.NET CLR for Objective C : C

Is there a Mono or .NET compiler for Objective-C? I'm curious about
the idea of doing GNUstep in and through .NET for cross platform
development. I know that there is a "write once compile anywhere"
cross platform ability, but I was just doing some preliminary research
into hooking it into the entire .NET framework. Anyone have any ideas
about projects that are attempting this and their status?

Hank Grabowski wrote:
> Is there a Mono or .NET compiler for Objective-C? I'm curious about
> the idea of doing GNUstep in and through .NET for cross platform
> development. I know that there is a "write once compile anywhere"
> cross platform ability, but I was just doing some preliminary research
> into hooking it into the entire .NET framework. Anyone have any ideas
> about projects that are attempting this and their status?

It's hard to see how you could map Objective-C messaging to .NET method
calls with good performance while maintaining the semantics of the
language. Even if that's overcome, other aspects of Objective-C such as
class objects or categories have no ****og in .NET and would be hard to
implement.

But I'm hardly an expert on .NET and I could be wrong. Do let us know
what you find out.

--
Pull out a splinter to reply.

I've heard talk about making an Obective-C to CIL bytecode compiler but
I don't believe there are any active projects. If anyone would be
interested in working on one, I suggest collaborating with the
Portable.NET project. They are already working on adding a C front-end
in addition to their C# front-end.

I, personally, would rather see some effort to cleaning up GNUstep and
getting it to run on more than just 32-bit Linux. Viola...
Cross-platform Objective-C framework.

--jm

In article <9vg3uvo4j8vuq6k4a4i1lo9mn9ojpcg99h@4ax.com>,
Hank Grabowski <hgrabows@hotmail.com> wrote:

> Is there a Mono or .NET compiler for Objective-C? I'm curious about
> the idea of doing GNUstep in and through .NET for cross platform
> development. I know that there is a "write once compile anywhere"
> cross platform ability, but I was just doing some preliminary research
> into hooking it into the entire .NET framework. Anyone have any ideas
> about projects that are attempting this and their status?

"Peter Ammon" <gershwin@splintermac.com> wrote in message
news:qauEb.41890$LC2.15405@newssvr29.news.prodigy.com...
> Hank Grabowski wrote:
> > Is there a Mono or .NET compiler for Objective-C? I'm curious about
> > the idea of doing GNUstep in and through .NET for cross platform
> > development. I know that there is a "write once compile anywhere"
> > cross platform ability, but I was just doing some preliminary research
> > into hooking it into the entire .NET framework. Anyone have any ideas
> > about projects that are attempting this and their status?
>
> It's hard to see how you could map Objective-C messaging to .NET method
> calls with good performance while maintaining the semantics of the
> language.

This is not quite hopeless. VB.NET supports something vaguely similar
in calls against Object:

Dim x As Object = ...
x.Foo(bar,baz)

This works even though Object has no method named Foo. It
searches for the method at runtime.

The semantics of this aren't the same as Objective-C- it actually
dispatches on all arguments, and throws if it can't find a method
to call. But I don't see a problem implement Objective-C
semantics instead.

The main obstacle is that the semantics of casting are quite
different. An Objective-C program would have only
variables of type Object once compiled, and so could not
ever optimize the full dispatch away. VB.NET, by contrast,
can do a normal method call when the variable's type is something
specific.

I think that it would be hard to acheive good performance
if that can't be overcome.

> Even if that's overcome, other aspects of Objective-C such as
> class objects or categories have no ****og in .NET and would be hard to
> implement.

Class objects are just implicitly defined singletons; that should not
be too hard. Categories are going to be a bit rough; I can see no
way to load a category that override methods so that languages
other than Objective-C are affected.

[snip]