grammar.py 3.9 KB

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  1. from typing import Any, Dict, Optional, Tuple, ClassVar, Sequence
  2. from .utils import Serialize
  3. ###{standalone
  4. TOKEN_DEFAULT_PRIORITY = 0
  5. class Symbol(Serialize):
  6. __slots__ = ('name',)
  7. name: str
  8. is_term: ClassVar[bool] = NotImplemented
  9. def __init__(self, name: str) -> None:
  10. self.name = name
  11. def __eq__(self, other):
  12. if not isinstance(other, Symbol):
  13. return NotImplemented
  14. return self.is_term == other.is_term and self.name == other.name
  15. def __ne__(self, other):
  16. return not (self == other)
  17. def __hash__(self):
  18. return hash(self.name)
  19. def __repr__(self):
  20. return '%s(%r)' % (type(self).__name__, self.name)
  21. fullrepr = property(__repr__)
  22. def renamed(self, f):
  23. return type(self)(f(self.name))
  24. class Terminal(Symbol):
  25. __serialize_fields__ = 'name', 'filter_out'
  26. is_term: ClassVar[bool] = True
  27. def __init__(self, name: str, filter_out: bool = False) -> None:
  28. self.name = name
  29. self.filter_out = filter_out
  30. @property
  31. def fullrepr(self):
  32. return '%s(%r, %r)' % (type(self).__name__, self.name, self.filter_out)
  33. def renamed(self, f):
  34. return type(self)(f(self.name), self.filter_out)
  35. class NonTerminal(Symbol):
  36. __serialize_fields__ = 'name',
  37. is_term: ClassVar[bool] = False
  38. def serialize(self, memo=None) -> Dict[str, Any]:
  39. # TODO this is here because self.name can be a Token instance.
  40. # remove this function when the issue is fixed. (backwards-incompatible)
  41. return {'name': str(self.name), '__type__': 'NonTerminal'}
  42. class RuleOptions(Serialize):
  43. __serialize_fields__ = 'keep_all_tokens', 'expand1', 'priority', 'template_source', 'empty_indices'
  44. keep_all_tokens: bool
  45. expand1: bool
  46. priority: Optional[int]
  47. template_source: Optional[str]
  48. empty_indices: Tuple[bool, ...]
  49. def __init__(self, keep_all_tokens: bool=False, expand1: bool=False, priority: Optional[int]=None, template_source: Optional[str]=None, empty_indices: Tuple[bool, ...]=()) -> None:
  50. self.keep_all_tokens = keep_all_tokens
  51. self.expand1 = expand1
  52. self.priority = priority
  53. self.template_source = template_source
  54. self.empty_indices = empty_indices
  55. def __repr__(self):
  56. return 'RuleOptions(%r, %r, %r, %r)' % (
  57. self.keep_all_tokens,
  58. self.expand1,
  59. self.priority,
  60. self.template_source
  61. )
  62. class Rule(Serialize):
  63. """
  64. origin : a symbol
  65. expansion : a list of symbols
  66. order : index of this expansion amongst all rules of the same name
  67. """
  68. __slots__ = ('origin', 'expansion', 'alias', 'options', 'order', '_hash')
  69. __serialize_fields__ = 'origin', 'expansion', 'order', 'alias', 'options'
  70. __serialize_namespace__ = Terminal, NonTerminal, RuleOptions
  71. origin: NonTerminal
  72. expansion: Sequence[Symbol]
  73. order: int
  74. alias: Optional[str]
  75. options: RuleOptions
  76. _hash: int
  77. def __init__(self, origin: NonTerminal, expansion: Sequence[Symbol],
  78. order: int=0, alias: Optional[str]=None, options: Optional[RuleOptions]=None):
  79. self.origin = origin
  80. self.expansion = expansion
  81. self.alias = alias
  82. self.order = order
  83. self.options = options or RuleOptions()
  84. self._hash = hash((self.origin, tuple(self.expansion)))
  85. def _deserialize(self):
  86. self._hash = hash((self.origin, tuple(self.expansion)))
  87. def __str__(self):
  88. return '<%s : %s>' % (self.origin.name, ' '.join(x.name for x in self.expansion))
  89. def __repr__(self):
  90. return 'Rule(%r, %r, %r, %r)' % (self.origin, self.expansion, self.alias, self.options)
  91. def __hash__(self):
  92. return self._hash
  93. def __eq__(self, other):
  94. if not isinstance(other, Rule):
  95. return False
  96. return self.origin == other.origin and self.expansion == other.expansion
  97. ###}