From: William James <w_a_x_man@...>
Date: 2007-01-14T18:45:22+09:00
Subject: Re: return_on

Joel VanderWerf wrote:
> Gavin Sinclair wrote:
> > On Jan 14, 1:34 am, "Trans" <transf...@gmail.com> wrote:
> >>   def x
> >>     return_on @cache[:x]
> >>     # do stuff
> >>     @cache[:x] = result_of_stuff
> >>   end
> >>
> >
> > def x
> >   @cache[:x] ||= begin
> >     # do stuff
> >   end
> > end
>
> Or (saving an exception handler setup):
>
> def reverse x
>    @cache[:x] ||= (
>      puts "CACHING"
>      x.reverse
>    )
> end
>
> @cache = {}
>
> p reverse("foo")
> p reverse("foo")
>
> __END__
>
> Output:
>
> CACHING
> "oof"
> "oof"

It doesn't work correctly.

def reverse x
   @cache[:x] ||= (
     puts "CACHING"
     x.reverse
   )
end

@cache = {}

p reverse("foo")
p reverse("what?")
p reverse("And this is cached, you think???")

---  output  -----
CACHING
"oof"
"oof"
"oof"