From: ncohen@watson.ibm.com (Norman H. Cohen)
Subject: Re: Ada 95 case statement incompatibility?
Date: 1996/08/28
Date: 1996-08-28T00:00:00+00:00 [thread overview]
Message-ID: <5007k4$164a@watnews1.watson.ibm.com> (raw)
In-Reply-To: 4vvmra$k3t@linus.mitre.org
In article <4vvmra$k3t@linus.mitre.org>, mfb@mbunix.mitre.org
(Michael F Brenner) writes:
|> Another difference between 83 and 95 that was not documented is the
|> later rule that generics instantiated with signed numbers are
|> incompatible with generics instantiated with unsigned numbers.
But there were no unsigned types in the Ada-83 standard! It is true that
some implementations provided implementation-defined (signed) integer
types whose operators were redefined to behave in roughly the same manner
as Ada-95 modular types. However, since these types were
implementation-defined, an Ada-83 program using them was not portable
even to other Ada-83 compilers. The fact that they may not be portable
to some Ada-95 compilers either is neither a surprise nor an
incompatiblity between the Ada-83 and Ada-95 standards!
There is nothing in Ada-95 to prevent vendors who provided these signed
types with modular behavior in their Ada-83 compilers from also providing
them in their Ada-95 compilers, in addition to the modular types required
by the Ada-95 standard. Such types are redundant in the presence of
Ada-95 modular types, but provide a path for customers to migrate their
legacy Ada-83 code to Ada 95.
--
Norman H. Cohen ncohen@watson.ibm.com
next prev parent reply other threads:[~1996-08-28 0:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
1996-08-27 0:00 Ada 95 case statement incompatibility? Gavin Finnie
1996-08-27 0:00 ` Michael F Brenner
1996-08-28 0:00 ` Norman H. Cohen [this message]
1996-08-28 0:00 ` Robert Dewar
1996-08-28 0:00 ` Robert Dewar
1996-08-28 0:00 ` Robert Dewar
1996-08-28 0:00 ` Gavin Finnie
1996-08-29 0:00 ` Robert A Duff
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