Tuesday, May 22, 2007

Learning a New Programming Language

I'm a self-professed language maven. I love learning new programming languages. Recently, I've been learning Erlang, thanks to Programming Erlang by Joe Armstrong, the online documentation, and the Erlang mailing list.

I'm a hands-on learner (see Just Try It). For me, there are a few phases to learning a new language:

  • Overview
  • Installation and Documentation
  • Syntax
  • Standard libraries
  • Philosophy
  • Frameworks

These phases don't occur sequentially; they blur together. For example, when trying to absorb what I call the philosophy of a language, I'll be writing code that forces me to look for how to use the standard libraries and look for existing frameworks.

The overview phase is when I initially hear about a language. It might be through posts in mailing lists or discussions groups, the various RSS feeds to which I subscribe, or on Reddit. During this phase I tend to form a few first impressions about a language: is it really different? How? Why does it exist? Will it be useful to me in my day-to-day work? Is it worth learning to exercise my brain, or because I will learn new concepts?

Next comes installation and documentation. I grab a copy of the language and whatever documentation I can. This is a key step: if I can't install the language or get it running, or if the documentation doesn't give me enough information to get started, then I'm done.

Learning the syntax gets me as far as being able to follow along with a book or the documentation. This is also another place for me to be turned off by a language. For example, when I started playing with Python, I decided it wasn't for me for a few reasons: significant whitespace, the __funky__ naming convention for magic OO methods, and having to refer to "self" all the time. Please remember, Pythonistas (all one of you that might read this :-), that I'm talking about my impressions and my decisions, not yours or anybody else's.

I'm not sure what made me temporarily abandon Scala (see Scala Baby-Steps) for Erlang. Partly, I was seeing references to Erlang when reading about Scala. Partly, it felt a bit less developed and complete then Erlang. Mostly, I think I'm learning more new things with Erlang.

Becoming familiar with a language's standard libraries or classes lets me know what comes "out of the box", as opposed to what I'll have to go look for or build for myself. It also gives me a good sense of the language's approach to solving various kinds of problems, large and small, and at different levels (from one-liners like iterating through a list through larger libraries like parsers or network communications). Again, the libraries can be make-or-break for me: while playing with Python, I found that simple string and regular expression operations were too difficult to find. (Actually, this is a problem with Erlang, too: string operations are all over the place in different libraries. One place for making a string upper case, another for making it lower case.)

By philosophy I mean a few different things: what the language is best at (and worst at), what it was designed for, what its strengths and weaknesses are, and what good code in the language looks like. Philosophy often, but not always, goes hand-in-hand with learning the syntax and the standard libraries.

During this phase, I usually pick for myself a small number of decent-sized tasks. By this time, I've been writing code in the new language for a while, but mostly toy exercises. It's time to write a larger program. Usually I take a project I've already written in a few different languages and port it to the new language. The code starts as a straight port, but as I progress I try to rewrite it using the idioms and techniques offered by the new language.

By this time, I've usually look for and found a few different language frameworks on the order of as a Web application server or app development framework. This gives me an idea not only of what's available, but what the community is like.

Speaking of community, by this time I've probably joined the language's primary mailing list.

I plan to blog about three different projects I've been working on in Erlang: a MIDI file reader/writer, a Boids simulation, and a simple Web application using Erlyweb.

2 comments:

t said...

One of the members of the HiPE group was involved in developing Scala. Also Erlang was one of the inspiration sources for Scala.

Jim Menard said...

Based on what I've read about Scala and what I have learned of both it and Erlang so far, I can see where Erlang influenced Scala.

I wasn't familiar with HiPE (http://www.it.uu.se/research/group/hipe/); thank you for pointing it out.