This thesis explores real-life calendars, calendar expressions, and time formats, focusing on developing computer-based tools for modeling and processing calendric data. It adopts a programming language approach that contrasts with logic-based and algebraic methods. The thesis presents two main ideas: (1) "Calendar as Type," where time and calendar expressions are modeled using data types instead of logic or algebra, providing user-friendly constructs (type constructors) that enhance modeling efficiency, consistency, and abstraction. (2) "Theory Reasoning," which formulates problems like appointment scheduling and travel planning within a constraint solver tailored to various calendar domains, utilizing user-defined data types such as "day" or "consultation hour." This solver maintains the semantics of different calendric types and enables efficient constraint solving. The work connects to Computer Science research on modeling language design and programming language constructs, emphasizing data types for time and calendar expressions, type checking, and constraint solving. Practically, it offers user-friendly constructs for modeling calendars and constraints, vital for Semantic Web applications. The tools proposed can integrate into any Web language, showcasing future research possibilities in using data types and inference algorithms for specific theories like topologies and locational data.
