This is a critical bug, since the code generation is left incomplete: [pjb@larissa :0.0 mocl]$ tail -20 /private/tmp/informatimago/jni/mocl/program.c COPY(ARG(2), ARG(8)); CALL0("+", Fplus(ARG(7), 2)); COPY(ARG(0), ARG(8)); COPY(ARG(7), ARG(9)); CALL0("<", Flt(ARG(8), 2)); if (CL_TRUEP(ARG(8))) { LOAD_SYMBOL(SYMBOL(Slisp, 0), ARG(0)); /* T */ COPY(ARG(7), ARG(1)); COPY(ARG(6), ARG(2)); CALL0("*", Fmult(ARG(1), 2)); COPY(ARG(1), &mv_buf[0]); mv_count = 2; } else { LOAD_NIL(ARG(8)); COPY(ARG(0), ARG(9)); COPY(ARG(2), ARG(10)); CO[pjb@larissa :0.0 mocl]$