Experience report: implementing a real-world, medium-sized program derived from a legislative specification

Résumé En

Implementing computer programs from legislative specifications has been a longstanding academic endeavor. However, few of these experiments has so far sought to replicate a computer program that is already in production in public administration; most of them have created new programs or formalizations that cover sections of the law not previously automatically enforced by public administration. A somewhat dated but accurate state of the artof the use of legal expert systems in government agencies was compiled by Oskamp (2002). Building on the work around the Catala domain-specific language, we have chosen to engage in an exercise of replication of the existing IT system that computes the French housing benefits (and various other benefits) within the CNAF administrative agency, CRISTAL. More general context and main non-technical findings of this replication exercise can be found in a companion paper; this presentation will focus on the challenges and lessons learned about the programming act itself, in an effort of consolidation of knowledge for this line of research.