[Pythonmac-SIG] PyObjC tutorial without Xcode

[Dav Clark]

I sent this just to Craig, but figured I should probably send to the  
group in retrospect - at least this way something'll be online in the  
pythonmac-sig archives...


Below my signature is a sample script demonstrating a really minimal  
use of pyobjc.  This is meant to be run from the command line, and  
uses the BTop2 framework from Perfectly Scientific.  You can download  
that framework for free, but it won't do much if you don't have the  
hardware!

Not exactly a tutorial, but darned simple for sure... I can't remember  
if that __getattr__ thing ever worked... I don't think it did.  The  
Exception thing is _way_ useful (as indicated in the comments there).   
The standard exception messages you'll get while using pyobjc are  
close to useless.

I'll add also that I'd not be averse to chipping in to a non-Xcode  
pyobjc tutorial online somewhere.  I'm not terribly self-motivated on  
that, but would do if someone asked for more.

Cheers,
Dav
--
Statistical Motion R&D
http://socrates.berkeley.edu/~ivrylab/

import objc

# # Way useful for debugging
# import PyObjCTools.Debugging as Debugging
# Debugging.installVerboseExceptionHandler()

btop_path = objc.pathForFramework('/Users/dav/Code/bTop.framework')
objc.loadBundle('btop', globals(), bundle_path=btop_path)
# Not sure why I need to do this... I shouldn't!
BTopBoard.setBTopFirmwareDirectory_(btop_path + '/Versions/A/Resources')

class BoardContainer(NSObject):
     """BoardContainer should be initialized by BoardControl below"""
     board = None

     def bTopAddBoard_(self, board):
         self.board = board
         self.board.setPortBit_direction_('B', 255)
         self.board.refreshDigitalPortValues()

     def send(self, val):
         self.board.setPortBit_value_('B', 255-val)
         self.board.refreshDigitalPortValues()

class BoardControl:
     """Instantiate the BoardContainer and provide a more pythonic  
interface

     Ultimately, this should implement a standard Parallel Port API"""
     board = None

     def __init__(self):
         # Cocoa objects are constructed differently...
         self.board = BoardContainer.alloc().init()
         BTopBoard.setBTopPrimaryObserver_(self.board)
         BTopBoard.allocBTopObserver()

     # # try writing a function dispatch to catch undeclared funcs...  
see
     # # what's going on!
     # def __getattr__(self, name):
     #     def handler(*args, **kwargs):
     #         print '*name*', name
     #         print '*args*', args
     #         print '*kwargs*', kwargs
     #     return handler

     def send(self, val):
         self.board.send(val)