Re: [Pyobjc-dev] NSCoding support for python list & dict

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

On Nov 26, 2007, at 9:59 PM, Ronald Oussoren wrote:
> NSCoding support for other objects should also be doable, but is  
> more work and requires a lot of testing. Pickling Objective-C  
> objects on the other hand has the outlooks of being a very hard  
> problem.

NSArchiver and NSKeyedArchiver support arbitrary archival of objects.   
That is, you can create an archiving session and then archive the sub- 
graphs of objects of objects in arbitrary order and with arbitrary  
references between the subgraphs.

Pickling of a graph containing a mix of Python and Objective-C objects  
could be done by creating a UUID for each object in the graph at the  
pickle/archiver boundary.  The UUID could be stored in the pickle,  
could be used to archive the sub-graph of Objective-C objects and  
store 'em away via -encodeObject:forKey:, and then the resulting BLOB  
of archived Objective-C data could be stored in the pickle as a  
<string>.

Completely trivial, right?

Only because of my ignorance.   There is a definite chicken-and-egg  
problem in that archival will produce the archived obj-c objects  
*last* whereas unarchival will need them to be decoded *first*.   And  
that is just scratching the surface.

b.bum