Data.NonNull

Warning, this is Experimental!

Data.NonNull attempts to extend the concepts from Data.List.NonEmpty to any MonoFoldable.

NonNull is a typeclass for a container with 1 or more elements. Data.List.NonEmpty and 'NotEmpty a' are members of the typeclass

Documentation

type NonNull mono = MinLen (Succ Zero) mono

A monomorphic container that is not null.

fromNullable :: MonoFoldable mono => mono -> Maybe (NonNull mono)

Safely convert from an unsafe monomorphic container to a safe non-null monomorphic container.

nonNull :: MonoFoldable mono => mono -> NonNull mono

Unsafely convert from an unsafe monomorphic container to a safe non-null monomorphic container.

Throws an exception if the monomorphic container is empty.

toNullable :: NonNull mono -> mono

Safely convert from a non-null monomorphic container to a nullable monomorphic container.

fromNonEmpty :: IsSequence seq => NonEmpty (Element seq) -> NonNull seq

Safely convert from a NonEmpty list to a non-null monomorphic container.

ncons :: SemiSequence seq => Element seq -> seq -> NonNull seq

Prepend an element to a SemiSequence, creating a non-null SemiSequence.

Generally this uses cons underneath. cons is not efficient for most data structures.

Alternatives:

• if you don't need to cons, use fromNullable or nonNull if you can create your structure in one go.
• if you need to cons, you might be able to start off with an efficient data structure such as a NonEmpty List. fronNonEmpty will convert that to your data structure using the structure's fromList function.

nuncons :: IsSequence seq => NonNull seq -> (Element seq, Maybe (NonNull seq))

Extract the first element of a sequnce and the rest of the non-null sequence if it exists.

splitFirst :: IsSequence seq => NonNull seq -> (Element seq, seq)

Same as nuncons with no guarantee that the rest of the sequence is non-null.

nfilter :: IsSequence seq => (Element seq -> Bool) -> NonNull seq -> seq

Equivalent to Data.Sequence.filter, but works on non-nullable sequences.

nfilterM :: (Monad m, IsSequence seq) => (Element seq -> m Bool) -> NonNull seq -> m seq

Equivalent to Data.Sequence.filterM, but works on non-nullable sequences.

nReplicate :: IsSequence seq => Index seq -> Element seq -> NonNull seq

Equivalent to Data.Sequence.replicate

i must be > 0

i <= 0 is treated the same as providing 1

head :: MonoFoldable mono => MinLen (Succ nat) mono -> Element mono

Return the first element of a monomorphic container.

Safe version of headEx, only works on monomorphic containers wrapped in a MinLen (Succ nat).

tail :: IsSequence seq => NonNull seq -> seq

Safe version of tailEx, only working on non-nullable sequences.

last :: MonoFoldable mono => MinLen (Succ nat) mono -> Element mono

Return the last element of a monomorphic container.

Safe version of lastEx, only works on monomorphic containers wrapped in a MinLen (Succ nat).

init :: IsSequence seq => NonNull seq -> seq

Safe version of initEx, only working on non-nullable sequences.

ofoldMap1 :: (MonoFoldable mono, Semigroup m) => (Element mono -> m) -> MinLen (Succ nat) mono -> m

Map each element of a monomorphic container to a semigroup, and combine the results.

Safe version of ofoldMap1Ex, only works on monomorphic containers wrapped in a MinLen (Succ nat).

Examples

> let xs = ("hello", 1 :: Integer) `mlcons` (" world", 2) `mlcons` (toMinLenZero [])
> ofoldMap1 fst xs
"hello world"

ofold1 :: (MonoFoldable mono, Semigroup (Element mono)) => MinLen (Succ nat) mono -> Element mono

Join a monomorphic container, whose elements are Semigroups, together.

Safe, only works on monomorphic containers wrapped in a MinLen (Succ nat).

Examples

> let xs = "a" `mlcons` "b" `mlcons` "c" `mlcons` (toMinLenZero [])
> xs
MinLen {unMinLen = ["a","b","c"]}

> ofold1 xs
"abc"

ofoldr1 :: MonoFoldable mono => (Element mono -> Element mono -> Element mono) -> MinLen (Succ nat) mono -> Element mono

Right-associative fold of a monomorphic container with no base element.

Safe version of ofoldr1Ex, only works on monomorphic containers wrapped in a MinLen (Succ nat).

foldr1 f = Prelude.foldr1 f . otoList

Examples

> let xs = "a" `mlcons` "b" `mlcons` "c" `mlcons` (toMinLenZero [])
> ofoldr1 (++) xs
"abc"

ofoldl1' :: MonoFoldable mono => (Element mono -> Element mono -> Element mono) -> MinLen (Succ nat) mono -> Element mono

Strict left-associative fold of a monomorphic container with no base element.

Safe version of ofoldl1Ex', only works on monomorphic containers wrapped in a MinLen (Succ nat).

foldl1' f = Prelude.foldl1' f . otoList

Examples

> let xs = "a" `mlcons` "b" `mlcons` "c" `mlcons` (toMinLenZero [])
> ofoldl1' (++) xs
"abc"

maximum :: MonoFoldableOrd mono => MinLen (Succ nat) mono -> Element mono

Get the maximum element of a monomorphic container.

Safe version of maximumEx, only works on monomorphic containers wrapped in a MinLen (Succ nat).

Examples

> let xs = toMinLen [1,2,3] :: Maybe (MinLen (Succ Zero) [Int])
> fmap maximum xs
Just 3

maximumBy :: MonoFoldable mono => (Element mono -> Element mono -> Ordering) -> MinLen (Succ nat) mono -> Element mono

Get the maximum element of a monomorphic container, using a supplied element ordering function.

Safe version of maximumByEx, only works on monomorphic containers wrapped in a MinLen (Succ nat).

minimum :: MonoFoldableOrd mono => MinLen (Succ nat) mono -> Element mono

Get the minimum element of a monomorphic container.

Safe version of minimumEx, only works on monomorphic containers wrapped in a MinLen (Succ nat).

Examples

> let xs = toMinLen [1,2,3] :: Maybe (MinLen (Succ Zero) [Int])
> fmap minimum xs
Just 1

minimumBy :: MonoFoldable mono => (Element mono -> Element mono -> Ordering) -> MinLen (Succ nat) mono -> Element mono

Get the minimum element of a monomorphic container, using a supplied element ordering function.

Safe version of minimumByEx, only works on monomorphic containers wrapped in a MinLen (Succ nat).

(<|) :: SemiSequence seq => Element seq -> NonNull seq -> NonNull seq infixr 5

Prepend an element to a non-null SemiSequence.

toMinList :: NonEmpty a -> NonNull [a]

Specializes fromNonEmpty to lists only.