Helper functions, giving a parse error

Question

I am new to Haskell. In the example below, the function deletes all occurrences of a particular element from a list and returns a new list. In addition, I am trying to use a helper function to get that returned list and output the length of it.

The problem I am having is a parse error during compile time, pointing to the line that contains delete _ [] = [].

I appreciate any assistance in finding out the cause of the error.

countDelete y (x:xs) = length outputList
    where outputList = delete y (x:xs)

    delete _ [] = []
    delete y (x:xs)  |  x==y = delete y xs
                     |  otherwise = x:delete y xs

Daniel Fischer Daniel Fischer · Accepted Answer · 2013-02-24T01:09:41

All the bindings in the where clause must begin in the same column,

countDelete y (x:xs) = length outputList
  where
    outputList = delete y (x:xs)

    delete _ [] = []
    delete y (x:xs)
        |  x==y      = delete y xs
        |  otherwise = x:delete y xs

works.

Helper functions, giving a parse error

1 Answers