final Object startValue = parameters.getValue(1);
final Type lengthType = parameters.getType(2);
final Object lengthValue = parameters.getValue(2);
final String newText = typeRegistry.convertToText(newTextType, newTextValue);
final String text = typeRegistry.convertToText(textType, textValue);
final Number start = typeRegistry.convertToNumber(startType, startValue);
final Number length = typeRegistry.convertToNumber(lengthType, lengthValue);
final MidFunction function = new MidFunction();
final String result1 = function.process(text, new Integer(1), new Integer(start.intValue() - 1));