10. Interpret

  Suppose you have a variable "inst" which contains the string "a=a+1".  You
  can execute that string as an instruction, by typing:

      interpret inst

  The interpret instruction may be used to accept Rexx instructions from
  the user, or to assign values to variables whose names are not known in
  advance.

      /* Input the name of a variable, and set that variable to 42 */
      parse pull var
      interpret var "=" 42