
7 Dec
2009
7 Dec
'09
12:15 p.m.
On Tue, Dec 08, 2009 at 12:45:59AM +0800, L.Guo wrote:
Hi there:
My friend asked me a question, and i suppose he has found a bug of `groupBy'.
Here is the code piece:
List.groupBy (\a b -> Foreign.unsafePerformIO (Text.Printf.printf "\t%d <= %d ?: %s\n" a b (show (a<=b)) >> return (a<=b))) [7,3,5,9,6,8,3,5,4]
I have tested it in GHC 6.10.4 (Win XP) and GHC 6.8.3 (Linux), both give the wrong result (categaried):
7 <= 3 ?: False 3 <= 5 ?: True 3 <= 9 ?: True 3 <= 6 ?: True 3 <= 8 ?: True 3 <= 3 ?: True 3 <= 5 ?: True 3 <= 4 ?: True [[7],[3,5,9,6,8,3,5,4]]
This looks like the right result to me. What makes you think it is wrong? What result do you expect? -Brent