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

Class ReduceLeft<A>

java.lang.Object

com.jnape.palatable.lambda.functions.builtin.fn2.ReduceLeft<A>

Type Parameters:

A - The input Iterable element type, as well as the accumulation type

All Implemented Interfaces:

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

public final class ReduceLeft<A>
extends java.lang.Object
implements Fn2<Fn2<? super A,? super A,? extends A>,java.lang.Iterable<A>,Maybe<A>>

Given an Iterable<A> and a Fn2<A, A, A>, iteratively accumulate over the Iterable, returning Maybe<A>. If the Iterable is empty, the result is Maybe.nothing(); otherwise, the result is wrapped in Maybe.just(A). For this reason, null accumulation results are considered erroneous and will throw.

This function is isomorphic to a left fold over the Iterable where the head element is the starting accumulation value and the result is lifted into Maybe.

See Also:

ReduceRight, FoldLeft

Field Summary

Fields

Modifier and Type	Field	Description
private static ReduceLeft<?>	INSTANCE

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ReduceLeft()

Method Summary

Modifier and Type	Method	Description
Maybe<A>	checkedApply(Fn2<? super A,? super A,? extends A> fn, java.lang.Iterable<A> as)
static <A> ReduceLeft<A>	reduceLeft()
static <A> Fn1<java.lang.Iterable<A>,Maybe<A>>	reduceLeft(Fn2<? super A,? super A,? extends A> fn)
static <A> Maybe<A>	reduceLeft(Fn2<? super A,? super A,? extends A> fn, java.lang.Iterable<A> as)

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 ReduceLeft<?> INSTANCE

Constructor Detail

ReduceLeft

private ReduceLeft()

Method Detail

checkedApply

public Maybe<A> checkedApply(Fn2<? super A,? super A,? extends A> fn,
                             java.lang.Iterable<A> as)

Specified by:

checkedApply in interface Fn2<Fn2<? super A,? super A,? extends A>,java.lang.Iterable<A>,Maybe<A>>

reduceLeft

public static <A> ReduceLeft<A> reduceLeft()

reduceLeft

public static <A> Fn1<java.lang.Iterable<A>,Maybe<A>> reduceLeft(Fn2<? super A,? super A,? extends A> fn)

reduceLeft

public static <A> Maybe<A> reduceLeft(Fn2<? super A,? super A,? extends A> fn,
                                      java.lang.Iterable<A> as)