From: MikkelFJ <mikkelfj-anti-spam@...>
Date: 2002-12-01T05:59:39+09:00
Subject: Re: Ruby ++, the one element and generators


"MikkelFJ" <mikkelfj-anti-spam@bigfoot.com> wrote in message
news:3de91a9b$0$47402$edfadb0f@dtext01.news.tele.dk...

> if my_collection.size > 1
>  begin
>   c = 0
>   a = my_collection.first
>   k = a
>   ++a
>   while a != my_collection.end
>     b = a
>     a++
>     if a.value > b.value
>       a.swap_values b
>       c++
>   end
>  end while c > 0
> end

In the above I was a bit loose on the semantics of a++ vs. ++a. These
semantics should be well known - i.e. return the old vs. returning the new
value:

++a <=> return a = a.next
a++ <=> b = a; a = a.next; return b

Clearly this doesn't make sense for ++! because we are destroying the old
value.
One solution would be to disallow a++!, and only allow ++!a, another
solution would be to to conclude that a is still referencing the same object
so the old value is the same as the new value, thus ++!a <=> a++!
I'd prefer the latter solution, although I can hardly imagine anyone writing
++!a.

Mikkel