public override Tuple<AST.Env, AST.ExprType> GetExprTypeEnv(AST.Env env, Boolean is_const, Boolean is_volatile) { if (enums == null) { // if there is no content in this enum type, we must find it's definition in the environment Option<AST.Env.Entry> entry_opt = env.Find($"enum {name}"); if (entry_opt.IsNone || entry_opt.Value.kind != AST.Env.EntryKind.TYPEDEF) { throw new InvalidOperationException($"Type 'enum {name}' has not been defined."); } } else { // so there are something in this enum type, we need to put this type into the environment Int32 idx = 0; foreach (Enumerator elem in enums) { Tuple<AST.Env, String, Int32> r_enum = elem.GetEnumerator(env, idx); env = r_enum.Item1; String name = r_enum.Item2; idx = r_enum.Item3; env = env.PushEnum(name, new AST.TLong(), idx); idx++; } env = env.PushEntry(AST.Env.EntryKind.TYPEDEF, "enum " + name, new AST.TLong()); } return new Tuple<AST.Env, AST.ExprType>(env, new AST.TLong(is_const, is_volatile)); }