Learning 7 More Languages - Part 1

23 Feb 2016     

This winter I worked through Seven More Languages in Seven Weeks by Bruce Tate, Fred Daoud, Jack Moffitt, and Ian Dees. As the name implies, this book introduced 7 recent programming languages and gave a quick introduction to each.

I wrote these reactions as I worked through the sections.

Lua

I found Lua to be a very approachable scripting language. The metaprogramming abilities were very interesting, though from a learning perspective, figuring out what functions to write in the metatable was a little tricky. This was also my first introduction to coroutines, which I will be interested in reading about further in other languages (a Scala coroutine library was announced just as I finished this section).

The final exercise for this section did a very nice job of showing how to embed Lua in C++ code, without making this a chapter about C++. The final result (a midi player where the song is scripted in Lua) was fun, engaging and illustrative, and made me want to keep playing with it. Very nice intro.

Factor

Factor is a concatenative programming language in the style of Forth. I've not worked with Forth or other concatenative programming languages, but I'm aware of stack-based assembly languages including the JVM. Getting used to this style of programming was an interesting challenge, and I could tell I was learning something. The way that stack-orientation and reverse polish notation combine to produce code that looks very imperative and sequential was very interesting.

Ultimately though, I was a little put off by how much stack manipulation is required to accomplish things. Even the canonical form for doing if - else if - else requires duplicating elements on the stack, which then get thrown out if the first branch applies, in order to have that element available for the second if. Otherwise there is lots of stack duplicating, swapping, grabbing earlier elements, and dropping elements.

I didn't find the exercises for this section quite as engaging as the Lua section. The exercises did a good job of giving reasons to try out features and research patterns and libraries, and there was a good curve of different difficulties. However, there was not a final project that stepped up from "exercise" to a clear use case.

Elm

I liked Elm a lot. Elm is a Haskell-style functional language that compiles to Javascript to run in a web browser. It has a very nice style of functional reactive programming to respond to events in the browser as signals. For example, mouse movement, used as a Signal, causes a function to fire, which potentially updates the state of the page. This allows for the functions to be very simple reponses to just a single state - for animations, each call just computes one frame. The structure of the language led to a big use of currying, almost to the extent that it isn't even something you need to think about as a technique - its just what you do.

The exercises for this section were highly focused around animation and built up to a game. I lost some interest as it got to working more on the game, but I might come back to this at some point. I spent a lot of time on the animations though, and enjoyed these quite a bit.

Elixir

I lost the plot on Elixir. It seems that one of the key selling points is that Elixir is a better syntax around Erlang, but I didn't find the syntax particularly compelling. Several parts of it were irritating - I did not care for the comma that gets added in the one-line do syntax - and it just never flowed very naturally for me. I liked the way Elixir does macros, and the actor-model-like distribution seemed quite interesting and powerful (though I skipped these exercises for now).

The examples and exercises in this section also didn't really work for me. The Elixir landing page doesn't specifically mention macros, only alluding to extensibility, but one of the days was oriented around macros. The last day was about distribution, which is interesting, but by this point I had already sortof given up on this section, and it felt like I was forcing myself to work through these, so I stopped. Maybe I'll revisit at some later point.

More to Come

This is an involved book, and 7 weeks is a good amount of time, even if I'm unblocked and on-schedule. I need to put this down for a bit, so let's stop here for now. I'll be back on this topic in a few weeks, to continue through Julia, miniKanren, and Idris.