Generalise type of deleteBy

[Malcolm Wallace]

On 11 Sep 2016, at 17:19, Henning Thielemann wrote:

> 
> I do not see why deleteBy should have an argument for the deleted element, anyway, since it is not even the element to delete (only an equivalent one). Wouldn't a function with type
> 
> newDeleteBy :: (a -> Bool) -> [a] -> [a]
> 
> be much more straight-forward?

It already exists, and is called "filter", modulo the sense of the boolean.

Regards,
    Malcolm