Struct field tags

core/odin/ast/ast.odin

@@ -435,7 +435,9 @@ Field_Flag :: enum {
 	C_Vararg,
 	Auto_Cast,
 	In,
+
 	Results,
+	Tags,
 	Default_Parameters,
 	Typeid_Token,
 }
@@ -443,18 +445,19 @@ Field_Flag :: enum {
 Field_Flags :: distinct bit_set[Field_Flag];
 
 Field_Flags_Struct :: Field_Flags{
-	Field_Flag.Using,
+	.Using,
+	.Tags,
 };
 Field_Flags_Record_Poly_Params :: Field_Flags{
-	Field_Flag.Typeid_Token,
+	.Typeid_Token,
 };
 Field_Flags_Signature :: Field_Flags{
-	Field_Flag.Ellipsis,
-	Field_Flag.Using,
-	Field_Flag.No_Alias,
-	Field_Flag.C_Vararg,
-	Field_Flag.Auto_Cast,
-	Field_Flag.Default_Parameters,
+	.Ellipsis,
+	.Using,
+	.No_Alias,
+	.C_Vararg,
+	.Auto_Cast,
+	.Default_Parameters,
 };
 
 Field_Flags_Signature_Params  :: Field_Flags_Signature | {Field_Flag.Typeid_Token};
@@ -483,6 +486,7 @@ Field :: struct {
 	names:         []^Expr, // Could be polymorphic
 	type:          ^Expr,
 	default_value: ^Expr,
+	tag:           token.Token,
 	flags:         Field_Flags,
 	comment:       ^Comment_Group,
 }

core/odin/parser/parser.odin

@@ -1388,19 +1388,18 @@ check_field_flag_prefixes :: proc(p: ^Parser, name_count: int, allowed_flags, se
 
 	for flag in ast.Field_Flag {
 		if flag notin allowed_flags && flag in flags {
-			using ast.Field_Flag;
 			#complete switch flag {
-			case Using:
+			case .Using:
 				error(p, p.curr_tok.pos, "'using' is not allowed within this field list");
-			case No_Alias:
+			case .No_Alias:
 				error(p, p.curr_tok.pos, "'#no_alias' is not allowed within this field list");
-			case C_Vararg:
+			case .C_Vararg:
 				error(p, p.curr_tok.pos, "'#c_vararg' is not allowed within this field list");
-			case Auto_Cast:
+			case .Auto_Cast:
 				error(p, p.curr_tok.pos, "'auto_cast' is not allowed within this field list");
-			case In:
+			case .In:
 				error(p, p.curr_tok.pos, "'in' is not allowed within this field list");
-			case Ellipsis, Results, Default_Parameters, Typeid_Token:
+			case .Tags, .Ellipsis, .Results, .Default_Parameters, .Typeid_Token:
 				panic("Impossible prefixes");
 			}
 			flags &~= {flag};
@@ -1540,6 +1539,7 @@ parse_field_list :: proc(p: ^Parser, follow: token.Kind, allowed_flags: ast.Fiel
 
 		type:          ^ast.Expr;
 		default_value: ^ast.Expr;
+		tag: token.Token;
 
 		expect_token_after(p, token.Colon, "field list");
 		if p.curr_tok.kind != token.Eq {
@@ -1579,9 +1579,19 @@ parse_field_list :: proc(p: ^Parser, follow: token.Kind, allowed_flags: ast.Fiel
 			error(p, p.curr_tok.pos, "extra parameter after ellipsis without a default value");
 		}
 
+		if type != nil && default_value == nil {
+			if p.curr_tok.kind == token.String {
+				tag = expect_token(p, token.String);
+				if .Tags notin allowed_flags {
+					error(p, tag.pos, "Field tags are only allowed within structures");
+				}
+			}
+		}
+
 		ok := expect_field_separator(p, type);
 
 		field := new_ast_field(names, type, default_value);
+		field.tag     = tag;
 		field.docs    = docs;
 		field.flags   = flags;
 		field.comment = p.line_comment;

core/runtime/core.odin

@@ -79,8 +79,9 @@ Type_Info_Tuple :: struct { // Only really used for procedures
 Type_Info_Struct :: struct {
 	types:        []^Type_Info,
 	names:        []string,
-	offsets:      []uintptr, // offsets may not be used in tuples
-	usings:       []bool,    // usings may not be used in tuples
+	offsets:      []uintptr,
+	usings:       []bool,
+	tags:         []string,
 	is_packed:    bool,
 	is_raw_union: bool,
 	custom_align: bool,