From: "Shot (Piotr Szotkowski)" <shot@...>
Date: 2009-09-26T02:36:19+09:00
Subject: Backporting Enumerator.new { ... } to Ruby 1.8.7

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Hello, good people of ruby-talk.

I=E2=80=99m trying to backport my code from Ruby 1.9 to Ruby 1.8.7 so that =
I can
profile it sanely with ruby-prof or zenprofile (neither of which works
sensibly under Ruby 1.9 as of now). Unfortunately, my code heavily uses
lazy-evaluated, nested Enumerator objects. What is the sanest way to
backport the following example so that it works more-or-less in the same
way under Ruby 1.8.7 as it does under Ruby 1.9?


def multiplier param
  Enumerator.new do |yielder|
    (1..10).each do |elem|
      sleep 1   # simulates a long-running process
      yielder.yield param * elem
    end
  end
end

multiplier(3).each do |e|
  puts e
end


I think I need a proxy object that can emulate Ruby 1.9=E2=80=99s Enumerato=
r.new
by taking a block and then being able to evaluate it in the original
calling place=E2=80=99s context (so that the =E2=80=98param=E2=80=99 above =
is available to it
upon subsequent Enumerator#each calls), but my still-limited Ruby-fu
fails to come up with a solution for this.

=E2=80=94 Shot
--=20
Local Man Plans To Run 3 Weeks=E2=80=99 Worth of Errands During
Twitter Maintenance Window             [Patently False]

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