LispEngine.Parsing.Parser.expression C# (CSharp) Method

        private Datum expression()
        {
            Datum d;
            if ((d = quotedExpression()) != null)
                return d;
            if ((d = symbol()) != null)
                return d;
            if ((d = atom()) != null)
                return d;
            if ((d = vectorExpr()) != null)
                return d;
            if ((d = compound()) != null)
                return d;
            throw fail("Unexpected token: {0}", next);
        }