Ruby by Example

#22 Using Procs for Compounded Filtering (matching_compound_members.rb)

In this script, we’ll filter Arrays using an arbitrary number of Procs. As before, we’ll open up the Array class, this time adding two methods. Again, we’ll filter digits based on simple mathematical tests. Let’s take a look at the source code and see what’s different.

The Code

  #!/usr/bin/env ruby
  # matching_compound_members.rb

  =begin rdoc
  Extend the built-in <b>Array</b> class.
  =end
  class Array

  =begin rdoc
  Takes a block as an argument and returns a list of
  members matching the criteria defined by that block.
  =end
❶   def matching_members(&some_block)    Block Arguments
      find_all(&some_block)
    end

  =begin rdoc
  Takes an <b>Array</b> of <b>Proc</b>s as an argument and returns all members ...