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hughfdjackson/xable.elm

Created June 22, 2014 01:39
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xable.elm
import List (foldl, map)
data Acceptable = X { x: Int } | XY { y: Int, x: Int }
list : [Acceptable]
list = [X { x = 10 }, XY { x = 20, y = 10 }]
type Xable a = { a | x: Int }
sumX : [Xable a] -> Int
sumX = foldl (+) 0 . map .x
main = asText <| sumX list
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hughfdjackson commented Jun 22, 2014

Fails compilation with:

Type error on line 14, column 23 to 27:
       list

  Expected Type: Acceptable
    Actual Type: Xable a

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