From: ara.t.howard@...
Date: 2006-04-27T02:29:15+09:00
Subject: Re: Rake task dependeny vs. method call

On Thu, 27 Apr 2006 Ara.T.Howard@noaa.gov wrote:

> but by redefining tasklib.rb to use tsort both task lists function correctly:
>
>
>    harp:~ > cat a.rb
>    require 'tasklib2'
>
>    task :uidgen do |*argv| (seed = argv.shift) ? rand(seed) : 
> $UID||=uidgen(42) end
>
>    task :a => :uidgen do y "a" => $UID end
>    task :b => :a do y "b" => uidgen(42) end
>    task :c => :a do y "c" => uidgen(42) end
>    task :d => [:b, :c] do y "d" end
>
>    d()
>
>
>    harp:~ > ruby a.rb
>    ---
>    a: 5
>    ---
>    b: 15
>    ---
>    a: 5
>    ---
>    c: 3
>    --- d


a sample fix:


   harp:~ > cat a.rb
   require 'tasklib2'

   task :uidgen do |*argv| (seed = argv.shift) ? rand(seed) : $UID||=uidgen(42) end

   task :a => :uidgen do y "a" => $UID end
   task :b => :a do y "b" => uidgen(42) end
   task :c => :a do y "c" => uidgen(42) end
   task :d => [:b, :c] do y "d" end

   make


   harp:~ > ruby a.rb
   ---
   a: 24
   ---
   b: 25
   ---
   c: 31
   --- d

   harp:~ > cat tasklib2.rb
   require 'cache'
   require 'yaml'
   require 'tsort'
   module Task
     class TSortHash < Hash
       include TSort
       alias_method 'tsort_each_node', 'each_key'
       def tsort_each_child(node, &block) fetch(node).each(&block) end
       def initialize(hash={}) update hash end
       def [](key) super || [] end
       def fetch(key) super rescue [] end
     end
     def task(args, &action)
       if Hash === args
         raise ArgumentError, "#{args.size} for 1" if args.size != 1
         name, *deps = *(args.to_a.flatten)
         name = name.to_sym
         deps = deps.compact.collect{ |e| e.to_sym }
       else
         name, deps = args.to_sym, []
       end
       # ensure no cycles in global graph
       dag.replace th.update(name => deps).tsort
       (class<<self;self;end).module_eval do
         define_method(name){|*__a__| action.call(*__a__) if action}
       end
     end
     def th() @th ||= TSortHash.new end
     def dag() @dag ||= [] end
     def make() @dag.each{|d| send d} end
     class ::Object; include Task; end
   end


sorry for noise.

-a
-- 
be kind whenever possible... it is always possible.
- h.h. the 14th dali lama