Commit3e6f644

committed

Fn1#withSelf for writing self-referencing Fn1s

1 parent10a229b commit3e6f644Copy full SHA for 3e6f644

File tree

+24

-1

lines changed

CHANGELOG.md
src
- main/java/com/jnape/palatable/lambda/functions
  - Fn1.java
- test/java/com/jnape/palatable/lambda/functions
  - Fn1Test.java

+24

-1

lines changed

Lines changed: 1 addition & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -7,6 +7,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/).`
`7`	`7`
`8`	`8`	`###Added`
`9`	`9`	-`$`, function application represented as a higher-order`Fn2`
	`10`	+-`Fn1#withSelf`, a static method for constructing a self-referencing`Fn1`
`10`	`11`
`11`	`12`	`##[5.2.0] - 2020-02-12`
`12`	`13`

Lines changed: 17 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -302,6 +302,10 @@ default <C, D> Fn2<A, C, D> andThen(Fn2<? super B, ? super C, ? extends D> after`
`302`	`302`	`return (a,c) ->after.apply(apply(a),c);`
`303`	`303`	`}`
`304`	`304`
	`305`	`+defaultFn1<A,B>self() {`
	`306`	`+returnthis;`
	`307`	`+ }`
	`308`	`+`
`305`	`309`	`/**`
`306`	`310`	`* Static factory method for avoid explicit casting when using method references as {@link Fn1}s.`
`307`	`311`	`*`
`@@ -335,4 +339,17 @@ static <A, B> Fn1<A, B> fromFunction(Function<? super A, ? extends B> function)`
`335`	`339`	`static <A>Pure<Fn1<A, ?>>pureFn1() {`
`336`	`340`	`returnConstantly::constantly;`
`337`	`341`	`}`
	`342`	`+`
	`343`	`+/**`
	`344`	`+ * Construct an {@link Fn1} that has a reference to itself in scope at the time it is executed (presumably for`
	`345`	`+ * recursive invocations).`
	`346`	`+ *`
	`347`	`+ * @param fn the body of the function, with access to itself`
	`348`	`+ * @param <A> the input type`
	`349`	`+ * @param <B> the output type`
	`350`	`+ * @return the {@link Fn1}`
	`351`	`+ */`
	`352`	`+static <A,B>Fn1<A,B>withSelf(Fn2<?superFn1<?superA, ?extendsB>, ?superA, ?extendsB>fn) {`
	`353`	`+returna ->fn.apply(withSelf(fn),a);`
	`354`	`+ }`
`338`	`355`	`}`

Lines changed: 6 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -8,8 +8,8 @@`
`8`	`8`	`importtestsupport.traits.Equivalence;`
`9`	`9`	`importtestsupport.traits.FunctorLaws;`
`10`	`10`	`importtestsupport.traits.MonadLaws;`
`11`		`-importtestsupport.traits.MonadRecLaws;`
`12`	`11`	`importtestsupport.traits.MonadReaderLaws;`
	`12`	`+importtestsupport.traits.MonadRecLaws;`
`13`	`13`	`importtestsupport.traits.MonadWriterLaws;`
`14`	`14`
`15`	`15`	`importjava.util.function.Function;`
`@@ -105,4 +105,9 @@ public void staticPure() {`
`105`	`105`	`Fn1<String,Integer>fn1 =Fn1.<String>pureFn1().apply(1);`
`106`	`106`	`assertEquals((Integer)1,fn1.apply("anything"));`
`107`	`107`	`}`
	`108`	`+`
	`109`	`+@Test`
	`110`	`+publicvoidwithSelf() {`
	`111`	`+assertEquals((Integer)15,Fn1.<Integer,Integer>withSelf((f,x) ->x >1 ?x +f.apply(x -1) :x).apply(5));`
	`112`	`+ }`
`108`	`113`	`}`

Comments

(0)