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Peter Amey <[log in to unmask]>
Tue, 8 Jul 2003 13:26:38 +0100
text/plain (50 lines)
 

-----Original Message-----
From: Apurva Shukla [mailto:[log in to unmask]]
Sent: 08 July 2003 12:29
To: [log in to unmask]
Subject: Re: The array range problem



I would hope that a(10..11) := b(0..1); would raise a rich crop of constraint errors.

  


but it Does give an error .
I tried and it compiles well and then gives a CONSTRAINT_ERROR on  running. and even 
a(10..11) := b(10..11)
gives and error.
BUT 
a(11..10) := b(10..9)
runs perfectly

Still strange for me. and hope to hear from you all
thanks in advance
Apurva

 

Apurva,
 
This behaviour is exactly what I would expect.  In the 11..10 case both ranges are statically empty, nothing is being assigned so there are no out-of-range values.  This is the answer I gave before, J-P Rosen added the LRM reference.
 
In the 10..11 case, the ranges are not null so the bounds are evaluated.  11 is outside the array index range of 1..10 so a constraint error occurs (the 0 in the second expression is also out of range).
 
The only surprise to me is that the error occurs at run-time; I would expect a compiler to spot the static out-of-range value during compilation.
 
Peter


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