Re: dynamic-wind

[David Kastrup <dak@gnu.org>]

Catonano <catonano@gmail.com> writes:

> Chris,
>
> thank you for your remarks.
>
> Yo're right that I was being caught up by continuations AND that I was
> probably missing the generality of the concept of dynamic wind
>
> And yet, I still want to clarify my point
>
> My point is not that the manual is incomplete or inaccurate
>
> My point is that the manual does not a good job of _introducing_ people to
> the concept of dynamic wind
>
> Especially people wo have not clear in mind a complete map of the use cases
> with relative possible solutions.
>
> The manual tends to be a very good reference for already educated people.
> But it's not as good in educating people in the first place, in my view.

Arguably the manual example is not done well because it does not cater
for the case that other continuations might get invoked from a different
cwd.  So the cwd should get caught in the entry path of the dynamic-wind
rather than outside, something which I find surprisingly hard to do.
It's also not clear to me what the semantics of delimited continuations
are: for those I don't see a formal reason that there couldn't be
several active at the same time, making resource management via
dynamic-wind even more tricky.

-- 
David Kastrup