_string`::
hex_ints = Word(hexnums)[1, ...].set_parse_action(token_map(int, 16))
hex_ints.run_tests('''
00 11 22 aa FF 0a 0d 1a
''')
upperword = Word(alphas).set_parse_action(token_map(str.upper))
upperword[1, ...].run_tests('''
my kingdom for a horse
''')
wd = Word(alphas).set_parse_action(token_map(str.title))
wd[1, ...].set_parse_action(' '.join).run_tests('''
now is the winter of our discontent made glorious summer by this sun of york
''')
prints::
00 11 22 aa FF 0a 0d 1a
[0, 17, 34, 170, 255, 10, 13, 26]
my kingdom for a horse
['MY', 'KINGDOM', 'FOR', 'A', 'HORSE']
now is the winter of our discontent made glorious summer by this sun of york
['Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York']
"""
def pa(s, l, t):
return [func(tokn, *args) for tokn in t]
func_name = getattr(func, "__name__", getattr(func, "__class__").__name__)
pa.__name__ = func_name
return pa
def autoname_elements() -> None:
"""
Utility to simplify mass-naming of parser elements, for
generating railroad diagram with named subdiagrams.
"""
# guard against _getframe not being implemented in the current Python
getframe_fn = getattr(sys, "_getframe", lambda _: None)
calling_frame = getframe_fn(1)
if calling_frame is None:
return
# find all locals in the calling frame that are ParserElements
calling_frame = typing.cast(types.FrameType, calling_frame)
for name, var in calling_frame.f_locals.items():
# if no custom name defined, set the name to the var name
if isinstance(var, ParserElement) and not var.customName:
var.set_name(name)
dbl_quoted_string = (
Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*"')
).set_name("string enclosed in double quotes")
sgl_quoted_string = Regex(
r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*'"
).set_name("string enclosed in single quotes")
quoted_string = Combine(
Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*"').set_name(
"double quoted string"
)
| Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*'").set_name(
"single quoted string"
)
).set_name("quoted string using single or double quotes")
# XXX: Is there some way to make this show up in API docs?
# .. versionadded:: 3.1.0
python_quoted_string = Combine(
Regex(r'"""(?:[^"\\]|""(?!")|"(?!"")|\\.)*"""', flags=re.MULTILINE).set_name(
"multiline double quoted string"
)
^ Regex(r"'''(?:[^'\\]|''(?!')|'(?!'')|\\.)*'''", flags=re.MULTILINE).set_name(
"multiline single quoted string"
)
^ Regex(r'"(?:[^"\n\r\\]|(?:\\")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*"').set_name(
"double quoted string"
)
^ Regex(r"'(?:[^'\n\r\\]|(?:\\')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*'").set_name(
"single quoted string"
)
).set_name("Python quoted string")
unicode_string = Combine("u" + quoted_string.copy()).set_name("unicode string literal")
alphas8bit = srange(r"[\0xc0-\0xd6\0xd8-\0xf6\0xf8-\0xff]")
punc8bit = srange(r"[\0xa1-\0xbf\0xd7\0xf7]")
# build list of built-in expressions, for future reference if a global default value
# gets updated
_builtin_exprs: list[ParserElement] = [
v for v in vars().values() if isinstance(v, ParserElement)
]
# Compatibility synonyms
# fmt: off
sglQuotedString = sgl_quoted_string
dblQuotedString = dbl_quoted_string
quotedString = quoted_string
unicodeString = unicode_string
lineStart = line_start
lineEnd = line_end
stringStart = string_start
stringEnd = string_end
nullDebugAction = replaced_by_pep8("nullDebugAction", null_debug_action)
traceParseAction = replaced_by_pep8("traceParseAction", trace_parse_action)
conditionAsParseAction = replaced_by_pep8("conditionAsParseAction", condition_as_parse_action)
tokenMap = replaced_by_pep8("tokenMap", token_map)
# fmt: on
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