Custom constructs in Scala

I ran accross a disscussion in the Scala list today, related to zero-parameter-function-values. One of the answers pointed to an interesting wiki enty about by-name parameters. Which walked through creating a home-made while loop in Scala (very DSL like). I had read about this (or seen it somewhere) but had not experimented with it, until now.

 1 def myWhile(condition: => Boolean)(body: => Unit): Unit = {
 2 
 3     if (condition) {
 4 
 5         body;
 6         myWhile(cond)(body)
 7     }
 8 }
 9 
10 var x = 0;
11 
12 myWhile(x < 5) {
13 
14     println(x)
15     x += 1
16 }

This is pretty cool, but I'm not sure at this point what I can do with a custom while loop (Scala has a perfectly useful one already). Then, I remembered something about creating constructs similar to the using statement in C#, for calling the dispose method of disposable types.

 1 trait Disposable {
 2     def dispose();
 3 }
 4 
 5 def using(resource: Disposable)(body: => Unit): Unit = {
 6     body
 7     resource.dispose()
 8 }
 9 
10 
11 class MyResource extends Disposable {
12 
13     def foo() {
14         println("doing something with my resource")
15     }
16 
17     override def dispose() {
18         println("closing resource")
19     }
20 }
21 
22 val myResource = new MyResource
23 
24 using(myResource) {
25     myResource.foo();
26 }

Now that is pretty cool. There might already be something in scala do to this "using" statement and I'm not quite sure where I can using this now, but it's nice to be able to create statements and constructs for increased readability.