Language of the Month: Lua

New month, new language. So far in this series:

May: Scala
June: Lua

I think I do want to amend the original rules set up for this Language of the Month series. At first I though I can write a new project in any language I learn. That is probably too ambitious. So new rules: every month write a new project in the given language OR contribute to an open-source project in that language. This should take away most of the stress and add some social aspect as well. :)

Lua

I’m intrigued by this language because of it’s niche: scripting language within other software. How one sets out to do something like this? What are the requirements for the language, in terms of design, syntax and so on?

See, the moon!

First impressions

So far I was trying out some code snippets and example scripts. First thing to notice was that Lua is pretty darn quick to start. And pretty quick to run as well, though I haven’t used it for very heavy computation yet. E.g. the “get_all_factors” code at the Lua Crash Course (using a larger example number, 1029384756) is timed at ~7ms, wheres the same version on Python (the language that I probably know best and compare other languages to) runs ~10x slower. The snappiness of a scripting language is a surprisingly happy feeling. :)

Tables look very interesting, how the same thing can implement several data structures at once (it’s like Python’s dict, list and kinda-struct at the same time).

Quite intriguing that the Lua Virtual Machine is stack based, probably that’s the reason the language is so embeddable. A while back I was looking for a language with small resource (especially memory) requirements. I had a few suggestions (Dalvik, Forth) that were interesting, but maybe Lua is the one?

The “local” keyword (and the reasons for having it) seems to be a possible source of many harder to debug scenarios. Got to keep this in mind, again not being in Pythonland anymore.

Interesting how the “function” can be defined inline, so looks like there’s essentially no need for a special “lambda” keyword, at the expense of tying a few characters more…

The interpreter is quite well done (with it’s intelligent indentation probably even better then ipython, though would love to see more colours ^^)

As an exercise, here’s a version of FizzBuzz:

function fizzbuzz(num)
   --[[--
   The usual FizzBuzz from Jeff Atwood
   Doing it a bit roundabout to try some Lua language features
   --]]--
   local answer = ""

   if (num % 5) == 0 then
      answer = "Fizz"
   end
   if (num % 3) == 0 then
      answer = answer .. "Buzz"
   end

   if answer ~= "" then
      print(answer)
   else
      print(num)
   end
end

-- Run the thing
for num=1,100,1 do
   fizzbuzz(num)
end

Lua

First impressions

Links

Install

Tutorials

Books

Articles and info

Source of code

Projects using Lua

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