Contents

# HoboSupport - Module extensions

    >> require 'hobosupport'
    >> HoboSupport::VERSION
    => "0.1"

## Module#included_in_class_callbacks

Bit involved, this one :-)

When a module is included in a class, it gets a callback on the `included` method, with the class passed as argument. However, if a module M2 is included in M1, and a class C includes M1, then M2 never gets to know about C. So, for example, M2 could not `alias_method_chain` a class method on C.

`included_in_class_callbacks` makes it easy to implement a notification from M1 to M2, so that M2 does have full access to the class. All you do is insert a call to `included_in_class_callbacks(base)` as the end of the module's `self.included` method.

(Note we're using the metaid extensions here too)

    >>
    module M2
      def self.included_in_class(klass)
        klass.metaclass_eval do
          def name_with_shouting; name_without_shouting.upcase; end
          alias_method_chain :name, :shouting
        end
      end
    end
    
    module M1
      def self.included(base)
        included_in_class_callbacks(base)
      end
      include M2
    end
    
    class C
      def self.name
        "my name is C"
      end
      include M1
    end
    
    C.name
    => "MY NAME IS C"
    
    
## Module#interiting_attr_accessor

Only for use on classes. Like `attr_accessor`, but the attribute is looked up on the superclass if not defined on the receiving class. In other words, the superclass defines a default that subclasses can override.

    >>
    class A
      class << self
        inheriting_attr_reader :name
      end
      @name = "Andy"
    end
    
    class B < A; end
    
`B` has the same name as its superclass `A`
    
    >> A.name
    => "Andy"
    >> B.name
    => "Andy"
    
Now we change the name of `B`. `A` retains it's existing name.
    
    >> class B; @name = "Bob"; end
    >> B.name
    => "Bob"
    >> A.name
    => "Andy"

Version data entries

2 entries across 2 versions & 2 rubygems

Version	Path
hobo-support-0.1	test/hobosupport/module.rdoctest
hobosupport-0.1	test/hobosupport/module.rdoctest