Sujet : Re: Ichbiah 2022 compiler mode
De : randy (at) *nospam* rrsoftware.com (Randy Brukardt)
Groupes : comp.lang.adaDate : 14. Sep 2024, 07:18:25
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <vc39rl$1b1jo$1@dont-email.me>
References : 1 2 3 4
User-Agent : Microsoft Outlook Express 6.00.2900.5931
"Lawrence D'Oliveiro" <
ldo@nz.invalid> wrote in message
news:vbvpmt$esm6$7@dont-email.me...On Wed, 11 Sep 2024 23:39:27 -0500, Randy Brukardt wrote:
>
"Lawrence D'Oliveiro" <ldo@nz.invalid> wrote in message
news:vbdk2t$hj0r$6@dont-email.me...
On Thu, 5 Sep 2024 19:03:22 -0500, Randy Brukardt wrote:
...
(10) Variable-returning functions are introduced.
>
Is this like updater functions in POP-11, or "setf" in Lisp?
>
No, it is a function that returns a variable, meaning you can assign
into the function result.
>
I think an updater function would be more generally useful. Because some
things you want to update might not (depending on the implementation) live
independently in an explicit variable. And it seems good not to constrain
implementations unnecessarily.
Unfortunately, "updater" functions don't work with the Ada model of
components, because you can't tell what to do when a component appears or
disappears in an assignment. (That's why Ada doesn't allow overloading
":=".) And composition is very important to Ada -- stand-alone objects are
pretty rare outside of those for scalar types. I don't think something that
only worked with stand-alone objects would be very useful (can't use those
with ODTs, for instance)..
Randy.