2-Term Charters

By: Alexander Knapp, María Victoria Cengarle


Building on Martin Gogolla’s algebraic formalisation of the “Object Constraint Language” (OCL), its expression part has been formalised as a syntactically and semantically heterogeneous language using the framework of term charters for faithfully integrating OCL’s features in a step-wise and compositional manner. This schema for the evaluation of OCL expressions on a single system state is now extended to comprise OCL contracts, i.e., the specification of operations with pre- and post-conditions. Under mild assumptions term charters can be systematically transformed into 2-term charters involving two system states. The application to OCL as a heterogeneous expression and contract language is illustrated by several examples.


Object Constraint Language, Term charters, Institutions.

Cite as:

Alexander Knapp, María Victoria Cengarle, “2-Term Charters”, Journal of Object Technology, Volume 19, no. 3 (October 2020), pp. 3:1-12, doi:10.5381/jot.2020.19.3.a10.

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The JOT Journal   |   ISSN 1660-1769   |   DOI 10.5381/jot   |   AITO   |   Open Access   |    Contact