On the surface, the (c)Pickle module looks like a good, simple wayfor your Python program to save and load its data; much like XML , it means you don't have to write a parseror even save and load routines as such, just some file and objectmanipulation code. However, through my experience in writing DWiki I'vecome to understand that this temptation would be a mistake (one thatI've actually half-made; DWiki 's caching layer uses pickling)

To follow on from yesterday's entry , suppose thatone is using (c)Pickle to save data in your Python program, and you wantto version your data somehow. I can think of a number of approaches:

• take the 'pickle as stored JSON' approach; serialize your complexobjects to simple objects (dictionaries, lists, etc), add versionnumbers, and only pickle the simple objects. Then you can do all ofthe usual version mismatch fixups when you de-serialize the reloadedsimple objects

I have heard it said that objects are data combined with behavior, whichas a snappy summary strikes me as pretty useful; something like ithas certainly guided me in structuring my programs. (Although I amnowhere nearly as strongly object-oriented as is popular these days; Istill have at least a foot in the procedural programming camp.)

It is also a sensible notion, in the abstract; since data by itself isuseless, so you might as well bundle it together with the code thatunderstands it and