ruby_map.rb

#Ruby mixin Enumerable implement each:
# hey presto you have .map (but not .map!)

class Core

   include Enumerable

   attr_reader :name, :data

   def initialize( name, data )
      @name  = name
      @data = data
   end

   # Mixin in .map
   #   http://ruby-doc.org/docs/ProgrammingRuby/html/tut_modules.html
   # Deligating each method from
   #   http://snippets.dzone.com/posts/show/8247
   def each( &blk )
      @data.each( &blk )
   end

   def map!( &blk )
      @data.map!( &blk )
   end

   def fibUpTo(max)
      i1, i2 = 1, 1        # parallel assignment
      while i1 <= max
         yield i1
         i1, i2 = i2, i1+i2
      end
   end


# Adding function to take param and block
   def map_row( id )
      val = []
      @data[id].each do |cell|
         val << yield( cell )
      end
      return val
      #@data[id].map( yield )
   end

   def map_row!( id, &blk)
      @data[id] = map_row( id, &blk )
   end

end

require 'pp'

a = Core.new( 'dave', [[1,2],[3,4]] )
b= a.map_row(0) { |f| f+1  }
pp b
pp a
a.map_row!(0) { |f| f+1  }
pp a