type of (/) ?
Hal Daume III
hdaume at ISI.EDU
Tue Dec 9 08:29:32 EST 2003
> ERROR "U:\slav\FP\Avg.hs":11 - Type error in application
> *** Expression : accum list / length list
> *** Term : accum list
> *** Type : Float
> *** Does not match : Int
> Why "accum list" should match to "Int"?
> When I try to replace (length list) with number - it works.
length :: [a] -> Int -- this is your problem
use genericLength :: Num k => [a] -> k instead
> my_avg list = (accum list) / 5 --works fine
This works because '5' is translated to 'fromInteger 5', which can be a
Float as desired.
> xx = 5
> my_avg list = (accum list) / xx --doesn't work
> -- same message as above
This doesn't work because defaulting occurs and xx is given type Integer.
Hal Daume III | hdaume at isi.edu
"Arrest this man, he talks in maths." | www.isi.edu/~hdaume
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