Data.SequenceClass

A type class for sequences.

See the package type-aligned for a generalization of this type class sequences.

Documentation

class (Functor s, Foldable s) => Sequence s where

A type class for (finite) sequences

Minimal complete defention: empty and singleton and (viewl or viewr) and (>< or |> or <|)

Instances should satisfy the following laws:

Monoid laws: > empty >< x == x > x >< empty == x > (x >y)= x(y< z)

Observation laws: > viewl (singleton e >< s) == e :< s > viewl empty == EmptyL

The behaviour of <|,|>, and viewr is implied by the above laws and their default definitions.

Minimal complete definition

empty, singleton

Methods

empty :: s c

singleton :: c -> s c

(><) :: s c -> s c -> s c infix 5

Append two sequences

viewl :: s c -> ViewL s c

View a sequence from the left

viewr :: s c -> ViewR s c

View a sequence from the right

Default definition: > viewr q = case viewl q of > EmptyL -> EmptyR > h :- case viewr t of > EmptyR -> empty :> h > p :> l -> (h p) : l

(|>) :: s c -> c -> s c infixl 5

Append a single element to the right

Default definition: > l |> r = l >< singleton r

(<|) :: c -> s c -> s c infixr 5

Append a single element to the left

Default definition: > l r = singleton l< r

Instances

Sequence []

Sequence Seq

Sequence Queue

Sequence FastQueue

Sequence q => Sequence (ToCatQueue q)

data ViewL s c where

Constructors

EmptyL :: ViewL s c

(:<) :: c -> s c -> ViewL s c

data ViewR s c where

Constructors

EmptyR :: ViewR s c

(:>) :: s c -> c -> ViewR s c