code: public boolean removeVariable(String varName) {
  	if (values == null) return false;
          Iterator iter = values.iterator();
          Binding binding;
          int i=0;
          int found = -1;
          while( iter.hasNext() ) {
              binding = (Binding)iter.next();
  	    if (binding.getName().equals(varName)) {
  		found = i;
  		break;
  	    }
  	    i++;
  	}
          if (found != -1) {
              values.remove(found);
              return true;
          } else {
              return false;
          }
      }
docs: Removes a specific variable definition from
  the list of bindings. The variable name must
  match exactly to be removed (it is case sensitive).
  
  @param varName variable name to remove the definition of.
  @return true if the variable was successfully removed.
  False, otherwise.