# # core.py # from typing import Optional from abc import ABC, abstractmethod from enum import Enum import string import copy import warnings import re import sre_constants from collections.abc import Iterable import traceback import types from operator import itemgetter from functools import wraps from threading import RLock from .util import ( _FifoCache, _UnboundedCache, __config_flags, _collapseStringToRanges, _escapeRegexRangeChars, _bslash, _flatten, LRUMemo as _LRUMemo, UnboundedMemo as _UnboundedMemo, ) from .exceptions import * from .actions import * from .results import ParseResults, _ParseResultsWithOffset _MAX_INT = sys.maxsize str_type = (str, bytes) # # Copyright (c) 2003-2019 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. # 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): 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:`oneOf` is incorrectly called with multiple str arguments - ``enable_debug_on_named_expressions`` - flag to auto-enable debug on all subsequent calls to :class:`ParserElement.setName` 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): """ Enable a global pyparsing diagnostic flag (see :class:`Diagnostics`). """ __diag__.enable(diag_enum.name) def disable_diag(diag_enum): """ Disable a global pyparsing diagnostic flag (see :class:`Diagnostics`). """ __diag__.disable(diag_enum.name) def enable_all_warnings(): """ Enable all global pyparsing diagnostic warnings (see :class:`Diagnostics`). """ __diag__.enable_all_warnings() # hide abstract class del __config_flags # build list of single arg builtins, that can be used as parse actions singleArgBuiltins = [sum, len, sorted, reversed, list, tuple, set, any, all, min, max] _generatorType = types.GeneratorType alphas = string.ascii_uppercase + string.ascii_lowercase 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 = None def _trim_arity(func, maxargs=2): """decorator to trim function calls to match the arity of the target""" global _trim_arity_call_line if func in singleArgBuiltins: 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 LINE_DIFF = 11 # 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 <= maxargs: limit += 1 continue raise # 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 return wrapper def conditionAsParseAction(fn, message=None, fatal=False): """ 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.addCondition` cannot be used (such as when adding a condition to an operator level in :class:`infixNotation`). 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 _defaultStartDebugAction(instring, loc, expr, cache_hit=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 _defaultSuccessDebugAction(instring, startloc, endloc, expr, toks, cache_hit=False): cache_hit_str = "*" if cache_hit else "" print("{}Matched {} -> {}".format(cache_hit_str, expr, toks.asList())) def _defaultExceptionDebugAction(instring, loc, expr, exc, cache_hit=False): cache_hit_str = "*" if cache_hit else "" print("{}{} raised: {}".format(cache_hit_str, type(exc).__name__, exc)) def nullDebugAction(*args): """'Do-nothing' debug action, to suppress debugging output during parsing.""" class ParserElement(ABC): """Abstract base level parser element class.""" DEFAULT_WHITE_CHARS = " \n\t\r" verbose_stacktrace = False @staticmethod def setDefaultWhitespaceChars(chars): r""" Overrides the default whitespace chars Example:: # default whitespace chars are space, and newline OneOrMore(Word(alphas)).parseString("abc def\nghi jkl") # -> ['abc', 'def', 'ghi', 'jkl'] # change to just treat newline as significant ParserElement.setDefaultWhitespaceChars(" \t") OneOrMore(Word(alphas)).parseString("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 = chars @staticmethod def inlineLiteralsUsing(cls): """ 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.parseString("1999/12/31") # -> ['1999', '/', '12', '/', '31'] # change to Suppress ParserElement.inlineLiteralsUsing(Suppress) date_str = integer("year") + '/' + integer("month") + '/' + integer("day") date_str.parseString("1999/12/31") # -> ['1999', '12', '31'] """ ParserElement._literalStringClass = cls def __init__(self, savelist=False): self.parseAction = list() self.failAction = 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() 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 = (None, None, None) self.re = None # avoid redundant calls to preParse self.callPreparse = True self.callDuringTry = False def copy(self): """ 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).setParseAction(lambda toks: int(toks[0])) integerK = integer.copy().addParseAction(lambda toks: toks[0] * 1024) + Suppress("K") integerM = integer.copy().addParseAction(lambda toks: toks[0] * 1024 * 1024) + Suppress("M") print(OneOrMore(integerK | integerM | integer).parseString("5K 100 640K 256M")) prints:: [5120, 100, 655360, 268435456] Equivalent form of ``expr.copy()`` is just ``expr()``:: integerM = integer().addParseAction(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 = ParserElement.DEFAULT_WHITE_CHARS return cpy def setResultsName(self, name, listAllMatches=False): """ Define name for referencing matching tokens as a nested attribute of the returned parse results. NOTE: this 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.setResultsName("name")`` - see :class:`__call__`. Example:: date_str = (integer.setResultsName("year") + '/' + integer.setResultsName("month") + '/' + integer.setResultsName("day")) # equivalent form: date_str = integer("year") + '/' + integer("month") + '/' + integer("day") """ 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 setBreak(self, breakFlag=True): """Method to invoke the Python pdb debugger when this element is about to be parsed. Set ``breakFlag`` to ``True`` to enable, ``False`` to disable. """ if breakFlag: _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 setParseAction(self, *fns, **kwargs): """ Define one or more actions to perform when successfully matching parse element definition. 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 If the functions in fns modify the tokens, they can return them as the return value from fn, and the modified list of tokens will replace the original. Otherwise, fn does not need to return any value. If None is passed as the parse action, all previously added parse actions for this expression are cleared. Optional keyword arguments: - callDuringTry = (default= ``False``) indicate if parse action should be run during lookaheads and alternate testing Note: the default parsing behavior is to expand tabs in the input string before starting the parsing process. See :class:`parseString` for more information on parsing strings containing ```` 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:: integer = Word(nums) date_str = integer + '/' + integer + '/' + integer date_str.parseString("1999/12/31") # -> ['1999', '/', '12', '/', '31'] # use parse action to convert to ints at parse time integer = Word(nums).setParseAction(lambda toks: int(toks[0])) date_str = integer + '/' + integer + '/' + integer # note that integer fields are now ints, not strings date_str.parseString("1999/12/31") # -> [1999, '/', 12, '/', 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 = list(map(_trim_arity, list(fns))) self.callDuringTry = kwargs.get("callDuringTry", False) return self def addParseAction(self, *fns, **kwargs): """ Add one or more parse actions to expression's list of parse actions. See :class:`setParseAction`. See examples in :class:`copy`. """ self.parseAction += list(map(_trim_arity, list(fns))) self.callDuringTry = self.callDuringTry or kwargs.get("callDuringTry", False) return self def addCondition(self, *fns, **kwargs): """Add a boolean predicate function to expression's list of parse actions. See :class:`setParseAction` for function call signatures. Unlike ``setParseAction``, functions passed to ``addCondition`` 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 - callDuringTry = boolean to indicate if this method should be called during internal tryParse calls, default=False Example:: integer = Word(nums).setParseAction(lambda toks: int(toks[0])) year_int = integer.copy() year_int.addCondition(lambda toks: toks[0] >= 2000, message="Only support years 2000 and later") date_str = year_int + '/' + integer + '/' + integer result = date_str.parseString("1999/12/31") # -> Exception: Only support years 2000 and later (at char 0), (line:1, col:1) """ for fn in fns: self.parseAction.append( conditionAsParseAction( fn, message=kwargs.get("message"), fatal=kwargs.get("fatal", False) ) ) self.callDuringTry = self.callDuringTry or kwargs.get("callDuringTry", False) return self def setFailAction(self, fn): """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: wt = self.whiteChars instrlen = len(instring) while loc < instrlen and instring[loc] in wt: 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): TRY, MATCH, FAIL = 0, 1, 2 debugging = self.debug # and doActions) if debugging or self.failAction: # print("Match {} at loc {}({}, {})".format(self, loc, lineno(loc, instring), col(loc, instring))) try: if callPreParse and self.callPreparse: preloc = self.preParse(instring, loc) else: preloc = loc tokensStart = preloc if self.debugActions[TRY]: self.debugActions[TRY](instring, tokensStart, self) if self.mayIndexError or preloc >= len(instring): try: loc, tokens = self.parseImpl(instring, preloc, doActions) except IndexError: raise ParseException(instring, len(instring), self.errmsg, self) else: loc, tokens = self.parseImpl(instring, preloc, doActions) except Exception as err: # print("Exception raised:", err) if self.debugActions[FAIL]: self.debugActions[FAIL](instring, tokensStart, self, err) if self.failAction: self.failAction(instring, tokensStart, self, err) raise else: if callPreParse and self.callPreparse: preloc = self.preParse(instring, loc) else: preloc = loc tokensStart = preloc if self.mayIndexError or preloc >= len(instring): try: loc, tokens = self.parseImpl(instring, preloc, doActions) except IndexError: raise ParseException(instring, len(instring), self.errmsg, self) else: loc, tokens = self.parseImpl(instring, preloc, doActions) tokens = self.postParse(instring, loc, tokens) retTokens = 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, tokensStart, retTokens) except IndexError as parse_action_exc: exc = ParseException("exception raised in parse action") exc.__cause__ = parse_action_exc raise exc if tokens is not None and tokens is not retTokens: retTokens = 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[FAIL]: self.debugActions[FAIL](instring, tokensStart, self, err) raise else: for fn in self.parseAction: try: tokens = fn(instring, tokensStart, retTokens) except IndexError as parse_action_exc: exc = ParseException("exception raised in parse action") exc.__cause__ = parse_action_exc raise exc if tokens is not None and tokens is not retTokens: retTokens = ParseResults( tokens, self.resultsName, asList=self.saveAsList and isinstance(tokens, (ParseResults, list)), modal=self.modalResults, ) if debugging: # print("Matched", self, "->", retTokens.asList()) if self.debugActions[MATCH]: self.debugActions[MATCH](instring, tokensStart, loc, self, retTokens) return loc, retTokens def tryParse(self, instring, loc, raise_fatal=False): try: return self._parse(instring, loc, doActions=False)[0] except ParseFatalException: if raise_fatal: raise raise ParseException(instring, loc, self.errmsg, self) def canParseNext(self, instring, loc): try: self.tryParse(instring, loc) except (ParseException, IndexError): return False else: return True # cache for left-recursion in Forward references recursion_lock = RLock() recursion_memos = {} # type: dict[tuple[int, Forward, bool], tuple[int, ParseResults | Exception]] # argument cache for optimizing repeated calls when backtracking through recursive expressions packrat_cache = ( {} ) # this is set later by enabledPackrat(); this is here so that resetCache() 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): 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[TRY]: try: self.debugActions[TRY](instring, loc, self, cache_hit=True) except TypeError: pass if isinstance(value, Exception): if self.debug and self.debugActions[FAIL]: try: self.debugActions[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[MATCH]: try: self.debugActions[MATCH]( instring, loc_, endloc, self, result, cache_hit=True ) except TypeError: pass return loc_, result _parse = _parseNoCache @staticmethod def resetCache(): 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(): """ 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.resetCache() ParserElement._left_recursion_enabled = False ParserElement._packratEnabled = False ParserElement._parse = ParserElement._parseNoCache @staticmethod def enable_left_recursion(cache_size_limit: Optional[int] = None, *, force=False): """ 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.parseString("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 enablePackrat(cache_size_limit=128, *, force=False): """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.enablePackrat`. For best results, call ``enablePackrat()`` immediately after importing pyparsing. Example:: import pyparsing pyparsing.ParserElement.enablePackrat() 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 parseString(self, instring, parseAll=False): """ 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 parseAll: If set, the entire input string must match the grammar. :raises ParseException: Raised if ``parseAll`` 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, ``parseAll`` flag must be set to ``True``. This is also equivalent to ending the grammar with :class:`StringEnd`(). To report proper column numbers, ``parseString`` 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 ``parseWithTabs`` on your grammar before calling ``parseString`` (see :class:`parseWithTabs`), - 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 ``parseString``. Examples: By default, partial matches are OK. >>> res = Word('a').parseString('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 parseAll flag is set and instring does not match the whole grammar. >>> res = Word('a').parseString('aaaaabaaa', parseAll=True) Traceback (most recent call last): ... pyparsing.ParseException: Expected end of text, found 'b' (at char 5), (line:1, col:6) """ ParserElement.resetCache() if not self.streamlined: self.streamline() # self.saveAsList = True 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 scanString(self, instring, maxMatches=_MAX_INT, overlap=False): """ Scan the input string for expression matches. Each match will return the matching tokens, start location, and end location. May be called with optional ``maxMatches`` 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:`parseString` for more information on parsing strings with embedded tabs. Example:: source = "sldjf123lsdjjkf345sldkjf879lkjsfd987" print(source) for tokens, start, end in Word(alphas).scanString(source): print(' '*start + '^'*(end-start)) print(' '*start + tokens[0]) prints:: sldjf123lsdjjkf345sldkjf879lkjsfd987 ^^^^^ sldjf ^^^^^^^ lsdjjkf ^^^^^^ sldkjf ^^^^^^ lkjsfd """ 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 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 transformString(self, instring): """ Extension to :class:`scanString`, to modify matching text with modified tokens that may be returned from a parse action. To use ``transformString``, define a grammar and attach a parse action to it that modifies the returned token list. Invoking ``transformString()`` on a target string will then scan for matches, and replace the matched text patterns according to the logic in the parse action. ``transformString()`` returns the resulting transformed string. Example:: wd = Word(alphas) wd.setParseAction(lambda toks: toks[0].title()) print(wd.transformString("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 = [] lastE = 0 # force preservation of s, to minimize unwanted transformation of string, and to # keep string locs straight between transformString and scanString self.keepTabs = True try: for t, s, e in self.scanString(instring): out.append(instring[lastE:s]) if t: if isinstance(t, ParseResults): out += t.asList() elif isinstance(t, Iterable) and not isinstance(t, str_type): out += list(t) else: out.append(t) lastE = e out.append(instring[lastE:]) out = [o for o in out if o] return "".join(map(str, _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 searchString(self, instring, maxMatches=_MAX_INT): """ Another extension to :class:`scanString`, simplifying the access to the tokens found to match the given parse expression. May be called with optional ``maxMatches`` 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.searchString("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.searchString("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'] """ try: return ParseResults( [t for t, s, e in self.scanString(instring, maxMatches)] ) 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, maxsplit=_MAX_INT, includeSeparators=False): """ 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 ``includeSeparators`` argument (default= ``False``), if the separating matching text should be included in the split results. Example:: punc = oneOf(list(".,;:/-!?")) print(list(punc.split("This, this?, this sentence, is badly punctuated!"))) prints:: ['This', ' this', '', ' this sentence', ' is badly punctuated', ''] """ splits = 0 last = 0 for t, s, e in self.scanString(instring, maxMatches=maxsplit): yield instring[last:s] if includeSeparators: yield t[0] last = e yield instring[last:] def __add__(self, other): """ 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.parseString(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): """ 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): """ 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): """ 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): """ 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: raise ValueError("cannot multiply ParserElement by 0 or (0, 0)") if optElements: def makeOptionalList(n): if n > 1: return Optional(self + makeOptionalList(n - 1)) else: return Optional(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): return self.__mul__(other) def __or__(self, other): """ 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): """ 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): """ 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): """ 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): """ 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): """ 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): """ Implementation of ``~`` operator - returns :class:`NotAny` """ return NotAny(self) def __iter__(self): # must implement __iter__ to override legacy use of sequential access to __getitem__ to # iterate over a sequence raise TypeError("{} object is not iterable".format(self.__class__.__name__)) 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=None): """ Shortcut for :class:`setResultsName`, with ``listAllMatches=False``. If ``name`` is given with a trailing ``'*'`` character, then ``listAllMatches`` will be passed as ``True``. If ``name` is omitted, same as calling :class:`copy`. Example:: # these are equivalent userdata = Word(alphas).setResultsName("name") + Word(nums + "-").setResultsName("socsecno") userdata = Word(alphas)("name") + Word(nums + "-")("socsecno") """ if name is not None: return self._setResultsName(name) else: return self.copy() def suppress(self): """ Suppresses the output of this :class:`ParserElement`; useful to keep punctuation from cluttering up returned output. """ return Suppress(self) def ignoreWhitespace(self, recursive=True): """ 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 leaveWhitespace(self, recursive=True): """ 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 setWhitespaceChars(self, chars, copy_defaults=False): """ Overrides the default whitespace chars """ self.skipWhitespace = True self.whiteChars = chars self.copyDefaultWhiteChars = copy_defaults return self def parseWithTabs(self): """ Overrides default behavior to expand ```` s to spaces before parsing the input string. Must be called before ``parseString`` when the input grammar contains elements that match ```` characters. """ self.keepTabs = True return self def ignore(self, other): """ 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 = OneOrMore(Word(alphas)) patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj'] patt.ignore(cStyleComment) patt.parseString('ablaj /* comment */ lskjd') # -> ['ablaj', 'lskjd'] """ if isinstance(other, str_type): other = Suppress(other) if isinstance(other, Suppress): if other not in self.ignoreExprs: self.ignoreExprs.append(other) else: self.ignoreExprs.append(Suppress(other.copy())) return self def setDebugActions(self, startAction, successAction, exceptionAction): """ Customize display of debugging messages while doing pattern matching:: - ``startAction`` - method to be called when an expression is about to be parsed; should have the signature ``fn(input_string, location, expression)`` - ``successAction`` - method to be called when an expression has successfully parsed; should have the signature ``fn(input_string, start_location, end_location, expression, parsed_tokens)`` - ``exceptionAction`` - method to be called when expression fails to parse; should have the signature ``fn(input_string, location, expression, exception)`` """ self.debugActions = ( startAction or _defaultStartDebugAction, successAction or _defaultSuccessDebugAction, exceptionAction or _defaultExceptionDebugAction, ) self.debug = True return self def setDebug(self, flag=True): """ Enable display of debugging messages while doing pattern matching. Set ``flag`` to ``True`` to enable, ``False`` to disable. Example:: wd = Word(alphas).setName("alphaword") integer = Word(nums).setName("numword") term = wd | integer # turn on debugging for wd wd.setDebug() OneOrMore(term).parseString("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:`setDebugActions`. Prior to attempting to match the ``wd`` expression, the debugging message ``"Match at loc (,)"`` 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:`setName` 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 ``setName`` is ``"W:(A-Za-z)"``. """ if flag: self.setDebugActions( _defaultStartDebugAction, _defaultSuccessDebugAction, _defaultExceptionDebugAction, ) else: self.debug = False return self @property def defaultName(self): 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 ``defaultName`` is set. """ def setName(self, name): """ Define name for this expression, makes debugging and exception messages clearer. Example:: Word(nums).parseString("ABC") # -> Exception: Expected W:(0-9) (at char 0), (line:1, col:1) Word(nums).setName("integer").parseString("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.setDebug() return self @property def name(self): # 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.defaultName def __str__(self): return self.name def __repr__(self): return str(self) def streamline(self): self.streamlined = True self._defaultName = None return self def recurse(self): return [] def _checkRecursion(self, parseElementList): subRecCheckList = parseElementList[:] + [self] for e in self.recurse(): e._checkRecursion(subRecCheckList) def validate(self, validateTrace=None): """ Check defined expressions for valid structure, check for infinite recursive definitions. """ self._checkRecursion([]) def parseFile(self, file_or_filename, encoding="utf-8", parseAll=False): """ 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. """ 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.parseString(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) elif isinstance(other, ParserElement): return vars(self) == vars(other) return False def __hash__(self): return id(self) def matches(self, testString, parseAll=True): """ 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: - ``testString`` - to test against this expression for a match - ``parseAll`` - (default= ``True``) - flag to pass to :class:`parseString` when running tests Example:: expr = Word(nums) assert expr.matches("100") """ try: self.parseString(str(testString), parseAll=parseAll) return True except ParseBaseException: return False def runTests( self, tests, parseAll=True, comment="#", fullDump=True, printResults=True, failureTests=False, postParse=None, file=None, ): """ 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 - ``parseAll`` - (default= ``True``) - flag to pass to :class:`parseString` when running tests - ``comment`` - (default= ``'#'``) - expression for indicating embedded comments in the test string; pass None to disable comment filtering - ``fullDump`` - (default= ``True``) - dump results as list followed by results names in nested outline; if False, only dump nested list - ``printResults`` - (default= ``True``) prints test output to stdout - ``failureTests`` - (default= ``False``) indicates if these tests are expected to fail parsing - ``postParse`` - (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`` Returns: a (success, results) tuple, where success indicates that all tests succeeded (or failed if ``failureTests`` 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.runTests(''' # 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.runTests(''' # stray character 100Z # missing leading digit before '.' -.100 # too many '.' 3.14.159 ''', failureTests=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.runTest(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'``.) """ if isinstance(tests, str_type): tests = list(map(type(tests).strip, tests.rstrip().splitlines())) if isinstance(comment, str_type): comment = Literal(comment) if file is None: file = sys.stdout print_ = file.write allResults = [] comments = [] success = True NL = Literal(r"\n").addParseAction(replaceWith("\n")).ignore(quotedString) BOM = "\ufeff" for t in tests: if comment is not None and comment.matches(t, False) or comments and not t: comments.append(t) continue if not t: continue out = ["\n" + "\n".join(comments) if comments else "", t] comments = [] try: # convert newline marks to actual newlines, and strip leading BOM if present t = NL.transformString(t.lstrip(BOM)) result = self.parseString(t, parseAll=parseAll) except ParseBaseException as pe: fatal = "(FATAL)" if isinstance(pe, ParseFatalException) else "" if "\n" in t: out.append(line(pe.loc, t)) out.append(" " * (col(pe.loc, t) - 1) + "^" + fatal) else: out.append(" " * pe.loc + "^" + fatal) out.append("FAIL: " + str(pe)) success = success and failureTests result = pe except Exception as exc: out.append("FAIL-EXCEPTION: " + str(exc)) 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(expr: "ParserElement", output_html, vertical=3, **kwargs): """ """ try: from .diagram import to_railroad, railroad_to_html except ImportError as ie: raise Exception( "must install 'Railroad-Diagram Generator' from https://pypi.org/project/railroad-diagrams to generate parser railroad diagrams" ) from ie railroad = to_railroad(expr, vertical=vertical, diagram_kwargs=kwargs) if isinstance(output_html, str): 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)) 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, must_skip=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): skipper = SkipTo(other).setName("...")("_skipped*") if self.must_skip: def must_skip(t): if not t._skipped or t._skipped.asList() == [""]: del t[0] t.pop("_skipped", None) def show_skip(t): if t._skipped.asList()[-1:] == [""]: skipped = t.pop("_skipped") t["_skipped"] = "missing <" + repr(self.anchor) + ">" return ( self.anchor + skipper().addParseAction(must_skip) | skipper().addParseAction(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').parseString('blah') # -> ['blah'] Literal('blah').parseString('blahfooblah') # -> ['blah'] Literal('blah').parseString('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, matchString): super().__init__() self.match = matchString self.matchLen = len(matchString) try: self.firstMatchChar = matchString[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 "$" - ``caseless`` allows case-insensitive matching, default is ``False``. Example:: Keyword("start").parseString("start") # -> ['start'] Keyword("start").parseString("starting") # -> Exception For case-insensitive matching, use :class:`CaselessKeyword`. """ DEFAULT_KEYWORD_CHARS = alphanums + "_$" def __init__(self, matchString, identChars=None, caseless=False): super().__init__() if identChars is None: identChars = Keyword.DEFAULT_KEYWORD_CHARS self.match = matchString self.matchLen = len(matchString) try: self.firstMatchChar = matchString[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 = matchString.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 setDefaultKeywordChars(chars): """Overrides the default characters used by :class:`Keyword` expressions. """ Keyword.DEFAULT_KEYWORD_CHARS = 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:: OneOrMore(CaselessLiteral("CMD")).parseString("cmd CMD Cmd10") # -> ['CMD', 'CMD', 'CMD'] (Contrast with example for :class:`CaselessKeyword`.) """ def __init__(self, matchString): super().__init__(matchString.upper()) # Preserve the defining literal. self.returnString = matchString 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:: OneOrMore(CaselessKeyword("CMD")).parseString("cmd CMD Cmd10") # -> ['CMD', 'CMD'] (Contrast with example for :class:`CaselessLiteral`.) """ def __init__(self, matchString, identChars=None): super().__init__(matchString, 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 - ``maxMismatches`` - (``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.parseString("ATCATCGAAXGGA") # -> (['ATCATCGAAXGGA'], {'mismatches': [[9]], 'original': ['ATCATCGAATGGA']}) patt.parseString("ATCAXCGAAXGGA") # -> Exception: Expected 'ATCATCGAATGGA' (with up to 1 mismatches) (at char 0), (line:1, col:1) # exact match patt.parseString("ATCATCGAATGGA") # -> (['ATCATCGAATGGA'], {'mismatches': [[]], 'original': ['ATCATCGAATGGA']}) # close match allowing up to 2 mismatches patt = CloseMatch("ATCATCGAATGGA", maxMismatches=2) patt.parseString("ATCAXCGAAXGGA") # -> (['ATCAXCGAAXGGA'], {'mismatches': [[4, 9]], 'original': ['ATCATCGAATGGA']}) """ def __init__(self, match_string, maxMismatches=1): 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.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 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: - ``initChars`` - string of all characters that should be used to match as a word; "ABC" will match "AAA", "ABAB", "CBAC", etc.; if ``bodyChars`` is also specified, then this is the string of initial characters - ``bodyChars`` - string of characters that can be used for matching after a matched initial character as given in ``initChars``; 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) - ``asKeyword`` - match as a keyword (default=``False``) - ``excludeChars`` - characters that might be found in the input ``bodyChars`` 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) 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, excludeChars=",") """ def __init__( self, initChars, bodyChars=None, min=1, max=0, exact=0, asKeyword=False, excludeChars=None, ): super().__init__() if not initChars: raise ValueError( "invalid {}, initChars cannot be empty string".format( type(self).__name__ ) ) if excludeChars: excludeChars = set(excludeChars) initChars = "".join(c for c in initChars if c not in excludeChars) if bodyChars: bodyChars = "".join(c for c in bodyChars if c not in excludeChars) self.initCharsOrig = initChars self.initChars = set(initChars) if bodyChars: self.bodyCharsOrig = bodyChars self.bodyChars = set(bodyChars) else: self.bodyCharsOrig = initChars self.bodyChars = set(initChars) self.maxSpecified = max > 0 if min < 1: raise ValueError( "cannot specify a minimum length < 1; use Optional(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 if " " not in self.initCharsOrig + self.bodyCharsOrig and ( min == 1 and max == 0 and exact == 0 ): if self.bodyCharsOrig == self.initCharsOrig: self.reString = "[{}]+".format( _collapseStringToRanges(self.initCharsOrig) ) elif len(self.initCharsOrig) == 1: self.reString = "{}[{}]*".format( re.escape(self.initCharsOrig), _collapseStringToRanges(self.bodyCharsOrig), ) else: self.reString = "[{}][{}]*".format( _collapseStringToRanges(self.initCharsOrig), _collapseStringToRanges(self.bodyCharsOrig), ) if self.asKeyword: self.reString = r"\b" + self.reString + r"\b" try: self.re = re.compile(self.reString) except sre_constants.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 = _collapseStringToRanges(s, re_escape=False) if len(s) > max_repr_len: return s[: max_repr_len - 3] + "..." else: return s if self.initCharsOrig != self.bodyCharsOrig: base = "W:({}, {})".format( charsAsStr(self.initCharsOrig), charsAsStr(self.bodyCharsOrig) ) else: base = "W:({})".format(charsAsStr(self.initCharsOrig)) # 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, asKeyword=False, excludeChars=None): super().__init__( charset, exact=1, asKeyword=asKeyword, excludeChars=excludeChars ) self.reString = "[{}]".format(_collapseStringToRanges(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 `_. If the given regex contains named groups (defined using ``(?P...)``), 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\d{4})-(?P\d\d?)-(?P\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, flags=0, asGroupList=False, asMatch=False): """The parameters ``pattern`` and ``flags`` are passed to the ``re.compile()`` function as-is. See the Python `re module `_ module for an explanation of the acceptable patterns and flags. """ super().__init__() if isinstance(pattern, str_type): if not pattern: raise ValueError("null string passed to Regex; use Empty() instead") self.pattern = pattern self.flags = flags try: self.re = re.compile(self.pattern, self.flags) self.reString = self.pattern except sre_constants.error: raise ValueError( "invalid pattern ({!r}) passed to Regex".format(pattern) ) 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.re_match = self.re.match self.errmsg = "Expected " + self.name self.mayIndexError = False self.mayReturnEmpty = self.re_match("") is not None self.asGroupList = asGroupList self.asMatch = asMatch if self.asGroupList: self.parseImpl = self.parseImplAsGroupList if self.asMatch: self.parseImpl = self.parseImplAsMatch 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() 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): r""" Return :class:`Regex` with an attached parse action to transform the parsed result as if called using `re.sub(expr, repl, string) `_. Example:: make_html = Regex(r"(\w+):(.*?):").sub(r"<\1>\2") print(make_html.transformString("h1:main title:")) # prints "

main title

" """ 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.addParseAction(pa) class QuotedString(Token): r""" Token for matching strings that are delimited by quoting characters. Defined with the following parameters: - ``quoteChar`` - string of one or more characters defining the quote delimiting string - ``escChar`` - character to re_escape quotes, typically backslash (default= ``None``) - ``escQuote`` - 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``) - ``unquoteResults`` - boolean indicating whether the matched text should be unquoted (default= ``True``) - ``endQuoteChar`` - string of one or more characters defining the end of the quote delimited string (default= ``None`` => same as quoteChar) - ``convertWhitespaceEscapes`` - convert escaped whitespace (``'\t'``, ``'\n'``, etc.) to actual whitespace (default= ``True``) Example:: qs = QuotedString('"') print(qs.searchString('lsjdf "This is the quote" sldjf')) complex_qs = QuotedString('{{', endQuoteChar='}}') print(complex_qs.searchString('lsjdf {{This is the "quote"}} sldjf')) sql_qs = QuotedString('"', escQuote='""') print(sql_qs.searchString('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, quoteChar, escChar=None, escQuote=None, multiline=False, unquoteResults=True, endQuoteChar=None, convertWhitespaceEscapes=True, ): super().__init__() # remove white space from quote chars - wont work anyway quoteChar = quoteChar.strip() if not quoteChar: raise ValueError("quoteChar cannot be the empty string") if endQuoteChar is None: endQuoteChar = quoteChar else: endQuoteChar = endQuoteChar.strip() if not endQuoteChar: raise ValueError("endQuoteChar cannot be the empty string") self.quoteChar = quoteChar self.quoteCharLen = len(quoteChar) self.firstQuoteChar = quoteChar[0] self.endQuoteChar = endQuoteChar self.endQuoteCharLen = len(endQuoteChar) self.escChar = escChar self.escQuote = escQuote self.unquoteResults = unquoteResults self.convertWhitespaceEscapes = convertWhitespaceEscapes if multiline: self.flags = re.MULTILINE | re.DOTALL self.pattern = r"{}(?:[^{}{}]".format( re.escape(self.quoteChar), _escapeRegexRangeChars(self.endQuoteChar[0]), (escChar is not None and _escapeRegexRangeChars(escChar) or ""), ) else: self.flags = 0 self.pattern = r"{}(?:[^{}\n\r{}]".format( re.escape(self.quoteChar), _escapeRegexRangeChars(self.endQuoteChar[0]), (escChar is not None and _escapeRegexRangeChars(escChar) or ""), ) if len(self.endQuoteChar) > 1: self.pattern += ( "|(?:" + ")|(?:".join( "{}[^{}]".format( re.escape(self.endQuoteChar[:i]), _escapeRegexRangeChars(self.endQuoteChar[i]), ) for i in range(len(self.endQuoteChar) - 1, 0, -1) ) + ")" ) if escQuote: self.pattern += r"|(?:{})".format(re.escape(escQuote)) if escChar: self.pattern += r"|(?:{}.)".format(re.escape(escChar)) self.escCharReplacePattern = re.escape(self.escChar) + "(.)" self.pattern += r")*{}".format(re.escape(self.endQuoteChar)) try: self.re = re.compile(self.pattern, self.flags) self.reString = self.pattern self.re_match = self.re.match except sre_constants.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(delimitedList(csv_value).parseString("dkls,lsdkjf,s12 34,@!#,213")) prints:: ['dkls', 'lsdkjf', 's12 34', '@!#', '213'] """ def __init__(self, notChars, min=1, max=0, exact=0): super().__init__() self.skipWhitespace = False self.notChars = notChars if min < 1: raise ValueError( "cannot specify a minimum length < 1; use " "Optional(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 = _collapseStringToRanges(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): if instring[loc] in self.notChars: raise ParseException(instring, loc, self.errmsg, self) start = loc loc += 1 notchars = self.notChars 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 = { " ": "", "\t": "", "\n": "", "\r": "", "\f": "", "\u00A0": "", "\u1680": "", "\u180E": "", "\u2000": "", "\u2001": "", "\u2002": "", "\u2003": "", "\u2004": "", "\u2005": "", "\u2006": "", "\u2007": "", "\u2008": "", "\u2009": "", "\u200A": "", "\u200B": "", "\u202F": "", "\u205F": "", "\u3000": "", } def __init__(self, ws=" \t\r\n", min=1, max=0, exact=0): super().__init__() self.matchWhite = ws self.setWhitespaceChars( "".join(c for c in self.whiteChars if c not in self.matchWhite), copy_defaults=True, ) # self.leaveWhitespace() 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): 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).searchString(test): print(t) prints:: ['AAA', ' this line'] ['AAA', ' and this line'] """ def __init__(self): super().__init__() self.errmsg = "Expected start of line" 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.setWhitespaceChars( ParserElement.DEFAULT_WHITE_CHARS.replace("\n", ""), 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 ``wordChars`` (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, wordChars=printables): 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 ``wordChars`` (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, wordChars=printables): 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, savelist=False): super().__init__(savelist) 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): return self.exprs[:] def append(self, other): self.exprs.append(other) self._defaultName = None return self def leaveWhitespace(self, recursive=True): """ Extends ``leaveWhitespace`` defined in base class, and also invokes ``leaveWhitespace`` on all contained expressions. """ super().leaveWhitespace(recursive) if recursive: self.exprs = [e.copy() for e in self.exprs] for e in self.exprs: e.leaveWhitespace(recursive) return self def ignoreWhitespace(self, recursive=True): """ Extends ``ignoreWhitespace`` defined in base class, and also invokes ``leaveWhitespace`` on all contained expressions. """ super().ignoreWhitespace(recursive) if recursive: self.exprs = [e.copy() for e in self.exprs] for e in self.exprs: e.ignoreWhitespace(recursive) return self def ignore(self, other): 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): 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): tmp = (validateTrace if validateTrace is not None else [])[:] + [self] for e in self.exprs: e.validate(tmp) self._checkRecursion([]) def copy(self): 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: for e in self.exprs: if isinstance(e, ParserElement) and e.resultsName: 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 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 = OneOrMore(Word(alphas)) 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.leaveWhitespace() def _generateDefaultName(self): return "-" def __init__(self, exprs, savelist=True): exprs = list(exprs) if exprs and Ellipsis in exprs: tmp = [] for i, expr in enumerate(exprs): if expr is Ellipsis: if i < len(exprs) - 1: skipto_arg = (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) self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs) self.setWhitespaceChars( self.exprs[0].whiteChars, copy_defaults=self.exprs[0].copyDefaultWhiteChars ) self.skipWhitespace = self.exprs[0].skipWhitespace self.callPreparse = True def streamline(self): # 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() self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs) return self def parseImpl(self, instring, loc, doActions=True): # pass False as last 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): return "{" + " ".join(str(e) for e in self.exprs) + "}" 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.searchString("123 3.1416 789")) prints:: [['123'], ['3.1416'], ['789']] """ def __init__(self, exprs, savelist=False): super().__init__(exprs, savelist) if self.exprs: self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs) else: self.mayReturnEmpty = True def streamline(self): super().streamline() self.saveAsList = any(e.saveAsList for e in self.exprs) 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.tryParse(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: if any(isinstance(e, And) 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".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 two expressions match, 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.searchString("123 3.1416 789")) # Fail! -> [['123'], ['3'], ['1416'], ['789']] # put more selective expression first number = Combine(Word(nums) + '.' + Word(nums)) | Word(nums) print(number.searchString("123 3.1416 789")) # Better -> [['123'], ['3.1416'], ['789']] """ def __init__(self, exprs, savelist=False): super().__init__(exprs, savelist) if self.exprs: self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs) self.callPreparse = all(e.callPreparse for e in self.exprs) else: self.mayReturnEmpty = True def streamline(self): super().streamline() self.saveAsList = any(e.saveAsList for e in self.exprs) if self.exprs: self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs) self.callPreparse = all(e.callPreparse for e in self.exprs) else: self.mayReturnEmpty = True return self def parseImpl(self, instring, loc, doActions=True): maxExcLoc = -1 maxException = None fatals = [] for e in self.exprs: try: ret = e._parse( instring, loc, doActions, callPreParse=not self.callPreparse ) return ret except ParseFatalException as pfe: pfe.__traceback__ = None pfe.parserElement = e fatals.append(pfe) maxException = None except ParseException as err: if not fatals and 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) # only got here if no expression matched, raise exception for match that made it the furthest 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 __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: if any(isinstance(e, And) for e in self.exprs): warnings.warn( "{}: setting results name {!r} on {} expression " "may only return a single token for an And alternative, " "in future will return the full list of tokens".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 = oneOf("RED ORANGE YELLOW GREEN BLUE PURPLE BLACK WHITE BROWN") shape_type = oneOf("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 & Optional(color_attr) & Optional(size_attr) shape_spec.runTests(''' 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, savelist=True): super().__init__(exprs, savelist) self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs) self.skipWhitespace = True self.initExprGroups = True self.saveAsList = True def streamline(self): super().streamline() self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs) 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, Optional) ) opt1 = [e.expr for e in self.exprs if isinstance(e, Optional)] opt2 = [ e for e in self.exprs if e.mayReturnEmpty and not isinstance(e, (Optional, Regex, ZeroOrMore)) ] self.optionals = opt1 + opt2 self.multioptionals = [ e.expr.setResultsName(e.resultsName, listAllMatches=True) for e in self.exprs if isinstance(e, _MultipleMatch) ] self.multirequired = [ e.expr.setResultsName(e.resultsName, listAllMatches=True) for e in self.exprs if isinstance(e, OneOrMore) ] self.required = [ e for e in self.exprs if not isinstance(e, (Optional, 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.tryParse(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 Optionals, in case they have default values defined matchOrder += [ e for e in self.exprs if isinstance(e, Optional) 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, savelist=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.setWhitespaceChars( 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): 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("", loc, self.errmsg, self) def leaveWhitespace(self, recursive=True): super().leaveWhitespace(recursive) if recursive: self.expr = self.expr.copy() if self.expr is not None: self.expr.leaveWhitespace(recursive) return self def ignoreWhitespace(self, recursive=True): super().ignoreWhitespace(recursive) if recursive: self.expr = self.expr.copy() if self.expr is not None: self.expr.ignoreWhitespace(recursive) return self def ignore(self, other): 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): 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): 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)) 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, stopOn=label).setParseAction(' '.join)) OneOrMore(attr_expr).parseString("shape: SQUARE color: BLACK posn: upper left").pprint() prints:: [['shape', 'SQUARE'], ['color', 'BLACK'], ['posn', 'upper left']] """ def __init__(self, expr): 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, retreat=None): super().__init__(expr) self.expr = self.expr().leaveWhitespace() 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 ```` characters, you may want to call :class:`ParserElement.parseWithTabs` Example:: wd = Word(alphas) for match in Located(wd).searchString("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 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 = Optional(NOT) + ident # very crude boolean expression - to support parenthesis groups and # operation hierarchy, use infixNotation boolean_expr = boolean_term + ZeroOrMore((AND | OR) + boolean_term) # integers that are followed by "." are actually floats integer = Word(nums) + ~Char(".") """ def __init__(self, expr): super().__init__(expr) # self.leaveWhitespace() self.skipWhitespace = ( False # do NOT use self.leaveWhitespace(), don't want to propagate to exprs ) self.mayReturnEmpty = True self.errmsg = "Found unwanted token, " + str(self.expr) def parseImpl(self, instring, loc, doActions=True): if self.expr.canParseNext(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, stopOn=None): super().__init__(expr) self.saveAsList = True ender = stopOn if isinstance(ender, str_type): ender = self._literalStringClass(ender) self.stopOn(ender) def stopOn(self, ender): 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: tokens += tmptokens except (ParseException, IndexError): pass return loc, tokens def _setResultsName(self, name, listAllMatches=False): if __diag__.warn_ungrouped_named_tokens_in_collection: for e in [self.expr] + self.expr.recurse(): if isinstance(e, ParserElement) and e.resultsName: 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 - stopOn - (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).setParseAction(' '.join)) text = "shape: SQUARE posn: upper left color: BLACK" OneOrMore(attr_expr).parseString(text).pprint() # Fail! read 'color' as data instead of next label -> [['shape', 'SQUARE color']] # use stopOn attribute for OneOrMore to avoid reading label string as part of the data attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join)) OneOrMore(attr_expr).parseString(text).pprint() # Better -> [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'BLACK']] # could also be written as (attr_expr * (1,)).parseString(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 - ``stopOn`` - 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, stopOn=None): super().__init__(expr, stopOn=stopOn) 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 Optional(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) + Optional('-' + Word(nums, exact=4))) zip.runTests(''' # 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, default=__optionalNotMatched): super().__init__(expr, savelist=False) self.saveAsList = self.expr.saveAsList self.defaultValue = default self.mayReturnEmpty = True def parseImpl(self, instring, loc, doActions=True): try: loc, tokens = self.expr._parse(instring, loc, doActions, callPreParse=False) except (ParseException, IndexError): if self.defaultValue is not self.__optionalNotMatched: if self.expr.resultsName: tokens = ParseResults([self.defaultValue]) tokens[self.expr.resultsName] = self.defaultValue else: tokens = [self.defaultValue] else: tokens = [] return loc, tokens def _generateDefaultName(self): return "[" + str(self.expr) + "]" 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 - ``failOn`` - (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=quotedString) string_data.setParseAction(tokenMap(str.strip)) ticket_expr = (integer("issue_num") + SEP + string_data("sev") + SEP + string_data("desc") + SEP + integer("days_open")) for tkt in ticket_expr.searchString(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, include=False, ignore=None, failOn=None): super().__init__(other) 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) expr = self.expr 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: 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 = 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:: fwdExpr << a | b | c will actually be evaluated as:: (fwdExpr << 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``:: fwdExpr << (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=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.setWhitespaceChars( 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 ): 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: 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: # walk stack until parseString, scanString, searchString, or transformString is found parse_fns = ["parseString", "scanString", "searchString", "transformString"] 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 leaveWhitespace(self, recursive=True): self.skipWhitespace = False return self def ignoreWhitespace(self, recursive=True): self.skipWhitespace = True return self def streamline(self): if not self.streamlined: self.streamlined = True if self.expr is not None: self.expr.streamline() return self def validate(self, validateTrace=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): if self.expr is not None: return super().copy() else: ret = Forward() ret <<= self return ret def _setResultsName(self, name, listAllMatches=False): if __diag__.warn_name_set_on_empty_Forward: 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, listAllMatches) class TokenConverter(ParseElementEnhance): """ Abstract subclass of :class:`ParseExpression`, for converting parsed results. """ def __init__(self, expr, 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.parseString('3.1416')) # -> ['3', '.', '1416'] # will also erroneously match the following print(real.parseString('3. 1416')) # -> ['3', '.', '1416'] real = Combine(Word(nums) + '.' + Word(nums)) print(real.parseString('3.1416')) # -> ['3.1416'] # no match when there are internal spaces print(real.parseString('3. 1416')) # -> Exception: Expected W:(0123...) """ def __init__(self, expr, joinString="", adjacent=True): super().__init__(expr) # suppress whitespace-stripping in contained parse expressions, but re-enable it on the Combine itself if adjacent: self.leaveWhitespace() self.adjacent = adjacent self.skipWhitespace = True self.joinString = joinString self.callPreparse = True def ignore(self, other): 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 + Optional(delimitedList(term)) print(func.parseString("fn a, b, 100")) # -> ['fn', 'a', 'b', '100'] func = ident + Group(Optional(delimitedList(term))) print(func.parseString("fn a, b, 100")) # -> ['fn', ['a', 'b', '100']] """ def __init__(self, expr, aslist=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(':') attr_expr = Group(label + Suppress(':') + OneOrMore(data_word).setParseAction(' '.join)) text = "shape: SQUARE posn: upper left color: light blue texture: burlap" attr_expr = (label + Suppress(':') + OneOrMore(data_word, stopOn=label).setParseAction(' '.join)) # print attributes as plain groups print(OneOrMore(attr_expr).parseString(text).dump()) # instead of OneOrMore(expr), parse using Dict(OneOrMore(Group(expr))) - Dict will auto-assign names result = Dict(OneOrMore(Group(attr_expr))).parseString(text) print(result.dump()) # access named fields as dict entries, or output as dict print(result['shape']) print(result.asDict()) 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, asdict=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" ) exc.__cause__ = None raise exc 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) return tokenlist if not self._asPythonDict else tokenlist.asDict() class Suppress(TokenConverter): """Converter for ignoring the results of a parsed expression. Example:: source = "a, b, c,d" wd = Word(alphas) wd_list1 = wd + ZeroOrMore(',' + wd) print(wd_list1.parseString(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 + ZeroOrMore(Suppress(',') + wd) print(wd_list2.parseString(source)) prints:: ['a', ',', 'b', ',', 'c', ',', 'd'] ['a', 'b', 'c', 'd'] (See also :class:`delimitedList`.) """ def postParse(self, instring, loc, tokenlist): return [] def suppress(self): return self def traceParseAction(f): """Decorator for debugging parse actions. When the parse action is called, this decorator will print ``">> entering method-name(line:, , )"``. 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) @traceParseAction def remove_duplicate_chars(tokens): return ''.join(sorted(set(''.join(tokens)))) wds = OneOrMore(wd).setParseAction(remove_duplicate_chars) print(wds.parseString("slkdjs sld sldd sdlf sdljf")) prints:: >>entering remove_duplicate_chars(line: 'slkdjs sld sldd sdlf sdljf', 0, (['slkdjs', 'sld', 'sldd', 'sdlf', 'sdljf'], {})) < 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("< "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.parseString(s).body) except Exception: return "" def tokenMap(func, *args): """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).setParseAction(tokenMap(int, 16))``, which will convert the parsed data to an integer using base 16. Example (compare the last to example in :class:`ParserElement.transformString`:: hex_ints = OneOrMore(Word(hexnums)).setParseAction(tokenMap(int, 16)) hex_ints.runTests(''' 00 11 22 aa FF 0a 0d 1a ''') upperword = Word(alphas).setParseAction(tokenMap(str.upper)) OneOrMore(upperword).runTests(''' my kingdom for a horse ''') wd = Word(alphas).setParseAction(tokenMap(str.title)) OneOrMore(wd).setParseAction(' '.join).runTests(''' 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 dblQuotedString = Combine( Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*') + '"' ).setName("string enclosed in double quotes") sglQuotedString = Combine( Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*") + "'" ).setName("string enclosed in single quotes") quotedString = Combine( Regex(r'"(?:[^"\n\r\\]|(?:"")|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*') + '"' | Regex(r"'(?:[^'\n\r\\]|(?:'')|(?:\\(?:[^x]|x[0-9a-fA-F]+)))*") + "'" ).setName("quotedString using single or double quotes") unicodeString = Combine("u" + quotedString.copy()).setName("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 = [v for v in vars().values() if isinstance(v, ParserElement)]