It does make sense that functions aren't equatable.
For example, in Haskell, this doesn't work, because it can't derive Eq on
the equation.
data TestType = Equation (Int -> Int)
| None
deriving (Eq)
eq1 = Equation (\x -> x+2)
eq2 = Equation (\x -> x+3)
main = (eq1 == eq2)
I get an error and have to define equality myself, like this.
instance Eq TestType where
(==) None None = True
(==) None (Equation x) = False
(==) (Equation x) None = False
(==) (Equation x) (Equation y) = True
Is there a way that I can define my own instance of equality for a type in
elm? Otherwise I can just define a function called isEqual.
I would really like the elm compiler to catch this kind of thing so it
doesn't mysteriously fail like this.
Tanya
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