[Haskell-cafe] Number overflow [was: Strange results when trying to create large Bool arrays.]

Andrew Coppin andrewcoppin at btinternet.com
Wed Jul 11 15:46:29 EDT 2007

Stefan O'Rear wrote:
> On Wed, Jul 11, 2007 at 08:16:50PM +0100, Andrew Coppin wrote:
>> Of course, sometimes you purposely write code which you know is going to 
>> overflow and wrap round in a specific way. But frequently you *don't* want 
>> this behaviour - and I wish there were some pragma or something to make 
>> this be checked. AFAIK, most CPU types give you an efficient way to testing 
>> for such conditions...
> Indeed.  I beleive that Int should be removed from the Prelude.  People
> who need the algebraic properties of rings modulo 2^(2^n) can use the
> sized integral types from Data.Int and Data.Word; people who want speed
> and can satisfy the proof obligations can use Int and Word from the same
> modules.  Everyone else can use Integer, which should be made shorter than
> Int for obvious psychological reasons.

Do we really want to do that?

I mean, make Haskell in general 2 orders of magnitude slower (and heaven 
knows how many orders of magnitude more RAM hungry) for any program 
using more than a handful of integers?

Personally, I'd prefer a way to just throw an exception when a numeric 
overflow happens. (Probably only for test purposes - so maybe a compiler 

How about the floating-point types? What do they currently do?

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