Boo.Lang.Parser.BooParserBase.type_name C# (CSharp) Method

        protected IToken type_name()
        {
            IToken id;

            IToken  c = null;
            IToken  ch = null;

                id = null;

            try {      // for error handling
            switch ( LA(1) )
            {
            case THEN:
            case ID:
            {
                id=identifier();
                break;
            }
            case CALLABLE:
            {
                c = LT(1);
                match(CALLABLE);
                if (0==inputState.guessing)
                {
                    id=c;
                }
                break;
            }
            case CHAR:
            {
                ch = LT(1);
                match(CHAR);
                if (0==inputState.guessing)
                {
                    id=ch;
                }
                break;
            }
            default:
            {
                throw new NoViableAltException(LT(1), getFilename());
            }
             }
            }
            catch (RecognitionException ex)
            {
            if (0 == inputState.guessing)
            {
                reportError(ex, "type_name");
                recover(ex,tokenSet_41_);
            }
            else
            {
                throw ex;
            }
            }
            return id;
        }