On 2021-06-05 14:05 +0200, Marc Nieper-Wißkirchen wrote:
> Wolfgang, what do you think? We should get it right with SRFI 224 first
> (before it is finalized) and then we can correct SRFI 113 and 146 (am I
> missing another relevant SRFI) ex post facto.

Marc, thanks to you and Shiro for all of the interesting
discussion.

I'm not sure I understand the proposed solution, or the exact
meanings of the terms "persistent" and "transient" in this
context.  Before changing the semantics of SRFI 224, I'd like to
make sure I'm clear on what we're suggesting, and how it will
impact interactions with other Scheme libraries.  Would all
functional procedures now be specified to return a persistent
value, while -! forms would be required to take transient
values?

If I understand correctly, the core of the problem is that the
expectation that "you, the programmer, know there are no other live
references to the value passed to the procedure" is unreasonable,
unless the library provides guarantees or adheres rigidly to the
(awful) "always copy everything" protocol.  (Please correct that
if I've misunderstood.)

--
Wolfgang Corcoran-Mathe  <xxxxxx@sigwinch.xyz>

"In the military more is not better." --_Sun Tzu_