CmdClosure design critique

[ichthyo]

Now, after roughly finishing the first implementation round, I'm unhappy with some parts of the command implementation. Especially the closure related parts feel somewhat misaligned.

• difficult to understand
• need to know too much implementation details so see how it works
• possible waste of storage by using too much vtables
• danger of template bloat by having too much virtual functions in templated subclasses

To my current understanding, the assets within this part of the command handling framework are:

• having a separate setup and usage API
• the usage API is small and not specifically typed (type erased)
• all storage is in-line and of limited size; handling of this is separated from the closure logic
• Command and even Closure doesn't know anything of the memento; UNDO state is completely owned by the implementing functions