add convenience function to allow variable->set() command with a single string argument

  nvar++;

}

/* ----------------------------------------------------------------------

   convenience function to allow defining a variable from a single string

------------------------------------------------------------------------- */

void Variable::set(const std::string &setcmd)

{

  std::vector<std::string> args = utils::split_words(setcmd);

  char **newarg = new char*[args.size()];

  int i=0;

  for (const auto &arg : args) {

    newarg[i++] = (char *)arg.c_str();

  }

  set(args.size(),newarg);

  delete[] newarg;

}

/* ----------------------------------------------------------------------

   INDEX variable created by command-line argument

   make it INDEX rather than STRING so cannot be re-defined in input script

 public:

  Variable(class LAMMPS *);

  ~Variable();

  void set(const std::string &);

  void set(int, char **);

  void set(char *, int, char **);

  int set_string(char *, char *);