"Cut 'n' Paste", the practice of creating a new software component or application by making a source copy of an existing body of code and "beating on it" mercilessly until it meets some new set of requirements, is often treated with disdain and contempt by the traditional software engineering community and (post-)modern object-oriented methodologists alike. Despite this, the ubiquity and enduring popularity of this approach begs the question: What are these people doing right?
Evidence suggests that cut 'n' paste is a nearly essential, and nearly universal, practice when new framework applications are constructed, be they for GUI code, Eclipse plug-ins, or what have you. Adaptations to complex applications such as compilers often demand an incremental, test-as-you-go approach as well.
The advantages to this approach, naturally, are the complements of those associated with factoring out duplication. A copy provides a safe sandbox off to the side of a vital development stream. Changes made to copies cannot disrupt production code, and like duplicate genes, copies can evolve new functionality without jeopardizing existing functionality in the original. Mere copies can avoid, for a time, the intricacies associated with engineering away duplicate functionality.
Indeed, expedient code copying has long been observed to be characteristic of an early, exploratory phase in the evolution of object-oriented components and systems, but its virtual indispensability to framework developers has been less widely acknowledged.
An OOPSLA 2005 Onward! Breakthrough Ideas Micro-Screed
