I’m quite fond of saying “I’m not a programmer or software developer,” on this blog, and while I don’t think that there’s a great chance that I’ll be employed as a developer, it’s becoming more apparent that the real difference between me and a “real developer” is vanishingly small. Stealth Developer, or something. In any case, my ongoing tooling around with common lisp and more recently the tumble manager project have given me opportunities to think about lisp and to think about why I enjoy it.

This post started when a friend asked me “so should I learn common lisp.” And my first response was something to the effect of “no, are you crazy?” or, alternately “well if you really want to.” And then I came to my senses and offered a more reasonable answer that I think some of you might find useful.

Let us start by asking “Should You Study Common Lisp?”

Yes! There are a number of great reasons to use Common Lisp:

  • There are a number of good open source implementations of the common lisp language including a couple of very interesting and viable options. They’re also stable: SBCL which is among the more recent entrants to this field is more than a decade old.
  • There are sophisticated development tools, notably SLIME (for emacs) which connects and integrates emacs with the lisp process, as well as advanced REPLs (i.e. interactive mode). So getting started isn’t difficult.
  • Common Lisp supports many different approaches to programming. Indeed, contemporary “advanced” languages like Ruby and Python borrow a lot from Lisp. So it’s not an “archaic” language by any means. Dynamic typing, garbage collection, macros, and so forth.
  • CL is capable of very high performance, so the chance of saying “damn, I wish I wrote this in a faster language,” down the road isn’t terribly likely. Most implementations run on most platforms of any consequence, which is nice.
  • You’re probably tired of hearing that “Learning Lisp will make your a better programmer in any language,” but it’s probably true on some level.

The reasons to not learn Lisp or to avoid using it are also multiple:

  • “Compiled” Lisp binaries are large compared to similarly functional programs in other languages. While most CL implementations will compile native binaries, they also have to compile in most of themselves.
  • Lisp is totally a small niche language, and we’d be dumb to assume that it’s ever going to take off. It’s “real” by most measurements, but it’s never really going to be popular or widely deployed in the way that other contemporary languages are.
  • Other programmers will think you’re weird.

Having said that all of I think we should still start projects in CL, and expand the amount of software that’s written in the language. Here’s why my next programing project is going to be written in lisp:

  • I enjoy it. I suspect this project like many projects you may be considering is something of an undertaking. Given that I don’t want to have to work in an environment that I don’t enjoy, simply because it’s popular or ubiquitous.
  • Although Lisp isn’t very popular, it’s popular enough that all of the things that you might want to do in your project have library support. So it’s not exactly a wasteland.
  • The Common Lisp community is small, but it’s dedicated and fairly close knit. Which means you may be able to get some exposure for your application in the CL community, simply because your app is written in CL. This is a question of scale, but it’s easier to stand out in a smaller niche.

Of course there are some advantages to “sticking with the crowd” and choosing a different platform to develop your application in:

  • If you want other people to contribute to your project, it’s probably best to pick a language that the people who might be contributing to your application already know.
  • While there are libraries for most common things that you might want to do with Common Lisp, there might not be libraries for very new or very esoteric tasks or interfaces. Which isn’t always a problem, but can be depending on your domain.
  • The binary size problem will be an issue if you plan to deploy in limited conditions (we’re talking like a 15 meg base size for SBCL, which is a non issue in most cases, but might become an issue.)
  • If you run into a problem, you might have a hard time finding an answer. This is often not the case, but it’s a risk.

Onward and Upward!