Conceptual Programming with constraints

1. Introduction This paper discusses the integration of constraint actors to the Conceptual Programming (CP) environment (Hartley 1988) developed at CRL. The CP system is an implementation of Conceptual Graphs (Sowa 1984) with an added layer called procedural overlays. These overlays allow the system to represent temporal and causal information using a temporal calculus and related time maps (similar to Allen's temporal relations (Allen 1983) and Dean and McDermott's (Dean and McDermott 1987) time maps. When executed, each procedure overlay produces a time map showing the relationships specified by the action. These inherently localized time maps are combined into a global time map by a further extension to CP called PRE (Eshner and Hartley 1988). Constraint overlays implement the original actors in conceptual graphs with two additions: each actor may behave like a formal constraint on a state or concept referent as well as a function, and constraint actors may take as input a state as well as a single concept referent. The next section briefly summarizes CP, procedural overlays and constraint overlays. The integration of constraint overlays and procedural overlays is then presented in an example that illustrates their use.