The following program
class Eq a => ShowEq a where
isEq :: a -> String
instance ShowEq Bool where
isEq n | n == not n = "Strange"
gives:
Main> isEq True
"
Program error: {instShowEq_v1885_v1898 (Make.ShowEq instEq_v97
(instShowEq_v1885_v1898 (Make.ShowEq instEq_v97 (instShowEq_v1885_v1898
(Make.ShowEq instEq_v97 (instShowEq_v1885_v1898 (Make.ShowEq instEq_v97
(instShowEq_v1885_v1898 (Make.ShowEq instEq_v97 (instShowEq_v1885_v1898
(Make.ShowEq instEq_v97 (instShowEq_v1885_v1898 (Make.ShowEq instEq_v97
(instShowEq_v1885_v1898 (Make.ShowEq instEq_v97 .....
Obviously a cyclic term gives an infinite error message.
But why is there anything cyclic in this situation?
Cheers,
Olaf
--
OLAF CHITIL, Lehrstuhl fuer Informatik II, RWTH Aachen, 52056 Aachen, Germany
Tel: (+49/0)241/80-21212; Fax: (+49/0)241/8888-217
URL: http://www-i2.informatik.rwth-aachen.de/~chitil/
