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Re: Newer features in Objective C
Re: Newer features in Objective C
Mon, 13 Feb 2023 10:32:17 +0000
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On 13/02/2023 00:52, Gregory Casamento wrote:
On Wed, Feb 8, 2023 at 09:57 Richard Stallman <firstname.lastname@example.org
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GNU Objective C supports the features that Objective C had in 1989.
It would be nice to add the newer Objective C features.
Is anyone interested in doing that?
Please write to me personally if you sare intested in working on this.
This is not true. Nicola Pero added declared properties a while ago,
and exceptions were already there. GCC is more or less feature-complete
with respect to Objective-C circa 2005. Apple subsequently invested
quite a few person-years of engineering effort on adding more modern
features, the largest of which is ARC. Subscripting is a fairly simple
transform, which would probably be quite easy to add to GCC. Some of
the other things, such as direct methods, require some careful design
work (the interaction between +initialize and direct methods is annoying
and I haven't yet come up with an ABI that would cause them to be a
I, personally, have the knowledge, but not the time. I think that is
the situation with a number of us, but I certainly don’t speak for us
all. We had hoped that someone in the existing GCC community might be
willing to take this on if it’s to be done on a volunteer basis.
I have tried to persuade GCC folks to do this a few times, but there are
a few problems:
- The current Objective-C code in GCC is *awful*. I started working
on Objective-C support in clang because it was less work to add
Objective-C codegen to clang *from scratch* than it was to add fairly
simple features that it was missing at the time (declared properties) to
GCC. If anything, that code has become even harder to work with in the
- The license for GCC means that none of the companies that might have
funded this work 10 years ago were willing to touch it. This has not
It’s my belief that this is a pretty large effort. It will likely be
multiple weeks or months of effort for one person to do as it involves
adding a number of missing features. In your email you say that GCC
supports the features from 1989… that’s true but there are also SOME 2.0
features that have been implemented but it is not complete so we have,
in effect, Objective C 1.5. :)
That is *incredibly* optimistic. Adding ARC support requires some very
subtle work related to lifetimes and has a lot of interactions with
other features (e.g. C++ copy constructors). I would put the estimate
in person-years, not less.
I am wondering if it might be necessary for the FSF to hire someone to
do this outside of the community (or within if that’s an option).
I am not sure what the way forward on this is at this point.
I see two viable options:
- Publicly acknowledge that GCC has not supported Objective-C for 15+
years, remove Objective-C support from the next release of GCC, and let
GNUstep focus on working with compilers that do support the language.
- Ensure that there is a pot of at least half a million dollars
available to properly fund the work on GCC and contract an experienced
developer to work on it full time for the next two years (or a company
with a team of developers for a shorter period) and then be on retainer
to fix the bugs going forward.
If the FSF has half a million to spend on Objective-C support in GCC
then that money could be *far* better spent on improving other bits of