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P3.java
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186 lines (164 loc) · 3.94 KB
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package fj;
/**
* A product-3.
*
* @version %build.number%
*/
public abstract class P3<A, B, C> {
/**
* Access the first element of the product.
*
* @return The first element of the product.
*/
public abstract A _1();
/**
* Access the second element of the product.
*
* @return The second element of the product.
*/
public abstract B _2();
/**
* Access the third element of the product.
*
* @return The third element of the product.
*/
public abstract C _3();
/**
* Map the first element of the product.
*
* @param f The function to map with.
* @return A product with the given function applied.
*/
public final <X> P3<X, B, C> map1(final F<A, X> f) {
return new P3<X, B, C>() {
public X _1() {
return f.f(P3.this._1());
}
public B _2() {
return P3.this._2();
}
public C _3() {
return P3.this._3();
}
};
}
/**
* Map the second element of the product.
*
* @param f The function to map with.
* @return A product with the given function applied.
*/
public final <X> P3<A, X, C> map2(final F<B, X> f) {
return new P3<A, X, C>() {
public A _1() {
return P3.this._1();
}
public X _2() {
return f.f(P3.this._2());
}
public C _3() {
return P3.this._3();
}
};
}
/**
* Map the third element of the product.
*
* @param f The function to map with.
* @return A product with the given function applied.
*/
public final <X> P3<A, B, X> map3(final F<C, X> f) {
return new P3<A, B, X>() {
public A _1() {
return P3.this._1();
}
public B _2() {
return P3.this._2();
}
public X _3() {
return f.f(P3.this._3());
}
};
}
/**
* Returns the 1-product projection over the first element.
*
* @return the 1-product projection over the first element.
*/
public final P1<A> _1_() {
return P3.<A, B, C>__1().lazy().f(this);
}
/**
* Returns the 1-product projection over the second element.
*
* @return the 1-product projection over the second element.
*/
public final P1<B> _2_() {
return P3.<A, B, C>__2().lazy().f(this);
}
/**
* Returns the 1-product projection over the third element.
*
* @return the 1-product projection over the third element.
*/
public final P1<C> _3_() {
return P3.<A, B, C>__3().lazy().f(this);
}
/**
* Provides a memoising P3 that remembers its values.
*
* @return A P3 that calls this P3 once for any given element and remembers the value for subsequent calls.
*/
public final P3<A, B, C> memo() {
return new P3<A, B, C>() {
private final P1<A> a = _1_().memo();
private final P1<B> b = _2_().memo();
private final P1<C> c = _3_().memo();
public A _1() {
return a._1();
}
public B _2() {
return b._1();
}
public C _3() {
return c._1();
}
};
}
/**
* Returns a function that returns the first element of a product.
*
* @return A function that returns the first element of a product.
*/
public static <A, B, C> F<P3<A, B, C>, A> __1() {
return new F<P3<A, B, C>, A>() {
public A f(final P3<A, B, C> p) {
return p._1();
}
};
}
/**
* Returns a function that returns the second element of a product.
*
* @return A function that returns the second element of a product.
*/
public static <A, B, C> F<P3<A, B, C>, B> __2() {
return new F<P3<A, B, C>, B>() {
public B f(final P3<A, B, C> p) {
return p._2();
}
};
}
/**
* Returns a function that returns the third element of a product.
*
* @return A function that returns the third element of a product.
*/
public static <A, B, C> F<P3<A, B, C>, C> __3() {
return new F<P3<A, B, C>, C>() {
public C f(final P3<A, B, C> p) {
return p._3();
}
};
}
}