Experience report: implementing a real-world, medium-sized program derived fr...
summary
Replication of the French housing benefits system CRISTAL from CNAF laws uses Catala to reimplement about 7,000 lines of code and 100 pages of regulations after finding the published COBOL unreadable; development costs ~50 hours of paired programming plus ~120 hours of legal research and testing. The prototype compiles to JavaScript, runs, and reproduces a split custody approximation bug and subtle rounding divergences, showing functional needs and the limits of the legacy system.
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chapters (10)
- 0:00Housing benefits study intro
- 1:10Why French benefits chosen
- 4:24Challenges in Crystal Cobol
- 8:38Legal split custody challenge
- 13:10Language design for benefits
- 15:20Rounding rules in regulations
- 18:10Functions in tax programs
- 21:17Catala demo and input form
- 23:25Key takeaways
- 24:51Q&A
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