watchr script to minify js files on save

manifest.yml

somepackage:
  - somefile.js
anotherpackage:
  - somefile.js

minify.watchr

#!/usr/bin/env ruby
# encoding: utf-8

#
# Run me with:
#
#   $ watchr minify.watchr

# --------------------------------------------------
# Convenience Methods
# --------------------------------------------------

begin
  require 'watchr'
  require 'yaml'
  @compiler = "/usr/local/gcc-compiler.jar"
  @manifest = YAML.load(File.open("javascripts/manifest.yml"))
  puts @manifest.inspect
rescue Exception => e
  puts e.message
end

def all_js_files
  Dir['javascripts/**/*.js']
end

def compile_package(package)
  libs = @manifest[package[1]]
  if libs.nil? or libs.empty?
    puts "Sorry, thanks for playing, but there were no matches for #{package}"  
  else
    sources = libs.map{ |lib| "--js javascripts/#{package[1]}/#{lib}" }.join(' ') 
    puts 'Minifying...'
    puts "java -jar #{@compiler} #{sources} --js_output_file javascripts/#{package[1]}.min.js"
    puts `java -jar #{@compiler} #{sources} --js_output_file javascripts/#{package[1]}.min.js`
    puts 'Done.'
  end
end

# --------------------------------------------------
# Watchr Rules
# --------------------------------------------------
watch('^javascripts/(.*)/(.*)\.js'){ |m| compile_package(m) }

# --------------------------------------------------
# Signal Handling
# --------------------------------------------------

Signal.trap 'INT' do
    puts "   quitting....FINE!."
    exit
end