model:clone function

[rlouapre]

• It would probably make sense to have a function to clone an existing object and only generate a new identity value.
• It is very close to the existing model:new.

[rlouapre]

@garyvidal does it make sense.

Any suggestion on the implementation

[skeptikos]

A model:clone would definitely be valuable. In particular it should be a "clone and update" ie. accept $update params and act like a combination of new (create a novel instance with generated ID, not contingent on an existing ID not being present) and update (supply values from the existing instance as $current to model:recursive-create, but stripping out the identity field). I imagine $partial would have to be fixed true() otherwise the clone will have holes — with an empty $update it should be identical to the original save the identity.

Of course "identical" leaves the hairier question of whether type="reference" fields duplicate the reference or cause a recursive clone. The semantics of automatic reference de-referencing probably should be considered in a larger context, but for clone() it would make sense for 1-level-deep control by providing each reference field definition with a property (attribute on <field> or perhaps <navigation>?) indicating whether it should be cloned on copy, ie. during a parent clone.