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));
}