YSupport

YSupport is a common support library for Y* gems (y_petri, yzz, y_nelson, sy...). At the moment, it is a collection of all and sundry helpful methods, which can be divided as follows

• NameMagic (lib/name_magic.rb) -- its main feature is that it allows constant magic so well known from Ruby classes (Foo = Class.new; Foo.name #=> "Foo") to work with any objects.
• Miscellaneous helpful methods (lib/misc.rb)
• Typing (runtime assertions, lib/typing.rb)
• Other smaller components:
  • unicode.rb -- shortcut letter for class (ç), singleton class (ⓒ) etc.
  • null_object.rb
  • try.rb -- a different kind of #try method
  • several other small fry components

Ruby classes are well known for their "constant magic": When they are assigned to constants, they acquire name attribute corresponding to the constant name.

  x = Class.new
  x.name #=> nil
  Foo = x
  x.name #=> "Foo"

NameMagic mixin lends this feature to any Ruby class. The class in which NameMagic is mixed in will also hold the registry of the instances, named or unnamed. Example code:

  require 'y_support/name_magic'

  class Animal
    include NameMagic
    def sound; "squeak" end
    def speak; 2.times { puts sound.capitalize << ?! } end
  end

  class Dog < Animal; def sound; "bark" end end
  class Cat < Animal; def sound; "meow" end end

  Pochi = Dog.new
  anonymous_kitten = Cat.new

Mixin NameMagic makes class Animal keep registry of its instances:

  Animal.instances.names
  #=> [:Pochi, nil]
  Tama = anonymous_kitten
  Animal.instances.names
  #=> [:Pochi, :Tama]
  # Name can also be supplied to the constructor explicitly:
  Animal.new name: :Cheburashka
  Animal.instance( "Cheburashka" )
  Animal.instance( "Cheburashka" ).name
  :Cheburashka
  Animal.instances.names
  #=> [:Pochi, :Tama, :Cheburashka]
  Dog.instances.names
  #=> [:Pochi]
  Animal.instances.each &:speak
  Dog.instances.each &:speak
  Cat.instances.each &:speak

The registry of instances is maintained by the namespace, so the instances can only be garbage collected after the namespace is garbage collected. If the user wants to enable this earlier, the namespace can be ordered to forget them:

  Animal.forget_all_instances
  Animal.instances
  []

Read the documentation of the individual methods.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request