v/vlib/datatypes/fsm/README.md

fsm

This module implements a Finite State Machine (FSM). The FSM is composed of states and transitions between them. These need to be specified by the client.

Usage

Have a look at fsm_test.v for usage examples.

On each run(), all the possible transitions from the current state are evaluated. The first transition for the current state, whose condition evaluates to true is taken (the condition is specified by a transition callback function).

In a successfull transition, the current state changes to the new one. When that happens:

• the client-specified on_exit() handler from the current state is called.
• the client-specified on_entry() handler of the new state is called.

After all transitions are checked, and thus the state is changed, the client-specified on_run() handler of the now current state is called.