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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Pascal Calling Convention
Date: Wed, 30 Mar 2011 08:40:46 -0400
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2011-03-30T08:40:46-04:00
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"Randy Brukardt" <randy@rrsoftware.com> writes:

> 99% of the time, executing data is a bug. Why allow it by default?

Ah, I didn't realize you were mainly focused on that issue.
I agree 100% that executing data is usually a bug, and should
be prevented by default.

But you don't need segments for that.  Paging hardware can do it.
(Well, you don't need segments in hardware.  The O.S. concocts
something like "segments" based on paging.  And protects code.)

>> Not at all.  The statement "All Ada implementations must use a stack
>> to implement procedure calls, because the semantics are FIFO."
>> is talking about implementations, but it's not target-specific.
>
> I think it is also close to junk. The semantics are FIFO is fine, but 
> anything about the underlying data structure is bogus. Unless you are 
> equating FIFO with stack in all cases, which I don't agree with. A stack is 
> FIFO, but I don't think that implies that all data structures that are FIFO 
> are stacks.

Of course we both mean "LIFO", not "FIFO" above.

> Anyway, this is a pointless discussion. Let's go back to discussing whether 
> membership is a set operation. ;-)

OK, fair enough.  ;-)

I'd still like to hear Keith's take on all this, if he's still
listening.

- Bob