From: itsme213 <itsme213@...>
Date: 2006-03-18T03:03:49+09:00
Subject: Re: rake rules question

Thanks, Jim!

"Jim Weirich" <jim@weirichhouse.org> wrote

> Basically, if you want your rules to trigger on something other than
> simple file extenstions, you need to write them in this format:
>
>   rule(REGEX => LAMBDA_TRANSFORMER) do
>     ACTIONS
>   end

Lovely. I will try this out.

> If you find rules confusing, an alternative is dynamically generate the
> tasks in a list.  For example:
>
>    SRC_FILES = FileList['source/*.png']
>
>    SRC_FILES.each do |fn|
>      stage1 = fn.sub(/^source/, 'stage1')
>      stage2 = fn.sub(/^source/, 'stage2')
>      task stage1 => stage2 do
>        do_stage_one_transform(fn, stage1)
>      end
>      task stage2 => stage1 do
>        do_stage_two_transform(stage2, stage1)
>      end
>    end
>
> In many ways this is easier than rules and just as flexible.
>
> Anyways, here is the example Rakefile using rules:
>
> ----------------------------------------------------------------
> #!/usr/bin/env ruby
>
> require 'rake/clean'
>
> CLOBBER.include 'stage1', 'stage2'
>
> task :default => %w(stage1 stage2 stage2/a.png)
>
> directory 'stage1'
> directory 'stage2'
> ----------------------------------------------------------------
>
> rule(%r{^stage1/.*\.png$} => lambda { |fn| fn.sub(/^stage1/, 'source')
> }) do |t|
>  File.open(t.source) do |ins|
>    File.open(t.name, "w") do |outs|
>      outs.write ins.read
>      outs.puts "Added to stage one"
>    end
>  end
> end
>
> rule(%r{^stage2/.*\.png$} => lambda { |fn| fn.sub(/^stage2/, 'stage1')
> }) do |t|
>  File.open(t.source) do |ins|
>    File.open(t.name, "w") do |outs|
>      outs.write ins.read
>      outs.puts "Added to stage two"
>    end
>  end
> end
> ----------------------------------------------------------------
>
> # Other tasks --------------------------------------------------------
>
> task :init => :clobber do
>  File.open("source/a.png", "w") do |outs|
>    outs.puts "A PNG FILE"
>  end
> end
>
> task :see do
>  puts "-- Contents of source/a.png -------------------------------"
>  puts File.read("source/a.png")
>  puts "-- Contents of stage2/a.png -------------------------------"
>  puts File.read("stage1/a.png")
>  puts "-- Contents of stage2/a.png -------------------------------"
>  puts File.read("stage2/a.png")
> end
> ----------------------------------------------------------------
>
> --
> -- Jim Weirich
>
> -- 
> Posted via http://www.ruby-forum.com/.
>
>