Next:<model> ( value -- model )


Class description
A mutable cell holding a single value. When the value is changed, a sequence of connected objects are notified. Models have the following slots:
value - the value of the model. Use set-model to change the value.
connections - a sequence of objects implementing the model-changed generic word, to be notified when the model's value changes.
dependencies - a sequence of models which should have this model added to their sequence of connections when activated.
ref - a reference count tracking the number of models which depend on this one.
locked? - a slot set by with-locked-model to ensure that the model doesn't get changed recursively

Other classes may inherit from model.


TUPLE: model < identity-tuple
value connections dependencies ref locked? ;