feat(parser)!: add new Midas AST nodes

gen/midas.py

@@ -13,40 +13,38 @@ from midas.lexer.token import Token
 
 
 ###> Stmt | Statements
-class SimpleTypeStmt:
+class TypeStmt:
     name: Token
-    template: Optional[TemplateExpr]
+    params: list[Param]
-    base: TypeExpr
+    type: Type
-    constraint: Optional[Expr]
 
-
+    @dataclass(frozen=True, kw_only=True)
-class ComplexTypeStmt:
+    class Param:
-    name: Token
+        location: Location
-    template: Optional[TemplateExpr]
+        name: Token
-    properties: list[PropertyStmt]
+        bound: Optional[Type]
 
 
 class PropertyStmt:
     name: Token
-    type: TypeExpr
+    type: Type
-    constraint: Optional[Expr]
 
 
 class ExtendStmt:
-    type: TypeExpr
+    type: Type
     operations: list[OpStmt]
 
 
 class OpStmt:
     name: Token
-    operand: TypeExpr
+    operand: Type
-    result: TypeExpr
+    result: Type
 
 
 class PredicateStmt:
     name: Token
     subject: Token
-    type: TypeExpr
+    type: Type
     condition: Expr
 
 
@@ -54,9 +52,6 @@ class PredicateStmt:
 
 
 ###> Expr | Expressions
-class SimpleTypeExpr:
-    name: Token
-    optional: bool
 
 
 class LogicalExpr:
@@ -97,14 +92,31 @@ class WildcardExpr:
     token: Token
 
 
-class TemplateExpr:
+###<
-    type: TypeExpr
+
+###> Type | Types
 
 
-class TypeExpr:
+class NamedType:
     name: Token
-    template: Optional[TemplateExpr]
+
-    optional: bool
+
+class GenericType:
+    type: Type
+    params: list[Type]
+
+
+class ConstraintType:
+    type: Type
+    constraint: Expr
+
+
+class UnionType:
+    types: list[Type]
+
+
+class ComplexType:
+    properties: list[PropertyStmt]
 
 
 ###<

midas/ast/midas.py

@@ -28,10 +28,7 @@ class Stmt(ABC):
 
     class Visitor(ABC, Generic[T]):
         @abstractmethod
-        def visit_simple_type_stmt(self, stmt: SimpleTypeStmt) -> T: ...
+        def visit_type_stmt(self, stmt: TypeStmt) -> T: ...
-
-        @abstractmethod
-        def visit_complex_type_stmt(self, stmt: ComplexTypeStmt) -> T: ...
 
         @abstractmethod
         def visit_property_stmt(self, stmt: PropertyStmt) -> T: ...
@@ -47,31 +44,25 @@ class Stmt(ABC):
 
 
 @dataclass(frozen=True)
-class SimpleTypeStmt(Stmt):
+class TypeStmt(Stmt):
     name: Token
-    template: Optional[TemplateExpr]
+    params: list[Param]
-    base: TypeExpr
+    type: Type
-    constraint: Optional[Expr]
+
+    @dataclass(frozen=True, kw_only=True)
+    class Param:
+        location: Location
+        name: Token
+        bound: Optional[Type]
 
     def accept(self, visitor: Stmt.Visitor[T]) -> T:
-        return visitor.visit_simple_type_stmt(self)
+        return visitor.visit_type_stmt(self)
-
-
-@dataclass(frozen=True)
-class ComplexTypeStmt(Stmt):
-    name: Token
-    template: Optional[TemplateExpr]
-    properties: list[PropertyStmt]
-
-    def accept(self, visitor: Stmt.Visitor[T]) -> T:
-        return visitor.visit_complex_type_stmt(self)
 
 
 @dataclass(frozen=True)
 class PropertyStmt(Stmt):
     name: Token
-    type: TypeExpr
+    type: Type
-    constraint: Optional[Expr]
 
     def accept(self, visitor: Stmt.Visitor[T]) -> T:
         return visitor.visit_property_stmt(self)
@@ -79,7 +70,7 @@ class PropertyStmt(Stmt):
 
 @dataclass(frozen=True)
 class ExtendStmt(Stmt):
-    type: TypeExpr
+    type: Type
     operations: list[OpStmt]
 
     def accept(self, visitor: Stmt.Visitor[T]) -> T:
@@ -89,8 +80,8 @@ class ExtendStmt(Stmt):
 @dataclass(frozen=True)
 class OpStmt(Stmt):
     name: Token
-    operand: TypeExpr
+    operand: Type
-    result: TypeExpr
+    result: Type
 
     def accept(self, visitor: Stmt.Visitor[T]) -> T:
         return visitor.visit_op_stmt(self)
@@ -100,7 +91,7 @@ class OpStmt(Stmt):
 class PredicateStmt(Stmt):
     name: Token
     subject: Token
-    type: TypeExpr
+    type: Type
     condition: Expr
 
     def accept(self, visitor: Stmt.Visitor[T]) -> T:
@@ -120,9 +111,6 @@ class Expr(ABC):
     def accept(self, visitor: Visitor[T]) -> T: ...
 
     class Visitor(ABC, Generic[T]):
-        @abstractmethod
-        def visit_simple_type_expr(self, expr: SimpleTypeExpr) -> T: ...
-
         @abstractmethod
         def visit_logical_expr(self, expr: LogicalExpr) -> T: ...
 
@@ -147,21 +135,6 @@ class Expr(ABC):
         @abstractmethod
         def visit_wildcard_expr(self, expr: WildcardExpr) -> T: ...
 
-        @abstractmethod
-        def visit_template_expr(self, expr: TemplateExpr) -> T: ...
-
-        @abstractmethod
-        def visit_type_expr(self, expr: TypeExpr) -> T: ...
-
-
-@dataclass(frozen=True)
-class SimpleTypeExpr(Expr):
-    name: Token
-    optional: bool
-
-    def accept(self, visitor: Expr.Visitor[T]) -> T:
-        return visitor.visit_simple_type_expr(self)
-
 
 @dataclass(frozen=True)
 class LogicalExpr(Expr):
@@ -233,19 +206,72 @@ class WildcardExpr(Expr):
         return visitor.visit_wildcard_expr(self)
 
 
-@dataclass(frozen=True)
+#########
-class TemplateExpr(Expr):
+# Types #
-    type: TypeExpr
+#########
 
-    def accept(self, visitor: Expr.Visitor[T]) -> T:
+
-        return visitor.visit_template_expr(self)
+@dataclass(frozen=True, kw_only=True)
+class Type(ABC):
+    location: Location
+
+    @abstractmethod
+    def accept(self, visitor: Visitor[T]) -> T: ...
+
+    class Visitor(ABC, Generic[T]):
+        @abstractmethod
+        def visit_named_type(self, type: NamedType) -> T: ...
+
+        @abstractmethod
+        def visit_generic_type(self, type: GenericType) -> T: ...
+
+        @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: ...
 
 
 @dataclass(frozen=True)
-class TypeExpr(Expr):
+class NamedType(Type):
     name: Token
-    template: Optional[TemplateExpr]
-    optional: bool
 
-    def accept(self, visitor: Expr.Visitor[T]) -> T:
+    def accept(self, visitor: Type.Visitor[T]) -> T:
-        return visitor.visit_type_expr(self)
+        return visitor.visit_named_type(self)
+
+
+@dataclass(frozen=True)
+class GenericType(Type):
+    type: Type
+    params: list[Type]
+
+    def accept(self, visitor: Type.Visitor[T]) -> T:
+        return visitor.visit_generic_type(self)
+
+
+@dataclass(frozen=True)
+class ConstraintType(Type):
+    type: Type
+    constraint: Expr
+
+    def accept(self, visitor: Type.Visitor[T]) -> T:
+        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]
+
+    def accept(self, visitor: Type.Visitor[T]) -> T:
+        return visitor.visit_complex_type(self)

midas/ast/printer.py

@@ -85,40 +85,39 @@ class AstPrinter(Generic[T]):
                 child.accept(self)
 
 
-class MidasAstPrinter(AstPrinter, m.Expr.Visitor[None], m.Stmt.Visitor[None]):
+class MidasAstPrinter(
+    AstPrinter, m.Expr.Visitor[None], m.Stmt.Visitor[None], m.Type.Visitor[None]
+):
     # Statements
 
-    def visit_simple_type_stmt(self, stmt: m.SimpleTypeStmt):
+    def visit_type_stmt(self, stmt: m.TypeStmt) -> None:
-        self._write_line("SimpleTypeStmt")
+        self._write_line("TypeStmt")
         with self._child_level():
             self._write_line(f'name: "{stmt.name.lexeme}"')
-            self._write_optional_child("template", stmt.template)
+            self._write_line("params")
-            self._write_line("base")
-            with self._child_level(single=True):
-                stmt.base.accept(self)
-            self._write_optional_child("constraint", stmt.constraint, last=True)
-
-    def visit_complex_type_stmt(self, stmt: m.ComplexTypeStmt):
-        self._write_line("ComplexTypeStmt")
-        with self._child_level():
-            self._write_line(f'name: "{stmt.name.lexeme}"')
-            self._write_optional_child("template", stmt.template)
-            self._write_line("properties", last=True)
             with self._child_level():
-                for i, prop in enumerate(stmt.properties):
+                for i, param in enumerate(stmt.params):
                     self._idx = i
-                    if i == len(stmt.properties) - 1:
+                    if i == len(stmt.params) - 1:
                         self._mark_last()
-                    prop.accept(self)
+                    self._print_type_stmt_param(param)
+            self._write_line("type", last=True)
+            with self._child_level(single=True):
+                stmt.type.accept(self)
+
+    def _print_type_stmt_param(self, param: m.TypeStmt.Param) -> None:
+        self._write_line("Param")
+        with self._child_level():
+            self._write_line(f'name: "{param.name.lexeme}"')
+            self._write_optional_child("bound", param.bound, last=True)
 
     def visit_property_stmt(self, stmt: m.PropertyStmt):
         self._write_line("PropertyStmt")
         with self._child_level():
             self._write_line(f'name: "{stmt.name.lexeme}"')
-            self._write_line("type")
+            self._write_line("type", last=True)
             with self._child_level(single=True):
                 stmt.type.accept(self)
-            self._write_optional_child("constraint", stmt.constraint, last=True)
 
     def visit_extend_stmt(self, stmt: m.ExtendStmt) -> None:
         self._write_line("ExtendStmt")
@@ -161,12 +160,6 @@ class MidasAstPrinter(AstPrinter, m.Expr.Visitor[None], m.Stmt.Visitor[None]):
 
     # Expressions
 
-    def visit_simple_type_expr(self, expr: m.SimpleTypeExpr):
-        self._write_line("SimpleTypeExpr")
-        with self._child_level():
-            self._write_line(f'name: "{expr.name.lexeme}"')
-            self._write_line(f"optional: {expr.optional}", last=True)
-
     def visit_logical_expr(self, expr: m.LogicalExpr):
         self._write_line("LogicalExpr")
         with self._child_level():
@@ -230,22 +223,59 @@ class MidasAstPrinter(AstPrinter, m.Expr.Visitor[None], m.Stmt.Visitor[None]):
     def visit_wildcard_expr(self, expr: m.WildcardExpr) -> None:
         self._write_line("WildcardExpr")
 
-    def visit_template_expr(self, expr: m.TemplateExpr) -> None:
+    def visit_named_type(self, type: m.NamedType) -> None:
-        self._write_line("TemplateExpr")
+        self._write_line("NamedType")
-        with self._child_level(single=True):
+        with self._child_level():
+            self._write_line(f'name: "{type.name.lexeme}"', last=True)
+
+    def visit_generic_type(self, type: m.GenericType) -> None:
+        self._write_line("GenericType")
+        with self._child_level():
+            self._write_line("type")
+            with self._child_level():
+                type.type.accept(self)
+            self._write_line("params", last=True)
+            with self._child_level():
+                for i, param in enumerate(type.params):
+                    self._idx = i
+                    if i == len(type.params) - 1:
+                        self._mark_last()
+                    param.accept(self)
+
+    def visit_constraint_type(self, type: m.ConstraintType) -> None:
+        self._write_line("ConstraintType")
+        with self._child_level():
             self._write_line("type")
             with self._child_level(single=True):
-                expr.type.accept(self)
+                type.type.accept(self)
+            self._write_line("constraint", last=True)
+            with self._child_level(single=True):
+                type.constraint.accept(self)
 
-    def visit_type_expr(self, expr: m.TypeExpr):
+    def visit_union_type(self, type: m.UnionType) -> None:
-        self._write_line("TypeExpr")
+        self._write_line("UnionType")
         with self._child_level():
-            self._write_line(f'name: "{expr.name.lexeme}"')
+            self._write_line("types", last=True)
-            self._write_optional_child("template", expr.template)
+            with self._child_level():
-            self._write_line(f"optional: {expr.optional}", last=True)
+                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():
+            self._write_line("properties", last=True)
+            with self._child_level():
+                for i, prop in enumerate(type.properties):
+                    self._idx = i
+                    if i == len(type.properties) - 1:
+                        self._mark_last()
+                    prop.accept(self)
 
 
-class MidasPrinter(m.Expr.Visitor[str], m.Stmt.Visitor[str]):
+class MidasPrinter(m.Expr.Visitor[str], m.Stmt.Visitor[str], m.Type.Visitor[str]):
     def __init__(self, indent: int = 4):
         self.indent: int = indent
         self.level: int = 0
@@ -257,29 +287,24 @@ class MidasPrinter(m.Expr.Visitor[str], m.Stmt.Visitor[str]):
         self.level = 0
         return expr.accept(self)
 
-    def visit_simple_type_stmt(self, stmt: m.SimpleTypeStmt):
+    def visit_type_stmt(self, stmt: m.TypeStmt) -> str:
-        template: str = stmt.template.accept(self) if stmt.template is not None else ""
+        template: str = ""
-        res: str = f"type {stmt.name.lexeme}{template}({stmt.base.accept(self)})"
+        if len(stmt.params) != 0:
-        if stmt.constraint is not None:
+            params: list[str] = [
-            res += " where " + stmt.constraint.accept(self)
+                self._print_type_template_param(param) for param in stmt.params
+            ]
+            template = f"[{', '.join(params)}]"
+        res: str = f"type {stmt.name.lexeme}{template} = {stmt.type.accept(self)}"
         return self.indented(res)
 
-    def visit_complex_type_stmt(self, stmt: m.ComplexTypeStmt):
+    def _print_type_template_param(self, param: m.TypeStmt.Param) -> str:
-        template: str = stmt.template.accept(self) if stmt.template is not None else ""
+        res: str = param.name.lexeme
-        res: str = self.indented(f"type {stmt.name.lexeme}{template}")
+        if param.bound is not None:
-        res += " {\n"
+            res += "<:" + param.bound.accept(self)
-        self.level += 1
-        for prop in stmt.properties:
-            res += prop.accept(self)
-            res += "\n"
-        self.level -= 1
-        res += self.indented("}")
         return res
 
     def visit_property_stmt(self, stmt: m.PropertyStmt):
         res: str = f"{stmt.name.lexeme}: {stmt.type.accept(self)}"
-        if stmt.constraint is not None:
-            res += " where " + stmt.constraint.accept(self)
         return self.indented(res)
 
     def visit_extend_stmt(self, stmt: m.ExtendStmt):
@@ -304,9 +329,6 @@ class MidasPrinter(m.Expr.Visitor[str], m.Stmt.Visitor[str]):
         condition: str = stmt.condition.accept(self)
         return self.indented(f"predicate {name}({subject}: {type}) = {condition}")
 
-    def visit_simple_type_expr(self, expr: m.SimpleTypeExpr):
-        return f"{expr.name.lexeme}{'?' if expr.optional else ''}"
-
     def visit_logical_expr(self, expr: m.LogicalExpr):
         left: str = expr.left.accept(self)
         operator: str = expr.operator.lexeme
@@ -342,12 +364,34 @@ class MidasPrinter(m.Expr.Visitor[str], m.Stmt.Visitor[str]):
     def visit_wildcard_expr(self, expr: m.WildcardExpr):
         return "_"
 
-    def visit_template_expr(self, expr: m.TemplateExpr):
+    def visit_named_type(self, type: m.NamedType) -> str:
-        return f"[{expr.type.accept(self)}]"
+        return type.name.lexeme
 
-    def visit_type_expr(self, expr: m.TypeExpr):
+    def visit_generic_type(self, type: m.GenericType) -> str:
-        template: str = expr.template.accept(self) if expr.template is not None else ""
+        res: str = type.type.accept(self)
-        return f"{expr.name.lexeme}{template}{'?' if expr.optional else ''}"
+        if len(type.params) != 0:
+            params: list[str] = [param.accept(self) for param in type.params]
+            res += f"[{', '.join(params)}]"
+        return res
+
+    def visit_constraint_type(self, type: m.ConstraintType) -> str:
+        res: str = type.type.accept(self)
+        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
+        for prop in type.properties:
+            res += prop.accept(self)
+            res += "\n"
+        self.level -= 1
+        res += self.indented("}")
+        return res
 
 
 class PythonAstPrinter(