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- # exceptions.py
- from __future__ import annotations
- import copy
- import re
- import sys
- import typing
- import warnings
- from functools import cached_property
- from .warnings import PyparsingDeprecationWarning
- from .unicode import pyparsing_unicode as ppu
- from .util import (
- _collapse_string_to_ranges,
- col,
- deprecate_argument,
- line,
- lineno,
- replaced_by_pep8,
- )
- class _ExceptionWordUnicodeSet(
- ppu.Latin1, ppu.LatinA, ppu.LatinB, ppu.Greek, ppu.Cyrillic
- ):
- pass
- _extract_alphanums = _collapse_string_to_ranges(_ExceptionWordUnicodeSet.alphanums)
- _exception_word_extractor = re.compile(fr"([{_extract_alphanums}]{{1,16}})|.")
- class ParseBaseException(Exception):
- """base exception class for all parsing runtime exceptions"""
- loc: int
- msg: str
- pstr: str
- parser_element: typing.Any # "ParserElement"
- args: tuple[str, int, typing.Optional[str]]
- __slots__ = (
- "loc",
- "msg",
- "pstr",
- "parser_element",
- "args",
- )
- # Performance tuning: we construct a *lot* of these, so keep this
- # constructor as small and fast as possible
- def __init__(
- self,
- pstr: str,
- loc: int = 0,
- msg: typing.Optional[str] = None,
- elem=None,
- ) -> None:
- if msg is None:
- msg, pstr = pstr, ""
- self.loc = loc
- self.msg = msg
- self.pstr = pstr
- self.parser_element = elem
- self.args = (pstr, loc, msg)
- @staticmethod
- def explain_exception(exc: Exception, depth: int = 16) -> str:
- """
- Method to take an exception and translate the Python internal traceback into a list
- of the pyparsing expressions that caused the exception to be raised.
- Parameters:
- - exc - exception raised during parsing (need not be a ParseException, in support
- of Python exceptions that might be raised in a parse action)
- - depth (default=16) - number of levels back in the stack trace to list expression
- and function names; if None, the full stack trace names will be listed; if 0, only
- the failing input line, marker, and exception string will be shown
- Returns a multi-line string listing the ParserElements and/or function names in the
- exception's stack trace.
- """
- import inspect
- from .core import ParserElement
- if depth is None:
- depth = sys.getrecursionlimit()
- ret: list[str] = []
- if isinstance(exc, ParseBaseException):
- ret.append(exc.line)
- ret.append(f"{'^':>{exc.column}}")
- ret.append(f"{type(exc).__name__}: {exc}")
- if depth <= 0 or exc.__traceback__ is None:
- return "\n".join(ret)
- callers = inspect.getinnerframes(exc.__traceback__, context=depth)
- seen: set[int] = set()
- for ff in callers[-depth:]:
- frm = ff[0]
- f_self = frm.f_locals.get("self", None)
- if isinstance(f_self, ParserElement):
- if not frm.f_code.co_name.startswith(("parseImpl", "_parseNoCache")):
- continue
- if id(f_self) in seen:
- continue
- seen.add(id(f_self))
- self_type = type(f_self)
- ret.append(f"{self_type.__module__}.{self_type.__name__} - {f_self}")
- elif f_self is not None:
- self_type = type(f_self)
- ret.append(f"{self_type.__module__}.{self_type.__name__}")
- else:
- code = frm.f_code
- if code.co_name in ("wrapper", "<module>"):
- continue
- ret.append(code.co_name)
- depth -= 1
- if not depth:
- break
- return "\n".join(ret)
- @classmethod
- def _from_exception(cls, pe) -> ParseBaseException:
- """
- internal factory method to simplify creating one type of ParseException
- from another - avoids having __init__ signature conflicts among subclasses
- """
- return cls(pe.pstr, pe.loc, pe.msg, pe.parser_element)
- @cached_property
- def line(self) -> str:
- """
- Return the line of text where the exception occurred.
- """
- return line(self.loc, self.pstr)
- @cached_property
- def lineno(self) -> int:
- """
- Return the 1-based line number of text where the exception occurred.
- """
- return lineno(self.loc, self.pstr)
- @cached_property
- def col(self) -> int:
- """
- Return the 1-based column on the line of text where the exception occurred.
- """
- return col(self.loc, self.pstr)
- @cached_property
- def column(self) -> int:
- """
- Return the 1-based column on the line of text where the exception occurred.
- """
- return col(self.loc, self.pstr)
- @cached_property
- def found(self) -> str:
- if not self.pstr:
- return ""
- if self.loc >= len(self.pstr):
- return "end of text"
- # pull out next word at error location
- found_match = _exception_word_extractor.match(self.pstr, self.loc)
- if found_match is not None:
- found_text = found_match[0]
- else:
- found_text = self.pstr[self.loc : self.loc + 1]
- return repr(found_text).replace(r"\\", "\\")
- # pre-PEP8 compatibility
- @property
- def parserElement(self):
- warnings.warn(
- "parserElement is deprecated, use parser_element",
- PyparsingDeprecationWarning,
- stacklevel=2,
- )
- return self.parser_element
- @parserElement.setter
- def parserElement(self, elem):
- warnings.warn(
- "parserElement is deprecated, use parser_element",
- PyparsingDeprecationWarning,
- stacklevel=2,
- )
- self.parser_element = elem
- def copy(self):
- return copy.copy(self)
- def formatted_message(self) -> str:
- """
- Output the formatted exception message.
- Can be overridden to customize the message formatting or contents.
- .. versionadded:: 3.2.0
- """
- found_phrase = f", found {self.found}" if self.found else ""
- return f"{self.msg}{found_phrase} (at char {self.loc}), (line:{self.lineno}, col:{self.column})"
- def __str__(self) -> str:
- """
- .. versionchanged:: 3.2.0
- Now uses :meth:`formatted_message` to format message.
- """
- try:
- return self.formatted_message()
- except Exception as ex:
- return (
- f"{type(self).__name__}: {self.msg}"
- f" ({type(ex).__name__}: {ex} while formatting message)"
- )
- def __repr__(self):
- return str(self)
- def mark_input_line(
- self, marker_string: typing.Optional[str] = None, **kwargs
- ) -> str:
- """
- Extracts the exception line from the input string, and marks
- the location of the exception with a special symbol.
- """
- markerString: str = deprecate_argument(kwargs, "markerString", ">!<")
- markerString = marker_string if marker_string is not None else markerString
- line_str = self.line
- line_column = self.column - 1
- if markerString:
- line_str = f"{line_str[:line_column]}{markerString}{line_str[line_column:]}"
- return line_str.strip()
- def explain(self, depth: int = 16) -> str:
- """
- Method to translate the Python internal traceback into a list
- of the pyparsing expressions that caused the exception to be raised.
- Parameters:
- - depth (default=16) - number of levels back in the stack trace to list expression
- and function names; if None, the full stack trace names will be listed; if 0, only
- the failing input line, marker, and exception string will be shown
- Returns a multi-line string listing the ParserElements and/or function names in the
- exception's stack trace.
- Example:
- .. testcode::
- # an expression to parse 3 integers
- expr = pp.Word(pp.nums) * 3
- try:
- # a failing parse - the third integer is prefixed with "A"
- expr.parse_string("123 456 A789")
- except pp.ParseException as pe:
- print(pe.explain(depth=0))
- prints:
- .. testoutput::
- 123 456 A789
- ^
- ParseException: Expected W:(0-9), found 'A789' (at char 8), (line:1, col:9)
- Note: the diagnostic output will include string representations of the expressions
- that failed to parse. These representations will be more helpful if you use `set_name` to
- give identifiable names to your expressions. Otherwise they will use the default string
- forms, which may be cryptic to read.
- Note: pyparsing's default truncation of exception tracebacks may also truncate the
- stack of expressions that are displayed in the ``explain`` output. To get the full listing
- of parser expressions, you may have to set ``ParserElement.verbose_stacktrace = True``
- """
- return self.explain_exception(self, depth)
- # Compatibility synonyms
- # fmt: off
- markInputline = replaced_by_pep8("markInputline", mark_input_line)
- # fmt: on
- class ParseException(ParseBaseException):
- """
- Exception thrown when a parse expression doesn't match the input string
- Example:
- .. testcode::
- integer = Word(nums).set_name("integer")
- try:
- integer.parse_string("ABC")
- except ParseException as pe:
- print(pe, f"column: {pe.column}")
- prints:
- .. testoutput::
- Expected integer, found 'ABC' (at char 0), (line:1, col:1) column: 1
- """
- class ParseFatalException(ParseBaseException):
- """
- User-throwable exception thrown when inconsistent parse content
- is found; stops all parsing immediately
- """
- class ParseSyntaxException(ParseFatalException):
- """
- Just like :class:`ParseFatalException`, but thrown internally
- when an :class:`ErrorStop<And._ErrorStop>` ('-' operator) indicates
- that parsing is to stop immediately because an unbacktrackable
- syntax error has been found.
- """
- class RecursiveGrammarException(Exception):
- """
- .. deprecated:: 3.0.0
- Only used by the deprecated :meth:`ParserElement.validate`.
- Exception thrown by :class:`ParserElement.validate` if the
- grammar could be left-recursive; parser may need to enable
- left recursion using :class:`ParserElement.enable_left_recursion<ParserElement.enable_left_recursion>`
- """
- def __init__(self, parseElementList) -> None:
- self.parseElementTrace = parseElementList
- def __str__(self) -> str:
- return f"RecursiveGrammarException: {self.parseElementTrace}"
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