Re: Record type with check?

[Matthias Teege <matthias@mteege.de>]

Stephen Leake <stephen.a.leake.1@gsfc.nasa.gov> writes:

> Matthias Teege <matthias@mteege.de> writes:
> 
> > Moin,
> > 
> > ist there any way to build a record type like this: 
> > 
> > type Datum is
> >    record
> >       Var_A  : Integer;
> >       Var_B  : Integer;
> >    end record;
> > 
> > which guarantees that Var_B is bigger than Var_A?
> 
> This sounds like a homework problem, so I'll only give hints. If it's
> not homework, please reply with more info on why you need this.

No it isn't a homework (see http://www.mteege.de/index_en.html) 
but your assumption describe my knowledge level very
well. ;-) Learning Ada is only a hobby. 

The type should represent ranges from Var_A to Var_B and
associate Var_C with this range. Somthing like this:

Var_A  Var_B  Var_C
 1      2      10
 2      4      12
 4      7      13
..

> You cannot simply declare a type that has this property. But you can
> write a package that declares an abstract data type that does enforce
> this property. It must have a Create procedure that checks that A < B,
> and access procedures that let clients access A and B.

Ok, thats the answer I'm looking for. If nobody knows a
better representation I'll made a private type. ;-)

Many thanks
Matthias

-- 
Matthias Teege -- matthias@mteege.de -- http://emugs.de
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