Blocks are a very unique and important part of Ruby’s syntax.

 1 ['Rover', 'Spot', 'Rex'].each do |dog_name|
 2   puts "The dog's name is #{ dog_name }"
 3 end
 4 
 5 >> ['Rover', 'Spot', 'Rex'].map {|name| name.upcase }
 6 => ['ROVER', 'SPOT', 'REX']
 7 
 8 >> a_block = lambda {|name| name.upcase }
 9 >> ['Rover', 'Spot', 'Rex'].map &:a_block
10 => ['ROVER', 'SPOT', 'REX']

In this screencast, we cover:

• Review of common Ruby methods that accept blocks
• How to refactor your blocks into variables
• How to create methods that accept blocks
• yield and block_given? (and other ways to work with blocks)
• How to create DSLs like Rails’ Routes.draw {|map| map.resources :dogs } DSL
• How to create DSLs like Rails 3’s Routes.draw { resources :dogs } DSL
• Some of the differences between lambda, proc, and Proc.new