parmap

#function that takes an array and a block and aplies the block to each element in a thread returning the results in a array
#it is in fact a parallel map
def parmap(arr,&block)
  threads = arr.map do |element|
    Thread.new do
      block.call(element)
    end
  end
  threads.each { |th| th.join }
  threads.map { |th| th.value}
end

#example
#fetch pages in parallel
require 'net/http'

pages = %w( www.rubycentral.com
            www.awl.com
            www.pragmaticprogrammer.com
           )

results = parmap pages do |page|
  h = Net::HTTP.new(page, 80)
  resp, data = h.get('/', nil )
  data
end

results.each {|res| puts res}