coffee compiling rakefile

Rakefile

require 'coffee_script'
require 'rake/clean'

def coffee_to_js(coffee)
  File.join(BUILDDIR, File.dirname(coffee.split('/')[1..-1].join('/')), File.basename(coffee).ext('js'))
end

JSFILE   = 'app.js'
JSPATH   = "_attachments/js/app/#{JSFILE}"
COFFEE   = FileList['coffeescript/**/*.coffee']
BUILDDIR = 'js'
JS       = COFFEE.collect { |fn| coffee_to_js(fn) }

CLEAN.include(JS, BUILDDIR)
CLOBBER.include(JSPATH)

task :build => [JSFILE]

file JSFILE => JS do
  puts "assembling #{JSFILE}"
  `cat #{JS.join(' ')} > #{JSPATH}`
end

directory BUILDDIR

rule '.js' => lambda { |objfile| find_source(objfile) } do |t|
  Rake::Task[BUILDDIR].invoke

  outfile = coffee_to_js(t.source)
  mkdir_p File.dirname(outfile)

  puts "#{t.source} -> #{outfile}"
  f = open(outfile, 'w')
  f.write(CoffeeScript.compile(open(t.source)))
  f.flush
  f.close
end

def find_source(objfile)
  base = File.basename(objfile, '.js')
  COFFEE.find { |s| File.basename(s, '.coffee') == base }
end