Stk.PackerSourceval init :
((< id : Stk.Oid.Map.key.. > as 'a) -> int) ->
('a -> int option) ->
('a -> int) ->
'a list ->
int * t Stk.Oid.Map.tval compute :
int ->
(Widget.widget -> int) ->
(Widget.widget -> int option) ->
(Widget.widget -> int) ->
Widget.widget list ->
t Stk.Oid.Map.t