138 lines
3.9 KiB
Python
138 lines
3.9 KiB
Python
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"""Classes for representing match statement patterns."""
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from typing import TypeVar, List, Optional, Union
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from mypy_extensions import trait
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from mypy.nodes import Node, RefExpr, NameExpr, Expression
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from mypy.visitor import PatternVisitor
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T = TypeVar('T')
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@trait
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class Pattern(Node):
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"""A pattern node."""
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__slots__ = ()
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def accept(self, visitor: PatternVisitor[T]) -> T:
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raise RuntimeError('Not implemented')
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class AsPattern(Pattern):
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"""The pattern <pattern> as <name>"""
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# The python ast, and therefore also our ast merges capture, wildcard and as patterns into one
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# for easier handling.
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# If pattern is None this is a capture pattern. If name and pattern are both none this is a
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# wildcard pattern.
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# Only name being None should not happen but also won't break anything.
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pattern: Optional[Pattern]
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name: Optional[NameExpr]
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def __init__(self, pattern: Optional[Pattern], name: Optional[NameExpr]) -> None:
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super().__init__()
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self.pattern = pattern
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self.name = name
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def accept(self, visitor: PatternVisitor[T]) -> T:
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return visitor.visit_as_pattern(self)
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class OrPattern(Pattern):
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"""The pattern <pattern> | <pattern> | ..."""
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patterns: List[Pattern]
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def __init__(self, patterns: List[Pattern]) -> None:
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super().__init__()
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self.patterns = patterns
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def accept(self, visitor: PatternVisitor[T]) -> T:
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return visitor.visit_or_pattern(self)
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class ValuePattern(Pattern):
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"""The pattern x.y (or x.y.z, ...)"""
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expr: Expression
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def __init__(self, expr: Expression):
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super().__init__()
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self.expr = expr
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def accept(self, visitor: PatternVisitor[T]) -> T:
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return visitor.visit_value_pattern(self)
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class SingletonPattern(Pattern):
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# This can be exactly True, False or None
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value: Union[bool, None]
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def __init__(self, value: Union[bool, None]):
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super().__init__()
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self.value = value
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def accept(self, visitor: PatternVisitor[T]) -> T:
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return visitor.visit_singleton_pattern(self)
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class SequencePattern(Pattern):
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"""The pattern [<pattern>, ...]"""
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patterns: List[Pattern]
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def __init__(self, patterns: List[Pattern]):
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super().__init__()
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self.patterns = patterns
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def accept(self, visitor: PatternVisitor[T]) -> T:
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return visitor.visit_sequence_pattern(self)
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class StarredPattern(Pattern):
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# None corresponds to *_ in a list pattern. It will match multiple items but won't bind them to
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# a name.
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capture: Optional[NameExpr]
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def __init__(self, capture: Optional[NameExpr]):
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super().__init__()
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self.capture = capture
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def accept(self, visitor: PatternVisitor[T]) -> T:
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return visitor.visit_starred_pattern(self)
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class MappingPattern(Pattern):
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keys: List[Expression]
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values: List[Pattern]
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rest: Optional[NameExpr]
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def __init__(self, keys: List[Expression], values: List[Pattern],
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rest: Optional[NameExpr]):
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super().__init__()
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assert len(keys) == len(values)
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self.keys = keys
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self.values = values
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self.rest = rest
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def accept(self, visitor: PatternVisitor[T]) -> T:
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return visitor.visit_mapping_pattern(self)
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class ClassPattern(Pattern):
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"""The pattern Cls(...)"""
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class_ref: RefExpr
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positionals: List[Pattern]
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keyword_keys: List[str]
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keyword_values: List[Pattern]
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def __init__(self, class_ref: RefExpr, positionals: List[Pattern], keyword_keys: List[str],
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keyword_values: List[Pattern]):
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super().__init__()
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assert len(keyword_keys) == len(keyword_values)
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self.class_ref = class_ref
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self.positionals = positionals
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self.keyword_keys = keyword_keys
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self.keyword_values = keyword_values
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def accept(self, visitor: PatternVisitor[T]) -> T:
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return visitor.visit_class_pattern(self)
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