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From: mheaney@on2.com (Matthew Heaney)
Newsgroups: comp.lang.ada
Subject: Re: "access constant" discriminant
Date: 19 Feb 2003 18:23:02 -0800
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Richard Riehle <richard@adaworks.com> wrote in message news:<3E4E9248.3E71D984@adaworks.com>...
> tmoran@acm.org wrote:
> 
> 
> A function may have a an access parameter, which almost has in
> semantics.   However,  it is possible to modify a component of
> an access parameter.  I would like the option of preventing that
> with,
> 
> function F (X : access constant parameter-name) 
>   return some-type;
> 
> This would make it illegal for the function to modify the components of
> an access parameter.   Without the word constant, one could still modify
> such components, but including it would make absolutely clear, in the
> contract, that such side-effects would be impossible.


The "access constant" locution will probably be incorporated into a
future update of the language.