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From: "Jeffrey R. Carter" <spam.not.jrcarter@acm.not.spam.org>
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Subject: Re: Ranges and (non)static constraints
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Maciej Sobczak wrote:
> 
> OK, now I see - but is there any preference I should give to one of 
> these two forms apart from that? I understand that the second form is 
> the only I can use if the range is not statically known and (what 
> surprised me) when the constraints come from formal generic parameters.
> But even if the range is known statically, I might choose to always use 
> the second form for notational consistency. Is this recommended?

No. You're relying on Integer, which is only required to be 16 bits. In 
addition, Integer is the only required predefined integer type. So using 
Long_Integer and its friends is not portable. So it's best to use the 
1st form whenever possible. When you must have a non-static range, you 
should define your own parent type using application limits on the 
possible range to derive from. If there are no such limits, then use a 
type based on System.Min_Int and System.Max_Int to derive from.

> Assuming that T'Size = U'Size, can I expect any run-time observable 
> (including performance) differences between T and U?

There should be none. In your example, U'Size = Integer'Size.

-- 
Jeff Carter
"Hello! Smelly English K...niggets."
Monty Python & the Holy Grail
08