Could it not be a bug in
a) printf
b) unsafePerformIO
c) >>
d) return
e) <=
f) show
g) GHC or GHCi?
All of the above?
Best wishes
Stephen
2009/12/7 L.Guo
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]]
Regards -------------- L.Guo 2009-12-08
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