Files
midas/midas/generator/constraints.py

225 lines
7.3 KiB
Python

import ast
from typing import Optional
import midas.ast.midas as m
from midas.checker.registry import TypesRegistry
from midas.checker.types import (
Function,
Predicate,
Type,
to_annotation,
)
from midas.lexer.token import TokenType
LOGICAL_OPERATORS: dict[TokenType, type[ast.boolop]] = {
TokenType.AND: ast.And,
# TokenType.OR: ast.Or,
}
BINARY_OPERATORS: dict[TokenType, type[ast.operator]] = {
# TokenType.PLUS: ast.Add,
TokenType.MINUS: ast.Sub,
TokenType.STAR: ast.Mult,
TokenType.SLASH: ast.Div,
}
UNARY_OPERATORS: dict[TokenType, type[ast.unaryop]] = {
# TokenType.PLUS: ast.UAdd,
TokenType.MINUS: ast.USub,
}
COMPARISON_OPERATORS: dict[TokenType, type[ast.cmpop]] = {
TokenType.GREATER: ast.Gt,
TokenType.GREATER_EQUAL: ast.GtE,
TokenType.LESS: ast.Lt,
TokenType.LESS_EQUAL: ast.LtE,
TokenType.EQUAL_EQUAL: ast.Eq,
TokenType.BANG_EQUAL: ast.NotEq,
}
class ConstraintGenerator(m.Expr.Visitor[ast.expr]):
def __init__(self, types: TypesRegistry):
self.types: TypesRegistry = types
self._id: int = 0
self._definitions: list[ast.stmt] = []
self._aliases: dict[str, str] = {}
def get_definitions(self) -> list[ast.stmt]:
return self._definitions
def generate(self, expr: m.Expr) -> ast.expr:
match expr:
case m.VariableExpr():
return expr.accept(self)
case _:
func = Function(
pos_args=[],
args=[
Function.Argument(
pos=0,
name="_",
type=self.types.get_type("Any"),
required=True,
)
],
kw_args=[],
returns=self.types.get_type("bool"),
)
alias: str = self.make_alias(None)
definition: ast.stmt = self.make_definition(
alias, Predicate(type=func, body=expr, alias=False)
)
self._definitions.append(definition)
return ast.Name(id=alias)
def make_alias(self, name: Optional[str]) -> str:
suffix: str
if name is None:
suffix = f"p{self._id}"
self._id += 1
else:
suffix = name
alias: str = f"__midas_{suffix}__"
return alias
def make_definition(self, name: str, predicate: Predicate) -> ast.stmt:
body: ast.expr = predicate.body.accept(self)
if predicate.alias:
return ast.Assign(
targets=[
ast.Name(id=name),
],
value=body,
)
return self.make_func(name, [ast.Return(value=body)], predicate.type)
def make_args(self, func: Function) -> ast.arguments:
return ast.arguments(
posonlyargs=[
ast.arg(
arg=arg.name,
annotation=ast.Constant(value=to_annotation(arg.type)),
)
for arg in func.pos_args
],
args=[
ast.arg(
arg=arg.name,
annotation=ast.Constant(value=to_annotation(arg.type)),
)
for arg in func.args
],
kwonlyargs=[
ast.arg(
arg=arg.name,
annotation=ast.Constant(value=to_annotation(arg.type)),
)
for arg in func.kw_args
],
defaults=[],
kw_defaults=[],
)
def make_func(
self, name: str, inner_body: list[ast.stmt], type: Type, level: int = 0
) -> ast.stmt:
match type:
case Function(returns=Function()):
inner_name: str = f"inner{level}"
return ast.FunctionDef(
name=name,
args=self.make_args(type),
body=[
self.make_func(inner_name, inner_body, type.returns, level + 1),
ast.Return(value=ast.Name(id=inner_name)),
],
returns=ast.Constant(value=to_annotation(type.returns)),
decorator_list=[],
)
case Function():
return ast.FunctionDef(
name=name,
args=self.make_args(type),
body=inner_body,
returns=ast.Constant(value=to_annotation(type.returns)),
decorator_list=[],
)
case _:
raise ValueError(f"Expected function, got {type!r}")
def get_predicate(self, name: str) -> Optional[ast.expr]:
if name not in self._aliases:
predicate: Optional[Predicate] = self.types.lookup_predicate(name)
if predicate is None:
return None
alias: str = self.make_alias(name)
self._aliases[name] = alias
self._definitions.append(self.make_definition(alias, predicate))
return ast.Name(id=self._aliases[name])
def visit_logical_expr(self, expr: m.LogicalExpr) -> ast.expr:
return ast.BoolOp(
op=LOGICAL_OPERATORS[expr.operator.type](),
values=[
expr.left.accept(self),
expr.right.accept(self),
],
)
def visit_binary_expr(self, expr: m.BinaryExpr) -> ast.expr:
op: TokenType = expr.operator.type
if op in BINARY_OPERATORS:
return ast.BinOp(
left=expr.left.accept(self),
op=BINARY_OPERATORS[op](),
right=expr.right.accept(self),
)
if op in COMPARISON_OPERATORS:
return ast.Compare(
left=expr.left.accept(self),
ops=[COMPARISON_OPERATORS[op]()],
comparators=[expr.right.accept(self)],
)
raise ValueError(f"Unexpected binary operator {op}")
def visit_unary_expr(self, expr: m.UnaryExpr) -> ast.expr:
return ast.UnaryOp(
op=UNARY_OPERATORS[expr.operator.type](),
operand=expr.right.accept(self),
)
def visit_call_expr(self, expr: m.CallExpr) -> ast.expr:
return ast.Call(
func=expr.callee.accept(self),
args=[arg.accept(self) for arg in expr.arguments],
keywords=[
ast.keyword(arg=name, value=arg.accept(self))
for name, arg in expr.keywords.items()
],
)
def visit_get_expr(self, expr: m.GetExpr) -> ast.expr:
return ast.Attribute(
value=expr.expr.accept(self),
attr=expr.name.lexeme,
)
def visit_variable_expr(self, expr: m.VariableExpr) -> ast.expr:
name: str = expr.name.lexeme
if (p := self.get_predicate(name)) is not None:
return p
return ast.Name(id=name)
def visit_grouping_expr(self, expr: m.GroupingExpr) -> ast.expr:
return expr.accept(self)
def visit_literal_expr(self, expr: m.LiteralExpr) -> ast.expr:
return ast.Constant(value=expr.value)
def visit_wildcard_expr(self, expr: m.WildcardExpr) -> ast.expr:
return ast.Name(id="_")