fix(checker): forward parsing errors as diagnostics

gen/midas.py

@@ -135,6 +135,7 @@ class ExtensionType:
 
 class FunctionType:
     pos_args: list[Argument]
+    args: list[Argument]
     kw_args: list[Argument]
     returns: Type
 

midas/ast/midas.py

@@ -293,6 +293,7 @@ class ExtensionType(Type):
 @dataclass(frozen=True)
 class FunctionType(Type):
     pos_args: list[Argument]
+    args: list[Argument]
     kw_args: list[Argument]
     returns: Type
 

midas/ast/printer.py

@@ -297,6 +297,14 @@ class MidasAstPrinter(
                         self._mark_last()
                     self._print_function_arg(arg)
 
+            self._write_line("args")
+            with self._child_level():
+                for i, arg in enumerate(type.args):
+                    self._idx = i
+                    if i == len(type.args) - 1:
+                        self._mark_last()
+                    self._print_function_arg(arg)
+
             self._write_line("kw_args")
             with self._child_level():
                 for i, arg in enumerate(type.kw_args):
@@ -447,11 +455,13 @@ class MidasPrinter(m.Expr.Visitor[str], m.Stmt.Visitor[str], m.Type.Visitor[str]
 
     def visit_function_type(self, type: m.FunctionType) -> str:
         pos_args: list[str] = [self._print_arg(arg) for arg in type.pos_args]
+        mixed_args: list[str] = [self._print_arg(arg) for arg in type.args]
         kw_args: list[str] = [self._print_arg(arg) for arg in type.kw_args]
         args: list[str] = pos_args
 
         if len(pos_args) != 0:
             args.append("/")
+        args += mixed_args
         if len(kw_args) != 0:
             args.append("*")
         args += kw_args

midas/checker/midas.py

@@ -43,6 +43,8 @@ class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[Type
         tokens: list[Token] = lexer.process()
         parser: MidasParser = MidasParser(tokens)
         stmts: list[m.Stmt] = parser.parse()
+        for error in parser.errors:
+            self.reporter.error(error.token.get_location(), error.message)
         self.resolve(stmts)
 
     def get_type(self, name: str) -> Type:
@@ -164,25 +166,23 @@ class MidasTyper(m.Stmt.Visitor[None], m.Expr.Visitor[None], m.Type.Visitor[Type
         )
 
     def visit_function_type(self, type: m.FunctionType) -> Type:
+        n_pos_args: int = len(type.pos_args)
+        n_args: int = len(type.args)
+
+        def process_arg(arg: m.FunctionType.Argument, i: int) -> Function.Argument:
+            return Function.Argument(
+                pos=i,
+                name=arg.name.lexeme if arg.name is not None else str(i),
+                type=arg.type.accept(self),
+                required=arg.required,
+            )
+
         return Function(
-            pos_args=[
+            pos_args=[process_arg(arg, i) for i, arg in enumerate(type.pos_args)],
-                Function.Argument(
+            args=[process_arg(arg, i + n_pos_args) for i, arg in enumerate(type.args)],
-                    pos=i,
-                    name=arg.name.lexeme if arg.name is not None else str(i),
-                    type=arg.type.accept(self),
-                    required=arg.required,
-                )
-                for i, arg in enumerate(type.pos_args)
-            ],
-            args=[],
             kw_args=[
-                Function.Argument(
+                process_arg(arg, i + n_pos_args + n_args)
-                    pos=i,
+                for i, arg in enumerate(type.kw_args)
-                    name=arg.name.lexeme if arg.name is not None else str(i),
-                    type=arg.type.accept(self),
-                    required=arg.required,
-                )
-                for i, arg in enumerate(type.kw_args, start=len(type.pos_args))
             ],
             returns=type.returns.accept(self),
         )

midas/checker/python.py

@@ -336,7 +336,7 @@ class PythonTyper(
                 if not self._is_binary_function(function):
                     self.reporter.error(
                         expr.location,
-                        f"Wrong definition of binary operation. Expected function with 2 positional-only parameters, got {function}",
+                        f"Wrong definition of binary operation. Expected function with 1 positional-only parameters, got {function}",
                     )
                     return UnknownType()
 
@@ -481,7 +481,13 @@ class PythonTyper(
         return self.types.apply_generic(list_type, [UnknownType()])
 
     def visit_base_type(self, node: p.BaseType) -> Type:
-        base: Type = self.types.get_type(node.base)
+        base: Type
+        try:
+            base = self.types.get_type(node.base)
+        except NameError:
+            self.reporter.warning(node.location, f"Unknown type '{node.base}'")
+            return UnknownType()
+
         if node.param is not None:
             param: Type = node.param.accept(self)
             return self.types.apply_generic(base, [param])

midas/parser/midas.py

@@ -499,19 +499,36 @@ class MidasParser(Parser):
             TokenType.LEFT_PAREN, "Expected '(' before function parameters"
         )
         pos_args: list[FunctionType.Argument] = []
+        args: list[FunctionType.Argument] = []
         kw_args: list[FunctionType.Argument] = []
 
-        positional: bool = True
+        args_first_tokens: list[Token] = []
+
+        section: int = 0
         while not self.is_at_end() and not self.check(TokenType.RIGHT_PAREN):
-            if positional and (
+            match section:
-                self.match(TokenType.STAR) or self.match(TokenType.SLASH)
+                case 0 if self.match(TokenType.SLASH):
-            ):
+                    pos_args = args
-                positional = False
+                    args = []
-            else:
+                    args_first_tokens = []
+                    section = 1
+                case 0 | 1 if self.match(TokenType.STAR):
+                    section = 2
+                case _:
+                    # Record first token of mixed argument for errors if unnamed
+                    if section != 2:
+                        args_first_tokens.append(self.peek())
+
                     name: Optional[Token] = None
-                if self.check_identifier() and self.check_next(TokenType.COLON):
+                    if section == 2:
+                        name = self.consume_identifier("Expected keyword argument name")
+                        self.consume(
+                            TokenType.COLON, "Expected ':' after argument name"
+                        )
+                    elif self.check_identifier() and self.check_next(TokenType.COLON):
                         name = self.advance()
                         self.advance()
+
                     type: Type = self.type_expr()
                     optional: bool = self.match(TokenType.QMARK)
                     arg = FunctionType.Argument(
@@ -520,13 +537,19 @@ class MidasParser(Parser):
                         type=type,
                         required=not optional,
                     )
-                if positional:
+                    if section == 2:
-                    pos_args.append(arg)
-                else:
                         kw_args.append(arg)
+                    else:
+                        args.append(arg)
 
             if not self.match(TokenType.COMMA):
                 break
+
+        for arg, token in zip(args, args_first_tokens):
+            if arg.name is None:
+                # Not raised because we can keep parsing
+                self.error(token, "Unnamed mixed argument")
+
         self.consume(TokenType.RIGHT_PAREN, "Expected ')' after function parameters")
 
         self.consume(TokenType.ARROW, "Expected '->' before result type")
@@ -535,6 +558,7 @@ class MidasParser(Parser):
         return FunctionType(
             location=l_paren.location_to(self.previous()),
             pos_args=pos_args,
+            args=args,
             kw_args=kw_args,
             returns=result,
         )

tests/serializer/midas.py

@@ -173,6 +173,7 @@ class MidasAstJsonSerializer(
         return {
             "_type": "FunctionType",
             "pos_args": [self._serialize_func_arg(arg) for arg in type.pos_args],
+            "args": [self._serialize_func_arg(arg) for arg in type.args],
             "kw_args": [self._serialize_func_arg(arg) for arg in type.kw_args],
             "returns": type.returns.accept(self),
         }