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- # exceptions.py
- import re
- import sys
- import typing
- from .util import (
- col,
- line,
- lineno,
- _collapse_string_to_ranges,
- replaced_by_pep8,
- )
- from .unicode import pyparsing_unicode as ppu
- class ExceptionWordUnicode(ppu.Latin1, ppu.LatinA, ppu.LatinB, ppu.Greek, ppu.Cyrillic):
- pass
- _extract_alphanums = _collapse_string_to_ranges(ExceptionWordUnicode.alphanums)
- _exception_word_extractor = re.compile("([" + _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: typing.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,
- ):
- self.loc = loc
- if msg is None:
- self.msg = pstr
- self.pstr = ""
- else:
- self.msg = msg
- self.pstr = pstr
- self.parser_element = elem
- self.args = (pstr, loc, msg)
- @staticmethod
- def explain_exception(exc, depth=16):
- """
- 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 = []
- if isinstance(exc, ParseBaseException):
- ret.append(exc.line)
- ret.append(" " * (exc.column - 1) + "^")
- ret.append(f"{type(exc).__name__}: {exc}")
- if depth > 0:
- callers = inspect.getinnerframes(exc.__traceback__, context=depth)
- seen = set()
- for i, ff in enumerate(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):
- """
- 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)
- @property
- def line(self) -> str:
- """
- Return the line of text where the exception occurred.
- """
- return line(self.loc, self.pstr)
- @property
- def lineno(self) -> int:
- """
- Return the 1-based line number of text where the exception occurred.
- """
- return lineno(self.loc, self.pstr)
- @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)
- @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)
- # pre-PEP8 compatibility
- @property
- def parserElement(self):
- return self.parser_element
- @parserElement.setter
- def parserElement(self, elem):
- self.parser_element = elem
- def __str__(self) -> str:
- if self.pstr:
- if self.loc >= len(self.pstr):
- foundstr = ", found end of text"
- else:
- # pull out next word at error location
- found_match = _exception_word_extractor.match(self.pstr, self.loc)
- if found_match is not None:
- found = found_match.group(0)
- else:
- found = self.pstr[self.loc : self.loc + 1]
- foundstr = (", found %r" % found).replace(r"\\", "\\")
- else:
- foundstr = ""
- return f"{self.msg}{foundstr} (at char {self.loc}), (line:{self.lineno}, col:{self.column})"
- def __repr__(self):
- return str(self)
- def mark_input_line(
- self, marker_string: typing.Optional[str] = None, *, markerString: str = ">!<"
- ) -> str:
- """
- Extracts the exception line from the input string, and marks
- the location of the exception with a special symbol.
- """
- markerString = marker_string if marker_string is not None else markerString
- line_str = self.line
- line_column = self.column - 1
- if markerString:
- line_str = "".join(
- (line_str[:line_column], markerString, line_str[line_column:])
- )
- return line_str.strip()
- def explain(self, depth=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::
- expr = pp.Word(pp.nums) * 3
- try:
- expr.parse_string("123 456 A789")
- except pp.ParseException as pe:
- print(pe.explain(depth=0))
- prints::
- 123 456 A789
- ^
- ParseException: Expected W:(0-9), found 'A' (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)
- # fmt: off
- @replaced_by_pep8(mark_input_line)
- def markInputline(self): ...
- # fmt: on
- class ParseException(ParseBaseException):
- """
- Exception thrown when a parse expression doesn't match the input string
- Example::
- try:
- Word(nums).set_name("integer").parse_string("ABC")
- except ParseException as pe:
- print(pe)
- print("column: {}".format(pe.column))
- prints::
- Expected integer (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):
- """
- 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):
- self.parseElementTrace = parseElementList
- def __str__(self) -> str:
- return f"RecursiveGrammarException: {self.parseElementTrace}"
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