fj.data.hlist

Class HList.HFoldr<G,V,L,R>

java.lang.Object

fj.data.hlist.HList.HFoldr<G,V,L,R>

Type Parameters:

G - The type of the function with which to fold.

V - The type of the value to be substituted for the empty list.

L - The type of the heterogeneous list to be folded.

R - The return type of the fold.

Enclosing class:

HList<A extends HList<A>>

public static final class HList.HFoldr<G,V,L,R>
extends java.lang.Object

The catamorphism over heterogeneous lists.

Method Summary

Modifier and Type	Method and Description
R	foldRight(G f, V v, L l) Folds a non-empty heterogeneous list.
static <G,V> HList.HFoldr<G,V,HList.HNil,V>	hFoldr() A fold instance for the empty list.
static <E,G,V,L extends HList<L>,R,RR,H extends HList.HFoldr<G,V,L,R>,PP extends HList.Apply<G,P2<E,R>,RR>> HList.HFoldr<G,V,HList.HCons<E,L>,RR>	hFoldr(PP p, H h) A fold instance for a non-empty heterogeneous list

Methods inherited from class java.lang.Object

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

Method Detail

hFoldr

public static <G,V> HList.HFoldr<G,V,HList.HNil,V> hFoldr()

A fold instance for the empty list.

Type Parameters:

G - The type of the function with which to fold.

V - The type of value that this fold returns.

Returns:

a fold instance for the empty list.

hFoldr

public static <E,G,V,L extends HList<L>,R,RR,H extends HList.HFoldr<G,V,L,R>,PP extends HList.Apply<G,P2<E,R>,RR>> HList.HFoldr<G,V,HList.HCons<E,L>,RR> hFoldr(PP p,
                                                                                                                                                                H h)

A fold instance for a non-empty heterogeneous list

Type Parameters:

E - The type of the head of the list.

G - The type of function to apply to the head of the list and the fold of its tail.

V - The type of value to substitute for the empty list.

L - The type of the tail of the list.

R - The type of the fold of the tail of the list.

RR - The return type of the fold.

H - The type of the fold instance for the tail of the list.

PP - The type of the given function application operator.

Parameters:

p - An operator that applies a function on the head of the list and the fold of its tail.

h - A fold instance for the tail of the list.

Returns:

A fold instance for a non-empty heterogeneous list.

foldRight

public R foldRight(G f,
                   V v,
                   L l)

Folds a non-empty heterogeneous list.

Parameters:

f - A function with which to fold.

v - The value to substitute for the empty list.

l - The heterogeneous list to be folded.

Returns:

a value obtained by folding the given list with the given function.