Revision: 3993 http://trac.macosforge.org/projects/ruby/changeset/3993 Author: lsansonetti@apple.com Date: 2010-04-30 21:04:37 -0700 (Fri, 30 Apr 2010) Log Message: ----------- more work on the blog post Modified Paths: -------------- MacRubyWebsite/trunk/content/blog/2010/04/30/macruby06.txt Modified: MacRubyWebsite/trunk/content/blog/2010/04/30/macruby06.txt =================================================================== --- MacRubyWebsite/trunk/content/blog/2010/04/30/macruby06.txt 2010-05-01 03:28:19 UTC (rev 3992) +++ MacRubyWebsite/trunk/content/blog/2010/04/30/macruby06.txt 2010-05-01 04:04:37 UTC (rev 3993) @@ -108,8 +108,33 @@ h3. Higher-Level APIs for Grand Central Dispatch -TODO +GCD is a revolutionary approach to multicore computing that is woven throughout the fabric of Mac OS X version 10.6 Snow Leopard. It is supported in MacRuby since version 0.5, through the Dispatch module. +In MacRuby 0.6, we improved the existing native bindings with additional, higher-level abstractions and convenience APIs in the "dispatch" library. We believe these features will help reduce the learning curve for GCD. + +The new "dispatch" library exposes the Job class, which is likely the easiest way to perform concurrent work. Say you have a complex, long-running calculation you want to happen in the background. Create a job by passing Dispatch::Job's initializer the block you want to execute: + +<pre class="commands"> +$ /usr/local/bin/macirb --simple-prompt +>> require 'dispatch' +=> true +>> job = Dispatch::Job.new { Math.sqrt(10**100) } +=> #<Dispatch::Job:0x40075d1e0 @queue=com.apple.root.default-priority @group=#<Dispatch::Group:0x40073c2c0> @values=[1.0e+50]> +</pre> + +This atomically adds the block to GCD's default concurrent queue, then returns immediately, so you don't stall the main thread. + +The downside is that you don't know exactly when your job will execute. The #value method can be used in order to obtain the result of executing that block. + +<pre class="commands"> +>> value = job.value +=> 1.0e+50 +</pre> + +This will wait until the value has been calculated, allowing it to be used as an "explicit Future":http://en.wikipedia.org/wiki/Futures_and_promises. However, this may stall the main thread indefinitely, which reduces the benefits of concurrency. + +There are much more convenience APIs in the "dispatch" library, such as the Proxy class or concurrent extensions to the builtin Enumerable module. Check out the "tutorial":http://svn.macosforge.org/repository/ruby/MacRuby/trunk/lib/dispatch/README.... for more information. + h3. Solid Foundations One of our intentions for this release was to change and rewrite the foundation layers of MacRuby in order to be much more solid for current and future uses. @@ -128,9 +153,9 @@ MacRuby 0.6 provides support for C extensions written for the genuine implementation of ruby. We were able to successfully use the Nokogiri, SQLite3 and PostgreSQL extensions from MacRuby. -This release also passes about 85% of RubySpecs, is able to run a modified version of Rails 3 and implements better support for Ruby 1.9 encodings. +This release also passes about 85% of "RubySpecs":http://rubyspec.org, is able to run a modified version of Rails 3 and implements better support for Ruby 1.9 encodings. -There are still several problems to address in order to provide a full-fidelity replacement of all the Ruby semantics. We intend to continue working on this, by looking at RubySpecs and Rails. +There are still several problems to address in order to provide a full-fidelity replacement of all the Ruby semantics. We intend to continue working on this, by focusing on RubySpecs and Rails. h3. Conclusions