Hack to Learn

‘jaap’ wrote a rake task to convert your Rails application from using Gettext translation into the new I18n support, which is really great!

WARNING: Before you run the new rake task rake gettext_to_i18n:transform, read “So How Do You Fix It?” below

OK, so you’ve followed along in the article and now you want to test out your new localization system. Problem is when you try to start the server up script/server you get this error message:

/Users/cblackburn/Source/ruby/bols/lib/active_support/memoizable.rb:71:in `path': can't modify frozen object (TypeError)

…or something similar.

What happened? Since you have frozen Rails and the rake task does not exclude the frozen vendor/rails directory, it modified memoizable.rb in ActiveSupport causing this error.

So How Do You Fix It?

Do one of the following:

• Backup lib/active_support/memoizable.rb before you run the rake task, then restore it after.
• Restore lib/active_support/memoizable.rb using your SCM.

For this project in my case it was

svn revert lib/active_support/memoizable.rb

Another ruby script for your Mac Terminal enjoyment.

I like to work on my Rails projects using at least three command line tabs with their current working directories set to the RAILS_ROOT of my project. This way I can run script/server in one tab, script/console in another and retain one tab to use for various project based work like rake and capistrano tasks. Frequently I found myself manually iterating through each Terminal tab and type ‘cd /Users/…/Source/ruby/projectname’. As we all know personal repetition is the mother of invention. This is what I came up with…

#!/usr/bin/env ruby

require 'rubygems'
require 'appscript'
include Appscript

DEFAULT_PROJ = '.'

project_dir = (ARGV.length > 0) ? ARGV[0] : DEFAULT_PROJ
project_dir = Dir.pwd if project_dir == "."

@term = app('Terminal')
@current_window = @term.windows.first
tab_count = @current_window.tabs.count

for t in 0..tab_count
  tab = @current_window.tabs[t]
  @term.do_script("cd #{project_dir}", :in => tab)
end

Save this file in your personal path as acd.rb

I use this frequently when I switch from one project to another.

Be logged into the directory you want to propagate through all open tabs. Then type: acd.rb which will automatically iterate through each open tab and change the current working directory to the directory you started acd.rb from.

Head on over to François Marier’s blog ”Feeding the Cloud”, to learn how to setup a centralized git repository.

Recently I upgraded my blog here and lost permalinks to several articles, as well as the articles themselves. For that I apologize, if you are looking for something unfound. One such article that I referred to often was ‘Scripting Mac Terminal Using Ruby’. Though this is not the original article, here is a script I recently needed. As will all source code published herein, this is hereby released into the public domain with no warranties of any kind.

This humble little script uses rb-appscript, to change the background color, in Terminal, of the current tab you are running. I like to change colors of tabs to mean different things. For instance, where I am tailing log files – dark green… running irb – dark blue, etc.

Maybe, like me, you stay logged into several machines around the world and want to color-code your tabs based on location.

I called mine colorme.rb. The command line expects a color in this format:

• array: [0,32767,65535] of color values [Red, Green, Blue], 0 to 65535
• string: ‘red’, ‘green’, ‘black’, etc., only the basic colors work as strings

Have fun and let me know if you are doing something interesting with Terminal using Appscript on Ruby.

#!/usr/bin/env ruby

require 'rubygems'
require 'appscript'
include Appscript

_color = (ARGV.length > 0) ? ARGV[0] : 'black'

begin
  term = app('Terminal')
  current_window = term.windows.first
  tab = current_window.tabs.first
  current_color = tab.background_color.get
  puts "Current Color is: #{current_color.inspect}"
  tab.background_color.set(_color)
rescue Exception => e
  puts "#{e}"
  puts "Usage: colorme.rb array"
  puts "  ...where array is an array of 3 color values like this [0,32767,65535]"
  puts "  ...values can be anywhere between 0 and 65535"
  puts "  ...values, in order, represent 'Red, Green Blue'"
end