#
# core.py
#
from abc import ABC, abstractmethod
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,
)
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 And expression is nested within an Or or 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):
"""
Diagnostic configuration (all default to False)
- warn_multiple_tokens_in_named_alternation - flag to enable warnings when a results
name is defined on a MatchFirst or Or expression with one or more 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 Forward is defined
with a results name, but has no contents defined
- warn_on_parse_using_empty_Forward - flag to enable warnings when a 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 Forward is defined
but is overwritten by assigning using '=' instead of '<<=' or '<<'
- warn_on_multiple_string_args_to_oneof - flag to enable warnings when oneOf is
incorrectly called with multiple str arguments
- enable_debug_on_named_expressions - flag to auto-enable debug on all subsequent
calls to ParserElement.setName()
"""
_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)
# 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 ParserElement.addCondition cannot be used (such as when adding a condition
to an operator level in infixNotation).
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
"""
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):
print(
(
"Match "
+ str(expr)
+ " at loc "
+ str(loc)
+ "(%d,%d)" % (lineno(loc, instring), col(loc, instring))
)
)
def _defaultSuccessDebugAction(instring, startloc, endloc, expr, toks):
print("Matched " + str(expr) + " -> " + str(toks.asList()))
def _defaultExceptionDebugAction(instring, loc, expr, exc):
print("Exception raised:" + str(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, <TAB> 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
self.mayReturnEmpty = False # used when checking for left-recursion
self.keepTabs = False
self.ignoreExprs = list()
self.debug = False
self.streamlined = False
self.mayIndexError = True # used to optimize exception handling for subclasses that don't advance parse index
self.errmsg = ""
self.modalResults = True # used to mark results names as modal (report only last) or cumulative (list all)
self.debugActions = (None, None, None) # custom debug actions
self.re = None
self.callPreparse = True # used to avoid redundant calls to preParse
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):
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 ``<TAB>`` s, and suggested
methods to maintain a consistent view of the parsed string, the parse
location, and line and column positions within the parsed string.
Example::
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", self, "at loc", loc, "(%d, %d)" % (lineno(loc, instring), col(loc, instring)))
if self.debugActions[TRY]:
self.debugActions[TRY](instring, loc, self)
try:
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)
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
# 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
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()))
return value
else:
ParserElement.packrat_cache_stats[HIT] += 1
if isinstance(value, Exception):
raise value
return value[0], value[1].copy()
_parse = _parseNoCache
@staticmethod
def resetCache():
ParserElement.packrat_cache.clear()
ParserElement.packrat_cache_stats[:] = [0] * len(
ParserElement.packrat_cache_stats
)
_packratEnabled = False
@staticmethod
def enablePackrat(cache_size_limit=128):
"""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()
"""
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 ``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 <TAB>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 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):
warnings.warn(
"Cannot combine element of type {} with ParserElement".format(
type(other).__name__
),
SyntaxWarning,
stacklevel=2,
)
return None
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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 ('%s', '%s') objects",
type(other[0]),
type(other[1]),
)
else:
raise TypeError(
"cannot multiply 'ParserElement' and '%s' objects", type(other)
)
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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):
warnings.warn(
"Cannot combine element of type %s with ParserElement" % type(other),
SyntaxWarning,
stacklevel=2,
)
return None
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("%r object is not iterable" % 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:
warnings.warn(
"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 ``<TAB>`` s to spaces before parsing the input string.
Must be called before ``parseString`` when the input grammar contains elements that
match ``<TAB>`` 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):
"""
Enable display of debugging messages while doing pattern matching.
"""
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 <exprname> at loc <n>(<line>,<col>)"``
is shown. Then if the parse succeeds, a ``"Matched"`` message is shown, or an ``"Exception raised"``
message is shown. Also note the use of :class:`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, 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") 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
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:
warnings.warn(
"null string passed to Literal; use Empty() instead",
SyntaxWarning,
stacklevel=2,
)
self.__class__ = Empty
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:
warnings.warn(
"null string passed to Keyword; use Empty() instead",
SyntaxWarning,
stacklevel=2,
)
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)
def copy(self):
c = super().copy()
c.identChars = Keyword.DEFAULT_KEYWORD_CHARS
return c
@staticmethod
def setDefaultKeywordChars(chars):
"""Overrides the default Keyword chars
"""
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 %d mismatches)" % (
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.
Defined with string containing all allowed initial characters, an
optional string containing allowed body characters (if omitted,
defaults to the initial character set), 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. An optional ``excludeChars`` parameter can
list characters that might be found in the input ``bodyChars``
string; useful to define a word of all printables except for one or
two characters, for instance.
: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 = "[%s]+" % _collapseStringToRanges(self.initCharsOrig)
elif len(self.initCharsOrig) == 1:
self.reString = "%s[%s]*" % (
re.escape(self.initCharsOrig),
_collapseStringToRanges(self.bodyCharsOrig),
)
else:
self.reString = "[%s][%s]*" % (
_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)
if len(s) > max_repr_len:
return s[: max_repr_len - 3] + "..."
else:
return s
if self.initCharsOrig != self.bodyCharsOrig:
return "W:({}, {})".format(
charsAsStr(self.initCharsOrig), charsAsStr(self.bodyCharsOrig),
)
else:
return "W:({})".format(charsAsStr(self.initCharsOrig))
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 ``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 <https://docs.python.org/3/library/re.html>`_.
If the given regex contains named groups (defined using ``(?P<name>...)``),
these will be preserved as named :class:`ParseResults`.
If instead of the Python stdlib re module you wish to use a different RE module
(such as the `regex` module), you can do so by building your Regex object with
a compiled RE that was compiled using regex.
Example::
realnum = Regex(r"[+-]?\d+\.\d*")
# ref: https://stackoverflow.com/questions/267399/how-do-you-match-only-valid-roman-numerals-with-a-regular-expression
roman = Regex(r"M{0,4}(CM|CD|D?{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})")
# named fields in a regex will be returned as named results
date = Regex(r'(?P<year>\d{4})-(?P<month>\d\d?)-(?P<day>\d\d?)')
# the Regex class will accept re's compiled using the regex module
import regex
parser = pp.Regex(regex.compile(r'[0-9]'))
"""
def __init__(self, pattern, 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 <https://docs.python.org/3/library/re.html>`_ module for an
explanation of the acceptable patterns and flags.
"""
super().__init__()
if isinstance(pattern, str_type):
if not pattern:
warnings.warn(
"null string passed to Regex; use Empty() instead",
SyntaxWarning,
stacklevel=2,
)
self.pattern = pattern
self.flags = flags
try:
self.re = re.compile(self.pattern, self.flags)
self.reString = self.pattern
except sre_constants.error:
warnings.warn(
"invalid pattern (%s) passed to Regex" % pattern,
SyntaxWarning,
stacklevel=2,
)
raise
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()
if d:
for k, v in d.items():
ret[k] = v
return loc, ret
def parseImplAsGroupList(self, instring, loc, doActions=True):
result = self.re_match(instring, loc)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
ret = result.groups()
return loc, ret
def parseImplAsMatch(self, instring, loc, doActions=True):
result = self.re_match(instring, loc)
if not result:
raise ParseException(instring, loc, self.errmsg, self)
loc = result.end()
ret = result
return loc, ret
def sub(self, repl):
r"""
Return :class:`Regex` with an attached parse action to transform the parsed
result as if called using `re.sub(expr, repl, string) <https://docs.python.org/3/library/re.html#re.sub>`_.
Example::
make_html = Regex(r"(\w+):(.*?):").sub(r"<\1>\2</\1>")
print(make_html.transformString("h1:main title:"))
# prints "<h1>main title</h1>"
"""
if self.asGroupList:
warnings.warn(
"cannot use sub() with Regex(asGroupList=True)",
SyntaxWarning,
stacklevel=2,
)
raise SyntaxError()
if self.asMatch and callable(repl):
warnings.warn(
"cannot use sub() with a callable with Regex(asMatch=True)",
SyntaxWarning,
stacklevel=2,
)
raise SyntaxError()
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']]
"""
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:
warnings.warn(
"quoteChar cannot be the empty string", SyntaxWarning, stacklevel=2
)
raise SyntaxError()
if endQuoteChar is None:
endQuoteChar = quoteChar
else:
endQuoteChar = endQuoteChar.strip()
if not endQuoteChar:
warnings.warn(
"endQuoteChar cannot be the empty string",
SyntaxWarning,
stacklevel=2,
)
raise SyntaxError()
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"%s(?:[^%s%s]" % (
re.escape(self.quoteChar),
_escapeRegexRangeChars(self.endQuoteChar[0]),
(escChar is not None and _escapeRegexRangeChars(escChar) or ""),
)
else:
self.flags = 0
self.pattern = r"%s(?:[^%s\n\r%s]" % (
re.escape(self.quoteChar),
_escapeRegexRangeChars(self.endQuoteChar[0]),
(escChar is not None and _escapeRegexRangeChars(escChar) or ""),
)
if len(self.endQuoteChar) > 1:
self.pattern += (
"|(?:"
+ ")|(?:".join(
"%s[^%s]"
% (
re.escape(self.endQuoteChar[:i]),
_escapeRegexRangeChars(self.endQuoteChar[i]),
)
for i in range(len(self.endQuoteChar) - 1, 0, -1)
)
+ ")"
)
if escQuote:
self.pattern += r"|(?:%s)" % re.escape(escQuote)
if escChar:
self.pattern += r"|(?:%s.)" % re.escape(escChar)
self.escCharReplacePattern = re.escape(self.escChar) + "(.)"
self.pattern += r")*%s" % 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:
warnings.warn(
"invalid pattern (%s) passed to Regex" % self.pattern,
SyntaxWarning,
stacklevel=2,
)
raise
self.errmsg = "Expected " + self.name
self.mayIndexError = False
self.mayReturnEmpty = True
def _generateDefaultName(self):
return "quoted string, starting with %s 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:
ws_map = {
r"\t": "\t",
r"\n": "\n",
r"\f": "\f",
r"\r": "\r",
}
for wslit, wschar in ws_map.items():
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 = {
" ": "<SP>",
"\t": "<TAB>",
"\n": "<LF>",
"\r": "<CR>",
"\f": "<FF>",
"\u00A0": "<NBSP>",
"\u1680": "<OGHAM_SPACE_MARK>",
"\u180E": "<MONGOLIAN_VOWEL_SEPARATOR>",
"\u2000": "<EN_QUAD>",
"\u2001": "<EM_QUAD>",
"\u2002": "<EN_SPACE>",
"\u2003": "<EM_SPACE>",
"\u2004": "<THREE-PER-EM_SPACE>",
"\u2005": "<FOUR-PER-EM_SPACE>",
"\u2006": "<SIX-PER-EM_SPACE>",
"\u2007": "<FIGURE_SPACE>",
"\u2008": "<PUNCTUATION_SPACE>",
"\u2009": "<THIN_SPACE>",
"\u200A": "<HAIR_SPACE>",
"\u200B": "<ZERO_WIDTH_SPACE>",
"\u202F": "<NNBSP>",
"\u205F": "<MMSP>",
"\u3000": "<IDEOGRAPHIC_SPACE>",
}
def __init__(self, ws=" \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 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 Or's and 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):
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 = []
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)
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
fatals = []
for e in self.exprs:
try:
ret = e._parse(instring, loc, doActions)
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))
]
self.optionals = opt1 + opt2
self.multioptionals = [
e.expr for e in self.exprs if isinstance(e, ZeroOrMore)
]
self.multirequired = [
e.expr 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[:]
matchOrder = []
keepMatching = True
failed = []
fatals = []
while keepMatching:
tmpExprs = tmpReqd + tmpOpt + self.multioptionals + self.multirequired
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 (%s)" % 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
]
resultlist = []
for e in matchOrder:
loc, results = e._parse(instring, loc, doActions)
resultlist.append(results)
finalResults = sum(resultlist, ParseResults([]))
return loc, finalResults
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 "%s:(%s)" % (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 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, callPreParse=False)
try:
hasIgnoreExprs = not not self.ignoreExprs
while 1:
if check_ender:
try_not_ender(instring, loc)
if hasIgnoreExprs:
preloc = self_skip_ignorables(instring, loc)
else:
preloc = loc
loc, tmptokens = self_expr_parse(instring, preloc, doActions)
if tmptokens or tmptokens.haskeys():
tokens += tmptokens
except (ParseException, IndexError):
pass
return loc, tokens
def _setResultsName(self, name, listAllMatches=False):
if __diag__.warn_ungrouped_named_tokens_in_collection:
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 - (default= ``None``) - expression for a terminating sentinel
(only required if the sentinel would ordinarily match the repetition
expression)
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 - (default= ``False``) if True, the target expression is also parsed
(the skipped text and target expression are returned as a 2-element list).
- 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 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 '<<='",
SyntaxWarning,
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 '<<'",
SyntaxWarning,
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",
UserWarning,
stacklevel=stacklevel,
)
return super().parseImpl(instring, loc, doActions)
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.
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):
super().__init__(expr)
self.saveAsList = True
def postParse(self, instring, loc, tokenlist):
return [tokenlist]
class Dict(TokenConverter):
"""Converter to return a repetitive expression as a list, but also
as a dictionary. Each element can also be referenced using the first
token in the expression as its key. Useful for tabular report
scraping when the first column can be used as a item key.
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):
super().__init__(expr)
self.saveAsList = True
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(tok[0]).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:
dictvalue = tok.copy() # ParseResults(i)
del dictvalue[0]
if len(dictvalue) != 1 or (
isinstance(dictvalue, ParseResults) and dictvalue.haskeys()
):
tokenlist[ikey] = _ParseResultsWithOffset(dictvalue, i)
else:
tokenlist[ikey] = _ParseResultsWithOffset(dictvalue[0], i)
if self.resultsName:
return [tokenlist]
else:
return tokenlist
class Suppress(TokenConverter):
"""Converter for ignoring the results of a parsed expression.
Example::
source = "a, b, c,d"
wd = Word(alphas)
wd_list1 = wd + 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
class OnlyOnce:
"""Wrapper for parse actions, to ensure they are only called once.
"""
def __init__(self, methodCall):
self.callable = _trim_arity(methodCall)
self.called = False
def __call__(self, s, l, t):
if not self.called:
results = self.callable(s, l, t)
self.called = True
return results
raise ParseException(s, l, "OnlyOnce obj called multiple times w/out reset")
def reset(self):
"""Allow the associated parse action to be called once more.
"""
self.called = False
def traceParseAction(f):
"""Decorator for debugging parse actions.
When the parse action is called, this decorator will print
``">> entering method-name(line:<current_source_line>, <parse_location>, <matched_tokens>)"``.
When the parse action completes, the decorator will print
``"<<"`` followed by the returned value, or any exception that the parse action raised.
Example::
wd = Word(alphas)
@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'], {}))
<<leaving remove_duplicate_chars (ret: 'dfjkls')
['dfjkls']
"""
f = _trim_arity(f)
def z(*paArgs):
thisFunc = f.__name__
s, l, t = paArgs[-3:]
if len(paArgs) > 3:
thisFunc = paArgs[0].__class__.__name__ + "." + thisFunc
sys.stderr.write(
">>entering %s(line: '%s', %d, %r)\n" % (thisFunc, line(l, s), l, t)
)
try:
ret = f(*paArgs)
except Exception as exc:
sys.stderr.write("<<leaving %s (exception: %s)\n" % (thisFunc, exc))
raise
sys.stderr.write("<<leaving %s (ret: %r)\n" % (thisFunc, ret))
return ret
try:
z.__name__ = f.__name__
except AttributeError:
pass
return z
# convenience constants for positional expressions
empty = Empty().setName("empty")
lineStart = LineStart().setName("lineStart")
lineEnd = LineEnd().setName("lineEnd")
stringStart = StringStart().setName("stringStart")
stringEnd = StringEnd().setName("stringEnd")
_escapedPunc = Word(_bslash, r"\[]-*.$+^?()~ ", exact=2).setParseAction(
lambda s, l, t: t[0][1]
)
_escapedHexChar = Regex(r"\\0?[xX][0-9a-fA-F]+").setParseAction(
lambda s, l, t: chr(int(t[0].lstrip(r"\0x"), 16))
)
_escapedOctChar = Regex(r"\\0[0-7]+").setParseAction(
lambda s, l, t: chr(int(t[0][1:], 8))
)
_singleChar = (
_escapedPunc | _escapedHexChar | _escapedOctChar | CharsNotIn(r"\]", exact=1)
)
_charRange = Group(_singleChar + Suppress("-") + _singleChar)
_reBracketExpr = (
Literal("[")
+ Optional("^").setResultsName("negate")
+ Group(OneOrMore(_charRange | _singleChar)).setResultsName("body")
+ "]"
)
def srange(s):
r"""Helper to easily define string ranges for use in :class:`Word`
construction. Borrows syntax from regexp '[]' string range
definitions::
srange("[0-9]") -> "0123456789"
srange("[a-z]") -> "abcdefghijklmnopqrstuvwxyz"
srange("[a-z$_]") -> "abcdefghijklmnopqrstuvwxyz$_"
The input string must be enclosed in []'s, and the returned string
is the expanded character set joined into a single string. The
values enclosed in the []'s may be:
- a single character
- an escaped character with a leading backslash (such as ``\-``
or ``\]``)
- an escaped hex character with a leading ``'\x'``
(``\x21``, which is a ``'!'`` character) (``\0x##``
is also supported for backwards compatibility)
- an escaped octal character with a leading ``'\0'``
(``\041``, which is a ``'!'`` character)
- a range of any of the above, separated by a dash (``'a-z'``,
etc.)
- any combination of the above (``'aeiouy'``,
``'a-zA-Z0-9_$'``, etc.)
"""
_expanded = (
lambda p: p
if not isinstance(p, ParseResults)
else "".join(chr(c) for c in range(ord(p[0]), ord(p[1]) + 1))
)
try:
return "".join(_expanded(part) for part in _reBracketExpr.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 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]
try:
func_name = getattr(func, "__name__", getattr(func, "__class__").__name__)
except Exception:
func_name = str(func)
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)]
