Re: Ranges and (non)static constraints

[Jean-Pierre Rosen <rosen@adalog.fr>]

Maciej Sobczak a �crit :
> Jean-Pierre Rosen wrote:
> 
>> 2) You want a "reasonable" type, given the capabilities of the 
>> machine. Either derive from Integer, or use Integer directly (not a 
>> bad choice for vector or matrix indices for example). That's what 
>> String did. But in that case, there is no reason to put an additional 
>> range constraint. What I was objecting to is putting a range on a 
>> derivation from Integer.
> 
> Then imagine that the following apply (both):
> 1. I want a "reasonable" type (matrix indices or even... strings), which 
> will play nice with the underlying machine architecture.
> 2. I want a named subtype with dynamically determined constraints so 
> that I can use this named subtype in subsequent array definitions, 
> loops, etc.
> 
> With such assumptions, the following:
> 
> type T is new Integer range 1..N;
> 
> seems reasonable, right?
> 
Hmmm... What *I* would do is define:
type My_Index is new Integer;

and use unconstrained array definitions with that type.
I would let the subtype to the user.

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            J-P. Rosen (rosen@adalog.fr)
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