[Haskell-cafe] Subsequence near solved hopefully
rturk at science.uva.nl
Sun Oct 17 10:57:22 EDT 2004
On Sun, Oct 17, 2004 at 07:16:51AM -0700, Peter Stranney wrote:
> equalString :: String -> String -> Bool
> equalString   = True
> equalString  (c':s') = False
> equalString(c:s)  = False
> equalString(c:s)(c':s') = equalChar c c'^ equalString s s'
> this function is to see if one string is equal to another.
> but when i compile this i get the error;
> - Instance of Integral Bool required for definition of equalString
You are using the raise-to-the-power-of operator, which requires
it's second parameter to be Integral...
(^) :: (Integral b, Num a) => a -> b -> a
You might also want to look at the earlier `any prefix of tails'
suggestion, as it makes the solution a rather simple one-liner.
Nobody can be exactly like me. Even I have trouble doing it.
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