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feat(parser): parse Midas type constraints

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This commit is contained in:
Louis Heredero
2026-05-18 12:18:41 +02:00
parent e10d71a66b
commit 74ac9c5381
4 changed files with 88 additions and 13 deletions
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28
core/ast/midas.py
View File

@@ -2,7 +2,7 @@ from __future__ import annotations
from abc import ABC, abstractmethod
from dataclasses import dataclass
from typing import Generic, Optional, TypeVar
from typing import Any, Generic, Optional, TypeVar
from lexer.token import Token
@@ -79,6 +79,12 @@ class Expr(ABC):
def accept(self, visitor: Visitor[T]) -> T: ...
class Visitor(ABC, Generic[T]):
@abstractmethod
def visit_wildcard_expr(self, expr: WildcardExpr) -> T: ...
@abstractmethod
def visit_literal_expr(self, expr: LiteralExpr) -> T: ...
@abstractmethod
def visit_type_expr(self, expr: TypeExpr) -> T: ...
@@ -89,6 +95,22 @@ class Expr(ABC):
def visit_type_body_expr(self, expr: TypeBodyExpr) -> T: ...
@dataclass(frozen=True)
class WildcardExpr(Expr):
token: Token
def accept(self, visitor: Expr.Visitor[T]) -> T:
return visitor.visit_wildcard_expr(self)
@dataclass(frozen=True)
class LiteralExpr(Expr):
value: Any
def accept(self, visitor: Expr.Visitor[T]) -> T:
return visitor.visit_literal_expr(self)
@dataclass(frozen=True)
class TypeExpr(Expr):
name: Token
@@ -100,6 +122,10 @@ class TypeExpr(Expr):
@dataclass(frozen=True)
class ConstraintExpr(Expr):
left: Expr
op: Token
right: Expr
def accept(self, visitor: Expr.Visitor[T]) -> T:
return visitor.visit_constraint_expr(self)

36
core/ast/printer.py
View File

@@ -102,7 +102,7 @@ class AnnotationAstPrinter(AstPrinter, a.Expr.Visitor[None], a.Stmt.Visitor[None
if i == len(expr.constraints) - 1:
self._mark_last()
constraint.accept(self)
def visit_constraint_expr(self, expr: a.ConstraintExpr) -> None:
self._write_line("ConstraintExpr")
with self._child_level():
@@ -110,9 +110,9 @@ class AnnotationAstPrinter(AstPrinter, a.Expr.Visitor[None], a.Stmt.Visitor[None
with self._child_level():
self._mark_last()
expr.left.accept(self)
self._write_line(f"operator: {expr.op.lexeme}")
self._write_line("right", last=True)
with self._child_level():
self._mark_last()
@@ -133,14 +133,14 @@ class AnnotationAstPrinter(AstPrinter, a.Expr.Visitor[None], a.Stmt.Visitor[None
name_text: str = "None" if expr.name is None else f'"{expr.name.lexeme}"'
self._write_line(f"name: {name_text}")
self._write_optional_child("type", expr.type, last=True)
def visit_wildcard_expr(self, expr: a.WildcardExpr) -> None:
self._write_line("WildcardExpr")
def visit_literal_expr(self, expr: a.LiteralExpr) -> None:
self._write_line("LiteralExpr")
with self._child_level():
self._write_line(f'value: {expr.value}', last=True)
self._write_line(f"value: {expr.value}", last=True)
class AnnotationPrinter(a.Expr.Visitor[str], a.Stmt.Visitor[str]):
@@ -158,12 +158,12 @@ class AnnotationPrinter(a.Expr.Visitor[str], a.Stmt.Visitor[str]):
for constraint in expr.constraints:
parts.append("(" + constraint.accept(self) + ")")
return " + ".join(parts)
def visit_constraint_expr(self, expr: a.ConstraintExpr) -> str:
parts: list[str] = [
expr.left.accept(self),
expr.op.lexeme,
expr.right.accept(self)
expr.right.accept(self),
]
return " ".join(parts)
@@ -257,6 +257,18 @@ class MidasAstPrinter(AstPrinter, m.Expr.Visitor[None], m.Stmt.Visitor[None]):
def visit_constraint_expr(self, expr: m.ConstraintExpr):
self._write_line("ConstraintExpr")
with self._child_level():
self._write_line("left")
with self._child_level():
self._mark_last()
expr.left.accept(self)
self._write_line(f"operator: {expr.op.lexeme}")
self._write_line("right", last=True)
with self._child_level():
self._mark_last()
expr.right.accept(self)
def visit_type_body_expr(self, expr: m.TypeBodyExpr):
self._write_line("TypeBodyExpr")
@@ -268,3 +280,11 @@ class MidasAstPrinter(AstPrinter, m.Expr.Visitor[None], m.Stmt.Visitor[None]):
if i == len(expr.properties) - 1:
self._mark_last()
property.accept(self)
def visit_wildcard_expr(self, expr: m.WildcardExpr) -> None:
self._write_line("WildcardExpr")
def visit_literal_expr(self, expr: m.LiteralExpr) -> None:
self._write_line("LiteralExpr")
with self._child_level():
self._write_line(f"value: {expr.value}", last=True)

2
parser/annotations.py
View File

@@ -68,8 +68,6 @@ class AnnotationParser(Parser):
constraints: list[ConstraintExpr] = []
while not self.is_at_end() and self.match(TokenType.PLUS):
print(self.peek())
print(self.tokens)
self.consume(TokenType.LEFT_PAREN, "Expected '(' before type constraint")
constraints.append(self.constraint_expr())
self.consume(TokenType.RIGHT_PAREN, "Expected ')' after type constraint")

35
parser/midas.py
View File

@@ -3,12 +3,15 @@ from typing import Optional
from core.ast.midas import (
ConstraintExpr,
ConstraintStmt,
Expr,
LiteralExpr,
OpStmt,
PropertyStmt,
Stmt,
TypeBodyExpr,
TypeExpr,
TypeStmt,
WildcardExpr,
)
from lexer.token import Token, TokenType
from parser.base import Parser
@@ -96,7 +99,9 @@ class MidasParser(Parser):
constraints: list[ConstraintExpr] = []
while not self.is_at_end() and self.match(TokenType.PLUS):
self.consume(TokenType.LEFT_PAREN, "Expected '(' before type constraint")
constraints.append(self.constraint_expr())
self.consume(TokenType.RIGHT_PAREN, "Expected ')' after type constraint")
return TypeExpr(name=name, constraints=constraints)
@@ -106,8 +111,34 @@ class MidasParser(Parser):
Returns:
ConstraintExpr: the parsed type constraint expression
"""
# TODO
return ConstraintExpr()
left: Expr = self.constraint_value()
op: Token = self.constraint_operator()
right: Expr = self.constraint_value()
return ConstraintExpr(left=left, op=op, right=right)
def constraint_value(self) -> Expr:
if self.match(TokenType.UNDERSCORE):
return WildcardExpr(self.previous())
return self.literal()
def literal(self) -> LiteralExpr:
if self.match(TokenType.FALSE):
return LiteralExpr(False)
if self.match(TokenType.TRUE):
return LiteralExpr(True)
if self.match(TokenType.NONE):
return LiteralExpr(None)
if self.match(TokenType.NUMBER):
return LiteralExpr(self.previous().value)
raise self.error(self.peek(), "Expected literal")
def constraint_operator(self) -> Token:
if self.match(TokenType.LESS, TokenType.LESS_EQUAL, TokenType.GREATER, TokenType.GREATER_EQUAL, TokenType.EQUAL_EQUAL, TokenType.BANG_EQUAL):
return self.previous()
raise self.error(self.peek(), "Expected constraint operator")
def type_body_expr(self) -> TypeBodyExpr:
"""Parse a type definition body