Package-level declarations

A_Variable is an interface that specifies the behavior specific to Avail variables that an AvailObject must implement. It's a sub-interface of A_BasicObject, the interface that defines the behavior that all AvailObjects are required to support.

My object instances are variables which can hold any object that agrees with my inner type. A variable may also hold no value at all. Any attempt to read the current value of a variable that holds no value will fail immediately.

My object instances are shared variables.

My object instances are shared variables that are acting as module variables or module constants.