Haskell errors: “lacks an accompanying binding” and “not in scope”

Question

I have created a piece of code this:

intToDigit :: Char -> Int
ord :: Char -> Int
intToDigit c = ord c - ord \'a\'

However, when I ru

Answer 1

Remove the line:

ord :: Char -> Int  

Or give it a definition.

And it's a bad idea to name your function intToDigit, while it's already used in Data.Char to do the opposite of what you are doing.

Your function is Data.Char.digitToInt, and its implementation also works with hexadecimal:

digitToInt :: Char -> Int
digitToInt c
 | isDigit c            =  ord c - ord '0'
 | c >= 'a' && c <= 'f' =  ord c - ord 'a' + 10
 | c >= 'A' && c <= 'F' =  ord c - ord 'A' + 10
 | otherwise            =  error ("Char.digitToInt: not a digit " ++ show c) -- sigh

Actually it's not what you defined... why 'a' in your code?