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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: Substrings as argument to procedures/functions
Date: Wed, 13 Apr 2016 09:57:27 -0700
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Date: 2016-04-13T09:57:27-07:00
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On 04/13/2016 05:30 AM, Mart van de Wege wrote:
>
> I do have a minor question here though: That does not work if you have
> any reason to try and modify the first character of a String. S(1) :=
> To_Upper(S(1)) works, but S'First := To_Upper(S'First) does not.

S is an array. 1 is an index into that array. S (1) is the component of S at 
index 1, which is a Character. So your 1st statement passes a Character to a 
function and assigns the result to a Character.

S'First is an index into S. It is also constant. So your 2nd statement attempts 
to pass an Integer to a function that expects a Character, and tries to assign 
the result to a constant.

If you use the index S'First in the same way as you used the index 1, things 
will probably work better for you.

-- 
Jeff Carter
"Violence is the last refuge of the incompetent."
Foundation
151