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Subject: Re: Adacore joins with Ferrous Systems to support Rust
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On Friday, February 4, 2022 at 4:28:26 AM UTC-6, Luke A. Guest wrote:
> On 04/02/2022 03:20, Randy Brukardt wrote:=20
>=20
> >> Just like we didn't touch generic packages until much later in the yea=
r,=20
> >> generic subprograms, yeah, because u_d was required early on.=20
> >>=20
> >>> objecting to this, I think he was right (philosophically; I've no ide=
a=20
> >>> about the practicality of alternate approaches).=20
> >>=20
> >> How else would you do controlled types?=20
> >=20
> > Ada 9x originally had a bunch of magic attributes (similar to streaming=
). It
> Now I want to know what these magic attributes were! Were they specific=
=20
> to a version of OO? Or were they to enable finalization?

Randy, I agree with Luke:  were these intermediate design proposals lost en=
tirely or have they (as still extant) have simply not been released publicl=
y?  I suspect that at least some of these attributes have nowadays analogue=
s in C++ smart pointer's & Objective-C/Swift's ARC {strong, weak, plain old=
 data not needing finalization, pointed-to-object ownership, presence of fi=
nalization subroutine/function/procedure a.k.a. finalizer/destructor, wheth=
er this finalizer in a subtype displaces its parent's finalizer versus this=
 finalizer in a subtype chains its finalizer to all of its ancestors' final=
izers unwound from most-derived to underived-root, =E2=80=A6 and so forth}.=
  Or was Tucker's set of magic attributes going an entirely different direc=
tion?  That intermediate proposal under consideration back in the 1st half =
of the 1990s might be a quite interesting read (especially by a reader with=
 an interest in envisioning an Ada-esque analogue of Rust's borrow-checker =
algorithm).