on Tue Oct 25 2011, Allan Johns <allan.johns-AT-drdstudios.com> wrote:
In my case I have several data types - tables, buffers, tuples, attributes etc. I need to be able to clone (ie deepcopy) any part of one of these hierarchical structures... there is no "entire structure", if you will.
I understand what's being said about memory ownership, but in this case I have full control of my problem domain, and such a generic deep copy library would be useful and save time - otherwise I'm just going to have to implement deep copy behaviour inside of all my classes anyway (which is actually what I have at the moment). This pattern has come up several times before in my work, so it isn't a one-off, and the motivation is not to deal with cyclic dependencies (although that should probably be dealt with).
Perhaps there should be a 'deep copy context' that you can create for your own code or share from other libraries, so for eg one library's idea of what "deep copying" an std::vector is, can differ from another library's. Would this address your concern over ambiguity of memory ownership?
Given that this behaviour is implemented as a standard module in another language (python) I'm surprised it's being dismissed so easily?
Pickling is considered "evil" in the BuildBot project precisely because you can't control the boundaries (http://irclogs.jackgrigg.com/irc.freenode.net/buildbot/2011-05-09), though I realize it's sometimes convenient. Seems to me that you could tackle this need by implementing a special "cloning_archive" type for Boost.Serialization, and be done with it. -- Dave Abrahams BoostPro Computing http://www.boostpro.com