Thanks for the answer. Indeed Ruby in general has the limitations inherent to its "non functional" nature. However regarding 2) Enumeration can now (in ruby 2.0

Thanks for the answer. Indeed Ruby in general has the limitations inherent to its "non functional" nature. However regarding 2) Enumeration can now (in ruby 2.0) be lazy and thus take each item one after the other through the whole chain. (1..Float::INFINITY).lazy.map{|a| p a; a*10}.map{|a| p a+1} # => 1 11 2 21 etc... So it can work with streams & so on... But I know (from a Jessica Kerr presentation) it also has limitations there.