Class LambdaIterable<A>

java.lang.Object

com.jnape.palatable.lambda.traversable.LambdaIterable<A>

Type Parameters:

A - the Iterable element type

All Implemented Interfaces:

Applicative<A, LambdaIterable<?>>, Functor<A, LambdaIterable<?>>, Monad<A, LambdaIterable<?>>, MonadRec<A, LambdaIterable<?>>, Traversable<A, LambdaIterable<?>>

public final class LambdaIterable<A>
extends Object
implements MonadRec<A, LambdaIterable<?>>, Traversable<A, LambdaIterable<?>>

Extension point for Iterable to adapt lambda core types like Monad and Traversable.

See Also:

• LambdaMap

Field Summary

Fields

Modifier and Type	Field	Description
private final Iterable<A>	as

Constructor Summary

Constructors

Modifier	Constructor	Description
private	LambdaIterable(Iterable<? extends A> as)

Method Summary

Modifier and Type	Method	Description
<B> LambdaIterable<B>	discardL(Applicative<B, LambdaIterable<?>> appB)	Sequence both this Applicative and appB, discarding this Applicative's result and returning appB.
<B> LambdaIterable<A>	discardR(Applicative<B, LambdaIterable<?>> appB)	Sequence both this Applicative and appB, discarding appB's result and returning this Applicative.
static <A> LambdaIterable<A>	empty()	Construct an empty LambdaIterable by wrapping Collections.emptyList().
boolean	equals(Object other)
<B> LambdaIterable<B>	flatMap(Fn1<? super A, ? extends Monad<B, LambdaIterable<?>>> f)	Chain dependent computations that may continue or short-circuit based on previous results.
<B> LambdaIterable<B>	fmap(Fn1<? super A, ? extends B> fn)	Covariantly transmute this functor's parameter using the given mapping function.
int	hashCode()
<B> Lazy<LambdaIterable<B>>	lazyZip(Lazy<? extends Applicative<Fn1<? super A, ? extends B>, LambdaIterable<?>>> lazyAppFn)	Given a lazy instance of this applicative over a mapping function, "zip" the two instances together using whatever application semantics the current applicative supports.
<B> LambdaIterable<B>	pure(B b)	Lift the value b into this applicative functor.
static Pure<LambdaIterable<?>>	pureLambdaIterable()	The canonical Pure instance for LambdaIterable.
<B> LambdaIterable<B>	trampolineM(Fn1<? super A, ? extends MonadRec<RecursiveResult<A,B>, LambdaIterable<?>>> fn)	Given some operation yielding a RecursiveResult inside this MonadRec, internally trampoline the operation until it yields a termination instruction.
<B, App extends Applicative<?,App>, TravB extends Traversable<B, LambdaIterable<?>>, AppTrav extends Applicative<TravB,App>> AppTrav	traverse(Fn1<? super A, ? extends Applicative<B,App>> fn, Fn1<? super TravB, ? extends AppTrav> pure)	Apply fn to each element of this traversable from left to right, and collapse the results into a single resulting applicative, potentially with the assistance of the applicative's pure function.
Iterable<A>	unwrap()	Unwrap the underlying Iterable.
static <A> LambdaIterable<A>	wrap(Iterable<? extends A> as)	Wrap an Iterable in a LambdaIterable.
<B> LambdaIterable<B>	zip(Applicative<Fn1<? super A, ? extends B>, LambdaIterable<?>> appFn)	Given another instance of this applicative over a mapping function, "zip" the two instances together using whatever application semantics the current applicative supports.

Methods inherited from class Object

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

Methods inherited from interface Functor

coerce

Field Details

as

private final Iterable<A> as

Constructor Details

LambdaIterable

private LambdaIterable(Iterable<? extends A> as)

Method Details

unwrap

public Iterable<A> unwrap()

Unwrap the underlying Iterable.

Returns:

the wrapped Iterable

fmap

public <B> LambdaIterable<B> fmap(Fn1<? super A, ? extends B> fn)

Covariantly transmute this functor's parameter using the given mapping function. Generally this method is specialized to return an instance of the class implementing Functor.

Specified by:

fmap in interface Applicative<A, LambdaIterable<?>>

Specified by:

fmap in interface Functor<A, LambdaIterable<?>>

Specified by:

fmap in interface Monad<A, LambdaIterable<?>>

Specified by:

fmap in interface MonadRec<A, LambdaIterable<?>>

Specified by:

fmap in interface Traversable<A, LambdaIterable<?>>

Type Parameters:

B - the new parameter type

Parameters:

fn - the mapping function

Returns:

a functor over B (the new parameter type)

pure

public <B> LambdaIterable<B> pure(B b)

Lift the value b into this applicative functor.

Specified by:

pure in interface Applicative<A, LambdaIterable<?>>

Specified by:

pure in interface Monad<A, LambdaIterable<?>>

Specified by:

pure in interface MonadRec<A, LambdaIterable<?>>

Type Parameters:

B - the type of the returned applicative's parameter

Parameters:

b - the value

Returns:

an instance of this applicative over b

zip

public <B> LambdaIterable<B> zip(Applicative<Fn1<? super A, ? extends B>, LambdaIterable<?>> appFn)

Given another instance of this applicative over a mapping function, "zip" the two instances together using whatever application semantics the current applicative supports.

In this case, calculate the cartesian product of applications of all functions in appFn to all values wrapped by this LambdaIterable.

Specified by:

zip in interface Applicative<A, LambdaIterable<?>>

Specified by:

zip in interface Monad<A, LambdaIterable<?>>

Specified by:

zip in interface MonadRec<A, LambdaIterable<?>>

Type Parameters:

B - the new parameter type

Parameters:

appFn - the other applicative instance

Returns:

the zipped LambdaIterable

lazyZip

public <B> Lazy<LambdaIterable<B>> lazyZip(Lazy<? extends Applicative<Fn1<? super A, ? extends B>, LambdaIterable<?>>> lazyAppFn)

Given a lazy instance of this applicative over a mapping function, "zip" the two instances together using whatever application semantics the current applicative supports. This is useful for applicatives that support lazy evaluation and early termination.

Specified by:

lazyZip in interface Applicative<A, LambdaIterable<?>>

Specified by:

lazyZip in interface Monad<A, LambdaIterable<?>>

Specified by:

lazyZip in interface MonadRec<A, LambdaIterable<?>>

Type Parameters:

B - the resulting applicative parameter type

Parameters:

lazyAppFn - the lazy other applicative instance

Returns:

the mapped applicative

See Also:

• Maybe
• Either

discardL

public <B> LambdaIterable<B> discardL(Applicative<B, LambdaIterable<?>> appB)

Sequence both this Applicative and appB, discarding this Applicative's result and returning appB. This is generally useful for sequentially performing side-effects.

Specified by:

discardL in interface Applicative<A, LambdaIterable<?>>

Specified by:

discardL in interface Monad<A, LambdaIterable<?>>

Specified by:

discardL in interface MonadRec<A, LambdaIterable<?>>

Type Parameters:

B - the type of the returned Applicative's parameter

Parameters:

appB - the other Applicative

Returns:

appB

discardR

public <B> LambdaIterable<A> discardR(Applicative<B, LambdaIterable<?>> appB)

Sequence both this Applicative and appB, discarding appB's result and returning this Applicative. This is generally useful for sequentially performing side-effects.

Specified by:

discardR in interface Applicative<A, LambdaIterable<?>>

Specified by:

discardR in interface Monad<A, LambdaIterable<?>>

Specified by:

discardR in interface MonadRec<A, LambdaIterable<?>>

Type Parameters:

B - the type of appB's parameter

Parameters:

appB - the other Applicative

Returns:

this Applicative

flatMap

public <B> LambdaIterable<B> flatMap(Fn1<? super A, ? extends Monad<B, LambdaIterable<?>>> f)

Chain dependent computations that may continue or short-circuit based on previous results.

Specified by:

flatMap in interface Monad<A, LambdaIterable<?>>

Specified by:

flatMap in interface MonadRec<A, LambdaIterable<?>>

Type Parameters:

B - the resulting monad parameter type

Parameters:

f - the dependent computation over A

Returns:

the new monad instance

trampolineM

public <B> LambdaIterable<B> trampolineM(Fn1<? super A, ? extends MonadRec<RecursiveResult<A,B>, LambdaIterable<?>>> fn)

Given some operation yielding a RecursiveResult inside this MonadRec, internally trampoline the operation until it yields a termination instruction.

Stack-safety depends on implementations guaranteeing that the growth of the call stack is a constant factor independent of the number of invocations of the operation. For various examples of how this can be achieved in stereotypical circumstances, see the referenced types.

Specified by:

trampolineM in interface MonadRec<A, LambdaIterable<?>>

Type Parameters:

B - the ultimate resulting carrier type

Parameters:

fn - the function to internally trampoline

Returns:

the trampolined MonadRec

See Also:

• for a basic implementation
• for a coproduct implementation
• for an implementation leveraging an already stack-safe Monad#flatMap(Fn1)
• for a monad transformer implementation

traverse

public <B, App extends Applicative<?,App>, TravB extends Traversable<B, LambdaIterable<?>>, AppTrav extends Applicative<TravB,App>>
AppTrav traverse(Fn1<? super A, ? extends Applicative<B,App>> fn,
 Fn1<? super TravB, ? extends AppTrav> pure)

Apply fn to each element of this traversable from left to right, and collapse the results into a single resulting applicative, potentially with the assistance of the applicative's pure function.

Specified by:

traverse in interface Traversable<A, LambdaIterable<?>>

Type Parameters:

B - the resulting element type

App - the result applicative type

TravB - this Traversable instance over B

AppTrav - the full inferred resulting type from the traversal

Parameters:

fn - the function to apply

pure - the applicative pure function

Returns:

the traversed Traversable, wrapped inside an applicative

equals

public boolean equals(Object other)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

wrap

public static <A> LambdaIterable<A> wrap(Iterable<? extends A> as)

Wrap an Iterable in a LambdaIterable.

Type Parameters:

A - the Iterable element type

Parameters:

as - the Iterable

Returns:

the Iterable wrapped in a LambdaIterable

empty

public static <A> LambdaIterable<A> empty()

Construct an empty LambdaIterable by wrapping Collections.emptyList().

Type Parameters:

A - the Iterable element type

Returns:

an empty LambdaIterable

pureLambdaIterable

public static Pure<LambdaIterable<?>> pureLambdaIterable()

The canonical Pure instance for LambdaIterable.

Returns:

the Pure instance