Create an OS X .app Executable With Your Choice Of Language For Script

mac-app.rb

require 'builder'

module MacApp
  class << self
    def new
      ask_name
      ask_file_extension
      ask_language

      create_directories
      create_files
    end

    def run
      system "open #@name"
    end

    private
    def ask_name
      print 'App Name: '
      @name = gets.chomp.split.map(&:capitalize).join << '.app'
    end

    def ask_file_extension
      print 'File Extension: '
      @file_extension = gets.chomp.delete('.').downcase
    end

    def ask_language
      print 'Language: '
      @language = gets.chomp.downcase
    end

    def create_directories
      Dir.mkdir @name
      Dir.mkdir "#@name/Contents"
      Dir.mkdir "#@name/Contents/MacOS"
      Dir.mkdir "#@name/Contents/Resources"
    end

    def create_files
      File.open "#@name/Contents/Info.plist", 'w' do |file|
        xml = Builder::XmlMarkup.new indent: 2
        
        xml.instruct! :xml, encoding: 'utf-8'
        
        xml.declare! :DOCTYPE, 
                     :plist,
                     :PUBLIC,
                     '-//Apple//DTD PLIST 1.0//EN',
                     'http://www.apple.com/DTDs/PropertyList-1.0.dtd'
        
        xml.plist version: '1.0' do |plist|
          plist.dict do |dict|
            dict.key    'CFBundlePackageType'
            dict.string 'APPL'
            
            dict.key    'CFBundleInfoDictionaryVersion'
            dict.string '6.0'
            
            dict.key    'CFBundleIconFile'
            dict.string "#@name.icns"
            
            dict.key    'CFBundleName'
            dict.string "#@name by Orchid Technologies"
            
            dict.key    'CFBundleExecutable'
            dict.string "app.#@file_extension"
            
            dict.key    'CFBundleIdentifier'
            dict.string @name
            
            dict.key    'CFBundleVersion'
            dict.string '0.1'
            
            dict.key    'NSHumanReadableCopyright'
            dict.string 'Author Copyright 2012'
          end
        end
        
        file << xml
      end
      
      File.open "#@name/Contents/MacOS/app.#@file_extension", 'w' do |file|
        file << "#!/usr/bin/env #@language\n# Code goes here..."
      end
      
      File.chmod 0755, "#@name/Contents/MacOS/app.#@file_extension"
      
      File.open "#@name/Contents/Resources/#@name.icns", 'w'
    end
  end
end

MacApp.new