Re: Extension as first class construct

On Thu, Oct 14, 2004 at 08:16:48PM -0700, Michael Latta wrote:
> I would like to suggest that the extension of a class/interface be a 
> first class construct in Groovy.  
> The methods that are added to JDK 
> classes should use a language defined construct, which can also be used 
> by any user class.  This allows a programmer using a binary library to 
> add methods to make the library classes polymorphic with custom 
> classes.  
> I am new to Groovy and from what I have read, the extensions 
> are currently performed by use of a meta model object that performs 
> dispatching, so it sounds like the mechanism is there.  I am asking for 
> the mechanism to be accessible from the language level, not just the 
> library level.  
I think you are describing the 'use' Groovy JDK method...

SomeThirdPartyClass.use {
  doSomeOfMyStuff()
}

> The Objective-C language has this construct, and it has 
> proven to be quite useful.  
To which specific syntax do you refer?

>In that context an extension is not able to 
> access any private parts of the class being extended.  This would be 
> required in Groovy to prevent security breaches, and because you are 
> really not changing the .class file of the extended class.

You can do this to instances, which has some of those features
for example adding a closure to an instance of Foo...
---
class Foo {
  property bar
}
foo = new Foo()

m = { println bar }
m.delegate = foo
m.call()



Thanks

Jez.