24 Nov
2013
24 Nov
'13
10:24 p.m.
W dniu 24.11.2013 23:02, AntC pisze:
Yes, you're almost there. You do need FlexibleInstances to be able to put [Char].
To ban [a], you need to ban overlapping instances. {-# LANGUAGE NoOverlappingInstances #-}
(Usually overlapping instances is on by default.)
You're next error meesage is probably going to be, Illegal overlapping instance declaration for ...
Avoiding them is subtle, but a valuable discipline ;-)
HTH
Thanks, exactly what I wanted :) Regards, Emanuel