🚀 go-pugleaf

According to jimad@microsoft.UUCP (Jim ADCOCK):
>I claim C++ *ought to* allow such implementations [that distinguish
>between primitive types and user-defined types].  Such implementations 
>could be interesting *at least* on lisp-machines, Rekursiv-like "OO"
>architectures, and on risc machines with 48-bit pointers.

Agreed on the "interesting" count, except for the last: RISC machines
are quite well cared for by the current language definition.

I must admit that it is not until now that I realize the purpose of
Jim's statements.  He does not speak to what C++ *is* (the subject on
which I have concentrated), but of what it *should be* (in his
opinion, of course).  I apologize to all readers, especially Jim, for
previous articles which may have been unnecessarily critical due to my
not having grasped this point.

>On at least some such machines, the tagged pointers might have 48-bit
>representations, the primitive pointers have 32-bit representations.
>The 48-bit pointers would be type-tag + ram-address, whereas the 32-bit
>pointers would be ram-address only.  Thus conversion from class X* to
>char* [for example] really would represent loss of information ...

Ah, a concrete example!  Thank you; it is quite helpful.  It sounds
very interesting, too, with a lot of potential for error checking,
among other things.  I'll keep it in mind.

>Should the C++ language be specified in such a way so as to prohibit, 
>for all time, any such implementations/CPUs ???

It is a truism that no language can be all things to all people.
-- 
Chip Salzenberg at Teltronics/TCT     <chip@tct.uucp>, <uunet!pdn!tct!chip>
 "Most of my code is written by myself.  That is why so little gets done."
                 -- Herman "HLLs will never fly" Rubin