add map typing (genshinsim#1696)

pkg/gcs/ast/node.go

@@ -1028,6 +1028,10 @@ type (
 	StringType struct {
 		Pos //position of :
 	}
+
+	MapType struct {
+		Pos //position of keyword map
+	}
 	FuncType struct {
 		Pos        //position of opening (
 		ArgsType   []ExprType
@@ -1038,6 +1042,7 @@ type (
 // exprTypeNode()
 func (*NumberType) exprTypeNode() {}
 func (*StringType) exprTypeNode() {}
+func (*MapType) exprTypeNode()    {}
 func (*FuncType) exprTypeNode()   {}
 
 // NumberType.
@@ -1088,6 +1093,30 @@ func (s *StringType) writeTo(sb *strings.Builder) {
 	sb.WriteString("string")
 }
 
+// MapType.
+func (m *MapType) CopyExprType() ExprType {
+	if m == nil {
+		return nil
+	}
+	return &MapType{
+		Pos: m.Pos,
+	}
+}
+
+func (m *MapType) Copy() Node {
+	return m.CopyExprType()
+}
+
+func (m *MapType) String() string {
+	var sb strings.Builder
+	m.writeTo(&sb)
+	return sb.String()
+}
+
+func (m *MapType) writeTo(sb *strings.Builder) {
+	sb.WriteString("map")
+}
+
 // FuncType.
 func (f *FuncType) copyFuncType() *FuncType {
 	next := &FuncType{

pkg/gcs/ast/parseFn_test.go

@@ -60,6 +60,11 @@ func TestFnTyping(t *testing.T) {
 		t,
 	)
 
+	parseAndPrint(
+		`fn z(a number, b number, c map) { print(c); }`,
+		t,
+	)
+
 }
 
 func TestAnonFn(t *testing.T) {

pkg/gcs/ast/parseTyping.go

@@ -42,6 +42,8 @@ func (p *Parser) parseBasicType() (ExprType, error) {
 		return &StringType{Pos: n.pos}, nil
 	case "number":
 		return &NumberType{Pos: n.pos}, nil
+	case "map":
+		return &MapType{Pos: n.pos}, nil
 	default:
 		return nil, fmt.Errorf("ln%v: unexpected basic type parsing type info; got %v", n.line, n.Val)
 	}