To my
>> Is not deleteBy :: (a->Bool) -> [a] -> [a]
>> more natural for the library than
>> deleteBy :: (a->a->Bool) -> a -> [a] -> [a]
>> ?
>> For example, to remove the first negative from a list, people
>> suggest usually deleteBy (< 0) [1,2,-1,3]
>> While deleteBy (>) 0 [1,2,-1,3]
>> needs thinking effort.
Mariano Suarez Alvarez <[EMAIL PROTECTED]> and
Hannah Schroeter <[EMAIL PROTECTED]>
A> isn't the first deleteBy simply filter?
S> That's just filter, with a reversed predicate.
[..]
No. A filter runs through all the list, and deleteBy stops after
the first needed element is found.
Marcin Qrczak Kowalczyk <[EMAIL PROTECTED]> writes
K> Possibly, but then IMHO it should not be called deleteBy, which
K> is a variant of delete with comparison given explicitly instead
K> of through the Eq class.
Maybe.
I propose for Haskell-2 to add to the library
delBy :: (a -> Bool) -> [a] -> [a]
delBy _ [] = []
delBy p (a:as) = if p a then as else a:(delBy p as)
------------------
Sergey Mechveliani
[EMAIL PROTECTED]
