@amoroso @aartaka Standardized #lisp #commonlisp has a bunch of different embedded languages (LOOP -> macro-based transpiler, FORMAT strings -> interpreter and transpiler, CLOS -> extension of Lisp, ...). As libraries there are zillions more of those. Then CL inherits features from Lisp 1, Maclisp variants and has evolved from CLtL1, CLtL2, ANSI CL. One thing that is missing: CL-USER . The CL-USER package contains an implementation specific largely extended version of Common Lisp.