Re: Rake dependencies unknown prior to running tasks

Thanks for the patch.   Here's a clunkier variation on your  
suggestion that seems to work with Drake.  Stage 1 serializes an  
unpredictable set of tasks.   Stage 2 creates instances of them and  
runs them if necessary.  There might be a better way that involves  
making the dependency tree modifiable dynamically.  I think allowing  
all possible dependency changes would get complicated.  Maybe that  
would require reevaluating the entire tree constantly and there's no  
way to un-execute a task anyway.  But most of the real world problems  
I can think of seem to involve adding tasks that wouldn't have been  
exercised yet anyway.  Could this be solved with an improved  
dependency tree walking algorithm?


require 'rake/clean'

# Stage 1 puts a random set of numbers in a file
STAGE_ONE_RESULTS =  "s1.txt"
file STAGE_ONE_RESULTS do
	open(STAGE_ONE_RESULTS, 'wb') do |file|
		(1..5).map{|i|rand 10}.uniq.each do |i|
			puts "stage1 creating dependency #{i}"
			file.puts i
		end
	end
end
task :stage1 => STAGE_ONE_RESULTS

# Stage 2 creates task based on those random numbers
task :stage2 => :stage1
if File.exists? STAGE_ONE_RESULTS
	IO.readlines(STAGE_ONE_RESULTS).each do |task_info|
		task task_info do
			puts "stage2 executing #{task_info}"
		end
		task :stage2 => task_info
	end
end

task :all => :stage1 do
	puts `drake -j4 stage2`
end

CLEAN.include STAGE_ONE_RESULTS
task :default => :all



On 24 sept. 08, at 20:29, James M. Lawrence wrote:

>
> If only the Internet came with an Undo button...
>
> Since in the previous example Rake complains unless main_a and main_b
> are defined, it sort of defeats the whole purpose.  This works:
>
>   task :setup_a do
>     puts "setup_a"
>   end
>
>   task :setup_b do
>     puts "setup_b"
>   end
>
>   task :setup => [:setup_a, :setup_b] do
>     puts "setup phase complete. defining new tasks..."
>
>     task :main_a do
>       puts "main_a"
>     end
>
>     task :main_b do
>       puts "main_b"
>     end
>
>     puts "restarting..."
>     throw :restart
>   end
>
>   task :main => [:main_a, :main_b] do
>     puts "main phase complete."
>   end
>
>   task :default => [:setup, :main] do
>     puts "all done."
>   end
>
> However this defeats Drake, which I suppose is another matter.
> -- 
> Posted via http://www.ruby-forum.com/.
>