I have a class that I want to reference by two different names when using it. The only way I can think to do this is.
class Entrance
def open
puts "the door is open"
end
end
class Exit < Entrance
end
The thing is that in this example I want to represent that Entrance and Exit are the exact same thing, not that an Exit is a type of Entrance. Is there a better way to represent this?
Easy and simple:
Exit = Entrance
Classes in Ruby are really just objects of class Class that are assigned to constants with their name. So, just have a new constant refer to the same object as the old constant.
Note that now Exit and Entrance are the exact same class, and anything you do to one happens to the other:
2.0.0p0 :009 > Exit.object_id == Entrance.object_id
=> true
Note: While this is possible, I'd think more carefully about your general architecture. Is their any difference between an Entrance and an Exit? Are they both just really Doors? Your architecture should be such that classes won't (usually) need to be aliased unless you have two synonymous names that you really want to use both, like Page and WebPage (I'd recommend against this too).
Add and Edit using this technique.In Ruby classes are also Object. So you can do as below :
Exit = Entrance
Remember that doesn't mean your class Entrance have now another name which is Exit. Rather Exit is a constant, which is now holding the reference to you class object Entrance.
Entrance.name # => "Entrance"
Exit.name # => "Entrance"
Exit.object_id == Entrance.object_id # => true
You can assign a constant name like anything else.
class Entrance; end
Exit = Entrance
Maybe add new class - Door. Exit < Door, Entrance < Door.
Exit = Entrance, you can haveEntrance = nilorEntrance = SomethingElse(without affectingExit), though Ruby will slap your hand with a warning that you've changed the definition ofEntrance.