A Closure variant of override_action.
Allows overriding the action for key_val and modifiers inside a
BindingPool. See
install_closure.
When an action has been activated using activate the passed callback
will be invoked (with data).
Actions can be blocked with block_action and then unblocked using unblock_action.
| this | |
| key_val |
key symbol |
| modifiers |
bitmask of modifiers |
| closure |
a Closure |