[morbidhawk]

> I never start anything from scratch, as I have about a dozen application skeletons ready for various specific purposes, plus similar libraries I wrote, plus a knowledge of several large commercial SDKs, and developer experience in several major FOSS applications

I've had a project manager (very insightful guy) tell me something similar before. He said "as you get more experienced you'll (ideally) write less code and instead reuse code from libraries you've written in the past". I've always wondered how that works for someone? I'm assuming certain projects will have requirements where specific technologies would be used in the front-end and persistent layers depending on the kind of project you are building and so those wouldn't be as reusable but perhaps algorithms you've written before might be reusable on the computational side of things. Like perhaps if you had a library that handles very advanced moving cost calculations you could ideally use that same library in different software forms (mobile, web, desktop, command-line).

Edit: Git might be a good example of a library that can be reused a lot and used within many kinds of applications (IE: inside web app, within IDE, from command-line, desktop app, etc)

[riprowan]

Everything you build becomes your code library that you carry forward.

Smart devs know this and cultivate their personal repetoire.

For example in the veeeery first days of .NET I had the opportunity to build a nice internal application for a client. Of course I didn't have a .NET library - the tech was just coming out of beta - but Microsoft was nice enough to provide a bunch of "example code" and "starter sites" to give all us noobs some patterns we could work from - at least most of the skeleton of a working, database back-ended website with a working security model.

From this .NET project it was easy to find another, and now I had a complete .NET library with solutions to all kinds of problems - how to do doc management, how to solve image resizing problems in .NET, how to talk to all kinds of heterogeneous systems using .NET, how to implement webservices, etc. because I'd built these once. With that toolbox I could easily solve all kinds of other problems with only a little creative remodelling of the skeleton app.

Then in 2007 when I jumped into OSS I got to start an all-new library building solutions on the LAMP stack. By 2009 I had a nice little library built up again.

The pattern is amenable to any software tech. Every project builds from the last one, if you do it right.

[webmaven]

Git is not a library, it's a program. There are, of course, libraries in many languages for using git[0] from within many other kinds of applications.

Another example of a library would be libjpeg[1] for reading and writing the jpeg image format and dealing with all the different ways the format can be adjusted, which gets incorporated into many applications, for example ImageMagick[2].

Basically, a library consists of code that is intended to be reused by calling it from other code.

[0] It's astonishing how often this gets reinvented. Here are just Python libraries: https://pypi.python.org/pypi?%3Aaction=search&term=git

[1] https://en.wikipedia.org/wiki/Libjpeg

[2] https://en.wikipedia.org/wiki/ImageMagick

[morbidhawk]

> It's astonishing how often this gets reinvented

Wow, I'd only heard of libgit2 before. I can't believe how many git-related python packages there are. Yes git isn't a library, it's a program like you said, good catch