Package com.github.tonivade.purefun.type

Interface Eval<A>

Type Parameters:

A - result of the computation

All Superinterfaces:

Bindable<Eval<?>,A>, EvalOf<A>, Kind<Eval<?>,A>, Mappable<Eval<?>,A>

All Known Implementing Classes:

Eval.Defer, Eval.Done, Eval.FlatMapped

public sealed interface Eval<A>
extends EvalOf<A>, Bindable<Eval<?>,A>
permits Eval.Done<A>, Eval.Defer<A>, Eval.FlatMapped<A,B>

This is a monad that allows to control the evaluation of a computation or a value.

There are 3 basic strategies:

• Eval.now(): evaluated immediately
• Eval.later(): the computation is evaluated later, but only the first time, the result is memoized.
• Eval.always(): the computation is evaluated later, but is always executed.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static final class	Eval.Defer<A>
static final class	Eval.Done<A>
static final class	Eval.FlatMapped<A,B>

Field Summary

Fields

Modifier and Type	Field	Description
static final Eval<Boolean>	FALSE
static final Eval<Integer>	ONE
static final Eval<Boolean>	TRUE
static final Eval<Unit>	UNIT
static final Eval<Integer>	ZERO

Method Summary

Modifier and Type	Method	Description
static <T> Eval<T>	always(Producer<? extends T> always)
private static <A, X> Eval<A>	collapse(Eval<A> self)
static <T> Eval<T>	defer(Producer<? extends Kind<Eval<?>,? extends T>> eval)
private static <A> A	evaluate(Eval<A> self)
<R> Eval<R>	flatMap(Function1<? super A,? extends Kind<Eval<?>,? extends R>> map)
static <T> Eval<T>	later(Producer<? extends T> later)
default <R> Eval<R>	map(Function1<? super A,? extends R> map)
static <T> Eval<T>	now(T value)
static <T> Eval<T>	raiseError(Throwable error)
A	value()

Methods inherited from interface com.github.tonivade.purefun.core.Bindable

andThen

Methods inherited from interface com.github.tonivade.purefun.Kind

fix, kind

Field Details

TRUE

static final Eval<Boolean> TRUE

FALSE

static final Eval<Boolean> FALSE

UNIT

static final Eval<Unit> UNIT

ZERO

static final Eval<Integer> ZERO

ONE

static final Eval<Integer> ONE

Method Details

value

A value()

map

default <R> Eval<R> map(Function1<? super A,? extends R> map)

Specified by:

map in interface Bindable<Eval<?>,A>

Specified by:

map in interface Mappable<Eval<?>,A>

flatMap

<R> Eval<R> flatMap(Function1<? super A,? extends Kind<Eval<?>,? extends R>> map)

Specified by:

flatMap in interface Bindable<Eval<?>,A>

now

static <T> Eval<T> now(T value)

later

static <T> Eval<T> later(Producer<? extends T> later)

always

static <T> Eval<T> always(Producer<? extends T> always)

defer

static <T> Eval<T> defer(Producer<? extends Kind<Eval<?>,? extends T>> eval)

raiseError

static <T> Eval<T> raiseError(Throwable error)

collapse

private static <A,
X> Eval<A> collapse(Eval<A> self)

evaluate

private static <A> A evaluate(Eval<A> self)