> On 18. Mar 2020, at 15:40, Massimiliano Gubinelli <m.gubine...@gmail.com>
> wrote:
>
> Good point with dynamic-wind. Does it pass along also multiple values or has
> the same problem?
>
Does not work...
mgubi@Ulrike guile3-usr % bin/guile
GNU Guile 3.0.1
Copyright (C) 1995-2020 Free Software Foundation, Inc.
Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.
Enter `,help' for help.
scheme@(guile-user)> (call-with-values (lambda ()
(dynamic-wind (lambda () (display "initialize\n"))
(lambda () (let ((a (values "a" "b" "c"))) a))
(lambda () (display "finalize\n"))))
(lambda body body))
initialize
finalize
$1 = ("a")
scheme@(guile-user)>
Isn't this a bug??? In my view it breaks composability of scheme code.
Best,
Max
> m
>
>
>> On 18. Mar 2020, at 15:06, John Cowan <co...@ccil.org> wrote:
>>
>> There is going to be a performance penalty, because you are taking multiple
>> values (which is not a value) and making it into a value by creating a list.
>> There is no getting away from that except to exclude multiple values.
>>
>> Note also that if the procedure throws an exception, your finalizer will
>> never be run. Consider using dynamic-wind, whose whole purpose is to make
>> sure that an initializer and a finalizer are always run.
>>
>> On Wed, Mar 18, 2020 at 9:11 AM Massimiliano Gubinelli
>> <m.gubine...@gmail.com> wrote:
>>
>> > On 18. Mar 2020, at 13:39, Matt Wette <matt.we...@gmail.com> wrote:
>> >
>> >
>> > How about calling (my-macro/values bar) where my-macro/values expands to
>> >
>> > (call-with-values (lambda () (bar))
>> > (lambda args (finalization-code) (apply values args))
>> >
>> > Matt
>> >
>> >
>>
>> Yeah! I like this better. But still wraps and unwraps the result.
>>
>> Is there any performance penalty in that?
>>
>> Apart from my specific user case I wonder how and why in general multiple
>> values are used. Seems they are not well integrated in the current Guile
>> implementation. In my naive opinion the behaviour of Guile 1.8 was more
>> consistent.
>>
>> Max
>>
>>
>>
>
