add type decl parsing

asl_xdsl/frontend/ast.py

@@ -47,3 +47,30 @@ def parse_ast_tail(parser: BaseParser) -> T_Exception:
     def parse_ast(parser: BaseParser) -> T_Exception:
         parser.parse_characters(T_Exception.__name__)
         return T_Exception.parse_ast_tail(parser)
+
+
+class D_TypeDecl(NamedTuple):
+    id: str
+    ty: Ty
+    fields: tuple[str, tuple[Field, ...]] | None
+
+    @staticmethod
+    def parse_optional_field(
+        parser: BaseParser,
+    ) -> tuple[str, tuple[Field, ...]] | None:
+        if parser.parse_characters("None"):
+            return None
+        else:
+            raise NotImplementedError()
+
+    @staticmethod
+    def parse_ast(parser: BaseParser) -> D_TypeDecl:
+        parser.parse_characters(D_TypeDecl.__name__)
+        parser.parse_punctuation("(")
+        id = parser.parse_str_literal()
+        parser.parse_punctuation(",")
+        ty = Ty.parse_ast(parser)
+        parser.parse_punctuation(",")
+        fields = D_TypeDecl.parse_optional_field(parser)
+        parser.parse_punctuation(")")
+        return D_TypeDecl(id, ty, fields)

tests/test_ast.py

@@ -2,7 +2,7 @@
 from xdsl.parser import BaseParser, ParserState
 from xdsl.utils.lexer import Input, Lexer
 
-from asl_xdsl.frontend.ast import T_Exception, Ty
+from asl_xdsl.frontend.ast import D_TypeDecl, T_Exception, Ty
 
 
 def p(input: str) -> BaseParser:
@@ -30,3 +30,10 @@ def test_parse_exception():
 def test_parse_type():
     parser = p("annot (T_Exception [])")
     assert Ty.parse_ast(parser) == Ty(T_Exception(()))
+
+
+def test_type_decl():
+    parser = p('D_TypeDecl ("except", annot (T_Exception []), None)')
+    assert D_TypeDecl.parse_ast(parser) == D_TypeDecl(
+        "except", Ty(T_Exception(())), None
+    )