code: public static boolean operate(PageContext pc, String[] varNames) {
  	int scope = VariableInterpreter.scopeString2Int(pc.ignoreScopes(), varNames[0]);
  	return _operate(pc, scope, KeyImpl.toKeyArray(varNames), scope == Scope.SCOPE_UNDEFINED ? 0 : 1);
      }
docs: called by the Elvis operator from the interpreter
  
  @param pc
  @param scope
  @param varNames
  @return