Re: objective-c @compatibility_alias construct documented

[Ovidiu Predescu <ovidiu at cup dot hp dot com>]

Thanks, I applied it.

Ovidiu

On Wed, 28 Feb 2001 19:35:41 +0100 (CET), Nicola Pero <n.pero@mi.flashnet.it> 
wrote:

> Hi, 
> 
> while looking at the Objective-C parser code I found out it accepts this
> construct -
> 
> @compatibility_alias ClassA ClassB;
> 
> which I have never seen documented anywhere - I completely ignored about
> its existence - and so I think do most Objective-C developers.
> 
> Anyway - I tested it and it works :-) - and probably could be useful in
> some particular situations - so here is a patch for
> gcc/libobjc/objc-features.texi to document this forgotten feature of the
> Objective-C compiler.
> 
> I suppose you want to put it only in the head branch since it's not a bug
> fix.
> 
> 
> Index: objc-features.texi
> ===================================================================
> RCS file: /cvs/gcc/gcc/libobjc/objc-features.texi,v
> retrieving revision 1.7
> diff -u -r1.7 objc-features.texi
> --- objc-features.texi	2001/01/12 17:06:15	1.7
> +++ objc-features.texi	2001/02/28 16:19:58
> @@ -21,6 +21,7 @@
>  * Type encoding::               
>  * Garbage Collection::          
>  * Constant string objects::     
> +* compatibility_alias::
>  @end menu
>  
>  @node Executing code before main, Type encoding, Top, Top
> @@ -386,7 +387,7 @@
>  as argument.
>  
>  @c =========================================================================
> -@node Constant string objects,  , Garbage Collection, Top
> +@node Constant string objects, compatibility_alias , Garbage Collection, Top
>  @comment  node-name,  next,  previous,  up
>  @section Constant string objects
>  
> @@ -429,6 +430,36 @@
>  as argument to this option. It is possible to have multiple compilation
>  units referring to different constant string classes, neither the
>  compiler nor the linker impose any restrictions in doing this.
> +
> +@c =========================================================================
> +@node compatibility_alias,  , Constant string objects, Top
> +@comment  node-name,  next,  previous,  up
> +@section compatibility_alias
> +
> +This is a feature of the Objective-C compiler rather than of the
> +runtime, anyway since it is documented nowhere and its existence was
> +forgotten, we are documenting it here.
> +
> +The keyword @code{@@compatibility_alias} allows you to define a class name 
> +as equivalent to another class name.  For example: 
> +
> +@example
> +@@compatibility_alias WOApplication GSWApplication;
> +@end example
> +
> +tells the compiler that each time it encounters @code{WOApplication} as 
> +a class name, it should replace it with @code{GSWApplication} (that is, 
> +@code{WOApplication} is just an alias for @code{GSWApplication}).
> +
> +There are some constraints on how this can be used - 
> +
> +@itemize @bullet 
> +
> +@item @code{WOApplication} (the alias) must not be an existing class;
> +
> +@item @code{GSWApplication} (the real class) must be an existing class.
> +
> +@end itemize
>  
>  @bye
>  
> 
>