On 9 October 2011 14:54, Joachim Breitner <m...@joachim-breitner.de> wrote: > Hi, > > Am Freitag, den 07.10.2011, 10:52 -0400 schrieb Ryan Newton: >> What about just using the Data.Bits instance of Integer? Well, >> presently, the setBit instance for very large integers creates a whole >> new integer, shifts, and xors: >> >> http://haskell.org/ghc/docs/latest/html/libraries/base/src/Data-Bits.html#setBit >> (I don't know if it's possible to do better. From quick googling GMP >> seems to use an array of "limbs" rather than a chunked list, so maybe >> there's no way to treat large Integers as a list and update only the >> front...) > > interesting idea. Should this be considered a bug in ghc? (Not that it > cannot represent the result, but that it crashes even out of ghci): > > $ ghci > GHCi, version 7.0.4: http://www.haskell.org/ghc/ :? for help > Loading package ghc-prim ... linking ... done. > Loading package integer-gmp ... linking ... done. > Loading package base ... linking ... done. > Prelude> :m + Data.Bits > Prelude Data.Bits> setBit 0 (2^63-1::Int) > gmp: overflow in mpz type > Abgebrochen
Yes, that's a bug. GMP shouldn't call abort(), but it should be turned into a Haskell exception. It probably doesn't make much of a difference in practise, but "safe" could should never crash GHC. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
