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From: Kilgallen@SpamCop.net (Larry Kilgallen)
Newsgroups: comp.lang.ada
Subject: Re: "access constant" discriminant
Date: 15 Feb 2003 13:59:43 -0600
Organization: LJK Software
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 <3CS1a.55972$2H6.1357@sccrnsc04> <3E4E9248.3E71D984@adaworks.com>
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Date: 2003-02-15T13:59:43-06:00
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In article <3E4E9248.3E71D984@adaworks.com>, Richard Riehle <richard@adaworks.com> writes:

> 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.

Why is it necessary to have the parameter be an access type ?