Data.SubG

Maintainer : [e-mail]

Some extension to the Foldable and Monoid classes. Introduces a new class InsertLeft -- the type of values that can be inserted from the left to the Foldable structure that is simultaneously the Monoid instance.

Documentation

class (Foldable t, Eq a, Eq (t a)) => InsertLeft t a where

Some extension to the Foldable and Monoid classes.

Methods

(%@) :: a -> t a -> t a infixr 1

(%^) :: t a -> t (t a) -> t (t a) infixr 1

Instances

Eq a => InsertLeft [] a

Defined in Data.SubG

Methods

(%@) :: a -> [a] -> [a]

(%^) :: [a] -> [[a]] -> [[a]]

subG :: (InsertLeft t a, Monoid (t a), Monoid (t (t a))) => t a -> t a -> t (t a)

Inspired by: https://hackage.haskell.org/package/base-4.14.0.0/docs/src/Data.OldList.html#words and Graham Hutton. A tutorial on the universality and expressiveness of fold. J. Functional Programming 9 (4): 355–372, July 1999. that is available at the URL: https://www.cs.nott.ac.uk/~pszgmh/fold.pdf.

dropWhile :: (InsertLeft t a, Monoid (t a)) => (a -> Bool) -> t a -> t a

takeWhile :: (InsertLeft t a, Monoid (t a)) => (a -> Bool) -> t a -> t a

span :: (InsertLeft t a, Monoid (t a)) => (a -> Bool) -> t a -> (t a, t a)

preAppend :: (InsertLeft t a, Monoid (t (t a))) => t a -> t (t a) -> t (t a) -> t (t a)

Prepends and appends the given two first arguments to the third one.