Tue, 24 Aug 2004

Erlang, Haskell, Scheme

It has been my intention to return to the Lisp family for some time and one of my big plans for this year was to get somewhere with that. I even bought a couple of books (which I’ll discuss later when I’ve read more than I’ve so far had time for). And I’ve installed implementations of Common Lisp and Scheme on my workstation so that I can play.

But, as always, other things come along to distract me. Andrae has also been a bad influence on me at Humbug meetings—his readiness to talk about other interesting languages has recently had me reading books on Haskell and Erlang as well as my planned reading.

Haskell looks like an interesting language, and if I was a twenty-something student I’d want to spend some time on it. But there’s not time for everything and, since Haskell fails my beauty test badly, I’ve decided to drop it—at least for now.

Erlang is still in there with a chance. I’m finding its syntax hard to swallow, although I can see that it might improve with exposure. The jury is still out on that. What it has going for it is plenty of easy-to-find documentation and freely-available implementations of some interesting software, in particular a web server that offers Erlang as its extension language and supports the basic stuff like SSL and PHP.

It will be a while before I decide which of these languages I’ll use for my next large project, but I expect that one of them will find itself in my toolbox in the next few months—and it will have to be a language that can step into the breach caused by my decision not to develop any more big applications in Python and tkinter.

Just in case somebody cares, the beauty test is the way I evaluate the “look” of a language. To take more well-known languages, Perl fails; Python passes. The idea is that programming languages exist for the humans who have to write and (more importantly) read them. A language that is easy to read is a good language. A hard-to-read language is, other things being equal, less good.

Beauty is not my sole criterion, of course. Other things matter a lot, in particular expressiveness. If you can express a program in three lines of code that’s easy to read, then that’s usually going to be better than 300 lines or 3,000 lines because it will be easier for you to get it right and easier for others to see that you’ve got it right. This means that high-level languages such as Perl or Python or Scheme will mostly be “better” than C—except for those times when C is the best or only choice. Fortunately, it’s easy to write beautiful C.

Posted at: 23:48

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