Peter Arrenbrecht <[EMAIL PROTECTED]> wrote:
> ERROR file:.\cube.hs:11 - Type error in explicitly typed binding
> *** Term : [(i,v) : ps]
> *** Type : [[(a,b)]]
> *** Does not match : [(Int,Double)]
> [10] test :: [(Int, Double)] -> Int
> [11] test [(i,v):ps] = i
The error message does contain the answer. Your pattern
[(i,v):ps]
represents a singleton list containing a list of pairs. That is a list
of lists. What the explicit type signature reveals to be your intention
was a single-level list of pairs. To fix, use round parens around the
pattern, not square brackets:
((i,v):ps)
Regards,
Malcolm
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