Hi, I am doing some simple exercises about recursive algebraic types and this
particular exercise asks to define a function which counts the number of
operators in an expression. I defined the function below, but i am not sure
if on the second line changing from "evalLength (Lit n) = n" to "(Lit n) =
0" is the right solution. although the function produces correct result.
data Expr = Lit Int | Add Expr Expr |
Sub Expr Expr
deriving (Eq, Show)
evalLength :: Expr -> Int
evalLength (Lit n) = 0
evalLength (Add e1 e2) = 1 + (evalLength e1) + (evalLength e2)
evalLength (Sub e1 e2) = 1 + (evalLength e1) - (evalLength e2)
Thank you
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