Practicing procs, still not sure why this works

New Collect

class Array
    def new_collect
        self.collect do |n|
            yield n
        end
    end
end


RSPEC:

describe Array do
  describe "new_collect" do
    it "collects the output of a block in an array" do
      my_friends = ["Sally", "Mary", "Joe"]
      expected_strings = ["I love Sally.", "I love Mary.", "I love Joe."]
      my_strings = my_friends.new_collect { |friend| "I love " + friend + "." }
      my_strings.should eq(expected_strings)
    end
 
    it "adds 1 to each element in an array" do
      [1,2,3].new_collect { |a| a + 1 }.should eq([2,3,4])
    end
    
    it "maps everything to nil" do
      [1,2,3].new_collect { nil }.should eq([nil, nil, nil])
    end
    
    it "maps classes" do
      [1, 'cat', 1..1].map { |e| e.class }.should eq([Fixnum, String, Range])
    end
  end
end