Re: use of attribute Pos

[Jerry Petrey <jdpetreyNOSPAM@west.raytheon.com>]

Alejandro Villanueva wrote:
> 
> Philippe Torres wrote:
> 
> > Hi, do you think the following behaviour is normal ?
> > -----
> > subtype Upper is character range 'A'..'Z' ;
> > begin
> > Put(Upper'Pos('A')) ;
> > -----
> > Output : 65
> >
> > I was expecting 0 since 'A' is the first element of Upper but i got
> > the ranking of 'A' in the Character type.
> >
> 
> Then you should have done this:
> -----
> type Upper is new Character range 'A' .. 'Z';
> begin
> Put (Upper'Pos ('A'));
> end;
> -----
> Output: 1


Actually this will also return the position in the base type Character
or 65.



> >
> > What's the point of defining constrained subtype if we can't use the
> >
> > attributes on it ? Or am i missing something ?
> >
> 
> If you use the subtype then the correct code would be:
> -----
> Put (Upper'Pos ('X') - Upper'Pos (Upper'First));
> 
> 

The above is the correct way to get what Philippe expected (with the X
being replaced by A)
since 'First does not apply to the base type.

Jerry
-- 
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-- Jerry Petrey                                                
-- Senior Principal Systems Engineer - Member Team Ada & Team Forth
-- Raytheon Missile Systems 
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