Dave Abrahams <dave@boostpro.com> writes:
on Mon Oct 24 2011, Allan Johns <allan.johns-AT-drdstudios.com> wrote:
Just gauging initial interest in a boost.deepcopy library
<pet peeve alert>
Sorry to slam this idea out of the gate, but the whole notion of a "deep copy" is broken and wrong (in my humble opinion). When you say you're going to "deep copy" an object it shows you don't understand the boundaries of that object's value. The object's value is copied by its copy constructor, and compared by its operator== (assuming it has one). If your "deep copy" extends beyond the boundaries of the value, there's no way of knowing how far it should extend.
Fascinating discussion. I'm curious about your statement here. Do you object to "deep copy" as implemented in a copy constructor or the notion of "deep copy" of some aggregate data structure in general? For example, I have often needed to clone some branch of a tree data structure where nodes contain pointers to other nodes. For me this is in the context of a compiler and subtree cloning is a convenient way to perform code duplication. In the past I have implemented a virtual clone() member for each kind of tree node in order to get polymorphic behavior. clone() clones child nodes and all that. If your objection covers cases like the above, I am very interested in alternative solutions. Thanks! -Dave