Thanks. I was implementing with-continuation-mark by just pushing
key&value to the current dynamic environment (and let the newest shadow the
previous one), but realized that the simple tail-call loop makes the
dynamic environment keeps growing.
It is, although, somewhat tricky if marks are interleaved.
(let loop ()
(with-continuation-mark 'a 1
(with-continuation-mark 'b 2
(with-continuation-mark 'a 3
(with-continuation-mark 'b 4
(loop))))))
So far, what I'm thinking is that each with-continuation-mark searches the
marks in the current continuation and reconstruct the alist of marks if
it's overriding the previous mark. Is there a better way than that?
--shiro
On Wed, Oct 26, 2022 at 10:48 AM Marc Nieper-Wißkirchen <
marc.nie...@gmail.com> wrote:
> Yes, indeed. The inner `with-continuation-mark' just replaces
> (non-destructively) the value of the mark "a".
>
> The tail-call guarantee is essential for several use cases of
> continuation marks. One is debugging; you can attach debugging
> information to frames, but you want to retain proper tail calls while
> doing so.
>
> Am Mi., 26. Okt. 2022 um 22:22 Uhr schrieb Shiro Kawai <
> shiro.ka...@gmail.com>:
> >
> > Quick question. The following code is expected to run in a bounded
> space, correct?
> >
> > (let loop ()
> > (with-continuation-mark 'a 'b
> > (with-continuation-mark 'a 'c
> > (loop))))
> >
> >
>
