Re: use of attribute Pos

["Pat Rogers" <progers@NOclasswideSPAM.com>]

"Philippe Torres" <ptorres@laas.fr> wrote in message
news:39E4A08D.B454CB1C@laas.fr...
> 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.
>
> What's the point of defining constrained subtype if we can't use the
> attributes on it ? Or am i missing something ?

A subtype does not introduce a new type -- it names a constraint on an
existing type.  Understand that and all else follows.

You can indeed use the attributes on the subtype, but you must
recognize that only those attributes that represent *constraints* will
be different than those of the actual type in question.  Thus
Upper'first will yield 'A', Upper'last will yield 'Z', and so on.

Its all in the "names for constraints" concept...

---
Patrick Rogers                      Consulting and Training in:
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Adam ... does not deserve all the credit; much is due to Eve, the
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