Changes between Version 158 and Version 159 of j2p

Timestamp:

11/13/24 13:58:38 (12 days ago)

Author:

wouter

Comment:

--

j2p

@@ -468 +468 @@
 * various small fixes, to work around a few restrictions of the translator.
 
+
+== Use of lambda notation, inner class extraction
+Java has the arrow notation (x,y) -> methodcall(x,y) to write lambda expressions. 
+This notation can also be translated. This feature is especially useful when pulling inner classes out of a parent class, to pass parent class functions over to the pulled-out class. 
+For example, suppose you have a class like this
+
+{{{
+class Parent {
+  public void f() {...}
+  public String g(int x) {...}
+
+
+  public X h() {
+    ....
+    return new X{
+      f()
+      g(1)
+    }
+}
+}}}
+
+The "new X" call has to be converted into an explicit class, but somehow it needs to be able to call f and g. We suggest to do it like this:
+
+{{{
+class MyX extends X {
+  public MyX(Runnable f, Function<Integer,String> g) {
+    f.run();
+    g.apply(1);
+  }
+}
+
+class Parent {
+  public void f() {...}
+  public String g(int x) {...}
+
+
+  public X h() {
+    ....
+    return new MyX{()->f,(x)->g(x));
+} 
+
+
 == FAQs
 ||=Question=||=Explanation=||