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Functional Java is an open source library that supports closures for the Java programming language
package fj;
import fj.data.*;
import fj.data.hlist.HList;
import fj.data.vector.V2;
import fj.data.vector.V3;
import fj.data.vector.V4;
import fj.data.vector.V5;
import fj.data.vector.V6;
import fj.data.vector.V7;
import fj.data.vector.V8;
import java.math.BigDecimal;
import java.math.BigInteger;
import static fj.Function.compose;
import static fj.P.p;
import static fj.Unit.unit;
import static fj.data.Stream.cons;
import static fj.data.Stream.fromString;
import static fj.data.Stream.join;
import static fj.data.Stream.single;
/**
* Renders an object for display.
*
* @version %build.number%
*/
public final class Show {
private final F> f;
private Show(final F> f) {
this.f = f;
}
/**
* Maps the given function across this show as a contra-variant functor.
*
* @param f The function to map.
* @return A new show.
*/
public Show contramap(final F f) {
return show(compose(this.f, f));
}
/**
* Returns the display rendering of the given argument.
*
* @param a The argument to display.
* @return The display rendering of the given argument.
*/
public Stream show(final A a) {
return f.f(a);
}
/**
* Returns the display rendering of the given argument.
*
* @param a The argument to display.
* @return The display rendering of the given argument.
*/
public List showl(final A a) {
return show(a).toList();
}
/**
* Returns the display rendering of the given argument as a String.
*
* @param a The argument to display.
* @return The display rendering of the given argument as a String.
*/
public String showS(final A a) {
return Stream.asString(show(a));
}
/**
* Returns the transformation equivalent to this show.
*
* @return the transformation equivalent to this show.
*/
public F showS_() {
return a -> showS(a);
}
/**
* Returns the transformation equivalent to this show.
*
* @return the transformation equivalent to this show.
*/
public F> show_() {
return f;
}
/**
* Prints the given argument to the standard output stream with a new line.
*
* @param a The argument to print.
* @return The unit value.
*/
public Unit println(final A a) {
print(a);
System.out.println();
return unit();
}
/**
* Prints the given argument to the standard output stream.
*
* @param a The argument to print.
* @return The unit value.
*/
public Unit print(final A a) {
final char[] buffer = new char[8192];
int c = 0;
for (Stream cs = show(a); cs.isNotEmpty(); cs = cs.tail()._1()) {
buffer[c] = cs.head();
c++;
if (c == 8192) {
System.out.print(buffer);
c = 0;
}
}
System.out.print(Array.copyOfRange(buffer, 0, c));
return unit();
}
/**
* Prints the given argument to the standard error stream with a new line.
*
* @param a The argument to print.
*/
public void printlnE(final A a) {
System.err.println(showS(a));
}
/**
* Returns a show instance using the given function.
*
* @param f The function to use for the returned show instance.
* @return A show instance.
*/
public static Show show(final F> f) {
return new Show<>(f);
}
/**
* Returns a show instance using the given function.
*
* @param f The function to use for the returned show instance.
* @return A show instance.
*/
public static Show showS(final F f) {
return show(a -> fromString(f.f(a)));
}
/**
* Returns a show instance that uses {@link Object#toString()} to perform the display rendering.
*
* @return A show instance that uses {@link Object#toString()} to perform the display rendering.
*/
public static Show anyShow() {
return show(a -> Stream.fromString((a == null) ? "null" : a.toString()));
}
/**
* A show instance for the boolean type.
*/
public static final Show booleanShow = anyShow();
/**
* A show instance for the byte type.
*/
public static final Show byteShow = anyShow();
/**
* A show instance for the char type.
*/
public static final Show charShow = anyShow();
/**
* A show instance for the double type.
*/
public static final Show doubleShow = anyShow();
/**
* A show instance for the float type.
*/
public static final Show floatShow = anyShow();
/**
* A show instance for the int type.
*/
public static final Show intShow = anyShow();
/**
* A show instance for the BigInteger type.
*/
public static final Show bigintShow = anyShow();
/**
* A show instance for the BigDecimal type.
*/
public static final Show bigdecimalShow = anyShow();
/**
* A show instance for the long type.
*/
public static final Show longShow = anyShow();
/**
* A show instance for the short type.
*/
public static final Show shortShow = anyShow();
/**
* A show instance for the {@link String} type.
*/
public static final Show stringShow = anyShow();
/**
* A show instance for the {@link StringBuffer} type.
*/
public static final Show stringBufferShow = anyShow();
/**
* A show instance for the {@link StringBuilder} type.
*/
public static final Show stringBuilderShow = anyShow();
/**
* A show instance for the {@link Option} type.
*
* @param sa Show for the element of the option.
* @return A show instance for the {@link Option} type.
*/
public static Show> optionShow(final Show sa) {
return show(o -> o.isNone() ?
fromString("None") :
fromString("Some(").append(sa.f.f(o.some())).append(single(')')));
}
/**
* A show instance for the {@link Either} type.
*
* @param sa Show for the left side of the {@link Either}.
* @param sb Show for the right side of the {@link Either}.
* @return A show instance for the {@link Either} type.
*/
public static Show> eitherShow(final Show sa, final Show sb) {
return show(e -> e.isLeft() ?
fromString("Left(").append(sa.f.f(e.left().value())).append(single(')')) :
fromString("Right(").append(sb.f.f(e.right().value())).append(single(')')));
}
/**
* A show instance for the {@link Validation} type.
*
* @param sa Show for the fail side of the {@link Validation}.
* @param sb Show for the success side of the {@link Validation}.
* @return A show instance for the {@link Validation} type.
*/
public static Show> validationShow(final Show sa, final Show sb) {
return show(v -> v.isFail() ?
fromString("Fail(").append(sa.f.f(v.fail())).append(single(')')) :
fromString("Success(").append(sb.f.f(v.success())).append(single(')')));
}
/**
* A show instance for the {@link Stream} type.
*
* @param sa Show for the elements of the Stream.
* @return A show instance for the {@link Stream} type.
*/
public static Show> listShow(final Show sa) {
return show(as -> streamShow(sa, "List(", ",", ")").show(as.toStream()));
}
/**
* A show instance for the {@link NonEmptyList} type.
*
* @param sa Show for the elements of the non-empty Stream.
* @return A show instance for the {@link NonEmptyList} type.
*/
public static Show> nonEmptyListShow(final Show sa) {
return listShow(sa).contramap(NonEmptyList.toList_());
}
/**
* A show instance for the {@link Tree} type.
*
* @param sa Show for the elements of the tree.
* @return A show instance for the {@link Tree} type.
*/
public static Show> treeShow(final Show sa) {
return show(a -> {
Stream result = sa.f.f(a.root());
if (!a.subForest()._1().isEmpty()) {
result = result.append(fromString(",")).append(streamShow(treeShow(sa), "", ",", "").f.f(a.subForest()._1()));
}
return fromString("Tree(").append(p(result)).append(fromString(")"));
});
}
public static Show> seqShow(final Show sa) {
return show(s -> streamShow(sa, "Seq(", ",", ")").show(s.toStream()));
}
/**
* A show instance for the {@link Set} type.
*
* @param sa Show for the elements of the set.
* @return A show instance for the {@link Set} type.
*/
public static Show> setShow(final Show sa) {
return show(s -> streamShow(sa, "Set(", ",", ")").show(s.toStream()));
}
/**
* A show instance for the {@link TreeMap} type.
*
* @param sk Show for the keys of the TreeMap.
* @param sv Show for the values of the TreeMap.
* @return A show instance for the {@link TreeMap} type.
*/
public static Show> treeMapShow(final Show sk, final Show sv) {
return show(tm -> {
Stream> stream = Stream.iteratorStream(tm.iterator());
return streamShow(Show.p2MapShow(sk, sv), "TreeMap(", ",", ")").show(stream);
});
}
/**
* A show instance for the {@link P2 tuple-2} type in the style of a mapping from A to B.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @return A show instance for the {@link P2 tuple-2} type.
*/
public static Show> p2MapShow(final Show sa, final Show sb) {
return p2Show(sa, sb, "(", ":", ")");
}
/**
* A show instance for the {@link P2 tuple-2} type.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @param start Prefix string for the show.
* @param sep Separator string between elements of the tuple.
* @param end Suffix string for the show.
* @return A show instance for the {@link P2 tuple-2} type.
*/
public static Show> p2Show(final Show sa, final Show sb, String start, String sep, String end) {
return show(p -> fromString(start).append(p(sa.show(p._1()))).append(fromString(sep)).append(sb.show(p._2())).append(fromString(end)));
}
/**
* A show instance for the {@link Stream} type.
*
* @param sa Show for the elements of the stream.
* @return A show instance for the {@link Stream} type.
*/
public static Show> streamShow(final Show sa) {
return streamShow(sa, "Stream(", ",", ")");
}
/**
* A show instance for the {@link Stream} type.
*
* @param sa Show for the first element of the tuple.
* @param start Prefix string for the show.
* @param sep Separator string between elements of the stream.
* @param end Suffix string for the show.
* @return A show instance for the {@link Stream} type.
*/
public static Show> streamShow(final Show sa, String start, String sep, String end) {
return show(streamShow_(sa, start, sep, end));
}
/**
* Returns the transformation equivalent for the stream show.
*/
public static F, Stream> streamShow_(final Show sa, String start, String sep, String end) {
return as -> join(as.map(sa.show_()).intersperse(fromString(sep)).cons(fromString(start)).snoc(p(fromString(end))));
}
/**
* A show instance for the {@link Array} type.
*
* @param sa Show for the elements of the array.
* @return A show instance for the {@link Array} type.
*/
public static Show> arrayShow(final Show sa) {
return show(as -> {
Stream b = fromString("Array(");
for (int i = 0; i < as.length(); i++) {
b = b.append(sa.f.f(as.get(i)));
if (i != as.length() - 1)
b = b.append(fromString(","));
}
return b.append(fromString(")"));
});
}
/**
* A show instance for the {@link Class} type.
*
* @return A show instance for the {@link Class} type.
*/
public static Show> classShow() {
return show(c -> anyShow().show(c.clas()));
}
/**
* A show instance for the {@link P1 tuple-1} type.
*
* @param sa Show for the first element of the tuple.
* @return A show instance for the {@link P1 tuple-1} type.
*/
public static Show> p1Show(final Show sa) {
return p1ShowLazy(sa);
}
public static Show> p1ShowLazy(final Show sa) {
return show(p -> Stream.fromString("(?)"));
}
public static Show> p1ShowEager(final Show sa) {
return show(p -> cons('(', p(sa.show(p._1()))).snoc(')'));
}
/**
* A show instance for the {@link P2 tuple-2} type.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @return A show instance for the {@link P2 tuple-2} type.
*/
public static Show> p2Show(final Show sa, final Show sb) {
return p2Show(sa, sb, "(", ",", ")");
}
/**
* A show instance for the {@link P3 tuple-3} type.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @param sc Show for the third element of the tuple.
* @return A show instance for the {@link P3 tuple-3} type.
*/
public static Show> p3Show(final Show sa, final Show sb, final Show sc) {
return show(p -> cons('(', p(sa.show(p._1()))).snoc(',').append(sb.show(p._2())).snoc(',')
.append(sc.show(p._3())).snoc(')'));
}
/**
* A show instance for the {@link P4 tuple-4} type.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @param sc Show for the third element of the tuple.
* @param sd Show for the fourth element of the tuple.
* @return A show instance for the {@link P4 tuple-4} type.
*/
public static Show> p4Show(final Show sa, final Show sb,
final Show sc, final Show sd) {
return show(p -> cons('(', p(sa.show(p._1()))).snoc(',').append(sb.show(p._2())).snoc(',')
.append(sc.show(p._3())).snoc(',').append(sd.show(p._4())).snoc(')'));
}
/**
* A show instance for the {@link P5 tuple-5} type.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @param sc Show for the third element of the tuple.
* @param sd Show for the fourth element of the tuple.
* @param se Show for the fifth element of the tuple.
* @return A show instance for the {@link P5 tuple-5} type.
*/
public static Show> p5Show(final Show sa, final Show sb,
final Show sc, final Show sd, final Show se) {
return show(p -> cons('(', p(sa.show(p._1()))).snoc(',').append(sb.show(p._2())).snoc(',')
.append(sc.show(p._3())).snoc(',').append(sd.show(p._4())).snoc(',').append(se.show(p._5())).snoc(')'));
}
/**
* A show instance for the {@link P6 tuple-6} type.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @param sc Show for the third element of the tuple.
* @param sd Show for the fourth element of the tuple.
* @param se Show for the fifth element of the tuple.
* @param sf Show for the sixth element of the tuple.
* @return A show instance for the {@link P6 tuple-6} type.
*/
public static Show> p6Show(final Show sa, final Show sb,
final Show sc, final Show sd,
final Show se, final Show sf) {
return show(p -> cons('(', p(sa.show(p._1()))).snoc(',').append(sb.show(p._2())).snoc(',')
.append(sc.show(p._3())).snoc(',').append(sd.show(p._4())).snoc(',')
.append(se.show(p._5())).snoc(',').append(sf.show(p._6())).snoc(')'));
}
/**
* A show instance for the {@link P7 tuple-7} type.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @param sc Show for the third element of the tuple.
* @param sd Show for the fourth element of the tuple.
* @param se Show for the fifth element of the tuple.
* @param sf Show for the sixth element of the tuple.
* @param sg Show for the seventh element of the tuple.
* @return A show instance for the {@link P7 tuple-7} type.
*/
public static Show> p7Show(final Show sa, final Show sb,
final Show sc, final Show sd,
final Show se, final Show sf,
final Show sg) {
return show(p -> cons('(', p(sa.show(p._1()))).snoc(',').append(sb.show(p._2())).snoc(',')
.append(sc.show(p._3())).snoc(',').append(sd.show(p._4())).snoc(',')
.append(se.show(p._5())).snoc(',').append(sf.show(p._6())).snoc(',').append(sg.show(p._7())).snoc(')'));
}
/**
* A show instance for the {@link P8 tuple-8} type.
*
* @param sa Show for the first element of the tuple.
* @param sb Show for the second element of the tuple.
* @param sc Show for the third element of the tuple.
* @param sd Show for the fourth element of the tuple.
* @param se Show for the fifth element of the tuple.
* @param sf Show for the sixth element of the tuple.
* @param sg Show for the seventh element of the tuple.
* @param sh Show for the eighth element of the tuple.
* @return A show instance for the {@link P8 tuple-8} type.
*/
public static Show> p8Show(final Show sa, final Show sb,
final Show sc, final Show sd,
final Show se, final Show sf,
final Show sg, final Show sh) {
return show(p -> cons('(', p(sa.show(p._1()))).snoc(',').append(sb.show(p._2())).snoc(',')
.append(sc.show(p._3())).snoc(',').append(sd.show(p._4())).snoc(',')
.append(se.show(p._5())).snoc(',').append(sf.show(p._6())).snoc(',')
.append(sg.show(p._7())).snoc(',').append(sh.show(p._8())).snoc(')'));
}
/**
* A show instance for a vector-2.
*
* @param ea A show for the elements of the vector.
* @return A show instance for a vector-2.
*/
public static Show> v2Show(final Show ea) {
return streamShow(ea, "V2(", ",", ")").contramap(V2.toStream_());
}
/**
* A show instance for a vector-3.
*
* @param ea A show for the elements of the vector.
* @return A show instance for a vector-3.
*/
public static Show> v3Show(final Show ea) {
return streamShow(ea, "V3(", ",", ")").contramap(V3.toStream_());
}
/**
* A show instance for a vector-4.
*
* @param ea A show for the elements of the vector.
* @return A show instance for a vector-4.
*/
public static Show> v4Show(final Show ea) {
return streamShow(ea, "V4(", ",", ")").contramap(V4.toStream_());
}
/**
* A show instance for a vector-5.
*
* @param ea A show for the elements of the vector.
* @return A show instance for a vector-5.
*/
public static Show> v5Show(final Show ea) {
return streamShow(ea, "V5(", ",", ")").contramap(V5.toStream_());
}
/**
* A show instance for a vector-6.
*
* @param ea A show for the elements of the vector.
* @return A show instance for a vector-6.
*/
public static Show> v6Show(final Show ea) {
return streamShow(ea, "V6(", ",", ")").contramap(V6.toStream_());
}
/**
* A show instance for a vector-7.
*
* @param ea A show for the elements of the vector.
* @return A show instance for a vector-7.
*/
public static Show> v7Show(final Show ea) {
return streamShow(ea, "V7(", ",", ")").contramap(V7.toStream_());
}
/**
* A show instance for a vector-8.
*
* @param ea A show for the elements of the vector.
* @return A show instance for a vector-8.
*/
public static Show> v8Show(final Show ea) {
return streamShow(ea, "V8(", ",", ")").contramap(V8.toStream_());
}
/**
* A show instance for natural numbers.
*/
public static final Show naturalShow = bigintShow.contramap(Natural::bigIntegerValue);
/**
* A show instance for streams that splits into lines.
*
* @param sa A show instance for the elements of a stream.
* @return A show instance for streams that splits into lines.
*/
public static Show> unlineShow(final Show sa) {
return show(as -> join(as.map(sa.show_()).intersperse(fromString("\n"))));
}
/**
* A show instance for lazy strings.
*/
public static final Show lazyStringShow = show(LazyString::toStream);
/**
* A show instance for the empty heterogeneous Stream.
*/
public static final Show HListShow = showS(Function.constant("Nil"));
/**
* A show instance for heterogeneous Streams.
*
* @param e A show instance for the first element of the Stream.
* @param l A show instance for the rest of the Stream.
* @return a show instance for heterogeneous Streams.
*/
public static > Show> HListShow(final Show e, final Show l) {
return show(c -> fromString("HList(").append(e.show(c.head())).append(l.show(c.tail())).append(fromString(")")));
}
}