linux-kernel - Re: [PATCH 2/6] treewide: remove using list iterator after loop body as a ptr

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Date:   Mon, 28 Feb 2022 12:14:44 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Christian König <christian.koenig@....com>
Cc:     Jakob Koschel <jakobkoschel@...il.com>,
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Subject: Re: [PATCH 2/6] treewide: remove using list iterator after loop body
 as a ptr

On Mon, Feb 28, 2022 at 12:10 PM Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
>
> We can do
>
>         typeof(pos) pos
>
> in the 'for ()' loop, and never use __iter at all.
>
> That means that inside the for-loop, we use a _different_ 'pos' than outside.

The thing that makes me throw up in my mouth a bit is that in that

        typeof(pos) pos

the first 'pos' (that we use for just the typeof) is that outer-level
'pos', IOW it's a *different* 'pos' than the second 'pos' in that same
declaration that declares the inner level shadowing new 'pos'
variable.

If I was a compiler person, I would say "Linus, that thing is too ugly
to live", and I would hate it. I'm just hoping that even compiler
people say "that's *so* ugly it's almost beautiful".

Because it does seem to work. It's not pretty, but hey, it's not like
our headers are really ever be winning any beauty contests...

                Linus