Scott Hackett over at SlickEdit has a blog entry where he talks about code scavenging as "a new software development methodology." The point being, of course, that code scavenging isn't new at all; it's at least as old as the UNIVAC I. Every new, and not so new, software developer has used it at one time or another, usually for quick bootstraps to get a specific part of the software under development working in spite of limited knowledge of the language and/or domain in question by the programmer, or limited resources (time/budget). Most times, it's at least felt to be some combination of the two.
What's changed recently, and what makes five-finger coding a screaming, begging candidate for formalization, as Mr. Hackett notes, are two distinct phenomena: the rise of new repositories on Web sites like Koders, Krugle, Google Code Search, among others, that at least hold the promise of finding "what you need right now", right now. Also, development professionals face ever-increasing resource constraints ("can you get that for us yesterday?") in a craft that is continually expanding in scope and detail.
What I found interesting, having visited sites like Krugle many times in the past, was the effect that open-source licensing like the GNU General Public License and the BSD License are having on one of the main limiting factors that Mr. Hackett identifies: trust. Many developers, for various reasons, don't trust the work of someone they don't know when their own jobs or reputations are on the line. What open source and the new search engines bring to the table is the idea that now, you don't always have to just accept a code fragment "on faith". Many of the more experienced developers have a track record of other code that they've written, often accessible via the same search engines that helped you find the one you're looking at. Open source and free licensing mean that you can look at other stuff that the guy in question has written, get a feel for how his style and competence match your own, and use that information as additional basis for evaluating the code fragment you're scavenging. The trick, obviously, is to keep the time and effort required for all this significantly below what it would take for you to write your own implementation from a clean sheet of paper. That's why search engines and good indexing are important.
Of course, none of this will help you make the changes that always have to be made to put a piece of "foreign" code into your handiwork. That's still going to take some work; hopefully not on the order of putting a Porsche engine into your Ford pick-up. We'll have to wait for — and work for — serious improvements in the state of the software development craft to have any effect on that. Development methods, languages, and so on are still in the cathedral at Rheims. I've been waiting 30 years for the binary Renaissance to hit my professional life.... anybody need a virtual stonemason?