After a time of much outer influence and inner struggle, I, a self-proclaimed Microsoft fanboy, decided to abandon everything I’ve known for the last 6 years as a .NET developer and sample the sweet simplicity and sheer power that is Ruby on Rails.

One of the first things I learned while working on my first Rails project was the use of Ruby’s yield statement.  Coming from C#, I expected the yield statement to act a bit differently than it does in Ruby.  Basically, the yield statement is provided as a way to ease the creation of iterators.  It gives control to a user-specified block from within a method’s body.

An example of this is:

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#!/usr/bin/ruby
def where_am_i
  puts "You are in the method"
  yield
  puts "You are in the method again"
  yield
end
where_am_i { puts "You are in the block" }

This will produce the following:

You can pass parameters with the yield statement as well:

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#/usr/bin/ruby
def my_name_is
  puts "Hi, my name is..."
  yield "Who?"
  puts "Hi, my name is..."
  yield "What?"
  puts "Hi, my name is..."
  yield "Slim Shady!"
end
my_name_is { |s| puts "#{s}" }

This will produce the following:

As you can see, the yield statement is written followed by the parameter(s) being passed. Yes…you can pass multiple parameters! Check out the next example:

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#/usr/bin/ruby
def i_have_twin_daughters
  puts "I have twin daughters"
  yield "Ruby", "Perl"
end
i_have_twin_daughters { |a, b| puts "Their names are #{a} and #{b}" }

This will produce the following result: