[timbaldridge]

I would go a step farther and say that OpenDoc should be in a separate interface from SaveDoc.

[mseebach]

That's what I meant - should have said interface_s_, I see now :)

Actually, opening a document is probably not even a good abstraction. DocProvider is better: You can have FileSystemDocProvider and BlankDocProvider - the latter can't meaningfully be said to "open" a document, but it's interacted with in the same way.