Alias and subclasses

ruby-talk
1

Hi everyone,

The quick version:
Is there a Ruby-ian way to get the alias method to propagate through subclasses?

The longer one:
I've got two classes with some simple inheritance:

class Ticket
  def unreserve
    ...
  end
  alias unhold unreserve
end

class FamilyTicket < Ticket
  def unreserve
    ...
  end
end

FamilyTicket adds a bit of functionality to Ticket, and are reserved in different ways, so it's unreserve method overwrites its parent class. I would still like to use the aliased method name - e.g.
  ft = FamilyTicket.new
  ft.unhold

However, the alias refers to Ticket#unreserve, not FamilyTicket#unreserve. From the docs I understand that this is by design, so my question is, is there a more Ruby-like way of doing the following?
class Ticket
  def unreserve
    ...
  end

  def unhold
    unreserve
  end
end

Cheers,
Tim Clark

2

Tim Clark wrote:

Hi everyone,

The quick version:
Is there a Ruby-ian way to get the alias method to propagate through subclasses?

The longer one:
I've got two classes with some simple inheritance:

class Ticket
    def unreserve
        ...
    end
    alias unhold unreserve
end

class FamilyTicket < Ticket
    def unreserve
        ...
    end
end

FamilyTicket adds a bit of functionality to Ticket, and are reserved in different ways, so it's unreserve method overwrites its parent class. I would still like to use the aliased method name - e.g.
    ft = FamilyTicket.new
    ft.unhold

However, the alias refers to Ticket#unreserve, not FamilyTicket#unreserve. From the docs I understand that this is by design, so my question is, is there a more Ruby-like way of doing the following?
class Ticket
    def unreserve
        ...
    end

    def unhold
        unreserve
    end
end

Alias it again?

I talk about this topic (for monkey patching, but it would apply to subclassing as well) at Monkey patching and aliases - Testing 1,2,3... — LiveJournal if anyone is interested.

Regards,

Dan

3

Hi everyone,

The quick version:
Is there a Ruby-ian way to get the alias method to propagate through
subclasses?

The longer one:
I've got two classes with some simple inheritance:

class Ticket
        def unreserve
                ...
        end
        alias unhold unreserve
end

class FamilyTicket < Ticket
        def unreserve
                ...
        end
end

FamilyTicket adds a bit of functionality to Ticket, and are reserved
in different ways, so it's unreserve method overwrites its parent
class. I would still like to use the aliased method name - e.g.
        ft = FamilyTicket.new
        ft.unhold

However, the alias refers to Ticket#unreserve, not
FamilyTicket#unreserve. From the docs I understand that this is by
design, so my question is, is there a more Ruby-like way of doing the
following?
class Ticket
        def unreserve
                ...
        end

        def unhold
                unreserve
        end
end

Of course now you have the problem of if the sublass decides to override
unhold instead of unreserve. The real solution to this problem IMO is to not
start aliasing things in the first place. A given method should have one
name. (I know Ruby does it with map/collect etc., but that doesn't mean I
have to agree does it? :slight_smile: )

Cheers,

···

On 6/24/07, Tim Clark <tim@bass.net.au> wrote:

Tim Clark

4

Also, I always look at this as a feature and not a bug, as in:

alias_method :old_something, :something

def something
  #do some hackery
  old_something
end

···

On 6/25/07, Logan Capaldo <logancapaldo@gmail.com> wrote:

Of course now you have the problem of if the sublass decides to override
unhold instead of unreserve. The real solution to this problem IMO is to not
start aliasing things in the first place. A given method should have one
name. (I know Ruby does it with map/collect etc., but that doesn't mean I
have to agree does it? :slight_smile: )