Application: gvSIG desktop

    public static ExpressionBuilder.Constant resolveAsConstant(SQLBuilder sqlbuilder, Formatter<Value> formatter, Value value) {

		GeometryExpressionBuilder builder = sqlbuilder.expression();

        if( value instanceof ExpressionBuilder.Constant) {

            Object x = ((ExpressionBuilder.Constant)value).value();

            return builder.constant(x);

        } else if( value instanceof ExpressionBuilder.Function && 

                StringUtils.equalsIgnoreCase(((ExpressionBuilder.Function)value).name(),FUNCTION_$CONSTANT) ) {

            SymbolTable symbolTable = (SymbolTable) value.getProperty(PROP_SYMBOLTABLE);

            Object x = ExpressionUtils.evaluate(symbolTable, value.toString());

            return builder.constant(x);

        } 

        throw new RuntimeException("Expected constant value or $$CONSTANT function ("+Objects.toString(value)+").");

    }