Class HListLens

java.lang.Object

com.jnape.palatable.lambda.optics.lenses.HListLens

public final class HListLens
extends Object

Lenses that operate on HLists.

Constructor Summary

Constructors

Constructor	Description
HListLens()

Method Summary

Modifier and Type	Method	Description
static <E, List extends HList.HCons<?,?>> Lens.Simple<List,E>	elementAt(Index<E,List> index)	Focus invariantly on the element at the specified Index in an HList.
static <Head, Tail extends HList> Lens.Simple<HList.HCons<Head, ? extends Tail>, Head>	head()	Focus on the head of an HList.
static <Head, Tail extends HList> Lens.Simple<HList.HCons<Head, ? extends Tail>, Tail>	tail()	Focus on the tail of an HList.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

HListLens

public HListLens()

Method Details

elementAt

public static <E, List extends HList.HCons<?,?>>
Lens.Simple<List,E> elementAt(Index<E,List> index)

Focus invariantly on the element at the specified Index in an HList.

Type Parameters:

E - the element type

List - the HList under focus

Parameters:

index - the index of the element to focus on

Returns:

a lens focusing on the element at index

head

public static <Head, Tail extends HList>
Lens.Simple<HList.HCons<Head, ? extends Tail>, Head> head()

Focus on the head of an HList.

Type Parameters:

Head - the head element type

Tail - the tail HList type

Returns:

a lens that focuses on the head of an HList

tail

public static <Head, Tail extends HList>
Lens.Simple<HList.HCons<Head, ? extends Tail>, Tail> tail()

Focus on the tail of an HList.

Type Parameters:

Head - the head element type

Tail - the tail HList type

Returns:

a lens that focuses on the tail of an HList