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From: prichtmyer@yahoo.com (Peter Richtmyer)
Newsgroups: comp.lang.ada
Subject: Re: In case statment? (was Re: is exception when others => null;
 smart?)
Date: 29 Oct 2002 10:23:19 -0800
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Robert A Duff <bobduff@shell01.TheWorld.com> wrote in message news:<wccpttyk1ia.fsf@shell01.TheWorld.com>...
> 
> "When others" is usually a very bad idea, and editors should not
> encourage it.  

I find this topic somewhat amusing because my previous employer
required a "when others" on ALL case statements, even when 
all values were covered by the "when" clauses. My current job
requires us to specify all cases, and we are not allowed to 
put a "when others" clause in.

As the following example illustrates, it really depends upon
the compiler too. A "bad" value is handled differently as
shown:
-----------------------------------------------------------
with system;
with text_io;
procedure test is
    
     a : character := character'val(2#11111111#);   
     for a'size use 8;
     b : boolean;
     for b'address use a'address;
     for b'size use 8;
     
begin 

   case b is
      when true =>
        text_io.put_line ("b is true");     
      when false =>
        text_io.put_line ("b is false");
      when others =>
        text_io.put_line ("ObjectAda for Windows V7.1.105 "    & 
                          "professional " edition gets here, " &
                          "and so does Rational Apex Ada 95 v. 4.0.0b");    
   end case;
     
exception
   when others =>  
      text_io.put_line ("Gnat 3.14P gets here ");  
end test;
---------------------------------------------------------------