Files
midas/midas/checker/checker.py
LordBaryhobal f882eebaf5 feat(checker): add basic checker
still very basic but lays out the structure and help methods
2026-05-28 17:35:00 +02:00

153 lines
5.5 KiB
Python

import logging
from pathlib import Path
from typing import Optional
import midas.ast.midas as m
import midas.ast.python as p
from midas.checker.environment import Environment
from midas.checker.operators import OPERATOR_METHODS
from midas.checker.types import BaseType, Type, UnknownType
from midas.lexer.midas import MidasLexer
from midas.lexer.token import Token
from midas.parser.midas import MidasParser
from midas.resolver.midas import MidasResolver
class Checker(
p.Stmt.Visitor[None],
p.Expr.Visitor[Type],
p.MidasType.Visitor[Type],
):
def __init__(self, locals: dict[p.Expr, int], base_dir: Path):
self.logger: logging.Logger = logging.getLogger("Checker")
self.base_dir: Path = base_dir
self.ctx: MidasResolver = MidasResolver()
self.global_env: Environment = Environment()
self.env: Environment = self.global_env
self.locals: dict[p.Expr, int] = locals
def evaluate(self, expr: p.Expr) -> Type:
return expr.accept(self)
def check(self, statements: list[p.Stmt]) -> None:
for stmt in statements:
stmt.accept(self)
self.logger.debug(f"Final environment: {self.env.flat_dict()}")
def look_up_variable(self, name: str, expr: p.Expr) -> Optional[Type]:
distance: Optional[int] = self.locals.get(expr)
if distance is not None:
return self.env.get_at(distance, name)
return self.global_env.get(name)
def parse_midas_import(self, expr: p.CallExpr) -> Optional[Path]:
match expr:
case p.CallExpr(
callee=p.GetExpr(
object=p.VariableExpr(name="midas"),
name="using",
),
arguments=[
p.LiteralExpr(value=path),
],
):
return Path(path)
return None
def import_midas(self, path: Path) -> None:
self.logger.debug(f"Importing type definitions from {path}")
path = (self.base_dir / path).resolve()
lexer: MidasLexer = MidasLexer(path.read_text())
tokens: list[Token] = lexer.process()
parser: MidasParser = MidasParser(tokens)
stmts: list[m.Stmt] = parser.parse()
self.ctx.resolve(stmts)
self.logger.debug(f"Midas types: {self.ctx._types}")
self.logger.debug(f"Midas operations: {self.ctx._operations}")
def visit_expression_stmt(self, stmt: p.ExpressionStmt) -> None:
self.evaluate(stmt.expr)
def visit_function(self, stmt: p.Function) -> None: ...
def visit_type_assign(self, stmt: p.TypeAssign) -> None:
# TODO check not yet defined locally
type: Type = stmt.type.accept(self)
self.env.define(stmt.name, type)
def visit_assign_stmt(self, stmt: p.AssignStmt) -> None:
value: Type = self.evaluate(stmt.value)
for target in stmt.targets:
if not isinstance(target, p.VariableExpr):
self.logger.warning(f"Unsupported assignment to {target}")
continue
name: str = target.name
var_type: Optional[Type] = self.look_up_variable(name, target)
if var_type is None:
self.env.define(name, value)
else:
# TODO: implement real comparison method
if var_type != value:
raise ValueError(
f"Cannot assign {value} to {name} of type {var_type}"
)
def visit_binary_expr(self, expr: p.BinaryExpr) -> Type:
method: Optional[str] = OPERATOR_METHODS.get(expr.operator.__class__)
if method is None:
self.logger.warning(f"Unsupported operator {expr.operator}")
return UnknownType()
left: Type = self.evaluate(expr.left)
right: Type = self.evaluate(expr.right)
result: Type = self.ctx.get_operation_result(left, method, right)
return result
def visit_compare_expr(self, expr: p.CompareExpr) -> Type: ...
def visit_unary_expr(self, expr: p.UnaryExpr) -> Type: ...
def visit_call_expr(self, expr: p.CallExpr) -> Type:
if path := self.parse_midas_import(expr):
self.import_midas(path)
return UnknownType()
callee: Type = self.evaluate(expr.callee)
arguments: list[Type] = [self.evaluate(arg) for arg in expr.arguments]
keywords: dict[str, Type] = {
name: self.evaluate(arg) for name, arg in expr.keywords.items()
}
return UnknownType()
def visit_get_expr(self, expr: p.GetExpr) -> Type: ...
def visit_literal_expr(self, expr: p.LiteralExpr) -> Type:
match expr.value:
case int():
return BaseType(name="int")
case float():
return BaseType(name="float")
case bool():
return BaseType(name="bool")
case str():
return BaseType(name="str")
case _:
return UnknownType()
def visit_variable_expr(self, expr: p.VariableExpr) -> Type:
return self.look_up_variable(expr.name, expr) or UnknownType()
def visit_logical_expr(self, expr: p.LogicalExpr) -> Type: ...
def visit_set_expr(self, expr: p.SetExpr) -> Type: ...
def visit_base_type(self, node: p.BaseType) -> Type:
return self.ctx.get_type(node.base)
def visit_constraint_type(self, node: p.ConstraintType) -> Type: ...
def visit_frame_column(self, node: p.FrameColumn) -> Type: ...
def visit_frame_type(self, node: p.FrameType) -> Type: ...