Re: dia2code objc

[Richard Frith-Macdonald]

On Tuesday, March 26, 2002, at 01:36 PM, Björn Gohla wrote:

> On Tuesday 26 March 2002 13:36, Helge Hess wrote:
> > Björn Gohla wrote:
> > > i am working on a dia2code plugin for objective-c. i have some issues
> > > with class member visibility. public attributes are represented in 
> > > objc
> > > via a set/get pair, and private ones by the absence of it. but is 
> > > there
> > > any useful interpretation of protected attributes, if so how?
> >
> > Actually private/protected/public attributes should probably be mapped
> > to instance variables ? ivars do support those flags:
> >
> > @interface MyClass
> > {
> > @private
> >    id myPrivate;
> > @protected
> >    id myProtected;
> > @public
> >    id myPublic;
> > }
> > @end
>
> perhaps this can be done without changing the compiler, by using an
> authentication mechanism like the one in NSProxy. the accessor methods 
> could
> check whether the caller is allowed to access the variable, we can even 
> have
> write only and read only access and different access rights for 
> different
> classes, try that with c++ ;) .

IMO getting very complex/sophisticated about this is a waste of 
programming
effort and produces confusing code.  Access restrictions cannot be 
enforced,
so sticking to simple conventions is more effective.

eg. provide different headers containing different categories listing 
methods
available for specialised use, and document who is supposed to use each 
API
in the appropriate header.

While you can provide methods which do clever checking at runtime, it's
rarely justified.