If code is law, as Lawrence Lessig famously argued, then the language of law is a programming language. The ProLaLa community is united by the recognition that PL theorists and legal theorists can learn from each other, and that PL tools can be usefully applied to legal problems. In this talk I will survey the history of PL+law, taxonomize types of PL+law research, and discuss some promising avenues for future efforts. My goals are to explain how PL+law is distinctive within the broader field of CS+law, and demonstrate with concrete examples the remarkable power of PL concepts in this new domain.