Onions have layers. Like ogres. Or parfaits.

Class tao::layer



method node_is_managed unit

Returns true if an object or record described by unit is managed by this object.

method type_is_managed unit

Returns true if an type, class or family of records described by unit is managed by this object.

Class tao::onion




method action activate_layers

Action to perform after all of the layer objects have been connected.

method activate_layers ?1|0?

Using the output of active_layers, build a nest of layers. If a 1 is given as the first argument, all existing layers are unmapped and destroyed before mapping new layers. Otherwise layers that were previously mapped and not present in the current incarnation of the object are destroyed. Layers which exist in the current incarnation, but which arent't mapped are created. Layers that are mapped, and present in the active_layers, but which have a different class implementation morph into the new class.

method active_layers

Return a dict describing the layers that should be mapped to this object.


method active_layers {} {
  set result {
    xtype     {prefix y class sde.layer.xtype}
    eqpt      {prefix e class sde.layer.eqpt}
    portal    {prefix p class sde.layer.portal}
  return $result

method layer layerid ?method? ?args...?

With only the layerid argument, return the object which implements the layer described by layerid. If the layer does not exist, ::noop (a command which takes any argument and does nothing) is returned.

If more arguments are specified, the command will exercise the method of the layer object using any additional args.


set obj [::db layer users]
set username [$obj record_exists $userid]


set exists [::db layer users record_exists $userid]

method layers

Return a dict describing the layers currently mapped to this object.

method Shared_Organs

Return a list of organs for this object which should also be grafted to any layers or other nodes spawned by it. The default implementation is to return the contents of the value of property shared_organs

Method SubObject layer name

Return the fully qualified name of the object which will implement this layer.

The default implementation return [namespace current]::SubObject_Layer_$name