This post originated from an RSS feed registered with Ruby Buzz by Brian Ford. Original Post: TSort in sirb Feed Title: def euler(x); cos(x) + i*sin(x); end Feed URL: http://feeds.feedburner.com/defeulerxcosxisinxend Feed Description: euler(PI) # => -1 Latest Ruby Buzz Posts Latest Ruby Buzz Posts by Brian Ford Latest Posts From def euler(x); cos(x) + i*sin(x); end

They say good things come in threes, or perhaps I���ll bore you with another post about Rubinius, but what the heck. So, the other day I imported Ruby���s standard library from the SVN repository into the Rubinius repository. I���ve been itching to go through and see what successfully loads. Ah, now that we have sirb, the perfect opportunity presents itself.

$ ./shotgun/rubinius apps/irb/sirb.rb
sirb(eval):000> require 'tsort'
Couldn't find tsort.rbc in runtime/compiler.rba (No such file/-1)
Couldn't find tsort.rb in runtime/compiler.rba (No such file/-1)
Unable to find 'tsort' to load
                 main.raise at bootstrap/04kernel.rb:26
               main.require at core/compile.rb:91
       main.__eval_script__ at (eval):1
    CompiledMethod#activate at bootstrap/compiled_method.rb:52
            main.__script__ at apps/irb/sirb.rb:79
                  main.load at core/compile.rb:56
            main.__script__ at core/__loader.rb:50

Hmm. Oh, yes! I think we need to check load path. (I���ve since added stdlib to the default load path.)

sirb(eval):001> p $:
[".", "runtime/compiler.rba", "lib"]
=> nil
sirb(eval):002> $:.push "stdlib" 
=> [".", "runtime/compiler.rba", "lib", "stdlib"]
sirb(eval):003> require 'tsort'
Couldn't find tsort.rbc in runtime/compiler.rba (No such file/-1)
Couldn't find tsort.rb in runtime/compiler.rba (No such file/-1)
=> true

Oh baby. Just ignore those couple complaints. It���s that => true that we���re looking for. Nice! Now, we���ll just try the example in the tsort.rb file.

sirb(eval):004> class Hash
sirb(eval):005>   include TSort
sirb(eval):006>   alias :tsort_each_node :each_key
sirb(eval):007>   def tsort_each_child(node, &block)
sirb(eval):008>     fetch(node).each(&block)
sirb(eval):009>   end
sirb(eval):010> end
=> nil
sirb(eval):011> {1=>[2, 3], 2=>[3], 3=>[], 4=>[]}.tsort
=> [3, 2, 1, 4]
sirb(eval):012> {1=>[2], 2=>[3, 4], 3=>[2], 4=>[]}.strongly_connected_components
=> [[4], [2, 3], [1]]
sirb(eval):013>

Excellent! Er, what���s that? Did I hear you say, ���So, big deal, tsort.rb isn���t that tough���? Well, ok, it isn���t. (I didn���t even know about TSort before browsing through the source.) But, we can do other stuff, too.

sirb(eval):008> require 'csv'
=> true
sirb(eval):009>

Yep, that���s right, csv.rb compiles! But, I���ll spare you the pain that ensued trying to use it. Baby steps. Ok, enough fun. C���mon kids, there���s a bunch of the core library still to implement!