[Pyobjc-dev] Structs, tuples and instances

[Dinu G. <gh...@da...>]

Hi,

I'm trying to fake some kind of a solution which is more struct-like
than plain Python tuples for things like NSPoint, NSSize, etc. Here's
a simple one:

class NSPoint:
     """An experimental NSPoint class/struct hybrid.

     This is supposed to be usable with attribute names
     as well as indices.
     """

     def __init__(self, x, y):
         self.x, self.y = x, y

     def __getitem__(self, index):
         assert index in (0, 1)
         return (self.x, self.y)[index]

     def __setitem__(self, index, value):
         assert index in (0, 1)
         setattr(self, "xy"[index], value)

Doing anything like the following:

     view = NSView.alloc().init()
     #origin = (10, 20)
     origin = NSPoint(10, 20)
     origin.x = 11
     origin[1] = 22
     print origin[0], origin[1]
     print origin.x, origin.y
     view.setFrameOrigin_(origin)

then gives me a "ValueError: depythonifying 'struct', got 'instance'"
on the last line, so I assume the background checks test for the type
of the argument and reject an instance.

What about testing only for __getitem__ and __len__? Then, I could
probably really use the type of hack above, which would make a cer-
tain kind of code much more readable?

Dinu

--
Dinu C. Gherman - http://python.net/~gherman
......................................................................
"I never apologize for the United States of America, I don't care what
the facts are." (George Bush, Sr.)