Re: GNAT-Problem Set_Line(), Set_Col()

[mfeldman@seas.gwu.edu (Michael Feldman)]

In article <3aad5q$qn9@watnews1.watson.ibm.com>,
Norman H. Cohen <ncohen@watson.ibm.com> wrote:
>In article <395jba$kbs@tucs6.rz.tu-cottbus.de>, ak@informatik.tu-cottbus.de
>(Andreas Krohn) writes: 
>
>|> When I use these functions with a variable then the compiler says
>|> "Invalid parameter list in call".
>|> If it is a number then it works. Where is the problem ?
>
>My guess is that you've declared the variables to be of type Integer.
>Set_Line and Set_Col take parameters of the integer type Text_IO.Count.
>(An integer literal is acceptable where a value of any integer type is
>expected.)

I'd like to hear from Norm or another Ada Wise Person why it was thought 
necessary to declare a new type for Text_IO.Count, instead of simply using 
Positive. I know the usual arguments about portability and predefined types, 
but of course Text_IO.Count is also a predefined type with implementation
defined range, so the advantage is not at all obvious.

In my opinion, the use of a new type here causes exactly the kind of
confusion Andreas encountered; are the benefits of a distinct type in
this case worth it when balanced against the confusion?

Mike Feldman
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Michael B. Feldman -  chair, SIGAda Education Working Group
Professor, Dept. of Electrical Engineering and Computer Science
The George Washington University -  Washington, DC 20052 USA
202-994-5919 (voice) - 202-994-0227 (fax) - mfeldman@seas.gwu.edu (Internet)
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