title: clear all variable and functions defined by user in V8 javascript engine console
body: <p>I am compiling a custom V8 javascript engine. What i want to do is delete only the functions and variables defined by users at runtime and not the functions defined in native code ie c++. currently i am making to shell.cc file given in samples of the v8 engine.
  If not possible is there a way to redefine all native functions again after a script finishes its execution in c++
  any help is appreciated</p>