On Friday, 13 April 2012 at 14:28:05 UTC, Jacob Carlborg wrote:
On 2012-04-13 15:34, Rizo Isrof wrote:
Hi,
I am planning to use D for creating native applications on Mac
OS X. For
that, of course, D must interact with the Cocoa API. I have no
knowledge
of how this bindings could be done. I've already looked at
Cocado[1] and
do know the Michel Fortin's D-ObjC bridge[2], and would like
to be
enlightened about some details:
* What is their (or any other possible) approach of porting
Cocoa to D?
-- here I essentially ask for technical reading sources
(books/articles/references, etc);
There are three ways (two deepening on how you look at it).
1. Use the Objective-C runtime manually, which is implement
with regular C functions.
https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ObjCRuntimeRef/Reference/reference.html
2. Use a bridge that handles everything nicely. The bridge uses
the same implementation as in the first way. The bridge also
performs type conversions automatically and other things to
ease the development.
http://www.dsource.org/projects/dstep
http://michelf.com/projects/d-objc-bridge/
3. Implement direct support in the language to be compatible
with Objective-C. This is what Michel Fortin did here:
http://michelf.com/projects/d-objc/
(Note, this is not a bridge)
He forked DMD and added support for extern(Objective-C) which
will output code similar to what GCC/Clang would do. This is a
more direct way to interface with Objective-C and won't add any
more overhead than using Objective-C directly would. I guess
this would mean the ABI's are compatible.
* Is it possible to establish an ABI compatibility with ObjC
directly or
through the C ABI? -- There's a question on _stackoverflow_[3]
where the
answers describe what could be achieved with Objective-C's
Runtime
Reference[4];
Both are possible, see above.
* Is it feasible to make this kind of stuff work nicely and
get the
level of performance and stability like, e.g., with Qt
framework on Mac
OS X?
I think so if you use Michel's fork of DMD.
I have no experience at all in this field so forgive me any
technical
faults. Any help would be appreciable.
Thanks in advance for your responses.
I think the best way is to use the third one mentioned in the
list above. Note that this is based on an older version of DMD.
The project is not finished yet and is currently on old.
Although an alpha version has been released.
The problem with a bridge is the it cause way to much bloat. A
Hello World application written using a bridge generated a 60MB
executable.
Using the Objective-C runtime manually is just too verbose and
tedious. If you are interested in this you can have a look at
my documentation of how my Objective-c/D bridge works and is
implemented:
http://www.dsource.org/projects/dstep/wiki/ObjcBridge/BridgeInternals
[1]: http://sourceforge.net/projects/cocodao/
[2]: http://michelf.com/projects/d-objc/
Note, this is not a bridge. This is third one mentioned in the
list above.
[3]:
http://stackoverflow.com/questions/5901508/calling-cocoa-apis-from-c
[4]:
http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ObjCRuntimeRef/Reference/reference.html
- Rizo
Thank you for such a detailed overview of the existing approaches
- it helped me a lot to understand the theory. As you suggested,
I will probably use a modified version of the compiler for tests.
But in order to fully understand the implementation details I
will try to write my own extension of D for LDC with
`extern(Objective-C)` support.
Thanks again for you answer.
- Rizo
