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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Intervention needed?
Date: Thu, 21 Mar 2019 21:16:22 -0500
Organization: JSA Research & Innovation
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Xref: reader01.eternal-september.org comp.lang.ada:55921
Date: 2019-03-21T21:16:22-05:00
List-Id: <comp.lang.ada>

"Optikos" <optikos@verizon.net> wrote in message 
news:74339f3f-9591-45a3-8632-8834b4b466ab@googlegroups.com...
...
>What you describe as (a[n ab]use case for) cursors is in reality
>a pointer in the end, ...

Not a pointer, since a pointer is essentially a raw machine address which 
cannot detect problems. I'd call it a reference, as the abstract way of 
designating something.

And cursors can be and often are implemented so that the likelihood of an 
undetected dangling reference is low to impossible. That's not possible for 
any sort of pointer. (You can do the Rust thing and do some sort of 
compile-time rules, but that doesn't help build complex data structures.)

I don't believe that it is possible to build a complex data structure like 
an Ada compiler without some form of references. One can argue about the 
form, but not the need. You have to be able to have long-lived connections 
between structures -- they could be strong or weak or a variety of other 
things, but you can't live without some form of references.

                            Randy.