From: MonkeeSage Date: 2007-11-29T14:45:02+09:00 Subject: Re: Ruby needs continuations... On Nov 28, 4:35 pm, MonkeeSage wrote: > On Nov 28, 3:22 pm, Charles Oliver Nutter > wrote: > > > > > MonkeeSage wrote: > > > On Nov 28, 9:41 am, Charles Oliver Nutter > > > wrote: > > >> MonkeeSage wrote: > > >>> You actually need a generator, which can be implemented with > > >>> continuations, but doesn't have to be (in 1.9 the generators are > > >>> implemented with threads -- have a look at generator.rb in 1.8 and 1.9 > > >>> to see the differences). Using generators, you can implement izip (and > > >>> all of itertools if you'd like, though most of it already has > > >>> equivalent ruby solutions). Here is a pretty close translation of the > > >>> python given in the itertools docs: > > >> Ruby 1.9 also moves continuations out of core, but provides a form of > > >> bounded continuations (coroutines) that's possible to implement in JRuby: > > > >> require 'fiber' > > >> f = Fiber.new { a = 1; while true; Fiber.yield a; a += 1; end } > > >> 5.times { puts f.resume } > > > >> $ jruby -J-Djruby.compat.version=ruby1_9 fiber_example.rb > > >> 1 > > >> 2 > > >> 3 > > >> 4 > > >> 5 > > > >> Under JRuby, it's using a native thread per live Fiber, so it's heavier > > >> than in Ruby 1.9 which uses green threads. However they'll actually run > > >> in parallel on JRuby, so that's a benefit. JRuby also supports a thread > > >> pool in 1.1 that helps blunt the cost of spinning up native threads. > > > >> - Charlie > > > > I just tried the above izip function in jruby, but it only gave me two > > > iterations... > > > Could be a bug in generator; could you try it on a more recent release > > (like 1.0.2 or 1.1b1) and report it if it's actually a problem? > > >http://jira.codehaus.org/browse/JRUBY > > > - Charlie > > I downloaded the precompiled versions of 1.0.2 and 1.1b1 and both > displayed the same behavior. I'll submit a bug report. > > Regards, > Jordan Bug #1635 [ http://jira.codehaus.org/browse/JRUBY-1635 ]