com.jnape.palatable.lambda.adt.coproduct

Interface CoProduct3<A,B,C,CP3 extends CoProduct3<A,B,C,?>>

Type Parameters:

A - the first possible type

B - the second possible type

C - the third possible type

CP3 - the recursive type of this coproduct (used for embedding)

All Known Implementing Classes:

Choice3, These

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface CoProduct3<A,B,C,CP3 extends CoProduct3<A,B,C,?>>

A generalization of the coproduct of three types.

See Also:

CoProduct2

Method Summary

Modifier and Type	Method and Description
default CoProduct2<A,B,? extends CoProduct2<A,B,?>>	converge(Fn1<? super C,? extends CoProduct2<A,B,?>> convergenceFn) Converge this coproduct down to a lower order coproduct by mapping the last possible type into an earlier possible type.
default <D> CoProduct4<A,B,C,D,? extends CoProduct4<A,B,C,D,?>>	diverge() Diverge this coproduct by introducing another possible type that it could represent.
default <R> R	embed(Fn1<? super CP3,? extends R> aFn, Fn1<? super CP3,? extends R> bFn, Fn1<? super CP3,? extends R> cFn) Embed this coproduct inside another value; that is, given morphisms from this coproduct to R, apply the appropriate morphism to this coproduct as a whole.
<R> R	match(Fn1<? super A,? extends R> aFn, Fn1<? super B,? extends R> bFn, Fn1<? super C,? extends R> cFn) Type-safe convergence requiring a match against all potential types.
default Product3<Maybe<A>,Maybe<B>,Maybe<C>>	project() Project this coproduct onto a product.
default Maybe<A>	projectA() Convenience method for projecting this coproduct onto a product and then extracting the first slot value.
default Maybe<B>	projectB() Convenience method for projecting this coproduct onto a product and then extracting the second slot value.
default Maybe<C>	projectC() Convenience method for projecting this coproduct onto a product and then extracting the third slot value.

Method Detail

match

<R> R match(Fn1<? super A,? extends R> aFn,
            Fn1<? super B,? extends R> bFn,
            Fn1<? super C,? extends R> cFn)

Type-safe convergence requiring a match against all potential types.

Type Parameters:

R - result type

Parameters:

aFn - morphism A -> R

bFn - morphism B -> R

cFn - morphism C -> R

Returns:

the result of applying the appropriate morphism to this coproduct's unwrapped value

See Also:

CoProduct2.match(Fn1, Fn1)

diverge

default <D> CoProduct4<A,B,C,D,? extends CoProduct4<A,B,C,D,?>> diverge()

Diverge this coproduct by introducing another possible type that it could represent.

Type Parameters:

D - the additional possible type of this coproduct

Returns:

a CoProduct4<A, B, C, D>

See Also:

CoProduct2.diverge()

converge

default CoProduct2<A,B,? extends CoProduct2<A,B,?>> converge(Fn1<? super C,? extends CoProduct2<A,B,?>> convergenceFn)

Converge this coproduct down to a lower order coproduct by mapping the last possible type into an earlier possible type. This is the categorical dual of CoProduct2.diverge(), which introduces the type C and raises the order from 2 to 3.

The following laws hold for any two coproducts of single order difference:

• Cancellation: coProductN.diverge().converge(CoProductN::a) == coProductN

Parameters:

convergenceFn - function from last possible type to earlier type

Returns:

a CoProduct2<A, B>

project

default Product3<Maybe<A>,Maybe<B>,Maybe<C>> project()

Project this coproduct onto a product.

Returns:

a product of the coproduct projection

See Also:

CoProduct2.project()

projectA

default Maybe<A> projectA()

Convenience method for projecting this coproduct onto a product and then extracting the first slot value.

Returns:

an optional value representing the projection of the "a" type index

projectB

default Maybe<B> projectB()

Convenience method for projecting this coproduct onto a product and then extracting the second slot value.

Returns:

an optional value representing the projection of the "b" type index

projectC

default Maybe<C> projectC()

Convenience method for projecting this coproduct onto a product and then extracting the third slot value.

Returns:

an optional value representing the projection of the "c" type index

embed

default <R> R embed(Fn1<? super CP3,? extends R> aFn,
                    Fn1<? super CP3,? extends R> bFn,
                    Fn1<? super CP3,? extends R> cFn)

Embed this coproduct inside another value; that is, given morphisms from this coproduct to R, apply the appropriate morphism to this coproduct as a whole. Like match(com.jnape.palatable.lambda.functions.Fn1<? super A, ? extends R>, com.jnape.palatable.lambda.functions.Fn1<? super B, ? extends R>, com.jnape.palatable.lambda.functions.Fn1<? super C, ? extends R>), but without unwrapping the value.

Type Parameters:

R - result type

Parameters:

aFn - morphism A v B v C -> R, applied in the A case

bFn - morphism A v B v C -> R, applied in the B case

cFn - morphism A v B v C -> R, applied in the C case

Returns:

the result of applying the appropriate morphism to this coproduct