Open minds leads to freedom

Some times ago I had to parse a XML messages’ file to produce some i18n properties files.

I decided to try it with Ruby, mainly because of two reasons:

1. I’m continuosly exploring some dynamically-typed languages, like Python and Ruby
2. I wanted to try the conciseness of programming with closures

So, I used the REXML API to process the XML file. The result code looks like the one below:

   1:require 'rexml/document'
   2:include REXML
   3:englishFile = File.new('englishFileName', 'w+')
   4:spanishFile = File.new('spanishFileName', 'w+')
   5:portugueseFile = File.new('portugueseFileName', 'w+')
   6:errorMessagesFile = File.new("errorMessages.xml")
   7:document = Document.new(file)
   8:root = document.root
   9:root.each_element("Property") do |propertyTag|
  10:  id = propertyTag.attributes['id']   
  11:  propertyTag.each_element("element") do |elementTag|
  12:      elementAttr = elementTag.attributes['otherTag']
  13:      error = elementTag.text == nil ? "" : "#{id} = #{elementTag.text}\n"
  14:      if elementAttr = "pt"
  15:          portugueseFile << error
  16:      elsif elementAttr == "es"
  17:          spanishFile << error
  18:      else 
  19:          portugueseFile << error
  20:      end
  21:  end
  22:end
  23:errorMessagesFile.close()
  24:englishFile.close()
  25:spanishFile.close()
  26:portugueseFile.close()
  27:  

I like to solve this kind of tasks with programming languages (mainly the dynamically-typed ones..) I don’t know very much because it’s an opportunity to put my hands on them! This way I could experience Ruby’s closures syntax, it was really nice and I’m gonna try something new with it often!

*Updated: line 13

There is a nice interview with the Twitter development team on Artima about using Scala in production on Twitter code. The team talks about some issues and facilities regarding the chose of Scala to develop Twitter’s queueing system and how Scala affected the team’s programming style.

My personal highlights:

And Ruby, like many scripting languages, has trouble being an environment for long lived processes. But the JVM is very good at that, because it’s been optimized for that over the last ten years..

So Scala provides a basis for writing long-lived servers…Another thing we really like about Scala is static typing that’s not painful. Sometimes it would be really nice in Ruby to say things like, here’s an optional type annotation

And because Ruby’s garbage collector is not quite as good as Java’s, each process uses up a lot of memory. We can’t really run very many Ruby daemon processes on a single machine without consuming large amounts of memory

In some cases we just decided to burrow down and use the Java collections from Scala, which is a nice advantage of Scala, that we have that option..

As I’ve learned more Scala I’ve started thinking more functionally than I did before. When I first started I would use the for expression, which is very much like Python’s. Now more often I find myself invoking map or foreach directly on iterators..

The reason you should care about immutability is that if you’re using threads and your objects are immutable, you don’t have to worry about things changing underneath you..

It’s very worth read. Post your comments here when you read it.