From: Louis J Scoras <louis.j.scoras@...>
Date: 2006-10-18T04:44:50+09:00
Subject: Re: ruby way to say this?

On 10/17/06, matt neuburg <matt@tidbits.com> wrote:
> In Ruby, zero isn't false and there is no equivalent of the ?: operator
> with the middle term omitted. So e.g. I'd like to say [pseudo-code from
> some other language]:
>
> oneThing()?:otherThing()
>
> meaning, if oneThing is nonzero, return oneThing, else return
> otherThing. Now, I don't want to evaluate oneThing twice, so I've ended
> up with this:
>
> (temp = oneThing()).nonzero? ? temp : otherThing()
>
> I don't like it. Is that culturally correct, or is there a ruby way to
> speak here, that I'm not thinking of? Thx - m.


Are you okay with adding an extra function call?

How about:

    def if_zero(exp,alt)
      exp == 0 ? alt : exp
    end

    x = 0

    if_zero( (x+=1) + 1, 7) # => 2
    if_zero(  x-=1     , 8) # => 8

So your original would look like:

    # if_zero(one_thing, other_thing)


-- 
Lou.