File r37/lisp/csl/jlisp/Symbol_set_envFn.java from the latest check-in
//07/03/02 //purely made for testing and looking at jvm Bytecodes by javap -c class Symbol_set_envFn extends BuiltinFunction { public LispObject op2(LispObject arg1, LispObject arg2) throws Exception { if (!(arg1 instanceof Symbol)) return Jlisp.nil; LispFunction f = ((Symbol)arg1).fn; if (f instanceof FnWithEnv) ((FnWithEnv)f).env = ((LispVector)arg2).vec; else return Jlisp.nil; // quiet in case it fails? return ((Symbol)((FnWithEnv)f).env[0]).fn.op0(); //return arg2; } }