From: Barry and Jackie Schiff <schiff@netspace.net.au>
Subject: A question for compiler vendors/lang experts. redefinition of "="
Date: 1997/12/16
Date: 1997-12-16T00:00:00+00:00 [thread overview]
Message-ID: <34964C63.F97005E6@netspace.net.au> (raw)
Got one answer from a large compiler vendor when another vendor's
implementation implies otherwise. Looked in the Rationale and LRM and it
was hard to find a clear answer. So here is the question for all those
language experts out there:
package Foo is
type objects is abstract tagged record
Some_value : some_type;
end record;
type class_wide_pointers is access all objects'class;
function "="(left, right : access objects) return boolean; --
Legal??
end Foo;
The question: Is the redefinition of "=" shown above legal and if so
what are the semantics. Specifically, is "=" a dispatching primitive
operation or is it ambiguous with the predefined equality defined for
the class_wide_pointers type.
--------------
In my reading the LRM it seems to me that the spirit of access
parameters is that the above operation is a dispatching operation. I
have had a large Ada compiler vendor tell me that the above is
ambiguous. While another compiler implements that above as a dispatching
operation. Can anyone point me to the definitive answer in the LRM.
Thanks in advance. If it is not to much trouble could you email answer.
--Barry Schiff
next reply other threads:[~1997-12-16 0:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-12-16 0:00 Barry and Jackie Schiff [this message]
1997-12-16 0:00 ` A question for compiler vendors/lang experts. redefinition of "=" Tucker Taft
1997-12-16 0:00 ` David Weller
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