Mapcar in Ruby

A Ruby version of Lisp's mapcar function:

require 'generator'
# One mapcar to rule all Enumerables.
def mapcar(*enums)
 generators = enums.collect {|e| Generator.new(e)}
 result = []
 while true
     begin
         params = generators.collect {|g| g.current; g.next}
         rescue EOFError
             return result
     end
     result << yield(*params)
 end
end

Sample usage:

qSorters = arrays.collect {QSort.new}
threads = mapcar(qSorters, arrays) {|q, a| Thread.new {q.quicksort(a)}}

This creates an Array of Threads that use the objects in qSorters to sort each element of arrays.
Please note that the QSort class is user-defined and omitted here for brevity (and sanity).
The above mapcar is based on recipe 7.9, pages 256-257 of the Ruby Cookbook, specifically the interosculate function.