On Sunday 04 February 2007 08:28, Stefan O'Rear wrote: > On Sun, Feb 04, 2007 at 08:20:23AM +0000, Dominic Steinitz wrote: > > Someone suggested > > > > pad :: Num a => [a] -> [a] > > pad = pad' 0 > > where pad' !l [] = [0x80] ++ ps ++ lb > > where pl = (64-(l+9)) `mod` 64 > > ps = replicate pl 0x00 > > lb = i2osp 8 (8*l) > > pad' !l (x:xs) = x : pad' (l+1) xs > > > > but that didn't compile > > > > *Main> :r > > [2 of 2] Compiling Main ( allInOne.hs, interpreted ) > > > > allInOne.hs:83:14: Parse error in pattern > > Failed, modules loaded: Codec.Utils. > > > > Dominic. > > The '!' is a GHC extension, enabled using the flag '-fbang-patterns'. > The test program runs to completion but still has a space leak consuming over 25m.
> Equivalently, you can use Haskell 98's "seq" : > > pad :: Num a => [a] -> [a] > pad = pad' 0 > where pad' l [] | l `seq` False = undefined > pad' l [] = [0x80] ++ ps ++ lb > where pl = (64-(l+9)) `mod` 64 > ps = replicate pl 0x00 > lb = i2osp 8 (8*l) > pad' l (x:xs) = x : pad' (l+1) xs > > The first alternative never succeeds, but to see that the compiler > must force the evaluation of 'l'. [EMAIL PROTECTED]:~/sha1> ./allInOne 1000001 +RTS -hc -RTS [2845392438,1191608682,3124634993,2018558572,2630932637] [2224569924,473682542,3131984545,4182845925,3846598897] Stack space overflow: current size 8388608 bytes. Use `+RTS -Ksize' to increase it. Dominic. PS I appreciate all the help I'm getting. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
