Definitions

• Variable Transition Value: Any variable value that depends on the level of recursion.
• Variable Transition Vector: The vector containing all variable transitions values, and is dynamically changed from level to level.
• Recursive State: A state calling another state recursively, and this state is responsible for changing the variable transition vector to its new value according to the new level.
• Dead-End State: A state that does not call any other state (no transition arrows come out of it). In DRFSM, when this state is reached, it means to go back to a previous level, or quit if it is the first level. This state is usually called the Error-trapping state. It is desirable to have several dead-end states to represent different types of errors that can happen in the system.