Thanks. I've realized that as soon as I was in my bed. ;-)
Nevertheless, a question comes to me - shouldn't compiler report a
warning? I know it cannot in the current state, but it should. :-) Quite
dummy C compilers tell me I'm "loosing significant digits of number
literals" if I'm doing that. Maybe, already seen in some other thread
some time ago, the compiler should be less general/should know more
about data types...
Thanks and regards
Dusan
Don Stewart wrote:
kolar:
Hello all,
Maybe there is something obvious I can't see, but I have this behavior
for 6.8.2 ghci:
$ghci ttest1p.hs
GHCi, version 6.8.2: http://www.haskell.org/ghc/ :? for help
Loading package base ... linking ... done.
[1 of 1] Compiling Main ( ttest1p.hs, interpreted )
Ok, modules loaded: Main.
*Main> encode' [1..100]
Loading package array-0.1.0.0 ... linking ... done.
Loading package bytestring-0.9.0.1 ... linking ... done.
[1,0,2,0,3,0,4,0,5,0,6,0,7,0,8,0,9,0,10,0,11,0,12,0,13,0,... // deleted
*Main> B.pack [0..100]
"\NUL\SOH\STX\ETX\EOT\ENQ\ACK\a\b\t\n\v\f\r\SO\SI\DLE\DC1\DC2\DC3\DC4\NAK\SYN\ETB\CAN\EM\SUB\ESC\FS\GS\RS\US
!\"#$%&'()*+,-./0123456789:;<=>[EMAIL PROTECTED]"
*Main> B.pack $ encode' [1..100]
"*** Exception: divide by zero
where ttest1p.hs:
import qualified Data.ByteString as B
encode' [] = []
encode' (x:xs) =
if x==0 then 0:0:encode' xs
else (x `mod` 256) : (x `div` 256) : encode' xs
What is the difference, except list length and value structure? Where is
my error?
ByteStrings take Word8 values as input, so x `div` 256 , where 256 ::
Word8, overflows to 0.
-- Don
--
Dusan Kolar tel: +420 54 114 1238
UIFS FIT VUT Brno fax: +420 54 114 1270
Bozetechova 2 e-mail: [EMAIL PROTECTED]
Brno 612 66
Czech Republic
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