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

        protected ExpressionPair expression_pair()
        {
            ExpressionPair ep;

            IToken  t = null;

                ep = null;
                Expression key = null;
                Expression value = null;

            try {      // for error handling
            key=expression();
            t = LT(1);
            match(COLON);
            value=expression();
            if (0==inputState.guessing)
            {
                ep = new ExpressionPair(ToLexicalInfo(t), key, value);
            }
            }
            catch (RecognitionException ex)
            {
            if (0 == inputState.guessing)
            {
                reportError(ex, "expression_pair");
                recover(ex,tokenSet_128_);
            }
            else
            {
                throw ex;
            }
            }
            return ep;
        }