Catala — A Programming Language for the Law

Why it matters for NETEVO

Catala completes the international Rules-as-Code substrate at the layer the AU implementation lineage does not occupy — the question of what a law-to-code language ought to look like as a programming-languages artefact. Where the Representing Legislative Rules as Code at Scale and DataLex XAI in Rules-as-Code papers cover Australian implementation, and the Bertl, Price and Draheim work covers the 2026 LLM-assisted-extraction frontier, Catala occupies the DSL-design seat.

Defeasible logic as the design substrate. Catala's language structure is built around defeasible logic — general rule, then exceptions, then exceptions to exceptions — which is the same logical structure the Income Tax Assessment Act 1997 (Cth) and the Corporations Act 2001 (Cth) actually use. NETEVO citing Catala signals that the Law-to-Code Methodology rests on a domain-specific-language tradition with academic provenance from Proceedings of the ACM on Programming Languages, not on ad-hoc code generation against statute text.

International defensibility. The INRIA and Microsoft Research authorship makes the citation legible to international audiences who do not recognise the AustLII and Greenleaf AU lineage. Paired with the Mowbray, Chung and Greenleaf papers, Catala gives NETEVO clients with international footprints a two-jurisdiction Rules-as-Code substrate spanning both Australian and European DSL development. The four-corner debate then sits cleanly in the catalogue — implementation, DSL-design archetype, public-law critique, and defeasible-deontic-logic methodology — which is the defensible posture against any objection that naive Rules-as-Code maximalism is the position being argued.