Archives: November 2, 2007

#ruby-talk gems of the week

If you have any hopes of becoming a Ruby guru, then regular dose of ruby-talk is a must. In this post, I would try to summarize some of the cool stuffs being discussed on ruby-talk.

  • In Ruby, having method names that contain “-” can be PITA. So David Black and others were quick to point following approach of doing so:

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    irb(main):002:0> class C
irb(main):003:1>   define_method("x-y") { puts "Weird method" }
irb(main):004:1> end
# At which point, the only way to call it is:
irb(main):005:0> C.new.send("x-y")   # Weird method

    In other words, it’s not worth the trouble and you should find some
    other solution.

  • Trans asked on ruby-talk, how can we know, which files are loading or requiring this file. Ara pointed following solution: 
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    p Kernel.requiree('main')
 
require 'b'
 
p Kernel.requiree('main')
 
BEGIN {
  module Kernel
    h = Hash.new
    define_method(:requiree) do |of|
      h[of]
    end
 
    r = method :require
    define_method(:require) do |*a|
      r.call *a
      h[a.first] = caller
    end
  end
}

    The interesting bit around, should be noted.

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      r = method :require

    When you call method and pass method name as a parameter, it returns a closure. Although as pointed by someone it breaks “Rubygems”, and above approach shouldn’t be used. Rather, one should use:

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      alias_method :old_require, :require