Key points are not available for this paper at this time.
A general purpose Production System interpreter, APRIL, has been developed to model aspects of students problem solving in a CAI environment. APRIL incorporates most of the facilities common to earlier interpreters and also includes several additional features. One new feature allows "high-level" routines, such as those used by the interpreter itself in the matching and cycling phases, to be actions in production rules: hence it is possible for the user to "create" an interpreter which is suitable for his particular domain. However, the most important features of APRIL are that: 1) memory is handled uniformly (Production Rules and data both being stored as states ) and 2) APRIL allows Production Rules to retrieve and modify any state. Together these latter features allow adaptive systems to be implemented.
Smith et al. (Wed,) studied this question.