47aabc1691
type5 is much more first principles based, so we get a lot of weird quirks removed: - FromLiteral no longer needs to understand AST - Type unifications works more like Haskell - Function types are just ordinary types, saving a lot of manual busywork and more.
42 lines
1.2 KiB
Python
42 lines
1.2 KiB
Python
"""
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Some expression have constraints - those are usually the outmost expressions.
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"""
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from dataclasses import dataclass
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from typing import Callable, Self
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from .kindexpr import KindExpr
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from .typeexpr import TypeExpr, TypeVariable, instantiate
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class TypeConstraint:
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"""
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Base class for type contraints
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"""
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__slots__ = ()
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def __str__(self) -> str:
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raise NotImplementedError
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def instantiate(self, known_map: dict[TypeVariable, TypeVariable], make_variable: Callable[[KindExpr, str], TypeVariable]) -> Self:
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raise NotImplementedError
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@dataclass
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class ConstrainedExpr:
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expr: TypeExpr
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constraints: tuple[TypeConstraint, ...]
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def instantiate_constrained(
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constrainedexpr: ConstrainedExpr,
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known_map: dict[TypeVariable, TypeVariable],
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make_variable: Callable[[KindExpr, str], TypeVariable],
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) -> ConstrainedExpr:
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"""
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Instantiates a type expression and its constraints
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"""
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expr = instantiate(constrainedexpr.expr, known_map, make_variable)
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constraints = tuple(
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x.instantiate(known_map, make_variable)
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for x in constrainedexpr.constraints
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)
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return ConstrainedExpr(expr, constraints)
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