> -----Original Message-----
> From: Jonathan Wakely <jwak...@redhat.com>
> Sent: Thursday, March 20, 2025 18:01
> To: James K. Lowden <jklow...@schemamania.org>
> Cc: gcc-patches@gcc.gnu.org; Robert Dubner <rdub...@symas.com>
> Subject: Re: [PATCH] cobol: Replace quadratic loop removing std::set
> elements
>
> On Thu, 20 Mar 2025 at 21:27, James K. Lowden <jklow...@schemamania.org>
> wrote:
> >
> > On Wed, 19 Mar 2025 20:33:36 +0000
> > Jonathan Wakely <jwak...@redhat.com> wrote:
> >
> > > There's no need to keep using std::find_if from the beginning of the
> > > container after every removal, just update the iterator after erasing
> > > an element.
> > >
> > > This is how C++20 std::erase_if is implemented.\
> >
> > LGTM. I am gun-shy about using iterators while modifying containers.
> > I know there are rules. :-/
>
> Yes, the erased iterator is invalidated, but it returns an iterator to
> the next element after the erased one, so we can continue iterating
> from there instead of using the no-invalid one. That's what the
> p=erase(p) patter does.
> The important thing is to _not_ increment in that case, because
> erasing *p and then pointing to the next element replaces the
> increment.
>
> > Likely you'll find other examples. The arrays are small and the
> > performance impact is too, but neatness counts and simpler is better.
> >
> > Jonathan, if your patches to the FE so far are awaiting *my* approval,
> > consider it done. I've read them and they're straightforward. If I
> > need to do more than just say that, please direct me.
>
> OK, thanks. On that topic, should you be listed in the MAINTAINERS
> file? I see Bob in there, but don't see your name.
>
> I won't make the changes to use 'auto' which Bob didn't like. I'll
> send another patch with a more minimal change for the remove_if call
> using isspace.
My dislike of 'auto' is "weakly dislike'. If we go down that route, we'll
end up backing down to C++98, with me muttering, "Damn kids" just before I
bellow, "Get off my lawn!" the whole time. So, don't let me throw a spanner
into the gears of progress.
