From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Tolpin <dvd@davidashen.net>
Message-Id: <200403021606.i22G6vl9074244@adat.davidashen.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] Re: advantages of limbo
In-Reply-To: <fe324c904b77de93a977cdd932061bbf@vitanuova.com>
Content-Type: text/plain; charset=KOI8-R
Date: Tue,  2 Mar 2004 20:06:57 +0400
Topicbox-Message-UUID: 0d0450fa-eacd-11e9-9e20-41e7f4b1d025

> From: C H Forsyth <forsyth@vitanuova.com>
>
> > Yet [Java] is more powerful in expressing algorithms. Things like closures
> > or message polymorphism are natural and easy to express in Java, while
>
> Java has closures?
>

Of course it does.

interface Appl {Object f(Object o);}

interface List {void foreach(Appl a);}

class test {
  void do(List l) {
    String s="element: ";
    l.foreach(new Appl() {
      String t=s;
      Object f(Object o) {
	System.out.println(t+o);
      }
    });
  }
}

Untested, but the idea is simple: foreach is passed a dynamic
closure with variable s inherited from the context.

t=s is to show how a local binding can be explicitely created,
one could simply write

    l.foreach(new Appl() {
      Object f(Object o) {
	System.out.println(s+o);
      }
...

David