Install

gem install functional

Usage

require 'functional'

obj = 0 .. 10**12
Functional.new( obj).select {|i| i.even? }.collect {|i| i/3 }.select {|i| i.even? }.each &method( :puts)

What's with #map?

Do you know MapReduce? In future #map will be used for MapReduce. Use #collect.