ruby - Determine given module is rails engine

Question

Hi I have two modules

1. Admin
2. Blog (Blog is a rails engine) where Admin is a module for namespacing admin features of app, but Blog is a module representing rails engine. Is there a better way to determine which among them is engine, like a function "is_engine?"

Admin.is_engine?

=> false

Blog.is_engine?

=> true

Definately I can have a try catch thing to determine this

def is_engine? module
  module::Engine
  true
rescue NameError
  false
end

here

is_engine? Admin

will return false

is_engine? Blog

will return true

Thanks

Answer 1

我不确定我是否理解您要做什么：Rails Engine 是一个类（的子类Rails::Engine），而不是模块。

如果你有一个实例，你可以使用：

admin.kind_of?(Rails::Engine)

如果你有一个类，你可以使用：

Something.ancestors.include?(Rails::Engine)

如果你拥有的是一个模块，那么它就不能是 Rails::Engine 的子类，也不是引擎。

编辑

如果您有一个模块或常量something，并且想知道其命名空间中是否有一个具有特定名称的常量，您可以使用：

something.constants.include?(:Engine)