From: Daniel Schierbeck <daniel.schierbeck@...>
Date: 2006-11-23T22:35:53+09:00
Subject: Re: Rubyish inst.var initializations

On Thu, 2006-11-23 at 10:04 +0900, Victor "Zverok" Shepelev wrote:
> Hi all.
> 
> I have some huge class with aspects of functionality spreaded in several
> source files.
> 
> And in some of those aspects there is the same picture:
> ---
> class MyClass
>   def push_something(obj)
>     @something_list ||= []
>     @something_list << obj
>   end
> 
>   def use_something(i)
>     (@something_list ||= [])[i]
>   end
> end
> ---
> 
> Then I note (through profiler) various push_XXX spend too much time in
> checking is @XXX_list initialized. Then I change it:
> 
> ---
> class MyClass
>   alias :initialize_without_something :initialize
> 
>   def initialize(*arg)
>     initialize_without_something(*arg)
>     @something_list = []
>   end
> 
>   def push_something(obj)
>     @something_list << obj
>   end
> 
>   def use_something(i)
>     @something_list[i]
>   end
> end
> ---
> 
> Now push_XXX and use_XXX work cleaner and faster, but all those initialize
> aliases (now I have 5 or 6) don't seem to be very elegant.
> 
> Is there better solution?
> 
> (to be clear, all those push_XXX are NOT similar - some of them push object
> to hashes, others to arrays, params count differ and so on - so, they can't
> be generated at once through metaprogramming)

  class MyClass
    def something_list
      @something_list ||= []
    end
  
    def push_something(obj)
      something_list << obj
    end
  end

Optionally you could make #something_list private if you don't wish to
expose it to the outside.


Cheers,
Daniel