[Pyobjc-dev] Quick summary of Perl bridges

[<bb...@ma...>]

On Monday, November 25, 2002, at 05:54 AM, Peter Montagner wrote:
> On another note, has anyone here looked at CamelBones? I'm not really 
> a Perl person but has anyone looked at how it does the Perl-ObjC 
> bridge? Could be interesting.

The author of CamelBones and I exchanged a few messages a bit ago.  
CamelBones doesn't currently do subclassing.   It hopefully will in the 
next version, but that won't be due out for a while.  The author sends 
his thanks-- he has been using the PyObjC module's source to solve some 
of the issues he has faces.

According to...

man PerlObjCBridge

... the PerlObjC bridge is bidirectional but does not yet support 
subclassing(?) ...

        Objective-C objects from Perl programs, allowing Cocoa
        objects in Apple Computer's Mac OS X to be directly manip-
        ulated from Perl. In addition, Perl objects can be mes-
        saged from Objective-C, making it possible for Perl
        objects to function as Cocoa delegates and as targets of
        notifications and other Cocoa call-back messages. Perl
        programs can take advantage of Cocoa's Distributed Objects
        mechanism to support messaging between Perl objects and
        Objective-C objects (or other Perl objects) in different
        address spaces, possibly on different machines.

It also uses the same name mangling as pyobjc.   Clearly, the author 
had some challenges in wrapping the NSProxy class [perfectly 
understandable] because the man page has a huge section on using the 
PerlObjC bridge with DO -- something that should "just work" once the 
bridge is working correctly.

This is interesting...

        When an Objective-C method declares a signed char or
        signed short argument, if a negative value is passed the
        actual value received by the method is coerced to an
        unsigned char or unsigned short, respectively. For exam-
        ple, if a method declares a signed char argument and -100
        is passed the actual value received by the method will be
        156. This is due to bug 2545453 in the Foundation frame-
        work.

... either the bug is fixed or our implementation doesn't suffer from 
it:

 >>> from Foundation import NSNumber
 >>> x = NSNumber.numberWithShort_(-100)
 >>> x
-100
 >>> x.intValue() + 2
-98

The PerlObjC bridge does not support all of the various #defines, 
typedef enums, and C Functions found in the Foundation or AppKit.  The 
author indicates that support is left to the developer.