com.jnape.palatable.lambda.adt.hlist

Class Index<Target,TargetList extends HList.HCons<?,?>>

java.lang.Object

com.jnape.palatable.lambda.adt.hlist.Index<Target,TargetList>

Type Parameters:

Target - the target element type

TargetList - type of compatible HList

public abstract class Index<Target,TargetList extends HList.HCons<?,?>>
extends Object

HList indexes representing a value at arbitrary depth in some compatible HList. HList compatibility requires identical element types up to and including the target element, but thereafter is unconstrained in length and element type.

Method Summary

Modifier and Type	Method and Description
<NewHead> Index<Target,HList.HCons<NewHead,? extends TargetList>>	after() Nest this index deeper by one element.
abstract Target	get(TargetList hList) Retrieve the value at this index in hList.
static <Target> Index<Target,HList.HCons<Target,?>>	index() Create a root index for a head value of type Target.
abstract <L extends TargetList> L	set(Target newElement, L hList) Set a new value of the same type at this index in an HList.

Methods inherited from class java.lang.Object

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

Method Detail

after

public final <NewHead> Index<Target,HList.HCons<NewHead,? extends TargetList>> after()

Nest this index deeper by one element.

Type Parameters:

NewHead - the type of the preceding element

Returns:

an index at the same Target, nested one level deep

get

public abstract Target get(TargetList hList)

Retrieve the value at this index in hList.

Parameters:

hList - the hList

Returns:

the value at this index

set

public abstract <L extends TargetList> L set(Target newElement,
                                             L hList)

Set a new value of the same type at this index in an HList.

Type Parameters:

L - the inferred tail type of the HList

Parameters:

newElement - the new value

hList - the HList

Returns:

the updated HList

index

public static <Target> Index<Target,HList.HCons<Target,?>> index()

Create a root index for a head value of type Target.

Type Parameters:

Target - the type of the value to get

Returns:

the root index