Package com.jnape.palatable.lambda.functions.builtin.fn2

Class Unfoldr<A,B>

java.lang.Object

com.jnape.palatable.lambda.functions.builtin.fn2.Unfoldr<A,B>

Type Parameters:

A - The output Iterable element type

B - The unfolding function input type

All Implemented Interfaces:

Fn1<Fn1<? super B,Maybe<Tuple2<A,B>>>,Fn1<B,java.lang.Iterable<A>>>, Fn2<Fn1<? super B,Maybe<Tuple2<A,B>>>,B,java.lang.Iterable<A>>, Applicative<Fn1<B,java.lang.Iterable<A>>,Fn1<Fn1<? super B,Maybe<Tuple2<A,B>>>,?>>, Cartesian<Fn1<? super B,Maybe<Tuple2<A,B>>>,Fn1<B,java.lang.Iterable<A>>,Fn1<?,?>>, Cocartesian<Fn1<? super B,Maybe<Tuple2<A,B>>>,Fn1<B,java.lang.Iterable<A>>,Fn1<?,?>>, Contravariant<Fn1<? super B,Maybe<Tuple2<A,B>>>,Profunctor<?,Fn1<B,java.lang.Iterable<A>>,Fn1<?,?>>>, Functor<Fn1<B,java.lang.Iterable<A>>,Fn1<Fn1<? super B,Maybe<Tuple2<A,B>>>,?>>, Profunctor<Fn1<? super B,Maybe<Tuple2<A,B>>>,Fn1<B,java.lang.Iterable<A>>,Fn1<?,?>>, Monad<Fn1<B,java.lang.Iterable<A>>,Fn1<Fn1<? super B,Maybe<Tuple2<A,B>>>,?>>, MonadReader<Fn1<? super B,Maybe<Tuple2<A,B>>>,Fn1<B,java.lang.Iterable<A>>,Fn1<Fn1<? super B,Maybe<Tuple2<A,B>>>,?>>, MonadRec<Fn1<B,java.lang.Iterable<A>>,Fn1<Fn1<? super B,Maybe<Tuple2<A,B>>>,?>>, MonadWriter<Fn1<? super B,Maybe<Tuple2<A,B>>>,Fn1<B,java.lang.Iterable<A>>,Fn1<Fn1<? super B,Maybe<Tuple2<A,B>>>,?>>

public final class Unfoldr<A,B>
extends java.lang.Object
implements Fn2<Fn1<? super B,Maybe<Tuple2<A,B>>>,B,java.lang.Iterable<A>>

Given an initial seed value and a function that takes the seed type and produces an Maybe<Tuple2<X, Seed>>, where the tuple's first slot represents the next Iterable element, and the second slot represents the next input to the unfolding function, unfold an Iterable of Xs. Returning Maybe.nothing() from the unfolding function is a signal that the Iterable is fully unfolded.

For more information, read about Anamorphisms.

Example:

 
 Iterable<Integer> zeroThroughTenInclusive = unfoldr(x -> x <= 10
         ? Maybe.just(tuple(x, x + 1))
         : Maybe.nothing(), 0);
 
 

Field Summary

Fields

Modifier and Type	Field	Description
private static Unfoldr<?,?>	INSTANCE

Constructor Summary

Constructors

Modifier	Constructor	Description
private	Unfoldr()

Method Summary

Modifier and Type	Method	Description
java.lang.Iterable<A>	checkedApply(Fn1<? super B,Maybe<Tuple2<A,B>>> fn, B b)
static <A,B> Unfoldr<A,B>	unfoldr()
static <A,B> Fn1<B,java.lang.Iterable<A>>	unfoldr(Fn1<? super B,Maybe<Tuple2<A,B>>> fn)
static <A,B> java.lang.Iterable<A>	unfoldr(Fn1<? super B,Maybe<Tuple2<A,B>>> fn, B b)

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.jnape.palatable.lambda.functions.Fn1

andThen, carry, cartesian, censor, choose, cocartesian, diMap, diMapR, discardL, flatMap, fmap, lazyZip, listens, local, pure, self, thunk, toFunction, trampolineM, zip, zip

Methods inherited from interface com.jnape.palatable.lambda.functions.Fn2

apply, apply, checkedApply, compose, contraMap, diMapL, discardR, flip, toBiFunction, uncurry, widen

Methods inherited from interface com.jnape.palatable.lambda.functor.Functor

coerce

Field Detail

INSTANCE

private static final Unfoldr<?,?> INSTANCE

Constructor Detail

Unfoldr

private Unfoldr()

Method Detail

checkedApply

public java.lang.Iterable<A> checkedApply(Fn1<? super B,Maybe<Tuple2<A,B>>> fn,
                                          B b)

Specified by:

checkedApply in interface Fn2<Fn1<? super B,Maybe<Tuple2<A,B>>>,B,java.lang.Iterable<A>>

unfoldr

public static <A,B> Unfoldr<A,B> unfoldr()

unfoldr

public static <A,B> Fn1<B,java.lang.Iterable<A>> unfoldr(Fn1<? super B,Maybe<Tuple2<A,B>>> fn)

unfoldr

public static <A,B> java.lang.Iterable<A> unfoldr(Fn1<? super B,Maybe<Tuple2<A,B>>> fn,
                                                        B b)