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From: dewar@cs.nyu.edu (Robert Dewar)
Subject: Re: How to do case conversion?
Date: 1996/08/11
Message-ID: <dewar.839797415@schonberg>#1/1
X-Deja-AN: 173574465
references: <320D5A34.41C67EA6@cs.cmu.edu>
 <01bb87b9$4194f040$138371a5@dhoossr.iquest.com>
organization: Courant Institute of Mathematical Sciences
newsgroups: comp.lang.ada
Date: 1996-08-11T00:00:00+00:00
List-Id: <comp.lang.ada>


David Hoos points out that Ada.Characters.Handling contains ready made
routines that use the maps in Ada.Strings.Maps.Constants, and yes, you
may as well use them if they fit. The coding is quite trivial:

   function To_Lower (Item : in Character) return Character is
   begin
      return Value (Lower_Case_Map, Item);
   end To_Lower;

   function To_Lower (Item : in String) return String is
      Result : String (1 .. Item'Length);

   begin
      for J in Item'Range loop
         Result (J - (Item'First - 1)) := Value (Lower_Case_Map, Item (J));
      end loop;

      return Result;
   end To_Lower;

It is Lower_Case_Map that is the difficult part! Note that in Ada 95 days
it is better if you can to always use this map rather than the old 
add/subtract 32 ASCII trick, since that way your code work fine for
all Latin-1 letters without any extra effort on your part, and indeed
in an implementation with localizations of these packages for other
Latin sets, your code will still work.