Re: Extensions vs categories

In article <fkvu51$56v$1@[EMAIL PROTECTED]
>, ActiveMan <basurero@[EMAIL PROTECTED]
> 
wrote:

> Hello, according to Apple do***entation "The Objective-C 2.0 
> Programming Language (pag 43)", extensions are a way to differentiate 
> between a public API and an API for the class of the framework. IMO 
> categories also accomplish the same requirement. So my doubts are:
> 
> 1. Are extension a new feature in Objective-C 2.0, because it's not 
> present in previous releases of "The Objective-C Programming Language".
> 2. Where is the conceptual difference between categories and 
> extensions. Or is just a question of flavors.
> 
> Regards.

The primary difference is right in the docs:

"Class extensions allow you to declare additional *required* API for a 
class in locations other than within the primary class @[EMAIL PROTECTED]
 block, 
...."

Extensions are a promise, categories are a suggestion. The compiler can 
impose more requirements and the runtime can make more assumptions. They 
mean an end, as people migrate to Obj-C 2.0, to the clutter of:

@[EMAIL PROTECTED]
 Foo (Foo_private)
//...
@[EMAIL PROTECTED]
 all you really wanted to do was avoid publi****ng some of your API 
via the header.