About procedures and functions in Ada Pure packages. Thanks!

97 views
Skip to first unread message

Daniel Norte Moraes

unread,
Aug 15, 2022, 6:31:56 AMAug 15
to
Hi! and Very Very Very Thanks!

I building and change some packages and I have some doubts
about procedures and functions in Ada Pure packages.
I'm asking mainly the Ada Language Lawers. the Ada version is Ada2012.

fact 1: Ada allow the compiler substitute a function with
the result of this function.

?This is valid to functions with 'in out' or 'out' parameters ?
?This is valid to functions with 'not null access' parameters ?
?This is valid to procedures with 'in out' or 'out' parameters ?
?This is valid to procedures with 'not null access' parameters ?

?If they are replaced (on the second call onwards) by the result,
will the 'in' 'in out' and 'not null access' parameters be updated
if they are changed within the function or procedure?

Very Very Very Thanks in Advance!
Best Wishes,
GrateFull,
Dani.

Randy Brukardt

unread,
Aug 17, 2022, 9:12:24 PMAug 17
to
"Daniel Norte Moraes" <daniel...@gmail.com> wrote in message
news:e1f43654-dba6-46d7...@googlegroups.com...
> Hi! and Very Very Very Thanks!
>
> I building and change some packages and I have some doubts
> about procedures and functions in Ada Pure packages.
> I'm asking mainly the Ada Language Lawers. the Ada version is Ada2012.
>
> fact 1: Ada allow the compiler substitute a function with
> the result of this function.
>
> ?This is valid to functions with 'in out' or 'out' parameters ?
> ?This is valid to functions with 'not null access' parameters ?
> ?This is valid to procedures with 'in out' or 'out' parameters ?
> ?This is valid to procedures with 'not null access' parameters ?

Yes, but there is a requirement that the input *values* are the same on both
calls, and in the case of access types, everything reachable is the same on
both calls. See 10.2.1(18/3) --
http://www.ada-auth.org/standards/rm12_w_tc1/html/RM-10-2-1.html#p18

Practically, compilers will exclude some or all of these cases.

> ?If they are replaced (on the second call onwards) by the result,
> will the 'in' 'in out' and 'not null access' parameters be updated
> if they are changed within the function or procedure?

If the "in out" parameters are changed, then the values don't match on the
second call, and the optimization isn't allowed. If the values are changed
to the *same* value as original, the optimization would be allowed, but you
couldn't tell whether or not the values were changed, so I think the
question is moot in that case.

Again, I doubt that an actual compiler would try to optimize in such cases
(too hard to prove that they're OK).

Randy.


Daniel Norte Moraes

unread,
Aug 21, 2022, 5:49:03 PMAug 21
to
Thanks Randy!

I'm satisfied.

Very Very Very GrateFull,
Best Wishes,
Dani.

Reply all
Reply to author
Forward
0 new messages