Hi,
I am trying to reproduce the fuzzy oscillator example by Jan Skibinski.
( http://www.numeric-quest.com/haskell/Fuzzy_oscillator.html )
I am having problems to compile the module Fuzzy.hs. As I am
just in an early learning stage, I need help to understand the error.
hugs98 e.g. says:
Reading file "/usr/local/share/hugs/lib/Prelude.hs":
Reading file "Fuzzy_oscillator.lhs":
Reading file "Fuzzy.hs":
Type checking
ERROR "Fuzzy.hs" (line 76): Cannot build superclass instance
*** Instance : Num (a -> b)
*** Context supplied : Num b
*** Required superclass : Show (a -> b)
Similar with hbc:
Errors:
"Fuzzy.hs", line 0, [76] Instance context does not imply class context (Prelude.Show
b, Prelude.Show c) => Prelude.Show (b -> c), Prelude.Show in (Num c) => Num (b -> c)
nhc98 and ghc4.06 show a different message:
Fuzzy.hs:188: Variable not in scope: `fromInt'
Perhaps this error masks the same problem in these compilers.
Do you have any hint ready?
