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Functional Java is an open source library that supports closures for the Java programming language
package fj.data.vector;
import fj.*;
import static fj.Function.curry;
import static fj.P.p2;
import fj.data.Array;
import fj.data.NonEmptyList;
import fj.data.Stream;
import java.util.Iterator;
/**
* A vector-4.
*/
public final class V4 implements Iterable {
private final V3 tail;
private final P1 head;
private V4(final P1 head, final V3 tail) {
this.head = head;
this.tail = tail;
}
/**
* Creates a vector-4 from a homogeneous product-4.
*
* @param p The product-4 from which to create a vector.
* @return A new vector-4.
*/
public static V4 p(final P4 p) {
return new V4<>(P.lazy(p::_1),
V3.p(new P3() {
public A _1() {
return p._2();
}
public A _2() {
return p._3();
}
public A _3() {
return p._4();
}
}));
}
/**
* Creates a vector-4 from a head and a tail.
*
* @param head The value to put as the first element of the vector.
* @param tail The vector representing all but the first element of the new vector.
* @return The new vector.
*/
public static V4 cons(final P1 head, final V3 tail) {
return new V4<>(head, tail);
}
/**
* Returns the first element of this vector.
*
* @return the first element of this vector.
*/
public A _1() {
return head._1();
}
/**
* Returns the second element of this vector.
*
* @return the second element of this vector.
*/
public A _2() {
return tail._1();
}
/**
* Returns the third element of this vector.
*
* @return the third element of this vector.
*/
public A _3() {
return tail._2();
}
/**
* Returns the fourth element of this vector.
*
* @return the fourth element of this vector.
*/
public A _4() {
return tail._3();
}
/**
* Returns all but the first element of this vector, as a vector-3.
*
* @return all but the first element of this vector, as a vector-3.
*/
public V3 tail() {
return tail;
}
/**
* Returns the first element of this vector, as a product-1.
*
* @return the first element of this vector, as a product-1.
*/
public P1 head() {
return head;
}
/**
* Returns an iterator for the elements of this vector.
*
* @return an iterator for the elements of this vector.
*/
public Iterator iterator() {
return toStream().iterator();
}
/**
* Returns a homogeneous product-4 equivalent to this vector.
*
* @return a homogeneous product-4 equivalent to this vector.
*/
public P4 p() {
return new P4() {
public A _1() {
return V4.this._1();
}
public A _2() {
return V4.this._2();
}
public A _3() {
return V4.this._3();
}
public A _4() {
return V4.this._4();
}
};
}
/**
* Returns a nonempty list with the elements of this vector.
*
* @return a nonempty list with the elements of this vector.
*/
public NonEmptyList toNonEmptyList() {
return NonEmptyList.nel(_1(), tail.toNonEmptyList().toList());
}
/**
* Returns a stream of the elements of this vector.
*
* @return a stream of the elements of this vector.
*/
public Stream toStream() {
return Stream.cons(head._1(), tail::toStream);
}
/**
* Returns an array with the elements of this vector.
*
* @return an array with the elements of this vector.
*/
@SuppressWarnings("unchecked")
public Array toArray() {
return Array.array(_1(), _2(), _3(), _4());
}
/**
* Maps the given function across this vector.
*
* @param f The function to map across this vector.
* @return A new vector after the given function has been applied to each element.
*/
public V4 map(final F f) {
return new V4<>(head.map(f), tail.map(f));
}
/**
* Performs function application within a vector (applicative functor pattern).
*
* @param vf The vector of functions to apply.
* @return A new vector after zipping the given vector of functions over this vector.
*/
public V4 apply(final V4> vf) {
return new V4<>(head.apply(vf.head()), tail.apply(vf.tail()));
}
/**
* Zips this vector with the given vector using the given function to produce a new vector.
*
* @param bs The vector to zip this vector with.
* @param f The function to zip this vector and the given vector with.
* @return A new vector with the results of the function.
*/
public V4 zipWith(final F> f, final V4 bs) {
return bs.apply(map(f));
}
/**
* Zips this vector with the given vector to produce a vector of pairs.
*
* @param bs The vector to zip this vector with.
* @return A new vector with a length the same as the shortest of this vector and the given
* vector.
*/
public V4> zip(final V4 bs) {
final F>> __2 = p2();
return zipWith(__2, bs);
}
/**
* Zips this vector with the given vector to produce a vector of vectors.
*
* @param bs The vector to zip this vector with.
* @return A new vector of vectors.
*/
public V4> vzip(final V4 bs) {
final F2> __2 = V.v2();
return zipWith(curry(__2), bs);
}
/**
* Returns a function that transforms a vector-4 to a stream of its elements.
*
* @return a function that transforms a vector-4 to a stream of its elements.
*/
public static F, Stream> toStream_() {
return V4::toStream;
}
/**
* Returns a function that transforms a vector-4 to the equivalent product-4.
*
* @return a function that transforms a vector-4 to the equivalent product-4.
*/
public static F, P4> p_() {
return V4::p;
}
/**
* A first-class function to get the first element of a vector.
*
* @return a function that gets the first element of a given vector.
*/
public static F, A> __1() {
return V4::_1;
}
/**
* A first-class function to get the second element of a vector.
*
* @return a function that gets the second element of a given vector.
*/
public static F, A> __2() {
return V4::_2;
}
/**
* A first-class function to get the third element of a vector.
*
* @return a function that gets the third element of a given vector.
*/
public static F, A> __3() {
return V4::_3;
}
/**
* A first-class function to get the fourth element of a vector.
*
* @return a function that gets the fourth element of a given vector.
*/
public static F, A> __4() {
return V4::_4;
}
}