# # Copyright (c) 2003-2022 Paul T. McGuire # # Permission is hereby granted, free of charge, to any person obtaining # a copy of this software and associated documentation files (the # "Software"), to deal in the Software without restriction, including # without limitation the rights to use, copy, modify, merge, publish, # distribute, sublicense, and/or sell copies of the Software, and to # permit persons to whom the Software is furnished to do so, subject to # the following conditions: # # The above copyright notice and this permission notice shall be # included in all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. # IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY # CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, # TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. #
if sys.version_info >= (3, 8): from functools import cached_property else:
class cached_property: def __init__(self, func):
self._func = func
def __get__(self, instance, owner=None):
ret = instance.__dict__[self._func.__name__] = self._func(instance) return ret
class __compat__(__config_flags): """
A cross-version compatibility configuration for pyparsing features that will be
released in a future version. By setting values in this configuration to True,
those features can be enabled in prior versions for compatibility development and testing.
- ``collect_all_And_tokens`` - flag to enable fix for Issue #63 that fixes erroneous grouping
of results names when an :class:`And` expression is nested within an :class:`Or` or :class:`MatchFirst`;
maintained for compatibility, but setting to ``False`` no longer restores pre-2.3.1
behavior """
_type_desc = "compatibility"
collect_all_And_tokens = True
_all_names = [__ for __ in locals() ifnot __.startswith("_")]
_fixed_names = """
collect_all_And_tokens """.split()
class __diag__(__config_flags):
_type_desc = "diagnostic"
_all_names = [__ for __ in locals() ifnot __.startswith("_")]
_warning_names = [name for name in _all_names if name.startswith("warn")]
_debug_names = [name for name in _all_names if name.startswith("enable_debug")]
@classmethod def enable_all_warnings(cls) -> None: for name in cls._warning_names:
cls.enable(name)
class Diagnostics(Enum): """
Diagnostic configuration (all default to disabled)
- ``warn_multiple_tokens_in_named_alternation`` - flag to enable warnings when a results
name is defined on a :class:`MatchFirst` or :class:`Or` expression with one or more :class:`And` subexpressions
- ``warn_ungrouped_named_tokens_in_collection`` - flag to enable warnings when a results
name is defined on a containing expression with ungrouped subexpressions that also
have results names
- ``warn_name_set_on_empty_Forward`` - flag to enable warnings when a :class:`Forward` is defined with a results name, but has no contents defined
- ``warn_on_parse_using_empty_Forward`` - flag to enable warnings when a :class:`Forward` is
defined in a grammar but has never had an expression attached to it
- ``warn_on_assignment_to_Forward`` - flag to enable warnings when a :class:`Forward` is defined
but is overwritten by assigning using ``'='`` instead of ``'<<='`` or ``'<<'``
- ``warn_on_multiple_string_args_to_oneof`` - flag to enable warnings when :class:`one_of` is
incorrectly called with multiple str arguments
- ``enable_debug_on_named_expressions`` - flag to auto-enable debug on all subsequent
calls to :class:`ParserElement.set_name`
Diagnostics are enabled/disabled by calling :class:`enable_diag` and :class:`disable_diag`.
All warnings can be enabled by calling :class:`enable_all_warnings`. """
def enable_diag(diag_enum: Diagnostics) -> None: """
Enable a global pyparsing diagnostic flag (see :class:`Diagnostics`). """
__diag__.enable(diag_enum.name)
def disable_diag(diag_enum: Diagnostics) -> None: """
Disable a global pyparsing diagnostic flag (see :class:`Diagnostics`). """
__diag__.disable(diag_enum.name)
def enable_all_warnings() -> None: """
Enable all global pyparsing diagnostic warnings (see :class:`Diagnostics`). """
__diag__.enable_all_warnings()
# hide abstract class del __config_flags
def _should_enable_warnings(
cmd_line_warn_options: typing.Iterable[str], warn_env_var: typing.Optional[str]
) -> bool:
enable = bool(warn_env_var) for warn_opt in cmd_line_warn_options:
w_action, w_message, w_category, w_module, w_line = (warn_opt + "::::").split( ":"
)[:5] ifnot w_action.lower().startswith("i") and ( not (w_message or w_category or w_module) or w_module == "pyparsing"
):
enable = True elif w_action.lower().startswith("i") and w_module in ("pyparsing", ""):
enable = False return enable
if _should_enable_warnings(
sys.warnoptions, os.environ.get("PYPARSINGENABLEALLWARNINGS")
):
enable_all_warnings()
# build list of single arg builtins, that can be used as parse actions
_single_arg_builtins = {
sum,
len,
sorted,
reversed,
list,
tuple,
set,
any,
all,
min,
max,
}
def _trim_arity(func, max_limit=3): """decorator to trim function calls to match the arity of the target""" global _trim_arity_call_line
if func in _single_arg_builtins: returnlambda s, l, t: func(t)
limit = 0
found_arity = False
# synthesize what would be returned by traceback.extract_stack at the call to # user's parse action 'func', so that we don't incur call penalty at parse time
# fmt: off
LINE_DIFF = 7 # IF ANY CODE CHANGES, EVEN JUST COMMENTS OR BLANK LINES, BETWEEN THE NEXT LINE AND # THE CALL TO FUNC INSIDE WRAPPER, LINE_DIFF MUST BE MODIFIED!!!!
_trim_arity_call_line = (_trim_arity_call_line or traceback.extract_stack(limit=2)[-1])
pa_call_line_synth = (_trim_arity_call_line[0], _trim_arity_call_line[1] + LINE_DIFF)
def wrapper(*args): nonlocal found_arity, limit while 1: try:
ret = func(*args[limit:])
found_arity = True return ret except TypeError as te: # re-raise TypeErrors if they did not come from our arity testing if found_arity: raise else:
tb = te.__traceback__
frames = traceback.extract_tb(tb, limit=2)
frame_summary = frames[-1]
trim_arity_type_error = (
[frame_summary[:2]][-1][:2] == pa_call_line_synth
) del tb
if trim_arity_type_error: if limit < max_limit:
limit += 1 continue
raise # fmt: on
# copy func name to wrapper for sensible debug output # (can't use functools.wraps, since that messes with function signature)
func_name = getattr(func, "__name__", getattr(func, "__class__").__name__)
wrapper.__name__ = func_name
wrapper.__doc__ = func.__doc__
return wrapper
def condition_as_parse_action(
fn: ParseCondition, message: typing.Optional[str] = None, fatal: bool = False
) -> ParseAction: """
Function to convert a simple predicate function that returns ``True`` or ``False``
into a parse action. Can be used in places when a parse action is required and :class:`ParserElement.add_condition` cannot be used (such as when adding a condition
to an operator level in :class:`infix_notation`).
Optional keyword arguments:
- ``message`` - define a custom message to be used in the raised exception
- ``fatal`` - ifTrue, will raise :class:`ParseFatalException` to stop parsing immediately;
otherwise will raise :class:`ParseException`
"""
msg = message if message isnotNoneelse"failed user-defined condition"
exc_type = ParseFatalException if fatal else ParseException
fn = _trim_arity(fn)
# default whitespace chars are space, <TAB> and newline
Word(alphas)[1, ...].parse_string("abc def\nghi jkl") # -> ['abc', 'def', 'ghi', 'jkl']
# change to just treat newline as significant
ParserElement.set_default_whitespace_chars(" \t")
Word(alphas)[1, ...].parse_string("abc def\nghi jkl") # -> ['abc', 'def'] """
ParserElement.DEFAULT_WHITE_CHARS = chars
# update whitespace all parse expressions defined in this module for expr in _builtin_exprs: if expr.copyDefaultWhiteChars:
expr.whiteChars = set(chars)
@staticmethod def inline_literals_using(cls: type) -> None: """
Set class to be used for inclusion of string literals into a parser.
Example::
# default literal class used is Literal
integer = Word(nums)
date_str = integer("year") + '/' + integer("month") + '/' + integer("day")
def suppress_warning(self, warning_type: Diagnostics) -> "ParserElement": """
Suppress warnings emitted for a particular diagnostic on this expression.
Example::
base = pp.Forward()
base.suppress_warning(Diagnostics.warn_on_parse_using_empty_Forward)
# statement would normally raise a warning, but is now suppressed
print(base.parse_string("x"))
def visit_all(self): """General-purpose method to yield all expressions and sub-expressions in a grammar. Typically just for internal use. """
to_visit = deque([self])
seen = set() while to_visit:
cur = to_visit.popleft()
# guard against looping forever through recursive grammars if cur in seen: continue
seen.add(cur)
to_visit.extend(cur.recurse()) yield cur
def copy(self) -> "ParserElement": """
Make a copy of this :class:`ParserElement`. Useful for defining
different parse actions for the same parsing pattern, using copies of
the original parse element.
def set_results_name(
self, name: str, list_all_matches: bool = False, *, listAllMatches: bool = False
) -> "ParserElement": """
Define name for referencing matching tokens as a nested attribute
of the returned parse results.
Normally, results names are assigned as you would assign keys in a dict:
any existing value is overwritten by later values. If it is necessary to
keep all values captured for a particular results name, call ``set_results_name`` with ``list_all_matches`` = True.
NOTE: ``set_results_name`` returns a *copy* of the original :class:`ParserElement` object;
this is so that the client can define a basic element, such as an
integer, and reference it in multiple places with different names.
You can also set results names using the abbreviated syntax,
``expr("name")`` in place of ``expr.set_results_name("name")``
- see :class:`__call__`. If ``list_all_matches`` is required, use
``expr("name*")``.
def _setResultsName(self, name, listAllMatches=False): if name isNone: return self
newself = self.copy() if name.endswith("*"):
name = name[:-1]
listAllMatches = True
newself.resultsName = name
newself.modalResults = not listAllMatches return newself
def set_break(self, break_flag: bool = True) -> "ParserElement": """
Method to invoke the Python pdb debugger when this element is
about to be parsed. Set ``break_flag`` to ``True`` to enable, ``False`` to
disable. """ if break_flag:
_parseMethod = self._parse
def set_parse_action(self, *fns: ParseAction, **kwargs) -> "ParserElement": """
Define one or more actions to perform when successfully matching parse element definition.
Parse actions can be called to perform data conversions, do extra validation,
update external data structures, or enhance or replace the parsed tokens.
Each parse action ``fn`` is a callable method with 0-3 arguments, called as
``fn(s, loc, toks)`` , ``fn(loc, toks)`` , ``fn(toks)`` , or just ``fn()`` , where:
- ``s`` = the original string being parsed (see note below)
- ``loc`` = the location of the matching substring
- ``toks`` = a list of the matched tokens, packaged as a :class:`ParseResults` object
The parsed tokens are passed to the parse action as ParseResults. They can be
modified in place using list-style append, extend, and pop operations to update
the parsed list elements; andwith dictionary-style item set anddel operations
to add, update, or remove any named results. If the tokens are modified in place,
it isnot necessary to return them with a return statement.
Parse actions can also completely replace the given tokens, with another ``ParseResults``
object, orwith some entirely different object (common for parse actions that perform data
conversions). A convenient way to build a new parse result is to define the values
using a dict, and then create the return value using :class:`ParseResults.from_dict`.
IfNoneis passed as the ``fn`` parse action, all previously added parse actions for this
expression are cleared.
Optional keyword arguments:
- ``call_during_try`` = (default= ``False``) indicate if parse action should be run during
lookaheads and alternate testing. For parse actions that have side effects, it is
important to only call the parse action once it is determined that it is being
called as part of a successful parse. For parse actions that perform additional
validation, then call_during_try should be passed asTrue, so that the validation
code is included in the preliminary "try" parses.
Note: the default parsing behavior is to expand tabs in the input string
before starting the parsing process. See :class:`parse_string` for more
information on parsing strings containing ``<TAB>`` s, and suggested
methods to maintain a consistent view of the parsed string, the parse
location, and line and column positions within the parsed string.
Example::
# parse dates in the form YYYY/MM/DD
# use parse action to convert toks from str to int at parse time def convert_to_int(toks): return int(toks[0])
# use a parse action to verify that the date is a valid date def is_valid_date(instring, loc, toks): from datetime import date
year, month, day = toks[::2] try:
date(year, month, day) except ValueError: raise ParseException(instring, loc, "invalid date given")
# note that integer fields are now ints, not strings
date_str.run_tests(''' # successful parse - note that integer fields were converted to ints
1999/12/31
# fail - invalid date
1999/13/31 ''') """ if list(fns) == [None]:
self.parseAction = [] else: ifnot all(callable(fn) for fn in fns): raise TypeError("parse actions must be callable")
self.parseAction = [_trim_arity(fn) for fn in fns]
self.callDuringTry = kwargs.get( "call_during_try", kwargs.get("callDuringTry", False)
) return self
def add_parse_action(self, *fns: ParseAction, **kwargs) -> "ParserElement": """
Add one or more parse actions to expression's list of parse actions. See :class:`set_parse_action`.
See examples in :class:`copy`. """
self.parseAction += [_trim_arity(fn) for fn in fns]
self.callDuringTry = self.callDuringTry or kwargs.get( "call_during_try", kwargs.get("callDuringTry", False)
) return self
def add_condition(self, *fns: ParseCondition, **kwargs) -> "ParserElement": """Add a boolean predicate function to expression's list of parse actions. See
:class:`set_parse_action` for function call signatures. Unlike ``set_parse_action``,
functions passed to ``add_condition`` need to return boolean success/fail of the condition.
Optional keyword arguments:
- ``message`` = define a custom message to be used in the raised exception
- ``fatal`` = ifTrue, will raise ParseFatalException to stop parsing immediately; otherwise will raise
ParseException
- ``call_during_try`` = boolean to indicate if this method should be called during internal tryParse calls,
default=False
Example::
integer = Word(nums).set_parse_action(lambda toks: int(toks[0]))
year_int = integer.copy()
year_int.add_condition(lambda toks: toks[0] >= 2000, message="Only support years 2000 and later")
date_str = year_int + '/' + integer + '/' + integer
result = date_str.parse_string("1999/12/31") # -> Exception: Only support years 2000 and later (at char 0),
(line:1, col:1) """ for fn in fns:
self.parseAction.append(
condition_as_parse_action(
fn,
message=str(kwargs.get("message")),
fatal=bool(kwargs.get("fatal", False)),
)
)
def set_fail_action(self, fn: ParseFailAction) -> "ParserElement": """
Define action to perform if parsing fails at this expression.
Fail acton fn is a callable function that takes the arguments
``fn(s, loc, expr, err)`` where:
- ``s`` = string being parsed
- ``loc`` = location where expression match was attempted and failed
- ``expr`` = the parse expression that failed
- ``err`` = the exception thrown
The function returns no value. It may throw :class:`ParseFatalException` if it is desired to stop parsing immediately."""
self.failAction = fn return self
def _skipIgnorables(self, instring: str, loc: int) -> int: ifnot self.ignoreExprs: return loc
exprsFound = True
ignore_expr_fns = [e._parse for e in self.ignoreExprs] while exprsFound:
exprsFound = False for ignore_fn in ignore_expr_fns: try: while 1:
loc, dummy = ignore_fn(instring, loc)
exprsFound = True except ParseException: pass return loc
def preParse(self, instring: str, loc: int) -> int: if self.ignoreExprs:
loc = self._skipIgnorables(instring, loc)
if self.skipWhitespace:
instrlen = len(instring)
white_chars = self.whiteChars while loc < instrlen and instring[loc] in white_chars:
loc += 1
class _CacheType(dict): """ class to help type checking """
not_in_cache: bool
def get(self, *args):
...
def set(self, *args):
...
# argument cache for optimizing repeated calls when backtracking through recursive expressions
packrat_cache = (
_CacheType()
) # set later by enable_packrat(); this is here so that reset_cache() doesn't fail
packrat_cache_lock = RLock()
packrat_cache_stats = [0, 0]
# this method gets repeatedly called during backtracking with the same arguments - # we can cache these arguments and save ourselves the trouble of re-parsing the contained expression def _parseCache(
self, instring, loc, doActions=True, callPreParse=True
) -> Tuple[int, ParseResults]:
HIT, MISS = 0, 1 TRY, MATCH, FAIL = 0, 1, 2
lookup = (self, instring, loc, callPreParse, doActions) with ParserElement.packrat_cache_lock:
cache = ParserElement.packrat_cache
value = cache.get(lookup) if value is cache.not_in_cache:
ParserElement.packrat_cache_stats[MISS] += 1 try:
value = self._parseNoCache(instring, loc, doActions, callPreParse) except ParseBaseException as pe: # cache a copy of the exception, without the traceback
cache.set(lookup, pe.__class__(*pe.args)) raise else:
cache.set(lookup, (value[0], value[1].copy(), loc)) return value else:
ParserElement.packrat_cache_stats[HIT] += 1 if self.debug and self.debugActions.debug_try: try:
self.debugActions.debug_try(instring, loc, self, cache_hit=True) # type: ignore [call-arg] except TypeError: pass if isinstance(value, Exception): if self.debug and self.debugActions.debug_fail: try:
self.debugActions.debug_fail(
instring, loc, self, value, cache_hit=True# type: ignore [call-arg]
) except TypeError: pass raise value
@staticmethod def disable_memoization() -> None: """
Disables active Packrat or Left Recursion parsing and their memoization
This method also works if neither Packrat nor Left Recursion are enabled.
This makes it safe to call before activating Packrat nor Left Recursion
to clear any previous settings. """
ParserElement.reset_cache()
ParserElement._left_recursion_enabled = False
ParserElement._packratEnabled = False
ParserElement._parse = ParserElement._parseNoCache
@staticmethod def enable_left_recursion(
cache_size_limit: typing.Optional[int] = None, *, force=False
) -> None: """
Enables "bounded recursion" parsing, which allows for both direct and indirect
left-recursion. During parsing, left-recursive :class:`Forward` elements are
repeatedly matched with a fixed recursion depth that is gradually increased
until finding the longest match.
Example::
from pip._vendor import pyparsing as pp
pp.ParserElement.enable_left_recursion()
E = pp.Forward("E")
num = pp.Word(pp.nums) # match `num`, or `num '+' num`, or `num '+' num '+' num`, ...
E <<= E + '+' - num | num
print(E.parse_string("1+2+3"))
Recursion search naturally memoizes matches of ``Forward`` elements and may
thus skip reevaluation of parse actions during backtracking. This may break
programs with parse actions which rely on strict ordering of side-effects.
Parameters:
- ``cache_size_limit`` - (default=``None``) - memoize at most this many
``Forward`` elements during matching; if ``None`` (the default),
memoize all ``Forward`` elements.
Bounded Recursion parsing works similar but not identical to Packrat parsing,
thus the two cannot be used together. Use ``force=True`` to disable any
previous, conflicting settings. """ if force:
ParserElement.disable_memoization() elif ParserElement._packratEnabled: raise RuntimeError("Packrat and Bounded Recursion are not compatible") if cache_size_limit isNone:
ParserElement.recursion_memos = _UnboundedMemo() # type: ignore[assignment] elif cache_size_limit > 0:
ParserElement.recursion_memos = _LRUMemo(capacity=cache_size_limit) # type: ignore[assignment] else: raise NotImplementedError("Memo size of %s" % cache_size_limit)
ParserElement._left_recursion_enabled = True
@staticmethod def enable_packrat(cache_size_limit: int = 128, *, force: bool = False) -> None: """
Enables "packrat" parsing, which adds memoizing to the parsing logic.
Repeated parse attempts at the same string location (which happens
often in many complex grammars) can immediately return a cached value,
instead of re-executing parsing/validating code. Memoizing is done of
both valid results and parsing exceptions.
Parameters:
- ``cache_size_limit`` - (default= ``128``) - if an integer value is provided
will limit the size of the packrat cache; ifNoneis passed, then
the cache size will be unbounded; if 0 is passed, the cache will
be effectively disabled.
This speedup may break existing programs that use parse actions that
have side-effects. For this reason, packrat parsing is disabled when
you first import pyparsing. To activate the packrat feature, your
program must call the class method :class:`ParserElement.enable_packrat`. For best results, call ``enable_packrat()`` immediately after
importing pyparsing.
Example::
from pip._vendor import pyparsing
pyparsing.ParserElement.enable_packrat()
Packrat parsing works similar but not identical to Bounded Recursion parsing,
thus the two cannot be used together. Use ``force=True`` to disable any
previous, conflicting settings. """ if force:
ParserElement.disable_memoization() elif ParserElement._left_recursion_enabled: raise RuntimeError("Packrat and Bounded Recursion are not compatible") ifnot ParserElement._packratEnabled:
ParserElement._packratEnabled = True if cache_size_limit isNone:
ParserElement.packrat_cache = _UnboundedCache() else:
ParserElement.packrat_cache = _FifoCache(cache_size_limit) # type: ignore[assignment]
ParserElement._parse = ParserElement._parseCache
def parse_string(
self, instring: str, parse_all: bool = False, *, parseAll: bool = False
) -> ParseResults: """
Parse a string with respect to the parser definition. This function is intended as the primary interface to the
client code.
:param instring: The input string to be parsed.
:param parse_all: If set, the entire input string must match the grammar.
:param parseAll: retained for pre-PEP8 compatibility, will be removed in a future release.
:raises ParseException: Raised if ``parse_all`` is set and the input string does not match the whole grammar.
:returns: the parsed data as a :class:`ParseResults` object, which may be accessed as a `list`, a `dict`, or
an object with attributes if the given parser includes results names.
If the input string is required to match the entire grammar, ``parse_all`` flag must be set to ``True``. This is also equivalent to ending the grammar with :class:`StringEnd`\\ ().
To report proper column numbers, ``parse_string`` operates on a copy of the input string where all tabs are
converted to spaces (8 spaces per tab, as per the default in ``string.expandtabs``). If the input string
contains tabs and the grammar uses parse actions that use the ``loc`` argument to index into the string
being parsed, one can ensure a consistent view of the input string by doing one of the following:
- calling ``parse_with_tabs`` on your grammar before calling ``parse_string`` (see :class:`parse_with_tabs`),
- define your parse action using the full ``(s,loc,toks)`` signature, and reference the input string using the
parse action's ``s`` argument, or
- explicitly expand the tabs in your input string before calling ``parse_string``.
Examples:
By default, partial matches are OK.
>>> res = Word('a').parse_string('aaaaabaaa')
>>> print(res)
['aaaaa']
The parsing behavior varies by the inheriting class of this abstract class. Please refer to the children
directly to see more examples.
It raises an exception if parse_all flag is set and instring does not match the whole grammar.
>>> res = Word('a').parse_string('aaaaabaaa', parse_all=True)
Traceback (most recent call last):
...
pyparsing.ParseException: Expected end of text, found 'b' (at char 5), (line:1, col:6) """
parseAll = parse_all or parseAll
ParserElement.reset_cache() ifnot self.streamlined:
self.streamline() for e in self.ignoreExprs:
e.streamline() ifnot self.keepTabs:
instring = instring.expandtabs() try:
loc, tokens = self._parse(instring, 0) if parseAll:
loc = self.preParse(instring, loc)
se = Empty() + StringEnd()
se._parse(instring, loc) except ParseBaseException as exc: if ParserElement.verbose_stacktrace: raise else: # catch and re-raise exception from here, clearing out pyparsing internal stack trace raise exc.with_traceback(None) else: return tokens
def scan_string(
self,
instring: str,
max_matches: int = _MAX_INT,
overlap: bool = False,
*,
debug: bool = False,
maxMatches: int = _MAX_INT,
) -> Generator[Tuple[ParseResults, int, int], None, None]: """
Scan the input string for expression matches. Each match will return the
matching tokens, start location, and end location. May be called with optional
``max_matches`` argument, to clip scanning after 'n' matches are found. If
``overlap`` is specified, then overlapping matches will be reported.
Note that the start and end locations are reported relative to the string
being parsed. See :class:`parse_string` for more information on parsing
strings with embedded tabs.
Example::
source = "sldjf123lsdjjkf345sldkjf879lkjsfd987"
print(source) for tokens, start, end in Word(alphas).scan_string(source):
print(' '*start + '^'*(end-start))
print(' '*start + tokens[0])
prints::
sldjf123lsdjjkf345sldkjf879lkjsfd987
^^^^^
sldjf
^^^^^^^
lsdjjkf
^^^^^^
sldkjf
^^^^^^
lkjsfd """
maxMatches = min(maxMatches, max_matches) ifnot self.streamlined:
self.streamline() for e in self.ignoreExprs:
e.streamline()
ifnot 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: int = preparseFn(instring, loc)
nextLoc: int
tokens: ParseResults
nextLoc, tokens = parseFn(instring, preloc, callPreParse=False) except ParseException:
loc = preloc + 1 else: if nextLoc > loc:
matches += 1 if debug:
print(
{ "tokens": tokens.asList(), "start": preloc, "end": nextLoc,
}
) yield tokens, preloc, nextLoc if overlap:
nextloc = preparseFn(instring, loc) if nextloc > loc:
loc = nextLoc else:
loc += 1 else:
loc = nextLoc else:
loc = preloc + 1 except ParseBaseException as exc: if ParserElement.verbose_stacktrace: raise else: # catch and re-raise exception from here, clears out pyparsing internal stack trace raise exc.with_traceback(None)
def transform_string(self, instring: str, *, debug: bool = False) -> str: """
Extension to :class:`scan_string`, to modify matching text with modified tokens that may
be returned from a parse action. To use ``transform_string``, define a grammar and
attach a parse action to it that modifies the returned token list.
Invoking ``transform_string()`` on a target string will then scan for matches, and replace the matched text patterns according to the logic in the parse
action. ``transform_string()`` returns the resulting transformed string.
print(wd.transform_string("now is the winter of our discontent made glorious summer by this sun of york."))
prints::
Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York. """
out: List[str] = []
lastE = 0 # force preservation of <TAB>s, to minimize unwanted transformation of string, and to # keep string locs straight between transform_string and scan_string
self.keepTabs = True try: for t, s, e in self.scan_string(instring, debug=debug):
out.append(instring[lastE:s]) if t: if isinstance(t, ParseResults):
out += t.as_list() elif isinstance(t, Iterable) andnot isinstance(t, str_type):
out.extend(t) else:
out.append(t)
lastE = e
out.append(instring[lastE:])
out = [o for o in out if o] return"".join([str(s) for s in _flatten(out)]) except ParseBaseException as exc: if ParserElement.verbose_stacktrace: raise else: # catch and re-raise exception from here, clears out pyparsing internal stack trace raise exc.with_traceback(None)
def search_string(
self,
instring: str,
max_matches: int = _MAX_INT,
*,
debug: bool = False,
maxMatches: int = _MAX_INT,
) -> ParseResults: """
Another extension to :class:`scan_string`, simplifying the access to the tokens found
to match the given parse expression. May be called with optional
``max_matches`` argument, to clip searching after 'n' matches are found.
Example::
# a capitalized word starts with an uppercase letter, followed by zero or more lowercase letters
cap_word = Word(alphas.upper(), alphas.lower())
print(cap_word.search_string("More than Iron, more than Lead, more than Gold I need Electricity"))
# the sum() builtin can be used to merge results into a single ParseResults object
print(sum(cap_word.search_string("More than Iron, more than Lead, more than Gold I need Electricity")))
prints::
[['More'], ['Iron'], ['Lead'], ['Gold'], ['I'], ['Electricity']]
['More', 'Iron', 'Lead', 'Gold', 'I', 'Electricity'] """
maxMatches = min(maxMatches, max_matches) try: return ParseResults(
[t for t, s, e in self.scan_string(instring, maxMatches, debug=debug)]
) except ParseBaseException as exc: if ParserElement.verbose_stacktrace: raise else: # catch and re-raise exception from here, clears out pyparsing internal stack trace raise exc.with_traceback(None)
def split(
self,
instring: str,
maxsplit: int = _MAX_INT,
include_separators: bool = False,
*,
includeSeparators=False,
) -> Generator[str, None, None]: """
Generator method to split a string using the given expression as a separator.
May be called with optional ``maxsplit`` argument, to limit the number of splits; and the optional ``include_separators`` argument (default= ``False``), if the separating
matching text should be included in the split results.
Example::
punc = one_of(list(".,;:/-!?"))
print(list(punc.split("This, this?, this sentence, is badly punctuated!")))
prints::
['This', ' this', '', ' this sentence', ' is badly punctuated', ''] """
includeSeparators = includeSeparators or include_separators
last = 0 for t, s, e in self.scan_string(instring, max_matches=maxsplit): yield instring[last:s] if includeSeparators: yield t[0]
last = e yield instring[last:]
def __add__(self, other) -> "ParserElement": """
Implementation of ``+`` operator - returns :class:`And`. Adding strings to a :class:`ParserElement`
converts them to :class:`Literal`\\ s by default.
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) ifnot isinstance(other, ParserElement): return NotImplemented returnAnd([self, other])
def __radd__(self, other) -> "ParserElement": """
Implementation of ``+`` operator when left operand isnot a :class:`ParserElement` """ if other is Ellipsis: return SkipTo(self)("_skipped*") + self
if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return other + self
def __sub__(self, other) -> "ParserElement": """
Implementation of ``-`` operator, returns :class:`And` with error stop """ if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return self + And._ErrorStop() + other
def __rsub__(self, other) -> "ParserElement": """
Implementation of ``-`` operator when left operand isnot a :class:`ParserElement` """ if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return other - self
def __mul__(self, other) -> "ParserElement": """
Implementation of ``*`` operator, allows use of ``expr * 3`` in place of
``expr + expr + expr``. Expressions may also be multiplied by a 2-integer
tuple, similar to ``{min, max}`` multipliers in regular expressions. Tuples
may also include ``None`` asin:
- ``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 notraise 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 isnot Ellipsis elseNonefor o in other)
other = (other + (None, None))[:2] if other[0] isNone:
other = (0, other[1]) if isinstance(other[0], int) and other[1] isNone: if other[0] == 0: return ZeroOrMore(self) if other[0] == 1: return OneOrMore(self) else: return self * other[0] + ZeroOrMore(self) elif isinstance(other[0], int) and isinstance(other[1], int):
minElements, optElements = other
optElements -= minElements else: return NotImplemented else: return NotImplemented
if minElements < 0: raise ValueError("cannot multiply ParserElement by negative value") if optElements < 0: raise ValueError( "second tuple value must be greater or equal to first tuple value"
) if minElements == optElements == 0: returnAnd([])
if optElements:
def makeOptionalList(n): if n > 1: return Opt(self + makeOptionalList(n - 1)) else: return Opt(self)
if minElements: if minElements == 1:
ret = self + makeOptionalList(optElements) else:
ret = And([self] * minElements) + makeOptionalList(optElements) else:
ret = makeOptionalList(optElements) else: if minElements == 1:
ret = self else:
ret = And([self] * minElements) return ret
def __or__(self, other) -> "ParserElement": """
Implementation of ``|`` operator - returns :class:`MatchFirst` """ if other is Ellipsis: return _PendingSkip(self, must_skip=True)
if isinstance(other, str_type): # `expr | ""` is equivalent to `Opt(expr)` if other == "": return Opt(self)
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return MatchFirst([self, other])
def __ror__(self, other) -> "ParserElement": """
Implementation of ``|`` operator when left operand isnot a :class:`ParserElement` """ if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return other | self
def __xor__(self, other) -> "ParserElement": """
Implementation of ``^`` operator - returns :class:`Or` """ if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented returnOr([self, other])
def __rxor__(self, other) -> "ParserElement": """
Implementation of ``^`` operator when left operand isnot a :class:`ParserElement` """ if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return other ^ self
def __and__(self, other) -> "ParserElement": """
Implementation of ``&`` operator - returns :class:`Each` """ if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return Each([self, other])
def __rand__(self, other) -> "ParserElement": """
Implementation of ``&`` operator when left operand isnot a :class:`ParserElement` """ if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return other & self
# disable __iter__ to override legacy use of sequential access to __getitem__ to # iterate over a sequence
__iter__ = None
def __getitem__(self, key): """
use ``[]`` indexing notation as a short form for expression repetition:
- ``expr[n]`` is equivalent to ``expr*n``
- ``expr[m, n]`` is equivalent to ``expr*(m, n)``
- ``expr[n, ...]`` or ``expr[n,]`` is equivalent
to ``expr*n + ZeroOrMore(expr)``
(read as"at least n instances of ``expr``")
- ``expr[..., n]`` is equivalent to ``expr*(0, n)``
(read as"0 to n instances of ``expr``")
- ``expr[...]`` and ``expr[0, ...]`` are equivalent to ``ZeroOrMore(expr)``
- ``expr[1, ...]`` is equivalent to ``OneOrMore(expr)``
``None`` may be used in place of ``...``.
Note that ``expr[..., n]`` and ``expr[m, n]`` do notraise an exception if more than ``n`` ``expr``\\ s exist in the input stream. If this behavior is
desired, then write ``expr[..., n] + ~expr``.
For repetition with a stop_on expression, use slice notation:
- ``expr[...: end_expr]`` and ``expr[0, ...: end_expr]`` are equivalent to ``ZeroOrMore(expr, stop_on=end_expr)``
- ``expr[1, ...: end_expr]`` is equivalent to ``OneOrMore(expr, stop_on=end_expr)``
# convert single arg keys to tuples if isinstance(key, str_type):
key = (key,) try:
iter(key) except TypeError:
key = (key, key)
if len(key) > 2: raise TypeError(
f"only 1 or 2 index arguments supported ({key[:5]}{f'... [{len(key)}]' if len(key) > 5 else ''})"
)
# clip to 2 elements
ret = self * tuple(key[:2])
ret = typing.cast(_MultipleMatch, ret)
if stop_on_defined:
ret.stopOn(stop_on)
return ret
def __call__(self, name: typing.Optional[str] = None) -> "ParserElement": """
Shortcut for :class:`set_results_name`, with ``list_all_matches=False``.
If ``name`` is given with a trailing ``'*'`` character, then ``list_all_matches`` will be
passed as ``True``.
If ``name`` is omitted, same as calling :class:`copy`.
Example::
# these are equivalent
userdata = Word(alphas).set_results_name("name") + Word(nums + "-").set_results_name("socsecno")
userdata = Word(alphas)("name") + Word(nums + "-")("socsecno") """ if name isnotNone: return self._setResultsName(name) else: return self.copy()
def suppress(self) -> "ParserElement": """
Suppresses the output of this :class:`ParserElement`; useful to keep punctuation from
cluttering up returned output. """ return Suppress(self)
def ignore_whitespace(self, recursive: bool = True) -> "ParserElement": """
Enables the skipping of whitespace before matching the characters in the
:class:`ParserElement`'s defined pattern.
:param recursive: If ``True`` (the default), also enable whitespace skipping in child elements (if any) """
self.skipWhitespace = True return self
def leave_whitespace(self, recursive: bool = True) -> "ParserElement": """
Disables the skipping of whitespace before matching the characters in the
:class:`ParserElement`'s defined pattern. This is normally only used internally by
the pyparsing module, but may be needed in some whitespace-sensitive grammars.
:param recursive: Iftrue (the default), also disable whitespace skipping in child elements (if any) """
self.skipWhitespace = False return self
def parse_with_tabs(self) -> "ParserElement": """
Overrides default behavior to expand ``<TAB>`` s to spaces before parsing the input string.
Must be called before ``parse_string`` when the input grammar contains elements that
match ``<TAB>`` characters. """
self.keepTabs = True return self
def ignore(self, other: "ParserElement") -> "ParserElement": """
Define expression to be ignored (e.g., comments) while doing pattern
matching; may be called repeatedly, to define multiple comment or other
ignorable patterns.
if isinstance(other, str_type):
other = Suppress(other)
if isinstance(other, Suppress): if other notin self.ignoreExprs:
self.ignoreExprs.append(other) else:
self.ignoreExprs.append(Suppress(other.copy())) return self
- ``start_action`` - method to be called when an expression is about to be parsed;
should have the signature ``fn(input_string: str, location: int, expression: ParserElement, cache_hit: bool)``
- ``success_action`` - method to be called when an expression has successfully parsed;
should have the signature ``fn(input_string: str, start_location: int, end_location: int, expression: ParserELement, parsed_tokens: ParseResults, cache_hit: bool)``
- ``exception_action`` - method to be called when expression fails to parse;
should have the signature ``fn(input_string: str, location: int, expression: ParserElement, exception: Exception, cache_hit: bool)`` """
self.debugActions = self.DebugActions(
start_action or _default_start_debug_action, # type: ignore[truthy-function]
success_action or _default_success_debug_action, # type: ignore[truthy-function]
exception_action or _default_exception_debug_action, # type: ignore[truthy-function]
)
self.debug = True return self
def set_debug(self, flag: bool = True, recurse: bool = False) -> "ParserElement": """
Enable display of debugging messages while doing pattern matching.
Set ``flag`` to ``True`` to enable, ``False`` to disable.
Set ``recurse`` to ``True`` to set the debug flag on this expression and all sub-expressions.
Match alphaword at loc 0(1,1)
Matched alphaword -> ['abc']
Match alphaword at loc 3(1,4)
Exception raised:Expected alphaword (at char 4), (line:1, col:5)
Match alphaword at loc 7(1,8)
Matched alphaword -> ['xyz']
Match alphaword at loc 11(1,12)
Exception raised:Expected alphaword (at char 12), (line:1, col:13)
Match alphaword at loc 15(1,16)
Exception raised:Expected alphaword (at char 15), (line:1, col:16)
The output shown is that produced by the default debug actions - custom debug actions can be
specified using :class:`set_debug_actions`. Prior to attempting
to match the ``wd`` expression, the debugging message ``"Match <exprname> at loc <n>(<line>,<col>)"`` is shown. Then if the parse succeeds, a ``"Matched"`` message is shown, or an ``"Exception raised"``
message is shown. Also note the use of :class:`set_name` to assign a human-readable name to the expression,
which makes debugging and exception messages easier to understand - for instance, the default
name created for the :class:`Word` expression without calling ``set_name`` is ``"W:(A-Za-z)"``. """ if recurse: for expr in self.visit_all():
expr.set_debug(flag, recurse=False) return self
@property def name(self) -> str: # This will use a user-defined name if available, but otherwise defaults back to the auto-generated name return self.customName if self.customName isnotNoneelse self.default_name
def _checkRecursion(self, parseElementList):
subRecCheckList = parseElementList[:] + [self] for e in self.recurse():
e._checkRecursion(subRecCheckList)
def validate(self, validateTrace=None) -> None: """
Check defined expressions for valid structure, check for infinite recursive definitions. """
warnings.warn( "ParserElement.validate() is deprecated, and should not be used to check for left recursion",
DeprecationWarning,
stacklevel=2,
)
self._checkRecursion([])
def parse_file(
self,
file_or_filename: Union[str, Path, TextIO],
encoding: str = "utf-8",
parse_all: bool = False,
*,
parseAll: bool = False,
) -> ParseResults: """
Execute the parse expression on the given file or filename. If a filename is specified (instead of a file object),
the entire file is opened, read, and closed before parsing. """
parseAll = parseAll or parse_all try:
file_or_filename = typing.cast(TextIO, file_or_filename)
file_contents = file_or_filename.read() except AttributeError:
file_or_filename = typing.cast(str, file_or_filename) with open(file_or_filename, "r", encoding=encoding) as f:
file_contents = f.read() try: return self.parse_string(file_contents, 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 matches(
self, test_string: str, parse_all: bool = True, *, parseAll: bool = True
) -> bool: """
Method for quick testing of a parser against a test string. Good for simple
inline microtests of sub expressions while building up larger parser.
Parameters:
- ``test_string`` - to test against this expression for a match
- ``parse_all`` - (default= ``True``) - flag to pass to :class:`parse_string` when running tests
def run_tests(
self,
tests: Union[str, List[str]],
parse_all: bool = True,
comment: typing.Optional[Union["ParserElement", str]] = "#",
full_dump: bool = True,
print_results: bool = True,
failure_tests: bool = False,
post_parse: typing.Optional[Callable[[str, ParseResults], str]] = None,
file: typing.Optional[TextIO] = None,
with_line_numbers: bool = False,
*,
parseAll: bool = True,
fullDump: bool = True,
printResults: bool = True,
failureTests: bool = False,
postParse: typing.Optional[Callable[[str, ParseResults], str]] = None,
) -> Tuple[bool, List[Tuple[str, Union[ParseResults, Exception]]]]: """
Execute the parse expression on a series of test strings, showing each
test, the parsed results or where the parse failed. Quick and easy way to
run a parse expression against a list of sample strings.
Parameters:
- ``tests`` - a list of separate test strings, or a multiline string of test strings
- ``parse_all`` - (default= ``True``) - flag to pass to :class:`parse_string` when running tests
- ``comment`` - (default= ``'#'``) - expression for indicating embedded comments in the test
string; passNone to disable comment filtering
- ``full_dump`` - (default= ``True``) - dump results as list followed by results names in nested outline; ifFalse, only dump nested list
- ``print_results`` - (default= ``True``) prints test output to stdout
- ``failure_tests`` - (default= ``False``) indicates if these tests are expected to fail parsing
- ``post_parse`` - (default= ``None``) optional callback for successful parse results; called as
`fn(test_string, parse_results)` and returns a string to be added to the test output
- ``file`` - (default= ``None``) optional file-like object to which test output will be written; ifNone, will default to ``sys.stdout``
- ``with_line_numbers`` - default= ``False``) show test strings with line and column numbers
Returns: a (success, results) tuple, where success indicates that all tests succeeded
(or failed if ``failure_tests`` isTrue), and the results contain a list of lines of each
test's output
Example::
number_expr = pyparsing_common.number.copy()
result = number_expr.run_tests(''' # unsigned integer
100 # negative integer
-100 # float with scientific notation
6.02e23 # integer with scientific notation
1e-12 ''')
print("Success"if result[0] else"Failed!")
result = number_expr.run_tests(''' # stray character
100Z # missing leading digit before '.'
-.100 # too many '.'
3.14.159 ''', failure_tests=True)
print("Success"if result[0] else"Failed!")
prints::
# unsigned integer
100
[100]
# negative integer
-100
[-100]
# float with scientific notation
6.02e23
[6.02e+23]
# integer with scientific notation
1e-12
[1e-12]
Success
# stray character
100Z
^
FAIL: Expected end of text (at char 3), (line:1, col:4)
# missing leading digit before '.'
-.100
^
FAIL: Expected {real number with scientific notation | real number | signed integer} (at char 0), (line:1, col:1)
# too many '.'
3.14.159
^
FAIL: Expected end of text (at char 4), (line:1, col:5)
Success
Each test string must be on a single line. If you want to test a string that spans multiple
lines, create a test like this::
expr.run_tests(r"this is a test\\n of strings that spans \\n 3 lines")
(Note that this is a raw string literal, you must include the leading ``'r'``.) """ from .testing import pyparsing_test
parseAll = parseAll and parse_all
fullDump = fullDump and full_dump
printResults = printResults and print_results
failureTests = failureTests or failure_tests
postParse = postParse or post_parse if isinstance(tests, str_type):
tests = typing.cast(str, tests)
line_strip = type(tests).strip
tests = [line_strip(test_line) for test_line in tests.rstrip().splitlines()]
comment_specified = comment isnotNone if comment_specified: if isinstance(comment, str_type):
comment = typing.cast(str, comment)
comment = Literal(comment)
comment = typing.cast(ParserElement, comment) if file isNone:
file = sys.stdout
print_ = file.write
result: Union[ParseResults, Exception]
allResults: List[Tuple[str, Union[ParseResults, Exception]]] = []
comments: List[str] = []
success = True
NL = Literal(r"\n").add_parse_action(replace_with("\n")).ignore(quoted_string)
BOM = "\ufeff" for t in tests: if comment_specified and comment.matches(t, False) or comments andnot t:
comments.append(
pyparsing_test.with_line_numbers(t) if with_line_numbers else t
) continue ifnot t: continue
out = [ "\n" + "\n".join(comments) if comments else"",
pyparsing_test.with_line_numbers(t) if with_line_numbers else t,
]
comments = [] try: # convert newline marks to actual newlines, and strip leading BOM if present
t = NL.transform_string(t.lstrip(BOM))
result = self.parse_string(t, parse_all=parseAll) except ParseBaseException as pe:
fatal = "(FATAL)"if isinstance(pe, ParseFatalException) else""
out.append(pe.explain())
out.append("FAIL: " + str(pe)) if ParserElement.verbose_stacktrace:
out.extend(traceback.format_tb(pe.__traceback__))
success = success and failureTests
result = pe except Exception as exc:
out.append(f"FAIL-EXCEPTION: {type(exc).__name__}: {exc}") if ParserElement.verbose_stacktrace:
out.extend(traceback.format_tb(exc.__traceback__))
success = success and failureTests
result = exc else:
success = success andnot failureTests if postParse isnotNone: try:
pp_value = postParse(t, result) if pp_value isnotNone: if isinstance(pp_value, ParseResults):
out.append(pp_value.dump()) else:
out.append(str(pp_value)) else:
out.append(result.dump()) except Exception as e:
out.append(result.dump(full=fullDump))
out.append(
f"{postParse.__name__} failed: {type(e).__name__}: {e}"
) else:
out.append(result.dump(full=fullDump))
out.append("")
if printResults:
print_("\n".join(out))
allResults.append((t, result))
return success, allResults
def create_diagram(
self,
output_html: Union[TextIO, Path, str],
vertical: int = 3,
show_results_names: bool = False,
show_groups: bool = False,
embed: bool = False,
**kwargs,
) -> None: """
Create a railroad diagram for the parser.
Parameters:
- ``output_html`` (str or file-like object) - output target for generated
diagram HTML
- ``vertical`` (int) - threshold for formatting multiple alternatives vertically
instead of horizontally (default=3)
- ``show_results_names`` - bool flag whether diagram should show annotations for
defined results names
- ``show_groups`` - bool flag whether groups should be highlighted with an unlabeled surrounding box
- ``embed`` - bool flag whether generated HTML should omit <HEAD>, <BODY>, and <DOCTYPE> tags to embed
the resulting HTML in an enclosing HTML source
- ``head`` - str containing additional HTML to insert into the <HEAD> section of the generated code;
can be used to insert custom CSS styling
- ``body`` - str containing additional HTML to insert at the beginning of the <BODY> section of the
generated code
Additional diagram-formatting keyword arguments can also be included;
see railroad.Diagram class. """
try: from .diagram import to_railroad, railroad_to_html except ImportError as ie: raise Exception( "must ``pip install pyparsing[diagrams]`` to generate parser railroad diagrams"
) from ie
self.streamline()
railroad = to_railroad(
self,
vertical=vertical,
show_results_names=show_results_names,
show_groups=show_groups,
diagram_kwargs=kwargs,
) if isinstance(output_html, (str, Path)): with open(output_html, "w", encoding="utf-8") as diag_file:
diag_file.write(railroad_to_html(railroad, embed=embed, **kwargs)) else: # we were passed a file-like object, just write to it
output_html.write(railroad_to_html(railroad, embed=embed, **kwargs))
class _PendingSkip(ParserElement): # internal placeholder class to hold a place were '...' is added to a parser element, # once another ParserElement is added, this placeholder will be replaced with a SkipTo def __init__(self, expr: ParserElement, must_skip: bool = False):
super().__init__()
self.anchor = expr
self.must_skip = must_skip
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 preceded and followed by whitespace or
non-keyword characters. Compare with :class:`Literal`:
- ``Literal("if")`` will match the leading ``'if'`` in
``'ifAndOnlyIf'``.
- ``Keyword("if")`` will not; it will only match the leading
``'if'`` in ``'if x=1'``, or ``'if(y==2)'``
Accepts two optional constructor arguments in addition to the
keyword string:
- ``ident_chars`` is a string of characters that would be valid
identifier characters, defaulting to all alphanumerics + "_"and "$"
- ``caseless`` allows case-insensitive matching, default is ``False``.
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() notin self.identChars: if (
loc >= len(instring) - self.matchLen or instring[loc + self.matchLen].upper() notin 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] notin self.identChars: if (
loc >= len(instring) - self.matchLen or instring[loc + self.matchLen] notin 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
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.
class CloseMatch(Token): """A variation on :class:`Literal` which matches "close" matches,
that is, strings with at most 'n' mismatching characters.
:class:`CloseMatch` takes parameters:
- ``match_string`` - string to be matched
- ``caseless`` - a boolean indicating whether to ignore casing when comparing characters
- ``max_mismatches`` - (``default=1``) maximum number of
mismatches allowed to count as a match
The results from a successful parse will contain the matched text from the input string and the following named results:
- ``mismatches`` - a list of the positions within the
match_string where mismatches were found
- ``original`` - the original match_string used to compare
against the input string
If ``mismatches`` is an empty list, then the match was an exact
match.
class Word(Token): """Token for matching words composed of allowed character sets.
Parameters:
- ``init_chars`` - string of all characters that should be used to
match as a word; "ABC" will match "AAA", "ABAB", "CBAC", etc.; if ``body_chars`` is also specified, then this is the string of
initial characters
- ``body_chars`` - string of characters that
can be used for matching after a matched initial character as
given in ``init_chars``; if omitted, same as the initial characters
(default=``None``)
- ``min`` - minimum number of characters to match (default=1)
- ``max`` - maximum number of characters to match (default=0)
- ``exact`` - exact number of characters to match (default=0)
- ``as_keyword`` - match as a keyword (default=``False``)
- ``exclude_chars`` - characters that might be
found in the input ``body_chars`` string but which should not be
accepted for matching ;useful to define a word of all
printables exceptfor one or two characters, for instance
(default=``None``)
:class:`srange` is useful for defining custom character set strings for defining :class:`Word` expressions, using range notation from
regular expression character sets.
A common mistake is to use :class:`Word` to match a specific literal
string, asin ``Word("Address")``. Remember that :class:`Word`
uses the string argument to define *sets* of matchable characters.
This expression would match "Add", "AAA", "dAred", or any other word
made up of the characters 'A', 'd', 'r', 'e', and's'. To match an
exact literal string, use :class:`Literal` or :class:`Keyword`.
pyparsing includes helper strings for building Words:
- :class:`alphas`
- :class:`nums`
- :class:`alphanums`
- :class:`hexnums`
- :class:`alphas8bit` (alphabetic characters in ASCII range 128-255
- accented, tilded, umlauted, etc.)
- :class:`punc8bit` (non-alphabetic characters in ASCII range
128-255 - currency, symbols, superscripts, diacriticals, etc.)
- :class:`printables` (any non-whitespace character)
``alphas``, ``nums``, and ``printables`` are also defined in several
Unicode sets - see :class:`pyparsing_unicode``.
Example::
# a word composed of digits
integer = Word(nums) # equivalent to Word("0123456789") or Word(srange("0-9"))
# a word with a leading capital, and zero or more lowercase
capital_word = Word(alphas.upper(), alphas.lower())
# hostnames are alphanumeric, with leading alpha, and '-'
hostname = Word(alphas, alphanums + '-')
# roman numeral (not a strict parser, accepts invalid mix of characters)
roman = Word("IVXLCDM")
# any string of non-whitespace characters, except for ','
csv_value = Word(printables, exclude_chars=",") """
if min < 1: raise ValueError( "cannot specify a minimum length < 1; use Opt(Word()) if zero-length word is permitted"
)
if self.maxSpecified and min > max: raise ValueError(
f"invalid args, if min and max both specified min must be <= max (min={min}, max={max})"
)
self.minLen = min
if max > 0:
self.maxLen = max else:
self.maxLen = _MAX_INT
if exact > 0:
min = max = exact
self.maxLen = exact
self.minLen = exact
self.errmsg = "Expected " + self.name
self.mayIndexError = False
self.asKeyword = asKeyword if self.asKeyword:
self.errmsg += " as a keyword"
# see if we can make a regex for this Word if" "notin (self.initChars | self.bodyChars): if len(self.initChars) == 1:
re_leading_fragment = re.escape(self.initCharsOrig) else:
re_leading_fragment = f"[{_collapse_string_to_ranges(self.initChars)}]"
if self.bodyChars == self.initChars: if max == 0:
repeat = "+" elif max == 1:
repeat = "" else: if self.minLen != self.maxLen:
repeat = f"{{{self.minLen},{'' if self.maxLen == _MAX_INT else self.maxLen}}}" else:
repeat = f"{{{self.minLen}}}"
self.reString = f"{re_leading_fragment}{repeat}" else: if max == 1:
re_body_fragment = ""
repeat = "" else:
re_body_fragment = f"[{_collapse_string_to_ranges(self.bodyChars)}]" if max == 0:
repeat = "*" elif max == 2:
repeat = "?"if min <= 1 else"" else: if min != max:
repeat = f"{{{min - 1 if min > 0 else 0},{max - 1}}}" else:
repeat = f"{{{min - 1 if min > 0 else 0}}}"
def _generateDefaultName(self) -> str: def charsAsStr(s):
max_repr_len = 16
s = _collapse_string_to_ranges(s, re_escape=False) if len(s) > max_repr_len: return s[: max_repr_len - 3] + "..." else: return s
if self.initChars != self.bodyChars:
base = f"W:({charsAsStr(self.initChars)}, {charsAsStr(self.bodyChars)})" else:
base = f"W:({charsAsStr(self.initChars)})"
# add length specification if self.minLen > 1 or self.maxLen != _MAX_INT: if self.minLen == self.maxLen: if self.minLen == 1: return base[2:] else: return base + f"{{{self.minLen}}}" elif self.maxLen == _MAX_INT: return base + f"{{{self.minLen},...}}" else: return base + f"{{{self.minLen},{self.maxLen}}}" return base
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)
class Char(Word): """A short-cut class for defining :class:`Word` ``(characters, exact=1)``,
when defining a match of any single character in a string of
characters. """
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``.
# named fields in a regex will be returned as named results
date = Regex(r'(?P<year>\d{4})-(?P<month>\d\d?)-(?P<day>\d\d?)')
# the Regex class will accept re's compiled using the regex module import regex
parser = pp.Regex(regex.compile(r'[0-9]')) """
def __init__(
self,
pattern: Any,
flags: Union[re.RegexFlag, int] = 0,
as_group_list: bool = False,
as_match: bool = False,
*,
asGroupList: bool = False,
asMatch: bool = False,
): """The parameters ``pattern`` and ``flags`` are passed
to the ``re.compile()`` function as-is. See the Python
`re module <https://docs.python.org/3/library/re.html>`_ module for an
explanation of the acceptable patterns and flags. """
super().__init__()
asGroupList = asGroupList or as_group_list
asMatch = asMatch or as_match
if isinstance(pattern, str_type): ifnot pattern: raise ValueError("null string passed to Regex; use Empty() instead")
def sub(self, repl: str) -> ParserElement:
r""" Return :class:`Regex` with an attached parse action to transform the parsed
result asif called using `re.sub(expr, repl, string) <https://docs.python.org/3/library/re.html#re.sub>`_.
Example::
make_html = Regex(r"(\w+):(.*?):").sub(r"<\1>\2</\1>")
print(make_html.transform_string("h1:main title:")) # prints "<h1>main title</h1>" """ if self.asGroupList: raise TypeError("cannot use sub() with Regex(as_group_list=True)")
if self.asMatch and callable(repl): raise TypeError( "cannot use sub() with a callable with Regex(as_match=True)"
)
class QuotedString(Token):
r"""
Token for matching strings that are delimited by quoting characters.
Defined with the following parameters:
- ``quote_char`` - string of one or more characters defining the
quote delimiting string
- ``esc_char`` - character to re_escape quotes, typically backslash
(default= ``None``)
- ``esc_quote`` - special quote sequence to re_escape an embedded quote
string (such as SQL's ``""`` to re_escape an embedded ``"``)
(default= ``None``)
- ``multiline`` - boolean indicating whether quotes can span
multiple lines (default= ``False``)
- ``unquote_results`` - boolean indicating whether the matched text
should be unquoted (default= ``True``)
- ``end_quote_char`` - string of one or more characters defining the
end of the quote delimited string (default= ``None`` => same as
quote_char)
- ``convert_whitespace_escapes`` - convert escaped whitespace
(``'\t'``, ``'\n'``, etc.) to actual whitespace
(default= ``True``)
Example::
qs = QuotedString('"')
print(qs.search_string('lsjdf "This is the quote" sldjf'))
complex_qs = QuotedString('{{', end_quote_char='}}')
print(complex_qs.search_string('lsjdf {{This is the "quote"}} sldjf'))
sql_qs = QuotedString('"', esc_quote='""')
print(sql_qs.search_string('lsjdf "This is the quote with ""embedded"" quotes" sldjf'))
prints::
[['This is the quote']]
[['This is the "quote"']]
[['This is the quote with "embedded" quotes']] """
ws_map = dict(((r"\t", "\t"), (r"\n", "\n"), (r"\f", "\f"), (r"\r", "\r")))
# remove white space from quote chars - wont work anyway
quote_char = quote_char.strip() ifnot quote_char: raise ValueError("quote_char cannot be the empty string")
if endQuoteChar isNone:
endQuoteChar = quote_char else:
endQuoteChar = endQuoteChar.strip() ifnot endQuoteChar: raise ValueError("end_quote_char cannot be the empty string")
if len(self.endQuoteChar) > 1:
inner_pattern += (
f"{sep}(?:"
+ "|".join(
f"(?:{re.escape(self.endQuoteChar[:i])}(?!{re.escape(self.endQuoteChar[i:])}))" for i in range(len(self.endQuoteChar) - 1, 0, -1)
)
+ ")"
)
sep = "|"
self.flags = re.RegexFlag(0)
if multiline:
self.flags = re.MULTILINE | re.DOTALL
inner_pattern += (
rf"{sep}(?:[^{_escape_regex_range_chars(self.endQuoteChar[0])}"
rf"{(_escape_regex_range_chars(escChar) if escChar is not None else '')}])"
) else:
inner_pattern += (
rf"{sep}(?:[^{_escape_regex_range_chars(self.endQuoteChar[0])}\n\r"
rf"{(_escape_regex_range_chars(escChar) if escChar is not None else '')}])"
)
if self.unquoteResults: if self.convertWhitespaceEscapes:
self.unquote_scan_re = re.compile(
rf"({'|'.join(re.escape(k) for k in self.ws_map)})|({re.escape(self.escChar)}.)|(\n|.)",
flags=self.flags,
) else:
self.unquote_scan_re = re.compile(
rf"({re.escape(self.escChar)}.)|(\n|.)", flags=self.flags
)
if self.unquoteResults: # strip off quotes
ret = ret[self.quoteCharLen : -self.endQuoteCharLen]
if isinstance(ret, str_type): if self.convertWhitespaceEscapes:
ret = "".join(
self.ws_map[match.group(1)] if match.group(1) else match.group(2)[-1] if match.group(2) else match.group(3) for match in self.unquote_scan_re.finditer(ret)
) else:
ret = "".join(
match.group(1)[-1] if match.group(1) else match.group(2) for match in self.unquote_scan_re.finditer(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 ifnot 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 isnot 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).parse_string("dkls,lsdkjf,s12 34,@!#,213"))
prints::
['dkls', 'lsdkjf', 's12 34', '@!#', '213'] """
def __init__(
self,
not_chars: str = "",
min: int = 1,
max: int = 0,
exact: int = 0,
*,
notChars: str = "",
):
super().__init__()
self.skipWhitespace = False
self.notChars = not_chars or notChars
self.notCharsSet = set(self.notChars)
if min < 1: raise ValueError( "cannot specify a minimum length < 1; use " "Opt(CharsNotIn()) if zero-length char group is permitted"
)
self.minLen = min
if max > 0:
self.maxLen = max else:
self.maxLen = _MAX_INT
if exact > 0:
self.maxLen = exact
self.minLen = exact
def parseImpl(self, instring, loc, doActions=True):
notchars = self.notCharsSet if instring[loc] in notchars: raise ParseException(instring, loc, self.errmsg, self)
start = loc
loc += 1
maxlen = min(start + self.maxLen, len(instring)) while loc < maxlen and instring[loc] notin 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 classis 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. """
def __init__(self, ws: str = " \t\r\n", min: int = 1, max: int = 0, exact: int = 0):
super().__init__()
self.matchWhite = ws
self.set_whitespace_chars( "".join(c for c in self.whiteStrs if c notin self.matchWhite),
copy_defaults=True,
) # self.leave_whitespace()
self.mayReturnEmpty = True
self.errmsg = "Expected " + self.name
self.minLen = min
if max > 0:
self.maxLen = max else:
self.maxLen = _MAX_INT
if exact > 0:
self.maxLen = exact
self.minLen = exact
def _generateDefaultName(self) -> str: return"".join(White.whiteStrs[c] for c in self.matchWhite)
def parseImpl(self, instring, loc, doActions=True): if instring[loc] notin 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)
def preParse(self, instring: str, loc: int) -> int: 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' + rest_of_line).search_string(test):
print(t)
def preParse(self, instring: str, loc: int) -> int: if loc == 0: return loc else:
ret = self.skipper.preParse(instring, loc) if"\n"in self.orig_whiteChars: while instring[ret : ret + 1] == "\n":
ret = self.skipper.preParse(instring, ret + 1) return ret
class LineEnd(PositionToken): """Matches if current position is at the end of a line within the
parse string """
def __init__(self):
super().__init__()
self.whiteChars.discard("\n")
self.set_whitespace_chars(self.whiteChars, copy_defaults=False)
self.errmsg = "Expected end of line"
def parseImpl(self, instring, loc, doActions=True): if loc < len(instring): if instring[loc] == "\n": return loc + 1, "\n" else: raise ParseException(instring, loc, self.errmsg, self) elif loc == len(instring): return loc + 1, [] else: raise ParseException(instring, loc, self.errmsg, self)
class StringStart(PositionToken): """Matches if current position is at the beginning of the parse
string """
def __init__(self):
super().__init__()
self.errmsg = "Expected start of text"
def parseImpl(self, instring, loc, doActions=True): if loc != 0: # see if entire string up to here is just whitespace and ignoreables if loc != self.preParse(instring, 0): raise ParseException(instring, loc, self.errmsg, self) return loc, []
class StringEnd(PositionToken): """
Matches if current position is at the end of the parse string """
def __init__(self):
super().__init__()
self.errmsg = "Expected end of text"
def parseImpl(self, instring, loc, doActions=True): if loc < len(instring): raise ParseException(instring, loc, self.errmsg, self) elif loc == len(instring): return loc + 1, [] elif loc > len(instring): return loc, [] else: raise ParseException(instring, loc, self.errmsg, self)
class WordStart(PositionToken): """Matches if the current position is at the beginning of a
:class:`Word`, andisnot preceded by any character in a given
set of ``word_chars`` (default= ``printables``). To emulate the
``\b`` behavior of regular expressions, use
``WordStart(alphanums)``. ``WordStart`` will also match at
the beginning of the string being parsed, or at the beginning of
a line. """
def __init__(self, word_chars: str = printables, *, wordChars: str = printables):
wordChars = word_chars if wordChars == printables else wordChars
super().__init__()
self.wordChars = set(wordChars)
self.errmsg = "Not at the start of a word"
def parseImpl(self, instring, loc, doActions=True): if loc != 0: if (
instring[loc - 1] in self.wordChars or instring[loc] notin 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`, andisnot followed by any character in a given set of ``word_chars``
(default= ``printables``). To emulate the ``\b`` behavior of
regular expressions, use ``WordEnd(alphanums)``. ``WordEnd``
will also match at the end of the string being parsed, or at the end
of a line. """
def __init__(self, word_chars: str = printables, *, wordChars: str = printables):
wordChars = word_chars if wordChars == printables else wordChars
super().__init__()
self.wordChars = set(wordChars)
self.skipWhitespace = False
self.errmsg = "Not at the end of a word"
def parseImpl(self, instring, loc, doActions=True):
instrlen = len(instring) if instrlen > 0 and loc < instrlen: if (
instring[loc] in self.wordChars or instring[loc - 1] notin 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 leave_whitespace(self, recursive: bool = True) -> ParserElement: """
Extends ``leave_whitespace`` defined in base class, and also invokes ``leave_whitespace`` on
all contained expressions. """
super().leave_whitespace(recursive)
if recursive:
self.exprs = [e.copy() for e in self.exprs] for e in self.exprs:
e.leave_whitespace(recursive) return self
def ignore_whitespace(self, recursive: bool = True) -> ParserElement: """
Extends ``ignore_whitespace`` defined in base class, and also invokes ``leave_whitespace`` on
all contained expressions. """
super().ignore_whitespace(recursive) if recursive:
self.exprs = [e.copy() for e in self.exprs] for e in self.exprs:
e.ignore_whitespace(recursive) return self
def ignore(self, other) -> ParserElement: if isinstance(other, Suppress): if other notin 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 streamline(self) -> ParserElement: if self.streamlined: return self
super().streamline()
for e in self.exprs:
e.streamline()
# collapse nested :class:`And`'s of the form ``And(And(And(a, b), c), d)`` to ``And(a, b, c, d)`` # but only if there are no parse actions or resultsNames on the nested And's # (likewise for :class:`Or`'s and :class:`MatchFirst`'s) if len(self.exprs) == 2:
other = self.exprs[0] if (
isinstance(other, self.__class__) andnot other.parseAction and other.resultsName isNone andnot 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__) andnot other.parseAction and other.resultsName isNone andnot other.debug
):
self.exprs = self.exprs[:-1] + other.exprs[:]
self._defaultName = None
self.mayReturnEmpty |= other.mayReturnEmpty
self.mayIndexError |= other.mayIndexError
self.errmsg = "Expected " + str(self)
return self
def validate(self, validateTrace=None) -> None:
warnings.warn( "ParserElement.validate() is deprecated, and should not be used to check for left recursion",
DeprecationWarning,
stacklevel=2,
)
tmp = (validateTrace if validateTrace isnotNoneelse [])[:] + [self] for e in self.exprs:
e.validate(tmp)
self._checkRecursion([])
def copy(self) -> ParserElement:
ret = super().copy()
ret = typing.cast(ParseExpression, ret)
ret.exprs = [e.copy() for e in self.exprs] return ret
def _setResultsName(self, name, listAllMatches=False): if (
__diag__.warn_ungrouped_named_tokens_in_collection and Diagnostics.warn_ungrouped_named_tokens_in_collection notin self.suppress_warnings_
): for e in self.exprs: if (
isinstance(e, ParserElement) and e.resultsName and Diagnostics.warn_ungrouped_named_tokens_in_collection notin e.suppress_warnings_
):
warnings.warn( "{}: setting results name {!r} on {} expression " "collides with {!r} on contained expression".format( "warn_ungrouped_named_tokens_in_collection",
name,
type(self).__name__,
e.resultsName,
),
stacklevel=3,
)
# Compatibility synonyms # fmt: off
@replaced_by_pep8(leave_whitespace) def leaveWhitespace(self): ...
@replaced_by_pep8(ignore_whitespace) def ignoreWhitespace(self): ... # fmt: on
classAnd(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.
expr = And([integer("id"), name_expr("name"), integer("age")]) # more easily written as:
expr = integer("id") + name_expr("name") + integer("age") """
class _ErrorStop(Empty): def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.leave_whitespace()
def _generateDefaultName(self) -> str: return"-"
def __init__(
self, exprs_arg: typing.Iterable[ParserElement], savelist: bool = True
):
exprs: List[ParserElement] = list(exprs_arg) if exprs and Ellipsis in exprs:
tmp = [] for i, expr in enumerate(exprs): if expr is Ellipsis: if i < len(exprs) - 1:
skipto_arg: ParserElement = typing.cast(
ParseExpression, (Empty() + exprs[i + 1])
).exprs[-1]
tmp.append(SkipTo(skipto_arg)("_skipped*")) else: raise Exception( "cannot construct And with sequence ending in ..."
) else:
tmp.append(expr)
exprs[:] = tmp
super().__init__(exprs, savelist) if self.exprs:
self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs) ifnot isinstance(self.exprs[0], White):
self.set_whitespace_chars(
self.exprs[0].whiteChars,
copy_defaults=self.exprs[0].copyDefaultWhiteChars,
)
self.skipWhitespace = self.exprs[0].skipWhitespace else:
self.skipWhitespace = False else:
self.mayReturnEmpty = True
self.callPreparse = True
def streamline(self) -> ParserElement: # collapse any _PendingSkip's if self.exprs: if any(
isinstance(e, ParseExpression) and e.exprs and isinstance(e.exprs[-1], _PendingSkip) for e in self.exprs[:-1]
):
deleted_expr_marker = NoMatch() for i, e in enumerate(self.exprs[:-1]): if e is deleted_expr_marker: continue if (
isinstance(e, ParseExpression) and e.exprs and isinstance(e.exprs[-1], _PendingSkip)
):
e.exprs[-1] = e.exprs[-1] + self.exprs[i + 1]
self.exprs[i + 1] = deleted_expr_marker
self.exprs = [e for e in self.exprs if e isnot deleted_expr_marker]
super().streamline()
# link any IndentedBlocks to the prior expression
prev: ParserElement
cur: ParserElement for prev, cur in zip(self.exprs, self.exprs[1:]): # traverse cur or any first embedded expr of cur looking for an IndentedBlock # (but watch out for recursive grammar)
seen = set() whileTrue: if id(cur) in seen: break
seen.add(id(cur)) if isinstance(cur, IndentedBlock):
prev.add_parse_action( lambda s, l, t, cur_=cur: setattr(
cur_, "parent_anchor", col(l, s)
)
) break
subs = cur.recurse()
next_first = next(iter(subs), None) if next_first isNone: break
cur = typing.cast(ParserElement, next_first)
self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs) return self
def parseImpl(self, instring, loc, doActions=True): # pass False as callPreParse arg to _parse for first element, since we already # pre-parsed the string as part of our And pre-parsing
loc, resultlist = self.exprs[0]._parse(
instring, loc, doActions, callPreParse=False
)
errorStop = False for e in self.exprs[1:]: # if isinstance(e, And._ErrorStop): if type(e) isAnd._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)
resultlist += exprtokens return loc, resultlist
def __iadd__(self, other): if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return self.append(other) # And([self, other])
def _checkRecursion(self, parseElementList):
subRecCheckList = parseElementList[:] + [self] for e in self.exprs:
e._checkRecursion(subRecCheckList) ifnot e.mayReturnEmpty: break
def _generateDefaultName(self) -> str:
inner = " ".join(str(e) for e in self.exprs) # strip off redundant inner {}'s while len(inner) > 1 and inner[0 :: len(inner) - 1] == "{}":
inner = inner[1:-1] return"{" + inner + "}"
classOr(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.
def __init__(self, exprs: typing.Iterable[ParserElement], savelist: bool = False):
super().__init__(exprs, savelist) if self.exprs:
self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
self.skipWhitespace = all(e.skipWhitespace for e in self.exprs) else:
self.mayReturnEmpty = True
def streamline(self) -> ParserElement:
super().streamline() if self.exprs:
self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
self.saveAsList = any(e.saveAsList for e in self.exprs)
self.skipWhitespace = all(
e.skipWhitespace andnot isinstance(e, White) for e in self.exprs
) else:
self.saveAsList = False return self
def parseImpl(self, instring, loc, doActions=True):
maxExcLoc = -1
maxException = None
matches = []
fatals = [] if all(e.callPreparse for e in self.exprs):
loc = self.preParse(instring, loc) for e in self.exprs: try:
loc2 = e.try_parse(instring, loc, raise_fatal=True) except ParseFatalException as pfe:
pfe.__traceback__ = None
pfe.parser_element = e
fatals.append(pfe)
maxException = None
maxExcLoc = -1 except ParseException as err: ifnot 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)
ifnot 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.parser_element))))
max_fatal = fatals[0] raise max_fatal
if maxException isnotNone: # infer from this check that all alternatives failed at the current position # so emit this collective error message instead of any single error message if maxExcLoc == loc:
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) ifnot isinstance(other, ParserElement): return NotImplemented return self.append(other) # Or([self, other])
def _generateDefaultName(self) -> str: return"{" + " ^ ".join(str(e) for e in self.exprs) + "}"
def _setResultsName(self, name, listAllMatches=False): if (
__diag__.warn_multiple_tokens_in_named_alternation and Diagnostics.warn_multiple_tokens_in_named_alternation notin self.suppress_warnings_
): if any(
isinstance(e, And) and Diagnostics.warn_multiple_tokens_in_named_alternation notin e.suppress_warnings_ for e in self.exprs
):
warnings.warn( "{}: setting results name {!r} on {} expression " "will return a list of all parsed tokens in an And alternative, " "in prior versions only the first token was returned; enclose " "contained argument in Group".format( "warn_multiple_tokens_in_named_alternation",
name,
type(self).__name__,
),
stacklevel=3,
)
class MatchFirst(ParseExpression): """Requires that at least one :class:`ParseExpression` is found. If
more than one expression matches, the first one listed is the one that will
match. May be constructed using the ``'|'`` operator.
Example::
# construct MatchFirst using '|' operator
# watch the order of expressions to match
number = Word(nums) | Combine(Word(nums) + '.' + Word(nums))
print(number.search_string("123 3.1416 789")) # Fail! -> [['123'], ['3'], ['1416'], ['789']]
# put more selective expression first
number = Combine(Word(nums) + '.' + Word(nums)) | Word(nums)
print(number.search_string("123 3.1416 789")) # Better -> [['123'], ['3.1416'], ['789']] """
def __init__(self, exprs: typing.Iterable[ParserElement], savelist: bool = False):
super().__init__(exprs, savelist) if self.exprs:
self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
self.skipWhitespace = all(e.skipWhitespace for e in self.exprs) else:
self.mayReturnEmpty = True
def streamline(self) -> ParserElement: if self.streamlined: return self
super().streamline() if self.exprs:
self.saveAsList = any(e.saveAsList for e in self.exprs)
self.mayReturnEmpty = any(e.mayReturnEmpty for e in self.exprs)
self.skipWhitespace = all(
e.skipWhitespace andnot isinstance(e, White) for e in self.exprs
) else:
self.saveAsList = False
self.mayReturnEmpty = True return self
for e in self.exprs: try: return e._parse(
instring,
loc,
doActions,
) except ParseFatalException as pfe:
pfe.__traceback__ = None
pfe.parser_element = e raise except ParseException as err: if err.loc > maxExcLoc:
maxException = err
maxExcLoc = err.loc except IndexError: if len(instring) > maxExcLoc:
maxException = ParseException(
instring, len(instring), e.errmsg, self
)
maxExcLoc = len(instring)
if maxException isnotNone: # infer from this check that all alternatives failed at the current position # so emit this collective error message instead of any individual error message if maxExcLoc == loc:
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) ifnot isinstance(other, ParserElement): return NotImplemented return self.append(other) # MatchFirst([self, other])
def _generateDefaultName(self) -> str: return"{" + " | ".join(str(e) for e in self.exprs) + "}"
def _setResultsName(self, name, listAllMatches=False): if (
__diag__.warn_multiple_tokens_in_named_alternation and Diagnostics.warn_multiple_tokens_in_named_alternation notin self.suppress_warnings_
): if any(
isinstance(e, And) and Diagnostics.warn_multiple_tokens_in_named_alternation notin e.suppress_warnings_ for e in self.exprs
):
warnings.warn( "{}: setting results name {!r} on {} expression " "will return a list of all parsed tokens in an And alternative, " "in prior versions only the first token was returned; enclose " "contained argument in Group".format( "warn_multiple_tokens_in_named_alternation",
name,
type(self).__name__,
),
stacklevel=3,
)
class Each(ParseExpression): """Requires all given :class:`ParseExpression` s to be found, but in
any order. Expressions may be separated by whitespace.
May be constructed using the ``'&'`` operator.
Example::
color = one_of("RED ORANGE YELLOW GREEN BLUE PURPLE BLACK WHITE BROWN")
shape_type = one_of("SQUARE CIRCLE TRIANGLE STAR HEXAGON OCTAGON")
integer = Word(nums)
shape_attr = "shape:" + shape_type("shape")
posn_attr = "posn:" + Group(integer("x") + ',' + integer("y"))("posn")
color_attr = "color:" + color("color")
size_attr = "size:" + integer("size")
# use Each (using operator '&') to accept attributes in any order # (shape and posn are required, color and size are optional)
shape_spec = shape_attr & posn_attr & Opt(color_attr) & Opt(size_attr)
shape_spec.run_tests('''
shape: SQUARE color: BLACK posn: 100, 120
shape: CIRCLE size: 50 color: BLUE posn: 50,80
color:GREEN size:20 shape:TRIANGLE posn:20,40 '''
)
def __init__(self, exprs: typing.Iterable[ParserElement], savelist: bool = True):
super().__init__(exprs, savelist) if self.exprs:
self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs) else:
self.mayReturnEmpty = True
self.skipWhitespace = True
self.initExprGroups = True
self.saveAsList = True
def __iand__(self, other): if isinstance(other, str_type):
other = self._literalStringClass(other) ifnot isinstance(other, ParserElement): return NotImplemented return self.append(other) # Each([self, other])
def streamline(self) -> ParserElement:
super().streamline() if self.exprs:
self.mayReturnEmpty = all(e.mayReturnEmpty for e in self.exprs) else:
self.mayReturnEmpty = True return self
def parseImpl(self, instring, loc, doActions=True): if self.initExprGroups:
self.opt1map = dict(
(id(e.expr), e) for e in self.exprs if isinstance(e, Opt)
)
opt1 = [e.expr for e in self.exprs if isinstance(e, Opt)]
opt2 = [
e for e in self.exprs if e.mayReturnEmpty andnot isinstance(e, (Opt, Regex, ZeroOrMore))
]
self.optionals = opt1 + opt2
self.multioptionals = [
e.expr.set_results_name(e.resultsName, list_all_matches=True) for e in self.exprs if isinstance(e, _MultipleMatch)
]
self.multirequired = [
e.expr.set_results_name(e.resultsName, list_all_matches=True) for e in self.exprs if isinstance(e, OneOrMore)
]
self.required = [
e for e in self.exprs ifnot isinstance(e, (Opt, ZeroOrMore, OneOrMore))
]
self.required += self.multirequired
self.initExprGroups = False
tmpLoc = loc
tmpReqd = self.required[:]
tmpOpt = self.optionals[:]
multis = self.multioptionals[:]
matchOrder = []
keepMatching = True
failed = []
fatals = [] while keepMatching:
tmpExprs = tmpReqd + tmpOpt + multis
failed.clear()
fatals.clear() for e in tmpExprs: try:
tmpLoc = e.try_parse(instring, tmpLoc, raise_fatal=True) except ParseFatalException as pfe:
pfe.__traceback__ = None
pfe.parser_element = e
fatals.append(pfe)
failed.append(e) except ParseException:
failed.append(e) else:
matchOrder.append(self.opt1map.get(id(e), e)) if e in tmpReqd:
tmpReqd.remove(e) elif e in tmpOpt:
tmpOpt.remove(e) if len(failed) == len(tmpExprs):
keepMatching = False
# look for any ParseFatalExceptions if fatals: if len(fatals) > 1:
fatals.sort(key=lambda e: -e.loc) if fatals[0].loc == fatals[1].loc:
fatals.sort(key=lambda e: (-e.loc, -len(str(e.parser_element))))
max_fatal = fatals[0] raise max_fatal
if tmpReqd:
missing = ", ".join([str(e) for e in tmpReqd]) raise ParseException(
instring,
loc,
f"Missing one or more required elements ({missing})",
)
# add any unmatched Opts, in case they have default values defined
matchOrder += [e for e in self.exprs if isinstance(e, Opt) and e.expr in tmpOpt]
total_results = ParseResults([]) for e in matchOrder:
loc, results = e._parse(instring, loc, doActions)
total_results += results
return loc, total_results
def _generateDefaultName(self) -> str: return"{" + " & ".join(str(e) for e in self.exprs) + "}"
class ParseElementEnhance(ParserElement): """Abstract subclass of :class:`ParserElement`, for combining and
post-processing parsed tokens. """
if recursive: if self.expr isnotNone:
self.expr = self.expr.copy()
self.expr.ignore_whitespace(recursive) return self
def ignore(self, other) -> ParserElement: if isinstance(other, Suppress): if other notin self.ignoreExprs:
super().ignore(other) if self.expr isnotNone:
self.expr.ignore(self.ignoreExprs[-1]) else:
super().ignore(other) if self.expr isnotNone:
self.expr.ignore(self.ignoreExprs[-1]) return self
def _checkRecursion(self, parseElementList): if self in parseElementList: raise RecursiveGrammarException(parseElementList + [self])
subRecCheckList = parseElementList[:] + [self] if self.expr isnotNone:
self.expr._checkRecursion(subRecCheckList)
def validate(self, validateTrace=None) -> None:
warnings.warn( "ParserElement.validate() is deprecated, and should not be used to check for left recursion",
DeprecationWarning,
stacklevel=2,
) if validateTrace isNone:
validateTrace = []
tmp = validateTrace[:] + [self] if self.expr isnotNone:
self.expr.validate(tmp)
self._checkRecursion([])
# Compatibility synonyms # fmt: off
@replaced_by_pep8(leave_whitespace) def leaveWhitespace(self): ...
@replaced_by_pep8(ignore_whitespace) def ignoreWhitespace(self): ... # fmt: on
class IndentedBlock(ParseElementEnhance): """
Expression to match one or more expressions at a given indentation level.
Useful for parsing text where structure is implied by indentation (like Python source code). """
class _IndentGreater(Empty): def __init__(self, ref_col: int):
super().__init__()
self.errmsg = f"expected indent at column greater than {ref_col}"
self.add_condition(lambda s, l, t: col(l, s) > ref_col)
def __init__(
self, expr: ParserElement, *, recursive: bool = False, grouped: bool = True
):
super().__init__(expr, savelist=True) # if recursive: # raise NotImplementedError("IndentedBlock with recursive is not implemented")
self._recursive = recursive
self._grouped = grouped
self.parent_anchor = 1
def parseImpl(self, instring, loc, doActions=True): # advance parse position to non-whitespace by using an Empty() # this should be the column to be used for all subsequent indented lines
anchor_loc = Empty().preParse(instring, loc)
# see if self.expr matches at the current location - if not it will raise an exception # and no further work is necessary
self.expr.try_parse(instring, anchor_loc, do_actions=doActions)
def parseImpl(self, instring, loc, doActions=True): if col(loc, instring) != 1: raise ParseException(instring, loc, "not found at line start") return super().parseImpl(instring, loc, doActions)
class FollowedBy(ParseElementEnhance): """Lookahead matching of the given parse expression.
``FollowedBy`` does *not* advance the parsing position within
the input string, it only verifies that the specified parse
expression matches at the current position. ``FollowedBy``
always returns a null token list. If any results names are defined in the lookahead expression, those *will* be returned for access by
name.
Example::
# use FollowedBy to match a label only if it is followed by a ':'
data_word = Word(alphas)
label = data_word + FollowedBy(':')
attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stop_on=label).set_parse_action(' '.join))
attr_expr[1, ...].parse_string("shape: SQUARE color: BLACK posn: upper left").pprint()
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 isnot 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 parseImpl(self, instring, loc, doActions=True):
start = loc
loc, tokens = self.expr._parse(instring, start, doActions, callPreParse=False)
ret_tokens = ParseResults([start, tokens, loc])
ret_tokens["locn_start"] = start
ret_tokens["value"] = tokens
ret_tokens["locn_end"] = loc if self.resultsName: # must return as a list, so that the name will be attached to the complete group return loc, [ret_tokens] else: return loc, ret_tokens
class NotAny(ParseElementEnhance): """
Lookahead to disallow matching with the given parse expression.
``NotAny`` does *not* advance the parsing position within the
input string, it only verifies that the specified parse expression
does *not* match at the current position. Also, ``NotAny`` does
*not* skip over leading whitespace. ``NotAny`` always returns
a null token list. May be constructed using the ``'~'`` operator.
Example::
AND, OR, NOT = map(CaselessKeyword, "AND OR NOT".split())
# take care not to mistake keywords for identifiers
ident = ~(AND | OR | NOT) + Word(alphas)
boolean_term = Opt(NOT) + ident
# very crude boolean expression - to support parenthesis groups and # operation hierarchy, use infix_notation
boolean_expr = boolean_term + ((AND | OR) + boolean_term)[...]
# integers that are followed by "." are actually floats
integer = Word(nums) + ~Char(".") """
def __init__(self, expr: Union[ParserElement, str]):
super().__init__(expr) # do NOT use self.leave_whitespace(), don't want to propagate to exprs # self.leave_whitespace()
self.skipWhitespace = False
# must be at least one (but first see if we are the stopOn sentinel; # if so, fail) if check_ender:
try_not_ender(instring, loc)
loc, tokens = self_expr_parse(instring, loc, doActions) try:
hasIgnoreExprs = notnot 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)
tokens += tmptokens except (ParseException, IndexError): pass
return loc, tokens
def _setResultsName(self, name, listAllMatches=False): if (
__diag__.warn_ungrouped_named_tokens_in_collection and Diagnostics.warn_ungrouped_named_tokens_in_collection notin self.suppress_warnings_
): for e in [self.expr] + self.expr.recurse(): if (
isinstance(e, ParserElement) and e.resultsName and Diagnostics.warn_ungrouped_named_tokens_in_collection notin e.suppress_warnings_
):
warnings.warn( "{}: setting results name {!r} on {} expression " "collides with {!r} on contained expression".format( "warn_ungrouped_named_tokens_in_collection",
name,
type(self).__name__,
e.resultsName,
),
stacklevel=3,
)
class OneOrMore(_MultipleMatch): """
Repetition of one or more of the given expression.
Parameters:
- ``expr`` - expression that must match one or more times
- ``stop_on`` - (default= ``None``) - expression for a terminating sentinel
(only required if the sentinel would ordinarily match the repetition
expression)
text = "shape: SQUARE posn: upper left color: BLACK"
attr_expr[1, ...].parse_string(text).pprint() # Fail! read 'color' as data instead of next label -> [['shape', 'SQUARE color']]
# use stop_on attribute for OneOrMore to avoid reading label string as part of the data
attr_expr = Group(label + Suppress(':') + OneOrMore(data_word, stop_on=label).set_parse_action(' '.join))
OneOrMore(attr_expr).parse_string(text).pprint() # Better -> [['shape', 'SQUARE'], ['posn', 'upper left'], ['color', 'BLACK']]
# could also be written as
(attr_expr * (1,)).parse_string(text).pprint() """
class ZeroOrMore(_MultipleMatch): """
Optional repetition of zero or more of the given expression.
Parameters:
- ``expr`` - expression that must match zero or more times
- ``stop_on`` - expression for a terminating sentinel
(only required if the sentinel would ordinarily match the repetition
expression) - (default= ``None``)
class DelimitedList(ParseElementEnhance): def __init__(
self,
expr: Union[str, ParserElement],
delim: Union[str, ParserElement] = ",",
combine: bool = False,
min: typing.Optional[int] = None,
max: typing.Optional[int] = None,
*,
allow_trailing_delim: bool = False,
): """Helper to define a delimited list of expressions - the delimiter
defaults to ','. By default, the list elements and delimiters can
have intervening whitespace, and comments, but this can be
overridden by passing ``combine=True`` in the constructor. If
``combine`` is set to ``True``, the matching tokens are
returned as a single token string, with the delimiters included;
otherwise, the matching tokens are returned as a list of tokens, with the delimiters suppressed.
If ``allow_trailing_delim`` is set to True, then the list may end with
a delimiter.
if min isnotNone: if min < 1: raise ValueError("min must be greater than 0") if max isnotNone: if min isnotNoneand max < min: raise ValueError("max must be greater than, or equal to min")
self.content = expr
self.raw_delim = str(delim)
self.delim = delim
self.combine = combine ifnot combine:
self.delim = Suppress(delim)
self.min = min or 1
self.max = max
self.allow_trailing_delim = allow_trailing_delim
class Opt(ParseElementEnhance): """
Optional matching of the given expression.
Parameters:
- ``expr`` - expression that must match zero or more times
- ``default`` (optional) - value to be returned if the optional expression isnot found.
Example::
# US postal code can be a 5-digit zip, plus optional 4-digit qualifier
zip = Combine(Word(nums, exact=5) + Opt('-' + Word(nums, exact=4)))
zip.run_tests(''' # traditional ZIP code
12345
# ZIP+4 form
12101-0001
# invalid ZIP
98765- ''')
prints::
# traditional ZIP code
12345
['12345']
# ZIP+4 form
12101-0001
['12101-0001']
# invalid ZIP
98765-
^
FAIL: Expected end of text (at char 5), (line:1, col:6) """
class SkipTo(ParseElementEnhance): """
Token for skipping over all undefined text until the matched
expression is found.
Parameters:
- ``expr`` - target expression marking the end of the data to be skipped
- ``include`` - if ``True``, the target expression is also parsed
(the skipped text and target expression are returned as a 2-element
list) (default= ``False``).
- ``ignore`` - (default= ``None``) used to define grammars (typically quoted strings and
comments) that might contain false matches to the target expression
- ``fail_on`` - (default= ``None``) define expressions that are not allowed to be
included in the skipped test; if found before the target expression is found,
the :class:`SkipTo` isnot a match
Example::
report = '''
Outstanding Issues Report - 1 Jan 2000
# | Severity | Description | Days Open
-----+----------+-------------------------------------------+-----------
101 | Critical | Intermittent system crash | 6
94 | Cosmetic | Spelling error on Login ('log|n') | 14
79 | Minor | System slow when running too many reports | 47 '''
integer = Word(nums)
SEP = Suppress('|') # use SkipTo to simply match everything up until the next SEP # - ignore quoted strings, so that a '|' character inside a quoted string does not match # - parse action will call token.strip() for each matched token, i.e., the description body
string_data = SkipTo(SEP, ignore=quoted_string)
string_data.set_parse_action(token_map(str.strip))
ticket_expr = (integer("issue_num") + SEP
+ string_data("sev") + SEP
+ string_data("desc") + SEP
+ integer("days_open"))
for tkt in ticket_expr.search_string(report):
print tkt.dump()
prints::
['101', 'Critical', 'Intermittent system crash', '6']
- days_open: '6'
- desc: 'Intermittent system crash'
- issue_num: '101'
- sev: 'Critical'
['94', 'Cosmetic', "Spelling error on Login ('log|n')", '14']
- days_open: '14'
- desc: "Spelling error on Login ('log|n')"
- issue_num: '94'
- sev: 'Cosmetic'
['79', 'Minor', 'System slow when running too many reports', '47']
- days_open: '47'
- desc: 'System slow when running too many reports'
- issue_num: '79'
- sev: 'Minor' """
def __init__(
self,
other: Union[ParserElement, str],
include: bool = False,
ignore: typing.Optional[Union[ParserElement, str]] = None,
fail_on: typing.Optional[Union[ParserElement, str]] = None,
*,
failOn: typing.Optional[Union[ParserElement, str]] = None,
):
super().__init__(other)
failOn = failOn or fail_on if ignore isnotNone:
self.ignore(ignore)
self.mayReturnEmpty = True
self.mayIndexError = False
self.includeMatch = include
self.saveAsList = False if isinstance(failOn, str_type):
self.failOn = self._literalStringClass(failOn) else:
self.failOn = failOn
self.errmsg = "No match found for " + str(self.expr)
def parseImpl(self, instring, loc, doActions=True):
startloc = loc
instrlen = len(instring)
self_expr_parse = self.expr._parse
self_failOn_canParseNext = (
self.failOn.canParseNext if self.failOn isnotNoneelseNone
)
self_preParse = self.preParse if self.callPreparse elseNone
tmploc = loc while tmploc <= instrlen: if self_failOn_canParseNext isnotNone: # break if failOn expression matches if self_failOn_canParseNext(instring, tmploc): break
try:
self_expr_parse(instring, tmploc, doActions=False, callPreParse=False) except (ParseException, IndexError): # no match, advance loc in string
tmploc += 1 else: # matched skipto expr, done break
else: # ran off the end of the input string without matching skipto expr, fail raise ParseException(instring, loc, self.errmsg, self)
# build up return values
loc = tmploc
skiptext = instring[startloc:loc]
skipresult = ParseResults(skiptext)
if self.includeMatch:
loc, mat = self_expr_parse(instring, loc, doActions, callPreParse=False)
skipresult += mat
return loc, skipresult
class Forward(ParseElementEnhance): """
Forward declaration of an expression to be defined later -
used for recursive grammars, such as algebraic infix notation.
When the expression is known, it is assigned to the ``Forward``
variable using the ``'<<'`` operator.
Note: take care when assigning to ``Forward`` not to overlook
precedence of operators.
Specifically, ``'|'`` has a lower precedence than ``'<<'``, so that::
fwd_expr << a | b | c
will actually be evaluated as::
(fwd_expr << a) | b | c
thereby leaving b and c out as parseable alternatives. It is recommended that you
explicitly group the values inserted into the ``Forward``::
fwd_expr << (a | b | c)
Converting to use the ``'<<='`` operator instead will avoid this problem.
See :class:`ParseResults.pprint` for an example of a recursive
parser created using ``Forward``. """
def __lshift__(self, other) -> "Forward": if hasattr(self, "caller_frame"): del self.caller_frame if isinstance(other, str_type):
other = self._literalStringClass(other)
def __or__(self, other) -> "ParserElement":
caller_line = traceback.extract_stack(limit=2)[-2] if (
__diag__.warn_on_match_first_with_lshift_operator and caller_line == self.lshift_line and Diagnostics.warn_on_match_first_with_lshift_operator notin self.suppress_warnings_
):
warnings.warn( "using '<<' operator with '|' is probably an error, use '<<='",
stacklevel=2,
)
ret = super().__or__(other) return ret
def __del__(self): # see if we are getting dropped because of '=' reassignment of var instead of '<<=' or '<<' if (
self.expr isNone and __diag__.warn_on_assignment_to_Forward and Diagnostics.warn_on_assignment_to_Forward notin self.suppress_warnings_
):
warnings.warn_explicit( "Forward defined here but no expression attached later using '<<=' or '<<'",
UserWarning,
filename=self.caller_frame.filename,
lineno=self.caller_frame.lineno,
)
def parseImpl(self, instring, loc, doActions=True): if (
self.expr isNone and __diag__.warn_on_parse_using_empty_Forward and Diagnostics.warn_on_parse_using_empty_Forward notin self.suppress_warnings_
): # walk stack until parse_string, scan_string, search_string, or transform_string is found
parse_fns = ( "parse_string", "scan_string", "search_string", "transform_string",
)
tb = traceback.extract_stack(limit=200) for i, frm in enumerate(reversed(tb), start=1): if frm.name in parse_fns:
stacklevel = i + 1 break else:
stacklevel = 2
warnings.warn( "Forward expression was never assigned a value, will not parse any input",
stacklevel=stacklevel,
) ifnot ParserElement._left_recursion_enabled: return super().parseImpl(instring, loc, doActions) # ## Bounded Recursion algorithm ## # Recursion only needs to be processed at ``Forward`` elements, since they are # the only ones that can actually refer to themselves. The general idea is # to handle recursion stepwise: We start at no recursion, then recurse once, # recurse twice, ..., until more recursion offers no benefit (we hit the bound). # # The "trick" here is that each ``Forward`` gets evaluated in two contexts # - to *match* a specific recursion level, and # - to *search* the bounded recursion level # and the two run concurrently. The *search* must *match* each recursion level # to find the best possible match. This is handled by a memo table, which # provides the previous match to the next level match attempt. # # See also "Left Recursion in Parsing Expression Grammars", Medeiros et al. # # There is a complication since we not only *parse* but also *transform* via # actions: We do not want to run the actions too often while expanding. Thus, # we expand using `doActions=False` and only run `doActions=True` if the next # recursion level is acceptable. with ParserElement.recursion_lock:
memo = ParserElement.recursion_memos try: # we are parsing at a specific recursion expansion - use it as-is
prev_loc, prev_result = memo[loc, self, doActions] if isinstance(prev_result, Exception): raise prev_result return prev_loc, prev_result.copy() except KeyError:
act_key = (loc, self, True)
peek_key = (loc, self, False) # we are searching for the best recursion expansion - keep on improving # both `doActions` cases must be tracked separately here!
prev_loc, prev_peek = memo[peek_key] = (
loc - 1,
ParseException(
instring, loc, "Forward recursion without base case", self
),
) if doActions:
memo[act_key] = memo[peek_key] whileTrue: try:
new_loc, new_peek = super().parseImpl(instring, loc, False) except ParseException: # we failed before getting any match – do not hide the error if isinstance(prev_peek, Exception): raise
new_loc, new_peek = prev_loc, prev_peek # the match did not get better: we are done if new_loc <= prev_loc: if doActions: # replace the match for doActions=False as well, # in case the action did backtrack
prev_loc, prev_result = memo[peek_key] = memo[act_key] del memo[peek_key], memo[act_key] return prev_loc, prev_result.copy() del memo[peek_key] return prev_loc, prev_peek.copy() # the match did get better: see if we can improve further else: if doActions: try:
memo[act_key] = super().parseImpl(instring, loc, True) except ParseException as e:
memo[peek_key] = memo[act_key] = (new_loc, e) raise
prev_loc, prev_peek = memo[peek_key] = new_loc, new_peek
def validate(self, validateTrace=None) -> None:
warnings.warn( "ParserElement.validate() is deprecated, and should not be used to check for left recursion",
DeprecationWarning,
stacklevel=2,
) if validateTrace isNone:
validateTrace = []
if self notin validateTrace:
tmp = validateTrace[:] + [self] if self.expr isnotNone:
self.expr.validate(tmp)
self._checkRecursion([])
def _generateDefaultName(self) -> str: # Avoid infinite recursion by setting a temporary _defaultName
self._defaultName = ": ..."
# Use the string representation of main expression.
retString = "..." try: if self.expr isnotNone:
retString = str(self.expr)[:1000] else:
retString = "None" finally: return self.__class__.__name__ + ": " + retString
def copy(self) -> ParserElement: if self.expr isnotNone: return super().copy() else:
ret = Forward()
ret <<= self return ret
def _setResultsName(self, name, list_all_matches=False): if (
__diag__.warn_name_set_on_empty_Forward and Diagnostics.warn_name_set_on_empty_Forward notin self.suppress_warnings_
): if self.expr isNone:
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,
)
class Combine(TokenConverter): """Converter to concatenate all matching tokens to a single string.
By default, the matching patterns must also be contiguous in the
input string; this can be disabled by specifying
``'adjacent=False'`` in the constructor.
Example::
real = Word(nums) + '.' + Word(nums)
print(real.parse_string('3.1416')) # -> ['3', '.', '1416'] # will also erroneously match the following
print(real.parse_string('3. 1416')) # -> ['3', '.', '1416']
real = Combine(Word(nums) + '.' + Word(nums))
print(real.parse_string('3.1416')) # -> ['3.1416'] # no match when there are internal spaces
print(real.parse_string('3. 1416')) # -> Exception: Expected W:(0123...) """
def __init__(
self,
expr: ParserElement,
join_string: str = "",
adjacent: bool = True,
*,
joinString: typing.Optional[str] = None,
):
super().__init__(expr)
joinString = joinString if joinString isnotNoneelse join_string # suppress whitespace-stripping in contained parse expressions, but re-enable it on the Combine itself if adjacent:
self.leave_whitespace()
self.adjacent = adjacent
self.skipWhitespace = True
self.joinString = joinString
self.callPreparse = True
if self.resultsName and retToks.haskeys(): return [retToks] else: return retToks
class Group(TokenConverter): """Converter to return the matched tokens as a list - useful for
returning tokens of :class:`ZeroOrMore` and :class:`OneOrMore` expressions.
The optional ``aslist`` argument when set to True will return the
parsed tokens as a Python list instead of a pyparsing ParseResults.
Example::
ident = Word(alphas)
num = Word(nums)
term = ident | num
func = ident + Opt(DelimitedList(term))
print(func.parse_string("fn a, b, 100")) # -> ['fn', 'a', 'b', '100']
def postParse(self, instring, loc, tokenlist): if self._asPythonList: return ParseResults.List(
tokenlist.asList() if isinstance(tokenlist, ParseResults) else list(tokenlist)
) else: return [tokenlist]
class Dict(TokenConverter): """Converter to return a repetitive expression as a list, but also as a dictionary. Each element can also be referenced using the first
token in the expression as its key. Useful for tabular report
scraping when the first column can be used as a item key.
The optional ``asdict`` argument when set to True will return the
parsed tokens as a Python dict instead of a pyparsing ParseResults.
text = "shape: SQUARE posn: upper left color: light blue texture: burlap"
attr_expr = (label + Suppress(':') + OneOrMore(data_word, stop_on=label).set_parse_action(' '.join))
# print attributes as plain groups
print(attr_expr[1, ...].parse_string(text).dump())
# instead of OneOrMore(expr), parse using Dict(Group(expr)[1, ...]) - Dict will auto-assign names
result = Dict(Group(attr_expr)[1, ...]).parse_string(text)
print(result.dump())
# access named fields as dict entries, or output as dict
print(result['shape'])
print(result.as_dict())
if len(dictvalue) != 1 or (
isinstance(dictvalue, ParseResults) and dictvalue.haskeys()
):
tokenlist[ikey] = _ParseResultsWithOffset(dictvalue, i) else:
tokenlist[ikey] = _ParseResultsWithOffset(dictvalue[0], i)
if self._asPythonDict: return [tokenlist.as_dict()] if self.resultsName else tokenlist.as_dict() else: return [tokenlist] if self.resultsName else tokenlist
class Suppress(TokenConverter): """Converter for ignoring the results of a parsed expression.
# often, delimiters that are useful during parsing are just in the # way afterward - use Suppress to keep them out of the parsed output
wd_list2 = wd + (Suppress(',') + wd)[...]
print(wd_list2.parse_string(source))
# Skipped text (using '...') can be suppressed as well
source = "lead in START relevant text END trailing text"
start_marker = Keyword("START")
end_marker = Keyword("END")
find_body = Suppress(...) + start_marker + ... + end_marker
print(find_body.parse_string(source)
def trace_parse_action(f: ParseAction) -> ParseAction: """Decorator for debugging parse actions.
When the parse action is called, this decorator will print
``">> entering method-name(line:<current_source_line>, <parse_location>, <matched_tokens>)"``.
When the parse action completes, the decorator will print
``"<<"`` followed by the returned value, or any exception that the parse action raised.
def srange(s: str) -> str:
r"""Helper to easily define string ranges for use in :class:`Word`
construction. Borrows syntax from regexp ``'[]'`` string range
definitions::
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 ifnot isinstance(p, ParseResults) else"".join(chr(c) for c in range(ord(p[0]), ord(p[1]) + 1))
) try: return"".join(_expanded(part) for part in _reBracketExpr.parse_string(s).body) except Exception as e: return""
def token_map(func, *args) -> ParseAction: """Helper to define a parse action by mapping a function to all
elements of a :class:`ParseResults` list. If any additional args are passed,
they are forwarded to the given function as additional arguments
after the token, asin
``hex_integer = Word(hexnums).set_parse_action(token_map(int, 16))``,
which will convert the parsed data to an integer using base 16.
Example (compare the last to example in :class:`ParserElement.transform_string`::
upperword = Word(alphas).set_parse_action(token_map(str.upper))
upperword[1, ...].run_tests('''
my kingdom for a horse ''')
wd = Word(alphas).set_parse_action(token_map(str.title))
wd[1, ...].set_parse_action(' '.join).run_tests('''
now is the winter of our discontent made glorious summer by this sun of york ''')
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]
def autoname_elements() -> None: """
Utility to simplify mass-naming of parser elements, for
generating railroad diagram with named subdiagrams. """
calling_frame = sys._getframe().f_back if calling_frame isNone: return
calling_frame = typing.cast(types.FrameType, calling_frame) for name, var in calling_frame.f_locals.items(): if isinstance(var, ParserElement) andnot var.customName:
var.set_name(name)
# build list of built-in expressions, for future reference if a global default value # gets updated
_builtin_exprs: List[ParserElement] = [
v for v in vars().values() if isinstance(v, ParserElement)
]
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