Re: Objective-C Support

[David M. Lloyd]

On Tue, 29 Oct 2002, Paul Eggert wrote:

> > From: "David M. Lloyd" <address@hidden>
> > Date: Tue, 29 Oct 2002 11:42:08 -0600 (CST)
> >
> > I am working on adding Objective-C support to autoconf, and I am wondering
> > if that is something that is generally useful to all.
>
> Sure!
>
> What are the technical issues here?  Objective-C is pretty close to C,
> for the thing that Autoconf already knows about.

Many things are similar, so I am "borrowing" from c.m4 quite a bit.  But
there are important differences.

Objective-C (I'll say ObjC from now on) is compiled in one of two ways:
By a preprocessor, or by a actual language compiler.  The compiler may be
called 'cc' or similar, or it may be 'objc' or 'objcc' or something else
entirely.

The runtimes vary substantially as well.  Sometimes the ObjC include files
can be included via #include <foo.h> and sometimes you need to prefix
objc/: #include <objc/foo.h>.  Sometimes the runtime has built in
refcounting or Boehm GC, and sometimes not.

Function names in the runtime vary as well, for instance, getting method
selectors is done by a function whose name varies depending on the
implementation: selUid("method"), sel_getUid("method"),
sel_get_any_uid("method"), etc.

Compiler flags vary substantially as well between various ObjC compilers,
especially relating to GC.

Dependency checking is slightly different as well, since some ObjC
compilers support the '#import' directive.

I hope to be able to reuse a lot of the C structure to shorten the time it
takes to develop good ObjC support.

- D

<address@hidden>