refactor(checker): rename methods

improve a couple methods names, namely evaluate → type_of and evaluate_block → process_block

gen/midas.py

@@ -111,10 +111,6 @@ class ConstraintType:
     constraint: Expr
 
 
-class UnionType:
-    types: list[Type]
-
-
 class ComplexType:
     properties: list[PropertyStmt]
 

midas/ast/midas.py

@@ -228,9 +228,6 @@ class Type(ABC):
         @abstractmethod
         def visit_constraint_type(self, type: ConstraintType) -> T: ...
 
-        @abstractmethod
-        def visit_union_type(self, type: UnionType) -> T: ...
-
         @abstractmethod
         def visit_complex_type(self, type: ComplexType) -> T: ...
 
@@ -261,14 +258,6 @@ class ConstraintType(Type):
         return visitor.visit_constraint_type(self)
 
 
-@dataclass(frozen=True)
-class UnionType(Type):
-    types: list[Type]
-
-    def accept(self, visitor: Type.Visitor[T]) -> T:
-        return visitor.visit_union_type(self)
-
-
 @dataclass(frozen=True)
 class ComplexType(Type):
     properties: list[PropertyStmt]

midas/ast/printer.py

@@ -252,17 +252,6 @@ class MidasAstPrinter(
             with self._child_level(single=True):
                 type.constraint.accept(self)
 
-    def visit_union_type(self, type: m.UnionType) -> None:
-        self._write_line("UnionType")
-        with self._child_level():
-            self._write_line("types", last=True)
-            with self._child_level():
-                for i, type_ in enumerate(type.types):
-                    self._idx = i
-                    if i == len(type.types) - 1:
-                        self._mark_last()
-                    type_.accept(self)
-
     def visit_complex_type(self, type: m.ComplexType) -> None:
         self._write_line("ComplexType")
         with self._child_level():
@@ -379,10 +368,6 @@ class MidasPrinter(m.Expr.Visitor[str], m.Stmt.Visitor[str], m.Type.Visitor[str]
         res += " where " + type.constraint.accept(self)
         return res
 
-    def visit_union_type(self, type: m.UnionType) -> str:
-        types: list[str] = [type_.accept(self) for type_ in type.types]
-        return " | ".join(types)
-
     def visit_complex_type(self, type: m.ComplexType) -> str:
         res: str = "{\n"
         self.level += 1

midas/checker/checker.py

@@ -74,7 +74,7 @@ class Checker(
             message=message,
         )
 
-    def evaluate(self, expr: p.Expr) -> Type:
+    def type_of(self, expr: p.Expr) -> Type:
         """Evaluate the type of an expression
 
         Args:
@@ -85,7 +85,7 @@ class Checker(
         """
         return expr.accept(self)
 
-    def evaluate_block(self, block: list[p.Stmt], env: Environment) -> bool:
+    def process_block(self, block: list[p.Stmt], env: Environment) -> bool:
         """Evaluate a sequence of statements
 
         Args:
@@ -181,7 +181,7 @@ class Checker(
         self.logger.debug(f"Midas operations: {self.ctx._operations}")
 
     def visit_expression_stmt(self, stmt: p.ExpressionStmt) -> None:
-        self.evaluate(stmt.expr)
+        self.type_of(stmt.expr)
 
     def visit_function(self, stmt: p.Function) -> None:
         env: Environment = Environment(self.env)
@@ -237,7 +237,7 @@ class Checker(
             )
             self.env.define(stmt.name, inside_function)
 
-        returned: bool = self.evaluate_block(stmt.body, env)
+        returned: bool = self.process_block(stmt.body, env)
         inferred_return: Type = UnknownType()
         if not returned:
             env.return_types.append(UnitType())
@@ -278,7 +278,7 @@ class Checker(
         self.env.define(stmt.name, type)
 
     def visit_assign_stmt(self, stmt: p.AssignStmt) -> None:
-        value: Type = self.evaluate(stmt.value)
+        value: Type = self.type_of(stmt.value)
         for target in stmt.targets:
             if not isinstance(target, p.VariableExpr):
                 self.logger.warning(f"Unsupported assignment to {target}")
@@ -317,8 +317,8 @@ class Checker(
             )
 
         env: Environment = Environment(self.env)
-        body_returned: bool = self.evaluate_block(stmt.body, env)
-        else_returned: bool = self.evaluate_block(stmt.orelse, env)
+        body_returned: bool = self.process_block(stmt.body, env)
+        else_returned: bool = self.process_block(stmt.orelse, env)
         self.env.return_types.extend(env.return_types)
         if body_returned and else_returned:
             raise ReturnException()
@@ -329,8 +329,8 @@ class Checker(
             self.logger.warning(f"Unsupported operator {expr.operator}")
             self.warning(expr.location, f"Unsupported operator {expr.operator}")
             return UnknownType()
-        left: Type = self.evaluate(expr.left)
-        right: Type = self.evaluate(expr.right)
+        left: Type = self.type_of(expr.left)
+        right: Type = self.type_of(expr.right)
 
         result: Optional[Type] = self.ctx.get_operation_result(left, method, right)
         if result is None:
@@ -347,8 +347,8 @@ class Checker(
             self.logger.warning(f"Unsupported operator {expr.operator}")
             self.warning(expr.location, f"Unsupported operator {expr.operator}")
             return UnknownType()
-        left: Type = self.evaluate(expr.left)
-        right: Type = self.evaluate(expr.right)
+        left: Type = self.type_of(expr.left)
+        right: Type = self.type_of(expr.right)
 
         result: Optional[Type] = self.ctx.get_operation_result(left, method, right)
         if result is None:
@@ -365,7 +365,7 @@ class Checker(
         if path := self.parse_midas_import(expr):
             self.import_midas(path)
             return UnknownType()
-        callee: Type = self.evaluate(expr.callee)
+        callee: Type = self.type_of(expr.callee)
         if not isinstance(callee, Function):
             self.error(expr.callee.location, "Callee is not a function")
             return UnknownType()
@@ -460,10 +460,10 @@ class Checker(
             list[MappedArgument]: the list of mapped arguments
         """
         positional: list[tuple[p.Expr, Type]] = [
-            (arg, self.evaluate(arg)) for arg in call.arguments
+            (arg, self.type_of(arg)) for arg in call.arguments
         ]
         keywords: dict[str, tuple[p.Expr, Type]] = {
-            name: (arg, self.evaluate(arg)) for name, arg in call.keywords.items()
+            name: (arg, self.type_of(arg)) for name, arg in call.keywords.items()
         }
         set_args: set[str] = set()
 

midas/checker/types.py

@@ -44,11 +44,4 @@ class ComplexType:
     properties: dict[str, Type]
 
 
-@dataclass(frozen=True, kw_only=True)
-class UnionType:
-    alternatives: list[Type]
-
-
-Type = (
-    BaseType | AliasType | UnknownType | UnitType | Function | ComplexType | UnionType
-)
+Type = BaseType | AliasType | UnknownType | UnitType | Function | ComplexType

midas/cli/highlighter.py

@@ -294,11 +294,6 @@ class MidasHighlighter(
         type.type.accept(self)
         type.constraint.accept(self)
 
-    def visit_union_type(self, type: m.UnionType) -> None:
-        self.wrap(type, "union-type")
-        for type_ in type.types:
-            type_.accept(self)
-
     def visit_complex_type(self, type: m.ComplexType) -> None:
         self.wrap(type, "complex-type")
         for prop in type.properties:

midas/cli/hl_midas.css

@@ -8,7 +8,6 @@ span {
     &.named-type,
     &.generic-type,
     &.constraint-type,
-    &.union-type,
     &.complex-type {
         --col: 150, 150, 150;
     }

midas/lexer/midas.py

@@ -18,8 +18,6 @@ class MidasLexer(Lexer):
                 self.add_token(TokenType.LEFT_BRACE)
             case "}":
                 self.add_token(TokenType.RIGHT_BRACE)
-            case "|":
-                self.add_token(TokenType.PIPE)
             case "<":
                 self.add_token(
                     TokenType.LESS_EQUAL if self.match("=") else TokenType.LESS

midas/lexer/token.py

@@ -23,7 +23,6 @@ class TokenType(Enum):
     AND = auto()
     QMARK = auto()
     DOT = auto()
-    PIPE = auto()
 
     # Operators
     # PLUS = auto()

midas/parser/midas.py

@@ -20,7 +20,6 @@ from midas.ast.midas import (
     Type,
     TypeStmt,
     UnaryExpr,
-    UnionType,
     VariableExpr,
     WildcardExpr,
 )
@@ -161,18 +160,7 @@ class MidasParser(Parser):
         Returns:
             TypeExpr: the parsed type expression
         """
-        return self.union_type()
-
-    def union_type(self) -> Type:
-        types: list[Type] = [self.constraint_type()]
-        while self.match(TokenType.PIPE):
-            types.append(self.constraint_type())
-        if len(types) == 1:
-            return types[0]
-        return UnionType(
-            location=Location.span(types[0].location, types[-1].location),
-            types=types,
-        )
+        return self.constraint_type()
 
     def constraint_type(self) -> Type:
         type: Type = self.base_type()

midas/resolver/midas.py

@@ -4,7 +4,6 @@ import midas.ast.midas as m
 from midas.checker.types import (
     AliasType,
     Type,
-    UnionType,
     UnknownType,
 )
 from midas.resolver.builtin import define_builtins
@@ -157,10 +156,6 @@ class MidasResolver(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[T
         # TODO
         return UnknownType()
 
-    def visit_union_type(self, type: m.UnionType) -> Type:
-        types: list[Type] = [type_.accept(self) for type_ in type.types]
-        return UnionType(alternatives=types)
-
     def visit_complex_type(self, type: m.ComplexType) -> Type:
         for prop in type.properties:
             prop.accept(self)

tests/cases/midas-parser/01_simple_types.midas

@@ -48,7 +48,7 @@ type Person = {
     name: str
 
     // Property with an inline constraint
-    age: None | (int where (0 <= _ < 150))
+    age: Optional[int where (0 <= _ < 150)]
 
     // Property referencing a predicate
     height: float where StrictlyPositive

tests/cases/midas-parser/01_simple_types.midas.ref.json

@@ -1982,123 +1982,99 @@
     },
     {
       "type": "IDENTIFIER",
-      "lexeme": "None",
+      "lexeme": "Optional",
       "line": 51,
       "column": 10
     },
     {
-      "type": "WHITESPACE",
-      "lexeme": " ",
+      "type": "LEFT_BRACKET",
+      "lexeme": "[",
       "line": 51,
-      "column": 14
-    },
-    {
-      "type": "PIPE",
-      "lexeme": "|",
-      "line": 51,
-      "column": 15
-    },
-    {
-      "type": "WHITESPACE",
-      "lexeme": " ",
-      "line": 51,
-      "column": 16
-    },
-    {
-      "type": "LEFT_PAREN",
-      "lexeme": "(",
-      "line": 51,
-      "column": 17
+      "column": 18
     },
     {
       "type": "IDENTIFIER",
       "lexeme": "int",
       "line": 51,
-      "column": 18
+      "column": 19
     },
     {
       "type": "WHITESPACE",
       "lexeme": " ",
       "line": 51,
-      "column": 21
+      "column": 22
     },
     {
       "type": "WHERE",
       "lexeme": "where",
       "line": 51,
-      "column": 22
+      "column": 23
     },
     {
       "type": "WHITESPACE",
       "lexeme": " ",
       "line": 51,
-      "column": 27
+      "column": 28
     },
     {
       "type": "LEFT_PAREN",
       "lexeme": "(",
       "line": 51,
-      "column": 28
+      "column": 29
     },
     {
       "type": "NUMBER",
       "lexeme": "0",
       "line": 51,
-      "column": 29
+      "column": 30
     },
     {
       "type": "WHITESPACE",
       "lexeme": " ",
       "line": 51,
-      "column": 30
+      "column": 31
     },
     {
       "type": "LESS_EQUAL",
       "lexeme": "<=",
       "line": 51,
-      "column": 31
+      "column": 32
     },
     {
       "type": "WHITESPACE",
       "lexeme": " ",
       "line": 51,
-      "column": 33
+      "column": 34
     },
     {
       "type": "UNDERSCORE",
       "lexeme": "_",
       "line": 51,
-      "column": 34
+      "column": 35
     },
     {
       "type": "WHITESPACE",
       "lexeme": " ",
       "line": 51,
-      "column": 35
+      "column": 36
     },
     {
       "type": "LESS",
       "lexeme": "<",
       "line": 51,
-      "column": 36
+      "column": 37
     },
     {
       "type": "WHITESPACE",
       "lexeme": " ",
       "line": 51,
-      "column": 37
+      "column": 38
     },
     {
       "type": "NUMBER",
       "lexeme": "150",
       "line": 51,
-      "column": 38
-    },
-    {
-      "type": "RIGHT_PAREN",
-      "lexeme": ")",
-      "line": 51,
-      "column": 41
+      "column": 39
     },
     {
       "type": "RIGHT_PAREN",
@@ -2106,11 +2082,17 @@
       "line": 51,
       "column": 42
     },
+    {
+      "type": "RIGHT_BRACKET",
+      "lexeme": "]",
+      "line": 51,
+      "column": 43
+    },
     {
       "type": "NEWLINE",
       "lexeme": "\n",
       "line": 51,
-      "column": 43
+      "column": 44
     },
     {
       "type": "NEWLINE",
@@ -2651,12 +2633,12 @@
             "_type": "PropertyStmt",
             "name": "age",
             "type": {
-              "_type": "UnionType",
-              "types": [
-                {
+              "_type": "GenericType",
+              "type": {
                 "_type": "NamedType",
-                  "name": "None"
+                "name": "Optional"
               },
+              "params": [
                 {
                   "_type": "ConstraintType",
                   "type": {

tests/serializer/midas.py

@@ -19,7 +19,6 @@ from midas.ast.midas import (
     Type,
     TypeStmt,
     UnaryExpr,
-    UnionType,
     VariableExpr,
     WildcardExpr,
 )
@@ -161,12 +160,6 @@ class MidasAstJsonSerializer(
             "constraint": type.constraint.accept(self),
         }
 
-    def visit_union_type(self, type: UnionType) -> dict:
-        return {
-            "_type": "UnionType",
-            "types": self._serialize_list(type.types),
-        }
-
     def visit_complex_type(self, type: ComplexType) -> dict:
         return {
             "_type": "ComplexType",