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#
# core.py
#
import os
import typing
from typing import (
NamedTuple,
Union,
Callable,
Any,
Generator,
Tuple,
List,
TextIO,
Set,
Sequence,
)
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 .util import (
_FifoCache,
_UnboundedCache,
__config_flags,
_collapse_string_to_ranges,
_escape_regex_range_chars,
_bslash,
_flatten,
LRUMemo as _LRUMemo,
UnboundedMemo as _UnboundedMemo,
)
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.
#
if sys.version_info >= (3, 8):
from functools import cached_property
else:
class cached_property:
def __init__(self, func):
self._func = func
def __get__(self, instance, owner=None):
ret = instance.__dict__[self._func.__name__] = self._func(instance)
return ret
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
_single_arg_builtins = {
sum,
len,
sorted,
reversed,
list,
tuple,
set,
any,
all,
min,
max,
}
_generatorType = types.GeneratorType
ParseAction = Union[
Callable[[], Any],
Callable[[ParseResults], Any],
Callable[[int, ParseResults], Any],
Callable[[str, int, ParseResults], Any],
]
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 = string.ascii_uppercase + string.ascii_lowercase
identchars = pyparsing_unicode.Latin1.identchars
identbodychars = pyparsing_unicode.Latin1.identbodychars
nums = "0123456789"
hexnums = nums + "ABCDEFabcdef"
alphanums = alphas + nums
printables = "".join([c for c in string.printable if c not in string.whitespace])
_trim_arity_call_line: traceback.StackSummary = None
def _trim_arity(func, max_limit=3):
"""decorator to trim function calls to match the arity of the target"""
global _trim_arity_call_line
if func in _single_arg_builtins:
return lambda s, l, t: func(t)
limit = 0
found_arity = False
def extract_tb(tb, limit=0):
frames = traceback.extract_tb(tb, limit=limit)
frame_summary = frames[-1]
return [frame_summary[:2]]
# 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 = 7
# 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 = (_trim_arity_call_line[0], _trim_arity_call_line[1] + LINE_DIFF)
def wrapper(*args):
nonlocal found_arity, 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__
trim_arity_type_error = (
extract_tb(tb, limit=2)[-1][:2] == pa_call_line_synth
)
del tb
if trim_arity_type_error:
if limit < max_limit:
limit += 1
continue
raise
# 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: 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 :class:`ParserElement.add_condition` cannot be used (such as when adding a condition
to an operator level in :class:`infix_notation`).
Optional keyword arguments:
- ``message`` - define a custom message to be used in the raised exception
- ``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
def _default_start_debug_action(
instring: str, loc: int, expr: "ParserElement", cache_hit: bool = False
):
cache_hit_str = "*" if cache_hit else ""
print(
(
"{}Match {} at loc {}({},{})\n {}\n {}^".format(
cache_hit_str,
expr,
loc,
lineno(loc, instring),
col(loc, instring),
line(loc, instring),
" " * (col(loc, instring) - 1),
)
)
)
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("{}Matched {} -> {}".format(cache_hit_str, 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(
"{}Match {} failed, {} raised: {}".format(
cache_hit_str, expr, type(exc).__name__, 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: typing.Optional[type] = None
@staticmethod
def set_default_whitespace_chars(chars: str) -> None:
r"""
Overrides the default whitespace chars
Example::
# default whitespace chars are space, <TAB> and newline
Word(alphas)[1, ...].parse_string("abc def\nghi jkl") # -> ['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") # -> ['abc', 'def']
"""
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::
# default literal class used is Literal
integer = Word(nums)
date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
date_str.parse_string("1999/12/31") # -> ['1999', '/', '12', '/', '31']
# change to Suppress
ParserElement.inline_literals_using(Suppress)
date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
date_str.parse_string("1999/12/31") # -> ['1999', '12', '31']
"""
ParserElement._literalStringClass = cls
class DebugActions(NamedTuple):
debug_try: typing.Optional[DebugStartAction]
debug_match: typing.Optional[DebugSuccessAction]
debug_fail: typing.Optional[DebugExceptionAction]
def __init__(self, savelist: bool = False):
self.parseAction: List[ParseAction] = list()
self.failAction: typing.Optional[ParseFailAction] = None
self.customName = None
self._defaultName = None
self.resultsName = None
self.saveAsList = savelist
self.skipWhitespace = True
self.whiteChars = set(ParserElement.DEFAULT_WHITE_CHARS)
self.copyDefaultWhiteChars = True
# used when checking for left-recursion
self.mayReturnEmpty = False
self.keepTabs = False
self.ignoreExprs: List["ParserElement"] = list()
self.debug = False
self.streamlined = False
# optimize exception handling for subclasses that don't advance parse index
self.mayIndexError = True
self.errmsg = ""
# mark results names as modal (report only last) or cumulative (list all)
self.modalResults = True
# custom debug actions
self.debugActions = self.DebugActions(None, None, None)
# avoid redundant calls to preParse
self.callPreparse = True
self.callDuringTry = False
self.suppress_warnings_: List[Diagnostics] = []
def suppress_warning(self, warning_type: Diagnostics) -> "ParserElement":
"""
Suppress warnings emitted for a particular diagnostic on this expression.
Example::
base = pp.Forward()
base.suppress_warning(Diagnostics.warn_on_parse_using_empty_Forward)
# statement would normally raise a warning, but is now suppressed
print(base.parseString("x"))
"""
self.suppress_warnings_.append(warning_type)
return self
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::
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::
[5120, 100, 655360, 268435456]
Equivalent form of ``expr.copy()`` is just ``expr()``::
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, *, listAllMatches: bool = False
) -> "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 :class:`__call__`. If ``list_all_matches`` is required, use
``expr("name*")``.
Example::
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 = listAllMatches or list_all_matches
return self._setResultsName(name, listAllMatches)
def _setResultsName(self, name, listAllMatches=False):
if name is None:
return self
newself = self.copy()
if name.endswith("*"):
name = name[:-1]
listAllMatches = True
newself.resultsName = name
newself.modalResults = not listAllMatches
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, doActions=True, callPreParse=True):
import pdb
# this call to pdb.set_trace() is intentional, not a checkin error
pdb.set_trace()
return _parseMethod(instring, loc, doActions, callPreParse)
breaker._originalParseMethod = _parseMethod
self._parse = breaker
else:
if hasattr(self._parse, "_originalParseMethod"):
self._parse = self._parse._originalParseMethod
return self
def set_parse_action(self, *fns: ParseAction, **kwargs) -> "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:
- 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 :class:`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
# use parse action to convert toks from str to int at parse time
def convert_to_int(toks):
return int(toks[0])
# use a parse action to verify that the date is a valid date
def is_valid_date(instring, loc, toks):
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)
# note that integer fields are now ints, not strings
date_str.run_tests('''
# successful parse - note that integer fields were converted to ints
1999/12/31
# fail - invalid date
1999/13/31
''')
"""
if list(fns) == [None]:
self.parseAction = []
else:
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 = kwargs.get(
"call_during_try", kwargs.get("callDuringTry", False)
)
return self
def add_parse_action(self, *fns: ParseAction, **kwargs) -> "ParserElement":
"""
Add one or more parse actions to expression's list of parse actions. See :class:`set_parse_action`.
See examples in :class:`copy`.
"""
self.parseAction += [_trim_arity(fn) for fn in fns]
self.callDuringTry = self.callDuringTry or kwargs.get(
"call_during_try", kwargs.get("callDuringTry", False)
)
return self
def add_condition(self, *fns: ParseCondition, **kwargs) -> "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::
integer = Word(nums).set_parse_action(lambda toks: int(toks[0]))
year_int = integer.copy()
year_int.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") # -> Exception: Only support years 2000 and later (at char 0),
(line:1, col:1)
"""
for fn in fns:
self.parseAction.append(
condition_as_parse_action(
fn, message=kwargs.get("message"), fatal=kwargs.get("fatal", False)
)
)
self.callDuringTry = self.callDuringTry or kwargs.get(
"call_during_try", kwargs.get("callDuringTry", False)
)
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, loc):
exprsFound = True
while exprsFound:
exprsFound = False
for e in self.ignoreExprs:
try:
while 1:
loc, dummy = e._parse(instring, loc)
exprsFound = True
except ParseException:
pass
return loc
def preParse(self, instring, loc):
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, doActions=True):
return loc, []
def postParse(self, instring, loc, tokenlist):
return tokenlist
# @profile
def _parseNoCache(
self, instring, loc, doActions=True, callPreParse=True
) -> Tuple[int, ParseResults]:
TRY, MATCH, FAIL = 0, 1, 2
debugging = self.debug # and doActions)
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, doActions)
except IndexError:
raise ParseException(instring, len_instring, self.errmsg, self)
else:
loc, tokens = self.parseImpl(instring, pre_loc, doActions)
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, doActions)
except IndexError:
raise ParseException(instring, len_instring, self.errmsg, self)
else:
loc, tokens = self.parseImpl(instring, pre_loc, doActions)
tokens = self.postParse(instring, loc, tokens)
ret_tokens = ParseResults(
tokens, self.resultsName, asList=self.saveAsList, modal=self.modalResults
)
if self.parseAction and (doActions or self.callDuringTry):
if debugging:
try:
for fn in self.parseAction:
try:
tokens = fn(instring, tokens_start, ret_tokens)
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)
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) -> int:
try:
return self._parse(instring, loc, doActions=False)[0]
except ParseFatalException:
if raise_fatal:
raise
raise ParseException(instring, loc, self.errmsg, self)
def can_parse_next(self, instring: str, loc: int) -> bool:
try:
self.try_parse(instring, loc)
except (ParseException, IndexError):
return False
else:
return True
# cache for left-recursion in Forward references
recursion_lock = RLock()
recursion_memos: typing.Dict[
Tuple[int, "Forward", bool], Tuple[int, Union[ParseResults, Exception]]
] = {}
# argument cache for optimizing repeated calls when backtracking through recursive expressions
packrat_cache = (
{}
) # this is set later by enabled_packrat(); this is here so that reset_cache() doesn't fail
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, doActions=True, callPreParse=True
) -> Tuple[int, ParseResults]:
HIT, MISS = 0, 1
TRY, MATCH, FAIL = 0, 1, 2
lookup = (self, instring, loc, callPreParse, doActions)
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, doActions, 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)
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
)
except TypeError:
pass
raise 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
)
except TypeError:
pass
return loc_, result
_parse = _parseNoCache
@staticmethod
def reset_cache() -> None:
ParserElement.packrat_cache.clear()
ParserElement.packrat_cache_stats[:] = [0] * len(
ParserElement.packrat_cache_stats
)
ParserElement.recursion_memos.clear()
_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.
"""
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::
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"))
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.
"""
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)
else:
raise NotImplementedError("Memo size of %s" % cache_size_limit)
ParserElement._left_recursion_enabled = True
@staticmethod
def enable_packrat(cache_size_limit: int = 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.
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.
"""
if force:
ParserElement.disable_memoization()
elif ParserElement._left_recursion_enabled:
raise RuntimeError("Packrat and Bounded Recursion are not compatible")
if not ParserElement._packratEnabled:
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, *, parseAll: bool = False
) -> 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.
>>> 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.
>>> res = Word('a').parse_string('aaaaabaaa', parse_all=True)
Traceback (most recent call last):
...
pyparsing.ParseException: Expected end of text, found 'b' (at char 5), (line:1, col:6)
"""
parseAll = 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 parseAll:
loc = self.preParse(instring, loc)
se = Empty() + StringEnd()
se._parse(instring, loc)
except ParseBaseException as exc:
if ParserElement.verbose_stacktrace:
raise
else:
# 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,
*,
debug: bool = False,
maxMatches: int = _MAX_INT,
) -> 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::
source = "sldjf123lsdjjkf345sldkjf879lkjsfd987"
print(source)
for tokens, start, end in Word(alphas).scan_string(source):
print(' '*start + '^'*(end-start))
print(' '*start + tokens[0])
prints::
sldjf123lsdjjkf345sldkjf879lkjsfd987
^^^^^
sldjf
^^^^^^^
lsdjjkf
^^^^^^
sldkjf
^^^^^^
lkjsfd
"""
maxMatches = 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
preparseFn = self.preParse
parseFn = self._parse
ParserElement.resetCache()
matches = 0
try:
while loc <= instrlen and matches < maxMatches:
try:
preloc = preparseFn(instring, loc)
nextLoc, tokens = parseFn(instring, preloc, callPreParse=False)
except ParseException:
loc = preloc + 1
else:
if nextLoc > loc:
matches += 1
if debug:
print(
{
"tokens": tokens.asList(),
"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
else:
# 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::
wd = Word(alphas)
wd.set_parse_action(lambda toks: toks[0].title())
print(wd.transform_string("now is the winter of our discontent made glorious summer by this sun of york."))
prints::
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):
out.append(instring[lastE:s])
if t:
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)
lastE = e
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
else:
# 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,
maxMatches: int = _MAX_INT,
) -> 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::
# 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("More than Iron, more than Lead, more than Gold I need Electricity"))
# the sum() builtin can be used to merge results into a single ParseResults object
print(sum(cap_word.search_string("More than Iron, more than Lead, more than Gold I need Electricity")))
prints::
[['More'], ['Iron'], ['Lead'], ['Gold'], ['I'], ['Electricity']]
['More', 'Iron', 'Lead', 'Gold', 'I', 'Electricity']
"""
maxMatches = min(maxMatches, max_matches)
try:
return ParseResults(
[t for t, s, e in self.scan_string(instring, maxMatches, debug=debug)]
)
except ParseBaseException as exc:
if ParserElement.verbose_stacktrace:
raise
else:
# 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,
*,
includeSeparators=False,
) -> 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::
punc = one_of(list(".,;:/-!?"))
print(list(punc.split("This, this?, this sentence, is badly punctuated!")))
prints::
['This', ' this', '', ' this sentence', ' is badly punctuated', '']
"""
includeSeparators = includeSeparators or include_separators
last = 0
for t, s, e in self.scan_string(instring, max_matches=maxsplit):
yield instring[last:s]
if includeSeparators:
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::
greet = Word(alphas) + "," + Word(alphas) + "!"
hello = "Hello, World!"
print(hello, "->", greet.parse_string(hello))
prints::
Hello, World! -> ['Hello', ',', 'World', '!']
``...`` may be used as a parse expression as a short form of :class:`SkipTo`.
Literal('start') + ... + Literal('end')
is equivalent to:
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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:] + (None,))[:2]
if isinstance(other, int):
minElements, optElements = other, 0
elif isinstance(other, tuple):
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:
raise TypeError(
"cannot multiply ParserElement and ({}) objects".format(
",".join(type(item).__name__ for item in other)
)
)
else:
raise TypeError(
"cannot multiply ParserElement and {} objects".format(
type(other).__name__
)
)
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:
def makeOptionalList(n):
if n > 1:
return Opt(self + makeOptionalList(n - 1))
else:
return Opt(self)
if minElements:
if minElements == 1:
ret = self + makeOptionalList(optElements)
else:
ret = And([self] * minElements) + makeOptionalList(optElements)
else:
ret = makeOptionalList(optElements)
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`
"""
if other is Ellipsis:
return _PendingSkip(self, must_skip=True)
if isinstance(other, str_type):
other = self._literalStringClass(other)
if not isinstance(other, ParserElement):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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):
raise TypeError(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
)
)
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``.
"""
# convert single arg keys to tuples
try:
if isinstance(key, str_type):
key = (key,)
iter(key)
except TypeError:
key = (key, key)
if len(key) > 2:
raise TypeError(
"only 1 or 2 index arguments supported ({}{})".format(
key[:5], "... [{}]".format(len(key)) if len(key) > 5 else ""
)
)
# clip to 2 elements
ret = self * tuple(key[:2])
return ret
def __call__(self, name: 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::
# 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)
else:
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::
patt = Word(alphas)[1, ...]
patt.parse_string('ablaj /* comment */ lskjd')
# -> ['ablaj']
patt.ignore(c_style_comment)
patt.parse_string('ablaj /* comment */ lskjd')
# -> ['ablaj', 'lskjd']
"""
import typing
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:
- ``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)``
- ``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)``
- ``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,
success_action or _default_success_debug_action,
exception_action or _default_exception_debug_action,
)
self.debug = True
return self
def set_debug(self, flag: bool = True) -> "ParserElement":
"""
Enable display of debugging messages while doing pattern matching.
Set ``flag`` to ``True`` to enable, ``False`` to disable.
Example::
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::
Match alphaword at loc 0(1,1)
Matched alphaword -> ['abc']
Match alphaword at loc 3(1,4)
Exception raised:Expected alphaword (at char 4), (line:1, col:5)
Match alphaword at loc 7(1,8)
Matched alphaword -> ['xyz']
Match alphaword at loc 11(1,12)
Exception raised:Expected alphaword (at char 12), (line:1, col:13)
Match alphaword at loc 15(1,16)
Exception raised:Expected alphaword (at char 15), (line:1, col:16)
The output shown is that produced by the default debug actions - custom debug actions can be
specified using :class:`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 :class:`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 ``set_name`` is ``"W:(A-Za-z)"``.
"""
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):
"""
Child classes must define this method, which defines how the ``default_name`` is set.
"""
def set_name(self, name: str) -> "ParserElement":
"""
Define name for this expression, makes debugging and exception messages clearer.
Example::
Word(nums).parse_string("ABC") # -> Exception: Expected W:(0-9) (at char 0), (line:1, col:1)
Word(nums).set_name("integer").parse_string("ABC") # -> Exception: Expected integer (at char 0), (line:1, col:1)
"""
self.customName = name
self.errmsg = "Expected " + self.name
if __diag__.enable_debug_on_named_expressions:
self.set_debug()
return self
@property
def name(self) -> str:
# This will use 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
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) -> Sequence["ParserElement"]:
return []
def _checkRecursion(self, parseElementList):
subRecCheckList = parseElementList[:] + [self]
for e in self.recurse():
e._checkRecursion(subRecCheckList)
def validate(self, validateTrace=None) -> None:
"""
Check defined expressions for valid structure, check for infinite recursive definitions.
"""
self._checkRecursion([])
def parse_file(
self,
file_or_filename: Union[str, Path, TextIO],
encoding: str = "utf-8",
parse_all: bool = False,
*,
parseAll: bool = False,
) -> 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 = parseAll or parse_all
try:
file_contents = file_or_filename.read()
except AttributeError:
with open(file_or_filename, "r", encoding=encoding) as f:
file_contents = f.read()
try:
return self.parse_string(file_contents, parseAll)
except ParseBaseException as exc:
if ParserElement.verbose_stacktrace:
raise
else:
# 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, *, parseAll: bool = True
) -> 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.
Parameters:
- ``test_string`` - to test against this expression for a match
- ``parse_all`` - (default= ``True``) - flag to pass to :class:`parse_string` when running tests
Example::
expr = Word(nums)
assert expr.matches("100")
"""
parseAll = parseAll and parse_all
try:
self.parse_string(str(test_string), parse_all=parseAll)
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: Callable[[str, ParseResults], 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: Callable[[str, ParseResults], 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
Example::
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
''')
print("Success" if result[0] else "Failed!")
result = number_expr.run_tests('''
# stray character
100Z
# missing leading digit before '.'
-.100
# too many '.'
3.14.159
''', failure_tests=True)
print("Success" if result[0] else "Failed!")
prints::
# 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]
Success
# stray character
100Z
^
FAIL: Expected end of text (at char 3), (line:1, col:4)
# missing leading digit before '.'
-.100
^
FAIL: Expected {real number with scientific notation | real number | signed integer} (at char 0), (line:1, col:1)
# too many '.'
3.14.159
^
FAIL: Expected end of text (at char 4), (line:1, col:5)
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::
expr.run_tests(r"this is a test\\n of strings that spans \\n 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):
line_strip = type(tests).strip
tests = [line_strip(test_line) for test_line in tests.rstrip().splitlines()]
if isinstance(comment, str_type):
comment = Literal(comment)
if file is None:
file = sys.stdout
print_ = file.write
result: Union[ParseResults, Exception]
allResults = []
comments = []
success = True
NL = Literal(r"\n").add_parse_action(replace_with("\n")).ignore(quoted_string)
BOM = "\ufeff"
for t in tests:
if comment is not None 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 = [
"\n" + "\n".join(comments) if comments else "",
pyparsing_test.with_line_numbers(t) if with_line_numbers else t,
]
comments = []
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=parseAll)
except ParseBaseException as pe:
fatal = "(FATAL)" if isinstance(pe, ParseFatalException) else ""
out.append(pe.explain())
out.append("FAIL: " + str(pe))
if ParserElement.verbose_stacktrace:
out.extend(traceback.format_tb(pe.__traceback__))
success = success and failureTests
result = pe
except Exception as exc:
out.append("FAIL-EXCEPTION: {}: {}".format(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(
"{} failed: {}: {}".format(
postParse.__name__, 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,
**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
Additional diagram-formatting keyword arguments can also be included;
see railroad.Diagram class.
"""
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,
diagram_kwargs=kwargs,
)
if isinstance(output_html, (str, Path)):
with open(output_html, "w", encoding="utf-8") as diag_file:
diag_file.write(railroad_to_html(railroad))
else:
# we were passed a file-like object, just write to it
output_html.write(railroad_to_html(railroad))
setDefaultWhitespaceChars = set_default_whitespace_chars
inlineLiteralsUsing = inline_literals_using
setResultsName = set_results_name
setBreak = set_break
setParseAction = set_parse_action
addParseAction = add_parse_action
addCondition = add_condition
setFailAction = set_fail_action
tryParse = try_parse
canParseNext = can_parse_next
resetCache = reset_cache
enableLeftRecursion = enable_left_recursion
enablePackrat = enable_packrat
parseString = parse_string
scanString = scan_string
searchString = search_string
transformString = transform_string
setWhitespaceChars = set_whitespace_chars
parseWithTabs = parse_with_tabs
setDebugActions = set_debug_actions
setDebug = set_debug
defaultName = default_name
setName = set_name
parseFile = parse_file
runTests = run_tests
ignoreWhitespace = ignore_whitespace
leaveWhitespace = leave_whitespace
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):
super().__init__()
self.anchor = expr
self.must_skip = must_skip
def _generateDefaultName(self):
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"] = "missing <" + repr(self.anchor) + ">"
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):
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):
super().__init__(savelist=False)
def _generateDefaultName(self):
return type(self).__name__
class Empty(Token):
"""
An empty token, will always match.
"""
def __init__(self):
super().__init__()
self.mayReturnEmpty = True
self.mayIndexError = False
class NoMatch(Token):
"""
A token that will never match.
"""
def __init__(self):
super().__init__()
self.mayReturnEmpty = True
self.mayIndexError = False
self.errmsg = "Unmatchable token"
def parseImpl(self, instring, loc, doActions=True):
raise ParseException(instring, loc, self.errmsg, self)
class Literal(Token):
"""
Token to exactly match a specified string.
Example::
Literal('blah').parse_string('blah') # -> ['blah']
Literal('blah').parse_string('blahfooblah') # -> ['blah']
Literal('blah').parse_string('bla') # -> Exception: Expected "blah"
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 __init__(self, match_string: str = "", *, matchString: str = ""):
super().__init__()
match_string = matchString or match_string
self.match = match_string
self.matchLen = len(match_string)
try:
self.firstMatchChar = match_string[0]
except IndexError:
raise ValueError("null string passed to Literal; use Empty() instead")
self.errmsg = "Expected " + self.name
self.mayReturnEmpty = False
self.mayIndexError = False
# Performance tuning: modify __class__ to select
# a parseImpl optimized for single-character check
if self.matchLen == 1 and type(self) is Literal:
self.__class__ = _SingleCharLiteral
def _generateDefaultName(self):
return repr(self.match)
def parseImpl(self, instring, loc, doActions=True):
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 _SingleCharLiteral(Literal):
def parseImpl(self, instring, loc, doActions=True):
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 followed by a non-keyword character. 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:
- ``identChars`` is a string of characters that would be valid
identifier characters, defaulting to all alphanumerics + "_" and
"$"
- ``caseless`` allows case-insensitive matching, default is ``False``.
Example::
Keyword("start").parse_string("start") # -> ['start']
Keyword("start").parse_string("starting") # -> Exception
For case-insensitive matching, use :class:`CaselessKeyword`.
"""
DEFAULT_KEYWORD_CHARS = alphanums + "_$"
def __init__(
self,
match_string: str = "",
ident_chars: typing.Optional[str] = None,
caseless: bool = False,
*,
matchString: str = "",
identChars: typing.Optional[str] = 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)
try:
self.firstMatchChar = match_string[0]
except IndexError:
raise ValueError("null string passed to Keyword; use Empty() instead")
self.errmsg = "Expected {} {}".format(type(self).__name__, self.name)
self.mayReturnEmpty = False
self.mayIndexError = False
self.caseless = caseless
if caseless:
self.caselessmatch = match_string.upper()
identChars = identChars.upper()
self.identChars = set(identChars)
def _generateDefaultName(self):
return repr(self.match)
def parseImpl(self, instring, loc, doActions=True):
errmsg = self.errmsg
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
else:
# 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
else:
if (
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
else:
# 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
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::
CaselessLiteral("CMD")[1, ...].parse_string("cmd CMD Cmd10")
# -> ['CMD', 'CMD', 'CMD']
(Contrast with example for :class:`CaselessKeyword`.)
"""
def __init__(self, match_string: str = "", *, matchString: str = ""):
match_string = matchString or match_string
super().__init__(match_string.upper())
# Preserve the defining literal.
self.returnString = match_string
self.errmsg = "Expected " + self.name
def parseImpl(self, instring, loc, doActions=True):
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::
CaselessKeyword("CMD")[1, ...].parse_string("cmd CMD Cmd10")
# -> ['CMD', 'CMD']
(Contrast with example for :class:`CaselessLiteral`.)
"""
def __init__(
self,
match_string: str = "",
ident_chars: typing.Optional[str] = None,
*,
matchString: str = "",
identChars: typing.Optional[str] = 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::
patt = CloseMatch("ATCATCGAATGGA")
patt.parse_string("ATCATCGAAXGGA") # -> (['ATCATCGAAXGGA'], {'mismatches': [[9]], 'original': ['ATCATCGAATGGA']})
patt.parse_string("ATCAXCGAAXGGA") # -> Exception: Expected 'ATCATCGAATGGA' (with up to 1 mismatches) (at char 0), (line:1, col:1)
# exact match
patt.parse_string("ATCATCGAATGGA") # -> (['ATCATCGAATGGA'], {'mismatches': [[]], 'original': ['ATCATCGAATGGA']})
# close match allowing up to 2 mismatches
patt = CloseMatch("ATCATCGAATGGA", max_mismatches=2)
patt.parse_string("ATCAXCGAAXGGA") # -> (['ATCAXCGAAXGGA'], {'mismatches': [[4, 9]], 'original': ['ATCATCGAATGGA']})
"""
def __init__(
self,
match_string: str,
max_mismatches: int = None,
*,
maxMismatches: int = 1,
caseless=False,
):
maxMismatches = max_mismatches if max_mismatches is not None else maxMismatches
super().__init__()
self.match_string = match_string
self.maxMismatches = maxMismatches
self.errmsg = "Expected {!r} (with up to {} mismatches)".format(
self.match_string, self.maxMismatches
)
self.caseless = caseless
self.mayIndexError = False
self.mayReturnEmpty = False
def _generateDefaultName(self):
return "{}:{!r}".format(type(self).__name__, self.match_string)
def parseImpl(self, instring, loc, doActions=True):
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:
- :class:`alphas`
- :class:`nums`
- :class:`alphanums`
- :class:`hexnums`
- :class:`alphas8bit` (alphabetic characters in ASCII range 128-255
- accented, tilded, umlauted, etc.)
- :class:`punc8bit` (non-alphabetic characters in ASCII range
128-255 - currency, symbols, superscripts, diacriticals, etc.)
- :class:`printables` (any non-whitespace character)
``alphas``, ``nums``, and ``printables`` are also defined in several
Unicode sets - see :class:`pyparsing_unicode``.
Example::
# a word composed of digits
integer = Word(nums) # equivalent to Word("0123456789") or Word(srange("0-9"))
# a word with a leading capital, and zero or more lowercase
capital_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=",")
"""
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,
*,
initChars: typing.Optional[str] = None,
bodyChars: typing.Optional[str] = None,
asKeyword: bool = False,
excludeChars: typing.Optional[str] = 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(
"invalid {}, initChars cannot be empty string".format(
type(self).__name__
)
)
initChars = set(initChars)
self.initChars = initChars
if excludeChars:
excludeChars = set(excludeChars)
initChars -= excludeChars
if bodyChars:
bodyChars = set(bodyChars) - excludeChars
self.initCharsOrig = "".join(sorted(initChars))
if bodyChars:
self.bodyCharsOrig = "".join(sorted(bodyChars))
self.bodyChars = set(bodyChars)
else:
self.bodyCharsOrig = "".join(sorted(initChars))
self.bodyChars = set(initChars)
self.maxSpecified = max > 0
if min < 1:
raise ValueError(
"cannot specify a minimum length < 1; use Opt(Word()) if zero-length word 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 = "Expected " + self.name
self.mayIndexError = False
self.asKeyword = asKeyword
# see if we can make a regex for this Word
if " " not in self.initChars | self.bodyChars and (min == 1 and exact == 0):
if self.bodyChars == self.initChars:
if max == 0:
repeat = "+"
elif max == 1:
repeat = ""
else:
repeat = "{{{},{}}}".format(
self.minLen, "" if self.maxLen == _MAX_INT else self.maxLen
)
self.reString = "[{}]{}".format(
_collapse_string_to_ranges(self.initChars),
repeat,
)
elif len(self.initChars) == 1:
if max == 0:
repeat = "*"
else:
repeat = "{{0,{}}}".format(max - 1)
self.reString = "{}[{}]{}".format(
re.escape(self.initCharsOrig),
_collapse_string_to_ranges(self.bodyChars),
repeat,
)
else:
if max == 0:
repeat = "*"
elif max == 2:
repeat = ""
else:
repeat = "{{0,{}}}".format(max - 1)
self.reString = "[{}][{}]{}".format(
_collapse_string_to_ranges(self.initChars),
_collapse_string_to_ranges(self.bodyChars),
repeat,
)
if self.asKeyword:
self.reString = r"\b" + self.reString + r"\b"
try:
self.re = re.compile(self.reString)
except re.error:
self.re = None
else:
self.re_match = self.re.match
self.__class__ = _WordRegex
def _generateDefaultName(self):
def charsAsStr(s):
max_repr_len = 16
s = _collapse_string_to_ranges(s, re_escape=False)
if len(s) > max_repr_len:
return s[: max_repr_len - 3] + "..."
else:
return s
if self.initChars != self.bodyChars:
base = "W:({}, {})".format(
charsAsStr(self.initChars), charsAsStr(self.bodyChars)
)
else:
base = "W:({})".format(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 + "{{{}}}".format(self.minLen)
elif self.maxLen == _MAX_INT:
return base + "{{{},...}}".format(self.minLen)
else:
return base + "{{{},{}}}".format(self.minLen, self.maxLen)
return base
def parseImpl(self, instring, loc, doActions=True):
if instring[loc] not in self.initChars:
raise ParseException(instring, loc, self.errmsg, self)
start = loc
loc += 1
instrlen = len(instring)
bodychars = self.bodyChars
maxloc = start + self.maxLen
maxloc = min(maxloc, instrlen)
while loc < maxloc and instring[loc] in bodychars:
loc += 1
throwException = False
if loc - start < self.minLen:
throwException = True
elif self.maxSpecified and loc < instrlen and instring[loc] in bodychars:
throwException = True
elif self.asKeyword:
if (
start > 0
and instring[start - 1] in bodychars
or loc < instrlen
and instring[loc] in bodychars
):
throwException = True
if throwException:
raise ParseException(instring, loc, self.errmsg, self)
return loc, instring[start:loc]
class _WordRegex(Word):
def parseImpl(self, instring, loc, doActions=True):
result = self.re_match(instring, loc)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
return loc, result.group()
class Char(_WordRegex):
"""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,
*,
asKeyword: bool = False,
excludeChars: typing.Optional[str] = None,
):
asKeyword = asKeyword or as_keyword
excludeChars = excludeChars or exclude_chars
super().__init__(
charset, exact=1, asKeyword=asKeyword, excludeChars=excludeChars
)
self.reString = "[{}]".format(_collapse_string_to_ranges(self.initChars))
if asKeyword:
self.reString = r"\b{}\b".format(self.reString)
self.re = re.compile(self.reString)
self.re_match = self.re.match
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``.
Example::
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 re's compiled using the regex module
import regex
parser = pp.Regex(regex.compile(r'[0-9]'))
"""
def __init__(
self,
pattern: Any,
flags: Union[re.RegexFlag, int] = 0,
as_group_list: bool = False,
as_match: bool = False,
*,
asGroupList: bool = False,
asMatch: bool = False,
):
"""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.
"""
super().__init__()
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.reString = self.pattern = pattern
self.flags = flags
elif hasattr(pattern, "pattern") and hasattr(pattern, "match"):
self._re = pattern
self.pattern = self.reString = pattern.pattern
self.flags = flags
else:
raise TypeError(
"Regex may only be constructed with a string or a compiled RE object"
)
self.errmsg = "Expected " + self.name
self.mayIndexError = False
self.asGroupList = asGroupList
self.asMatch = asMatch
if self.asGroupList:
self.parseImpl = self.parseImplAsGroupList
if self.asMatch:
self.parseImpl = self.parseImplAsMatch
@cached_property
def re(self):
if self._re:
return self._re
else:
try:
return re.compile(self.pattern, self.flags)
except re.error:
raise ValueError(
"invalid pattern ({!r}) passed to Regex".format(self.pattern)
)
@cached_property
def re_match(self):
return self.re.match
@cached_property
def mayReturnEmpty(self):
return self.re_match("") is not None
def _generateDefaultName(self):
return "Re:({})".format(repr(self.pattern).replace("\\\\", "\\"))
def parseImpl(self, instring, loc, doActions=True):
result = self.re_match(instring, loc)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
ret = ParseResults(result.group())
d = result.groupdict()
if d:
for k, v in d.items():
ret[k] = v
return loc, ret
def parseImplAsGroupList(self, instring, loc, doActions=True):
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, doActions=True):
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::
make_html = Regex(r"(\w+):(.*?):").sub(r"<\1>\2</\1>")
print(make_html.transform_string("h1:main title:"))
# prints "<h1>main title</h1>"
"""
if self.asGroupList:
raise TypeError("cannot use sub() with Regex(asGroupList=True)")
if self.asMatch and callable(repl):
raise TypeError("cannot use sub() with a callable with Regex(asMatch=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``)
Example::
qs = QuotedString('"')
print(qs.search_string('lsjdf "This is the quote" sldjf'))
complex_qs = QuotedString('{{', end_quote_char='}}')
print(complex_qs.search_string('lsjdf {{This is the "quote"}} sldjf'))
sql_qs = QuotedString('"', esc_quote='""')
print(sql_qs.search_string('lsjdf "This is the quote with ""embedded"" quotes" sldjf'))
prints::
[['This is the quote']]
[['This is the "quote"']]
[['This is the quote with "embedded" quotes']]
"""
ws_map = ((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,
*,
quoteChar: str = "",
escChar: typing.Optional[str] = None,
escQuote: typing.Optional[str] = None,
unquoteResults: bool = True,
endQuoteChar: typing.Optional[str] = None,
convertWhitespaceEscapes: bool = True,
):
super().__init__()
escChar = escChar or esc_char
escQuote = escQuote or esc_quote
unquoteResults = unquoteResults and unquote_results
endQuoteChar = endQuoteChar or end_quote_char
convertWhitespaceEscapes = (
convertWhitespaceEscapes and convert_whitespace_escapes
)
quote_char = quoteChar or quote_char
# remove white space from quote chars - wont work anyway
quote_char = quote_char.strip()
if not quote_char:
raise ValueError("quote_char cannot be the empty string")
if endQuoteChar is None:
endQuoteChar = quote_char
else:
endQuoteChar = endQuoteChar.strip()
if not endQuoteChar:
raise ValueError("endQuoteChar cannot be the empty string")
self.quoteChar = quote_char
self.quoteCharLen = len(quote_char)
self.firstQuoteChar = quote_char[0]
self.endQuoteChar = endQuoteChar
self.endQuoteCharLen = len(endQuoteChar)
self.escChar = escChar
self.escQuote = escQuote
self.unquoteResults = unquoteResults
self.convertWhitespaceEscapes = convertWhitespaceEscapes
sep = ""
inner_pattern = ""
if escQuote:
inner_pattern += r"{}(?:{})".format(sep, re.escape(escQuote))
sep = "|"
if escChar:
inner_pattern += r"{}(?:{}.)".format(sep, re.escape(escChar))
sep = "|"
self.escCharReplacePattern = re.escape(self.escChar) + "(.)"
if len(self.endQuoteChar) > 1:
inner_pattern += (
"{}(?:".format(sep)
+ "|".join(
"(?:{}(?!{}))".format(
re.escape(self.endQuoteChar[:i]),
re.escape(self.endQuoteChar[i:]),
)
for i in range(len(self.endQuoteChar) - 1, 0, -1)
)
+ ")"
)
sep = "|"
if multiline:
self.flags = re.MULTILINE | re.DOTALL
inner_pattern += r"{}(?:[^{}{}])".format(
sep,
_escape_regex_range_chars(self.endQuoteChar[0]),
(_escape_regex_range_chars(escChar) if escChar is not None else ""),
)
else:
self.flags = 0
inner_pattern += r"{}(?:[^{}\n\r{}])".format(
sep,
_escape_regex_range_chars(self.endQuoteChar[0]),
(_escape_regex_range_chars(escChar) if escChar is not None else ""),
)
self.pattern = "".join(
[
re.escape(self.quoteChar),
"(?:",
inner_pattern,
")*",
re.escape(self.endQuoteChar),
]
)
try:
self.re = re.compile(self.pattern, self.flags)
self.reString = self.pattern
self.re_match = self.re.match
except re.error:
raise ValueError(
"invalid pattern {!r} passed to Regex".format(self.pattern)
)
self.errmsg = "Expected " + self.name
self.mayIndexError = False
self.mayReturnEmpty = True
def _generateDefaultName(self):
if self.quoteChar == self.endQuoteChar and isinstance(self.quoteChar, str_type):
return "string enclosed in {!r}".format(self.quoteChar)
return "quoted string, starting with {} ending with {}".format(
self.quoteChar, self.endQuoteChar
)
def parseImpl(self, instring, loc, doActions=True):
result = (
instring[loc] == self.firstQuoteChar
and self.re_match(instring, loc)
or None
)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
ret = result.group()
if self.unquoteResults:
# strip off quotes
ret = ret[self.quoteCharLen : -self.endQuoteCharLen]
if isinstance(ret, str_type):
# replace escaped whitespace
if "\\" in ret and self.convertWhitespaceEscapes:
for wslit, wschar in self.ws_map:
ret = ret.replace(wslit, wschar)
# replace escaped characters
if self.escChar:
ret = re.sub(self.escCharReplacePattern, r"\g<1>", ret)
# replace escaped quotes
if self.escQuote:
ret = ret.replace(self.escQuote, self.endQuoteChar)
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::
# define a comma-separated-value as anything that is not a ','
csv_value = CharsNotIn(',')
print(delimited_list(csv_value).parse_string("dkls,lsdkjf,s12 34,@!#,213"))
prints::
['dkls', 'lsdkjf', 's12 34', '@!#', '213']
"""
def __init__(
self,
not_chars: str = "",
min: int = 1,
max: int = 0,
exact: int = 0,
*,
notChars: str = "",
):
super().__init__()
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 = "Expected " + self.name
self.mayReturnEmpty = self.minLen == 0
self.mayIndexError = False
def _generateDefaultName(self):
not_chars_str = _collapse_string_to_ranges(self.notChars)
if len(not_chars_str) > 16:
return "!W:({}...)".format(self.notChars[: 16 - 3])
else:
return "!W:({})".format(self.notChars)
def parseImpl(self, instring, loc, doActions=True):
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):
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.mayReturnEmpty = True
self.errmsg = "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):
return "".join(White.whiteStrs[c] for c in self.matchWhite)
def parseImpl(self, instring, loc, doActions=True):
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):
super().__init__()
self.mayReturnEmpty = 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):
super().__init__()
self.col = colno
def preParse(self, instring, loc):
if col(loc, instring) != self.col:
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, doActions=True):
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 beginning of a line within
the parse string
Example::
test = '''\
AAA this line
AAA and this line
AAA but not this one
B AAA and definitely not this one
'''
for t in (LineStart() + 'AAA' + restOfLine).search_string(test):
print(t)
prints::
['AAA', ' this line']
['AAA', ' and this line']
"""
def __init__(self):
super().__init__()
self.leave_whitespace()
self.orig_whiteChars = set() | self.whiteChars
self.whiteChars.discard("\n")
self.skipper = Empty().set_whitespace_chars(self.whiteChars)
self.errmsg = "Expected start of line"
def preParse(self, instring, loc):
if loc == 0:
return loc
else:
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, doActions=True):
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):
super().__init__()
self.whiteChars.discard("\n")
self.set_whitespace_chars(self.whiteChars, copy_defaults=False)
self.errmsg = "Expected end of line"
def parseImpl(self, instring, loc, doActions=True):
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):
super().__init__()
self.errmsg = "Expected start of text"
def parseImpl(self, instring, loc, doActions=True):
if loc != 0:
# see if entire string up to here is just whitespace and ignoreables
if 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):
super().__init__()
self.errmsg = "Expected end of text"
def parseImpl(self, instring, loc, doActions=True):
if loc < len(instring):
raise ParseException(instring, loc, self.errmsg, self)
elif loc == len(instring):
return loc + 1, []
elif loc > len(instring):
return loc, []
else:
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, *, wordChars: str = printables):
wordChars = word_chars if wordChars == printables else wordChars
super().__init__()
self.wordChars = set(wordChars)
self.errmsg = "Not at the start of a word"
def parseImpl(self, instring, loc, doActions=True):
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, *, wordChars: str = printables):
wordChars = word_chars if wordChars == printables else wordChars
super().__init__()
self.wordChars = set(wordChars)
self.skipWhitespace = False
self.errmsg = "Not at the end of a word"
def parseImpl(self, instring, loc, doActions=True):
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 ParseExpression(ParserElement):
"""Abstract subclass of ParserElement, for combining and
post-processing parsed tokens.
"""
def __init__(self, exprs: typing.Iterable[ParserElement], savelist: bool = False):
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) -> Sequence[ParserElement]:
return self.exprs[:]
def append(self, other) -> ParserElement:
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 ``leave_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:
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):
return "{}:({})".format(self.__class__.__name__, str(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:
other = self.exprs[0]
if (
isinstance(other, self.__class__)
and not other.parseAction
and other.resultsName is None
and not other.debug
):
self.exprs = other.exprs[:] + [self.exprs[1]]
self._defaultName = None
self.mayReturnEmpty |= other.mayReturnEmpty
self.mayIndexError |= other.mayIndexError
other = self.exprs[-1]
if (
isinstance(other, self.__class__)
and not other.parseAction
and other.resultsName is None
and not other.debug
):
self.exprs = self.exprs[:-1] + other.exprs[:]
self._defaultName = None
self.mayReturnEmpty |= other.mayReturnEmpty
self.mayIndexError |= other.mayIndexError
self.errmsg = "Expected " + str(self)
return self
def validate(self, validateTrace=None) -> None:
tmp = (validateTrace if validateTrace is not None else [])[:] + [self]
for e in self.exprs:
e.validate(tmp)
self._checkRecursion([])
def copy(self) -> ParserElement:
ret = super().copy()
ret.exprs = [e.copy() for e in self.exprs]
return ret
def _setResultsName(self, name, listAllMatches=False):
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.exprs:
if (
isinstance(e, ParserElement)
and e.resultsName
and Diagnostics.warn_ungrouped_named_tokens_in_collection
not in e.suppress_warnings_
):
warnings.warn(
"{}: setting results name {!r} on {} expression "
"collides with {!r} on contained expression".format(
"warn_ungrouped_named_tokens_in_collection",
name,
type(self).__name__,
e.resultsName,
),
stacklevel=3,
)
return super()._setResultsName(name, listAllMatches)
ignoreWhitespace = ignore_whitespace
leaveWhitespace = leave_whitespace
class And(ParseExpression):
"""
Requires all given :class:`ParseExpression` 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::
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):
super().__init__(*args, **kwargs)
self.leave_whitespace()
def _generateDefaultName(self):
return "-"
def __init__(
self, exprs_arg: typing.Iterable[ParserElement], savelist: bool = True
):
exprs: List[ParserElement] = list(exprs_arg)
if exprs and Ellipsis in exprs:
tmp = []
for i, expr in enumerate(exprs):
if expr is Ellipsis:
if i < len(exprs) - 1:
skipto_arg: ParserElement = (Empty() + exprs[i + 1]).exprs[-1]
tmp.append(SkipTo(skipto_arg)("_skipped*"))
else:
raise Exception(
"cannot construct And with sequence ending in ..."
)
else:
tmp.append(expr)
exprs[:] = tmp
super().__init__(exprs, savelist)
if self.exprs:
self.mayReturnEmpty = 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.mayReturnEmpty = True
self.callPreparse = True
def streamline(self) -> ParserElement:
# collapse any _PendingSkip's
if self.exprs:
if any(
isinstance(e, ParseExpression)
and e.exprs
and isinstance(e.exprs[-1], _PendingSkip)
for e in self.exprs[:-1]
):
for i, e in enumerate(self.exprs[:-1]):
if e is None:
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] = None
self.exprs = [e for e in self.exprs if e is not None]
super().streamline()
# link any IndentedBlocks to the prior expression
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 cur:
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()
cur = next(iter(subs), None)
self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
return self
def parseImpl(self, instring, loc, doActions=True):
# 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 = self.exprs[0]._parse(
instring, loc, doActions, callPreParse=False
)
errorStop = False
for e in self.exprs[1:]:
# if isinstance(e, And._ErrorStop):
if type(e) is And._ErrorStop:
errorStop = True
continue
if errorStop:
try:
loc, exprtokens = e._parse(instring, loc, doActions)
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, doActions)
if exprtokens or exprtokens.haskeys():
resultlist += exprtokens
return loc, resultlist
def __iadd__(self, other):
if isinstance(other, str_type):
other = self._literalStringClass(other)
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):
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 "{" + inner + "}"
class Or(ParseExpression):
"""Requires that at least one :class:`ParseExpression` is found. If
two expressions match, the expression that matches the longest
string will be used. May be constructed using the ``'^'``
operator.
Example::
# construct Or using '^' operator
number = Word(nums) ^ Combine(Word(nums) + '.' + Word(nums))
print(number.search_string("123 3.1416 789"))
prints::
[['123'], ['3.1416'], ['789']]
"""
def __init__(self, exprs: typing.Iterable[ParserElement], savelist: bool = False):
super().__init__(exprs, savelist)
if self.exprs:
self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
self.skipWhitespace = all(e.skipWhitespace for e in self.exprs)
else:
self.mayReturnEmpty = True
def streamline(self) -> ParserElement:
super().streamline()
if self.exprs:
self.mayReturnEmpty = 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, doActions=True):
maxExcLoc = -1
maxException = None
matches = []
fatals = []
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.parserElement = 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 doActions:
# 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, doActions)
longest = -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, doActions)
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.parserElement))))
max_fatal = fatals[0]
raise max_fatal
if maxException is not None:
maxException.msg = self.errmsg
raise maxException
else:
raise ParseException(
instring, loc, "no defined alternatives to match", self
)
def __ixor__(self, other):
if isinstance(other, str_type):
other = self._literalStringClass(other)
return self.append(other) # Or([self, other])
def _generateDefaultName(self):
return "{" + " ^ ".join(str(e) for e in self.exprs) + "}"
def _setResultsName(self, name, listAllMatches=False):
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
):
warnings.warn(
"{}: setting results name {!r} on {} 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".format(
"warn_multiple_tokens_in_named_alternation",
name,
type(self).__name__,
),
stacklevel=3,
)
return super()._setResultsName(name, listAllMatches)
class MatchFirst(ParseExpression):
"""Requires that at least one :class:`ParseExpression` 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
# 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):
super().__init__(exprs, savelist)
if self.exprs:
self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
self.skipWhitespace = all(e.skipWhitespace for e in self.exprs)
else:
self.mayReturnEmpty = 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.mayReturnEmpty = 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.mayReturnEmpty = True
return self
def parseImpl(self, instring, loc, doActions=True):
maxExcLoc = -1
maxException = None
for e in self.exprs:
try:
return e._parse(
instring,
loc,
doActions,
)
except ParseFatalException as pfe:
pfe.__traceback__ = None
pfe.parserElement = 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:
maxException.msg = self.errmsg
raise maxException
else:
raise ParseException(
instring, loc, "no defined alternatives to match", self
)
def __ior__(self, other):
if isinstance(other, str_type):
other = self._literalStringClass(other)
return self.append(other) # MatchFirst([self, other])
def _generateDefaultName(self):
return "{" + " | ".join(str(e) for e in self.exprs) + "}"
def _setResultsName(self, name, listAllMatches=False):
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
):
warnings.warn(
"{}: setting results name {!r} on {} 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".format(
"warn_multiple_tokens_in_named_alternation",
name,
type(self).__name__,
),
stacklevel=3,
)
return super()._setResultsName(name, listAllMatches)
class Each(ParseExpression):
"""Requires all given :class:`ParseExpression` s to be found, but in
any order. Expressions may be separated by whitespace.
May be constructed using the ``'&'`` operator.
Example::
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::
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):
super().__init__(exprs, savelist)
if self.exprs:
self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
else:
self.mayReturnEmpty = True
self.skipWhitespace = True
self.initExprGroups = True
self.saveAsList = True
def streamline(self) -> ParserElement:
super().streamline()
if self.exprs:
self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs)
else:
self.mayReturnEmpty = True
return self
def parseImpl(self, instring, loc, doActions=True):
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 = []
keepMatching = True
failed = []
fatals = []
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.parserElement = 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.parserElement))))
max_fatal = fatals[0]
raise max_fatal
if tmpReqd:
missing = ", ".join([str(e) for e in tmpReqd])
raise ParseException(
instring,
loc,
"Missing one or more required elements ({})".format(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, doActions)
total_results += results
return loc, total_results
def _generateDefaultName(self):
return "{" + " & ".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):
super().__init__(savelist)
if isinstance(expr, str_type):
if issubclass(self._literalStringClass, Token):
expr = self._literalStringClass(expr)
elif issubclass(type(self), self._literalStringClass):
expr = Literal(expr)
else:
expr = self._literalStringClass(Literal(expr))
self.expr = expr
if expr is not None:
self.mayIndexError = expr.mayIndexError
self.mayReturnEmpty = 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) -> Sequence[ParserElement]:
return [self.expr] if self.expr is not None else []
def parseImpl(self, instring, loc, doActions=True):
if self.expr is not None:
return self.expr._parse(instring, loc, doActions, callPreParse=False)
else:
raise ParseException(instring, loc, "No expression defined", self)
def leave_whitespace(self, recursive: bool = True) -> ParserElement:
super().leave_whitespace(recursive)
if recursive:
self.expr = self.expr.copy()
if self.expr is not None:
self.expr.leave_whitespace(recursive)
return self
def ignore_whitespace(self, recursive: bool = True) -> ParserElement:
super().ignore_whitespace(recursive)
if recursive:
self.expr = self.expr.copy()
if self.expr is not None:
self.expr.ignore_whitespace(recursive)
return self
def ignore(self, other) -> ParserElement:
if isinstance(other, Suppress):
if other not in self.ignoreExprs:
super().ignore(other)
if self.expr is not None:
self.expr.ignore(self.ignoreExprs[-1])
else:
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:
if validateTrace is None:
validateTrace = []
tmp = validateTrace[:] + [self]
if self.expr is not None:
self.expr.validate(tmp)
self._checkRecursion([])
def _generateDefaultName(self):
return "{}:({})".format(self.__class__.__name__, str(self.expr))
ignoreWhitespace = ignore_whitespace
leaveWhitespace = leave_whitespace
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).
"""
class _Indent(Empty):
def __init__(self, ref_col: int):
super().__init__()
self.errmsg = "expected indent at column {}".format(ref_col)
self.add_condition(lambda s, l, t: col(l, s) == ref_col)
class _IndentGreater(Empty):
def __init__(self, ref_col: int):
super().__init__()
self.errmsg = "expected indent at column greater than {}".format(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
):
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, doActions=True):
# 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, doActions)
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
return (wrapper(block) + Optional(trailing_undent)).parseImpl(
instring, anchor_loc, doActions
)
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]):
super().__init__(expr)
self.callPreparse = False
def parseImpl(self, instring, loc, doActions=True):
if loc != 0:
raise ParseException(instring, loc, "not found at string start")
return super().parseImpl(instring, loc, doActions)
class AtLineStart(ParseElementEnhance):
r"""Matches if an expression matches at the beginning of a line within
the parse string
Example::
test = '''\
AAA this line
AAA and this line
AAA but not this one
B AAA and definitely not this one
'''
for t in (AtLineStart('AAA') + restOfLine).search_string(test):
print(t)
prints::
['AAA', ' this line']
['AAA', ' and this line']
"""
def __init__(self, expr: Union[ParserElement, str]):
super().__init__(expr)
self.callPreparse = False
def parseImpl(self, instring, loc, doActions=True):
if col(loc, instring) != 1:
raise ParseException(instring, loc, "not found at line start")
return super().parseImpl(instring, loc, doActions)
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::
# 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::
[['shape', 'SQUARE'], ['color', 'BLACK'], ['posn', 'upper left']]
"""
def __init__(self, expr: Union[ParserElement, str]):
super().__init__(expr)
self.mayReturnEmpty = True
def parseImpl(self, instring, loc, doActions=True):
# 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, doActions=doActions)
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::
# 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: typing.Optional[int] = None
):
super().__init__(expr)
self.expr = self.expr().leave_whitespace()
self.mayReturnEmpty = True
self.mayIndexError = False
self.exact = False
if isinstance(expr, str_type):
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 = "not preceded by " + str(expr)
self.skipWhitespace = False
self.parseAction.append(lambda s, l, t: t.__delitem__(slice(None, None)))
def parseImpl(self, instring, loc=0, doActions=True):
if self.exact:
if loc < self.retreat:
raise ParseException(instring, loc, self.errmsg)
start = loc - self.retreat
_, ret = self.expr._parse(instring, start)
else:
# retreat specified a maximum lookbehind window, iterate
test_expr = self.expr + StringEnd()
instring_slice = instring[max(0, loc - self.retreat) : loc]
last_expr = ParseException(instring, loc, self.errmsg)
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::
wd = Word(alphas)
for match in Located(wd).search_string("ljsdf123lksdjjf123lkkjj1222"):
print(match)
prints::
[0, ['ljsdf'], 5]
[8, ['lksdjjf'], 15]
[18, ['lkkjj'], 23]
"""
def parseImpl(self, instring, loc, doActions=True):
start = loc
loc, tokens = self.expr._parse(instring, start, doActions, 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::
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]):
super().__init__(expr)
# do NOT use self.leave_whitespace(), don't want to propagate to exprs
# self.leave_whitespace()
self.skipWhitespace = False
self.mayReturnEmpty = True
self.errmsg = "Found unwanted token, " + str(self.expr)
def parseImpl(self, instring, loc, doActions=True):
if self.expr.can_parse_next(instring, loc):
raise ParseException(instring, loc, self.errmsg, self)
return loc, []
def _generateDefaultName(self):
return "~{" + str(self.expr) + "}"
class _MultipleMatch(ParseElementEnhance):
def __init__(
self,
expr: ParserElement,
stop_on: typing.Optional[Union[ParserElement, str]] = None,
*,
stopOn: typing.Optional[Union[ParserElement, str]] = None,
):
super().__init__(expr)
stopOn = stopOn or stop_on
self.saveAsList = True
ender = stopOn
if isinstance(ender, str_type):
ender = self._literalStringClass(ender)
self.stopOn(ender)
def stopOn(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
def parseImpl(self, instring, loc, doActions=True):
self_expr_parse = self.expr._parse
self_skip_ignorables = self._skipIgnorables
check_ender = self.not_ender is not None
if check_ender:
try_not_ender = self.not_ender.tryParse
# 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, doActions)
try:
hasIgnoreExprs = not not self.ignoreExprs
while 1:
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, doActions)
if tmptokens or tmptokens.haskeys():
tokens += tmptokens
except (ParseException, IndexError):
pass
return loc, tokens
def _setResultsName(self, name, listAllMatches=False):
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_
):
warnings.warn(
"{}: setting results name {!r} on {} expression "
"collides with {!r} on contained expression".format(
"warn_ungrouped_named_tokens_in_collection",
name,
type(self).__name__,
e.resultsName,
),
stacklevel=3,
)
return super()._setResultsName(name, listAllMatches)
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::
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"
attr_expr[1, ...].parse_string(text).pprint() # Fail! read 'color' as data instead of next label -> [['shape', 'SQUARE color']]
# 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()
"""
def _generateDefaultName(self):
return "{" + str(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: ParserElement,
stop_on: typing.Optional[Union[ParserElement, str]] = None,
*,
stopOn: typing.Optional[Union[ParserElement, str]] = None,
):
super().__init__(expr, stopOn=stopOn or stop_on)
self.mayReturnEmpty = True
def parseImpl(self, instring, loc, doActions=True):
try:
return super().parseImpl(instring, loc, doActions)
except (ParseException, IndexError):
return loc, ParseResults([], name=self.resultsName)
def _generateDefaultName(self):
return "[" + str(self.expr) + "]..."
class _NullToken:
def __bool__(self):
return False
def __str__(self):
return ""
class Opt(ParseElementEnhance):
"""
Optional matching of the given expression.
Parameters:
- ``expr`` - expression that must match zero or more times
- ``default`` (optional) - value to be returned if the optional expression is not found.
Example::
# 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::
# traditional ZIP code
12345
['12345']
# ZIP+4 form
12101-0001
['12101-0001']
# invalid ZIP
98765-
^
FAIL: Expected end of text (at char 5), (line:1, col:6)
"""
__optionalNotMatched = _NullToken()
def __init__(
self, expr: Union[ParserElement, str], default: Any = __optionalNotMatched
):
super().__init__(expr, savelist=False)
self.saveAsList = self.expr.saveAsList
self.defaultValue = default
self.mayReturnEmpty = True
def parseImpl(self, instring, loc, doActions=True):
self_expr = self.expr
try:
loc, tokens = self_expr._parse(instring, loc, doActions, 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]
else:
tokens = []
return loc, tokens
def _generateDefaultName(self):
inner = str(self.expr)
# strip off redundant inner {}'s
while len(inner) > 1 and inner[0 :: len(inner) - 1] == "{}":
inner = inner[1:-1]
return "[" + inner + "]"
Optional = Opt
class SkipTo(ParseElementEnhance):
"""
Token for skipping over all undefined text until the matched
expression is found.
Parameters:
- ``expr`` - target expression marking the end of the data to be skipped
- ``include`` - if ``True``, the target expression is also parsed
(the skipped text and target expression are returned as a 2-element
list) (default= ``False``).
- ``ignore`` - (default= ``None``) used to define grammars (typically quoted strings and
comments) that might contain false matches to the target expression
- ``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::
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::
['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: bool = None,
fail_on: typing.Optional[Union[ParserElement, str]] = None,
*,
failOn: Union[ParserElement, str] = None,
):
super().__init__(other)
failOn = failOn or fail_on
self.ignoreExpr = ignore
self.mayReturnEmpty = 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 = "No match found for " + str(self.expr)
def parseImpl(self, instring, loc, doActions=True):
startloc = loc
instrlen = len(instring)
self_expr_parse = self.expr._parse
self_failOn_canParseNext = (
self.failOn.canParseNext if self.failOn is not None else None
)
self_ignoreExpr_tryParse = (
self.ignoreExpr.tryParse if self.ignoreExpr is not None 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 self_ignoreExpr_tryParse is not None:
# advance past ignore expressions
while 1:
try:
tmploc = self_ignoreExpr_tryParse(instring, tmploc)
except ParseBaseException:
break
try:
self_expr_parse(instring, tmploc, doActions=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, doActions, 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``
variable 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 ``Forward``::
fwd_expr << (a | b | c)
Converting to use the ``'<<='`` operator instead will avoid this problem.
See :class:`ParseResults.pprint` for an example of a recursive
parser created using ``Forward``.
"""
def __init__(self, other: typing.Optional[Union[ParserElement, str]] = None):
self.caller_frame = traceback.extract_stack(limit=2)[0]
super().__init__(other, savelist=False)
self.lshift_line = None
def __lshift__(self, other):
if hasattr(self, "caller_frame"):
del self.caller_frame
if isinstance(other, str_type):
other = self._literalStringClass(other)
self.expr = other
self.mayIndexError = self.expr.mayIndexError
self.mayReturnEmpty = 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]
return self
def __ilshift__(self, other):
return self << other
def __or__(self, other):
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(
"using '<<' operator with '|' is probably an error, use '<<='",
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(
"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, doActions=True):
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(
"Forward expression was never assigned a value, will not parse any input",
stacklevel=stacklevel,
)
if not ParserElement._left_recursion_enabled:
return super().parseImpl(instring, loc, doActions)
# ## 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 `doActions=False` and only run `doActions=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, doActions]
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 `doActions` 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 doActions:
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 doActions:
# replace the match for doActions=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, prev_result.copy()
del memo[peek_key]
return prev_loc, prev_peek.copy()
# the match did get better: see if we can improve further
else:
if doActions:
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:
self.skipWhitespace = False
return self
def ignore_whitespace(self, recursive: bool = True) -> ParserElement:
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:
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):
# Avoid infinite recursion by setting a temporary _defaultName
self._defaultName = ": ..."
# Use the string representation of main expression.
retString = "..."
try:
if self.expr is not None:
retString = str(self.expr)[:1000]
else:
retString = "None"
finally:
return self.__class__.__name__ + ": " + retString
def copy(self) -> ParserElement:
if self.expr is not None:
return super().copy()
else:
ret = Forward()
ret <<= self
return ret
def _setResultsName(self, name, list_all_matches=False):
if (
__diag__.warn_name_set_on_empty_Forward
and Diagnostics.warn_name_set_on_empty_Forward
not in self.suppress_warnings_
):
if self.expr is None:
warnings.warn(
"{}: setting results name {!r} on {} expression "
"that has no contained expression".format(
"warn_name_set_on_empty_Forward", name, type(self).__name__
),
stacklevel=3,
)
return super()._setResultsName(name, list_all_matches)
ignoreWhitespace = ignore_whitespace
leaveWhitespace = leave_whitespace
class TokenConverter(ParseElementEnhance):
"""
Abstract subclass of :class:`ParseExpression`, for converting parsed results.
"""
def __init__(self, expr: Union[ParserElement, str], savelist=False):
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::
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')) # -> Exception: Expected W:(0123...)
"""
def __init__(
self,
expr: ParserElement,
join_string: str = "",
adjacent: bool = True,
*,
joinString: typing.Optional[str] = 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:
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::
ident = Word(alphas)
num = Word(nums)
term = ident | num
func = ident + Opt(delimited_list(term))
print(func.parse_string("fn a, b, 100"))
# -> ['fn', 'a', 'b', '100']
func = ident + Group(Opt(delimited_list(term)))
print(func.parse_string("fn a, b, 100"))
# -> ['fn', ['a', 'b', '100']]
"""
def __init__(self, expr: ParserElement, aslist: bool = False):
super().__init__(expr)
self.saveAsList = True
self._asPythonList = aslist
def postParse(self, instring, loc, tokenlist):
if self._asPythonList:
return ParseResults.List(
tokenlist.asList()
if isinstance(tokenlist, ParseResults)
else list(tokenlist)
)
else:
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::
data_word = Word(alphas)
label = data_word + FollowedBy(':')
text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
attr_expr = (label + Suppress(':') + OneOrMore(data_word, stop_on=label).set_parse_action(' '.join))
# print attributes as plain groups
print(attr_expr[1, ...].parse_string(text).dump())
# 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())
# access named fields as dict entries, or output as dict
print(result['shape'])
print(result.as_dict())
prints::
['shape', 'SQUARE', 'posn', 'upper left', 'color', 'light blue', 'texture', 'burlap']
[['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'light blue'], ['texture', 'burlap']]
- color: 'light blue'
- posn: 'upper left'
- shape: 'SQUARE'
- texture: 'burlap'
SQUARE
{'color': 'light blue', 'posn': 'upper left', 'texture': 'burlap', 'shape': 'SQUARE'}
See more examples at :class:`ParseResults` of accessing fields by results name.
"""
def __init__(self, expr: ParserElement, asdict: bool = False):
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()
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)
if self._asPythonDict:
return [tokenlist.as_dict()] if self.resultsName else tokenlist.as_dict()
else:
return [tokenlist] if self.resultsName else tokenlist
class Suppress(TokenConverter):
"""Converter for ignoring the results of a parsed expression.
Example::
source = "a, b, c,d"
wd = Word(alphas)
wd_list1 = wd + (',' + wd)[...]
print(wd_list1.parse_string(source))
# 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))
# 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)
prints::
['a', ',', 'b', ',', 'c', ',', 'd']
['a', 'b', 'c', 'd']
['START', 'relevant text ', 'END']
(See also :class:`delimited_list`.)
"""
def __init__(self, expr: Union[ParserElement, str], savelist: bool = False):
if expr is ...:
expr = _PendingSkip(NoMatch())
super().__init__(expr)
def __add__(self, other) -> "ParserElement":
if isinstance(self.expr, _PendingSkip):
return Suppress(SkipTo(other)) + other
else:
return super().__add__(other)
def __sub__(self, other) -> "ParserElement":
if isinstance(self.expr, _PendingSkip):
return Suppress(SkipTo(other)) - other
else:
return super().__sub__(other)
def postParse(self, instring, loc, tokenlist):
return []
def suppress(self) -> ParserElement:
return self
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::
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::
>>entering remove_duplicate_chars(line: 'slkdjs sld sldd sdlf sdljf', 0, (['slkdjs', 'sld', 'sldd', 'sdlf', 'sdljf'], {}))
<<leaving remove_duplicate_chars (ret: 'dfjkls')
['dfjkls']
"""
f = _trim_arity(f)
def z(*paArgs):
thisFunc = f.__name__
s, l, t = paArgs[-3:]
if len(paArgs) > 3:
thisFunc = paArgs[0].__class__.__name__ + "." + thisFunc
sys.stderr.write(
">>entering {}(line: {!r}, {}, {!r})\n".format(thisFunc, line(l, s), l, t)
)
try:
ret = f(*paArgs)
except Exception as exc:
sys.stderr.write("<<leaving {} (exception: {})\n".format(thisFunc, exc))
raise
sys.stderr.write("<<leaving {} (ret: {!r})\n".format(thisFunc, ret))
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 = Word(_bslash, r"\[]-*.$+^?()~ ", exact=2).set_parse_action(
lambda s, l, t: t[0][1]
)
_escapedHexChar = Regex(r"\\0?[xX][0-9a-fA-F]+").set_parse_action(
lambda s, l, t: chr(int(t[0].lstrip(r"\0x"), 16))
)
_escapedOctChar = Regex(r"\\0[0-7]+").set_parse_action(
lambda s, l, t: chr(int(t[0][1:], 8))
)
_singleChar = (
_escapedPunc | _escapedHexChar | _escapedOctChar | CharsNotIn(r"\]", exact=1)
)
_charRange = Group(_singleChar + Suppress("-") + _singleChar)
_reBracketExpr = (
Literal("[")
+ Opt("^").set_results_name("negate")
+ Group(OneOrMore(_charRange | _singleChar)).set_results_name("body")
+ "]"
)
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.)
"""
_expanded = (
lambda p: p
if not isinstance(p, ParseResults)
else "".join(chr(c) for c in range(ord(p[0]), ord(p[1]) + 1))
)
try:
return "".join(_expanded(part) for part in _reBracketExpr.parse_string(s).body)
except Exception:
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.
"""
for name, var in sys._getframe().f_back.f_locals.items():
if isinstance(var, ParserElement) and not var.customName:
var.set_name(name)
dbl_quoted_string = Combine(
Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*') + '"'
).set_name("string enclosed in double quotes")
sgl_quoted_string = Combine(
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]+)))*') + '"'
| Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*") + "'"
).set_name("quotedString using single or double quotes")
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)
]
# backward compatibility names
tokenMap = token_map
conditionAsParseAction = condition_as_parse_action
nullDebugAction = null_debug_action
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
traceParseAction = trace_parse_action