plyparser.py 1.6 KB

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  1. #-----------------------------------------------------------------
  2. # plyparser.py
  3. #
  4. # PLYParser class and other utilites for simplifying programming
  5. # parsers with PLY
  6. #
  7. # Copyright (C) 2008-2015, Eli Bendersky
  8. # License: BSD
  9. #-----------------------------------------------------------------
  10. class Coord(object):
  11. """ Coordinates of a syntactic element. Consists of:
  12. - File name
  13. - Line number
  14. - (optional) column number, for the Lexer
  15. """
  16. __slots__ = ('file', 'line', 'column', '__weakref__')
  17. def __init__(self, file, line, column=None):
  18. self.file = file
  19. self.line = line
  20. self.column = column
  21. def __str__(self):
  22. str = "%s:%s" % (self.file, self.line)
  23. if self.column: str += ":%s" % self.column
  24. return str
  25. class ParseError(Exception): pass
  26. class PLYParser(object):
  27. def _create_opt_rule(self, rulename):
  28. """ Given a rule name, creates an optional ply.yacc rule
  29. for it. The name of the optional rule is
  30. <rulename>_opt
  31. """
  32. optname = rulename + '_opt'
  33. def optrule(self, p):
  34. p[0] = p[1]
  35. optrule.__doc__ = '%s : empty\n| %s' % (optname, rulename)
  36. optrule.__name__ = 'p_%s' % optname
  37. setattr(self.__class__, optrule.__name__, optrule)
  38. def _coord(self, lineno, column=None):
  39. return Coord(
  40. file=self.clex.filename,
  41. line=lineno,
  42. column=column)
  43. def _parse_error(self, msg, coord):
  44. raise ParseError("%s: %s" % (coord, msg))