LIS (Language d'Implementation de Systèmes) was a system implementation programming language designed by Jean Ichbiah, who later designed Ada.
LIS was based on Pascal and Simula.[1] It was used to implement the compiler for the Ada-0 subset of Ada at Karlsruhe on the BS2000 Siemens operating system.[2] Later on the Karlsruhe Ada compilation system got rewritten in Ada-0 itself, which was easy, because LIS and Ada-0 are very close.
LIS was an experimental implementation language designed by Jean Ichbiah on Siris8. LIS was not used on commercial CII products. LIS was inspired by Pascal and Simula and has contributed to the definition of Ada.