Merge Source Code from Directories in Chain

Build your application by copy source files from a stack of modules.

Put a configuration file .app_stack.yml in your application directory, in format like:

stack: 
  - module-1
  - module-2: [defaults, tests]
stack_dir: '../stack-apps'
tpl_ext: '.erb'
verbose: 1
export:
  - lib/**/*.rb
  - app/**/*.rb
  - tests:
      - spec/**/*.rb
exclude:
  - lib/extra/*.rb
attrs:
  application_name: App Name
  application_code: app_code
  database_password: the very secret
  gems:
    default:
      - rspec: '~> 2.0.0'
      - ...
    development:
files:
  README.md: __self

stack : 设置导入的模块名，元素为字符串（只导入'default'组的文件）或Hash， : 为Hash时，key为模块名，值为文件组的数组（'all'代表全部）。

stack_dir（默认为../stack-apps） : 模块程序所在位置。

export（默认为空） : 可被拷贝至其他模块的文件pattern（为字符串时），或pattern的组 : （像上述示例中的tests一样）。

exclude（默认为空） : 导出到其它模块时，从export列表中除外的文件pattern。 : 注意如果模块中定义了.gitignore文件，则其中的内容也会被加载至 : exclude列表。

attrs : 用于assign至.erb文件的属性值。在上面的例子中module2会继承 : module1中设置的值。

files field is auto-generated, you should not edit it manually.

export defines files that should be copied when other modules include the current module. Besides export, the acquire module can use include and exclude adjust files that imports from other modules.

Variables defined in attrs will be assigned into .erb files.

gems need a support from Gemfile.erb.

If you have both a config.yml and a config.yml.erb file, when export, the config.yml.erb will be used instead of config.yml, and attrs will be assigned into this file.

Variables in attrs will be merged in chain follows the app-stack.