# fsm cheatsheetEvery export of @deckyard/fsm. Guides are listed in the introduction .
jennifer import "@deckyard/fsm/" as fsm;Every failure is Error{kind: "fsm"}; errors a guard or hook throws pass through unchanged. An m argument is a Machine. A ctx argument is a map of string to string, {} when there is none.
# ConstantsConstant Value Meaning ERROR_KIND"fsm"the kind of every error the deck throws MAX_NAME100the longest machine, state or event name MAX_EDGES10000the most transition sources load accepts, summed over all transitions MAX_STATES10000the most entries load accepts in states and in final
# Types# MachineField Meaning name as stringthe machine's name, in messages and diagrams initial as stringthe state a new instance starts in states as list of stringevery state, in the order added finals as list of stringthe final states transitions as list of Transitionin the order added enter as map of string to funcenter hooks by state leave as map of string to funcleave hooks by state exits as map of string to list of stringeach state's outgoing events; kept by the deck routes as map of string to list of int"<state> <event>" to its transitions; kept by the deck
# TransitionField Meaning event as stringthe event that takes it sources as list of stringthe states it leaves from target as stringthe state it enters guard as functhe guard; the null function when there is none
# StepField Meaning event as stringthe event fired source as stringthe state left target as stringthe state entered ctx as map of string to stringthe context; after fire, as the hooks returned it
# ProblemField Meaning kind as string"unreachable", "dead-end" or "final-exit"state as stringthe state it is about message as stringwhat is wrong
# DefiningFunction Returns Does fsm.machine(name, initial)Machinea machine with one state fsm.addStates(m, names)Machineadd states fsm.addFinals(m, names)Machinemark states final fsm.addTransition(m, event, sources, target)Machineadd a transition fsm.addGuarded(m, event, sources, target, guard)Machineadd a transition taken when guard(step) is true fsm.onEnter(m, state, hook)Machinerun hook(step) on entering a state fsm.onLeave(m, state, hook)Machinerun hook(step) on leaving a state fsm.load(text, format, funcs)Machineread a machine from "toml", "yaml" or "json"; funcs maps the names it uses to functions fsm.check(m)list of Problemunreachable states, dead ends, final states with exits
# RunningFunction Returns Does fsm.fire(m, state, event, ctx)Steptake the transition, run the hooks fsm.can(m, state, event, ctx)boolwhether fire would succeed; runs guards, not hooks fsm.events(m, state, ctx)list of stringthe events that can be fired now fsm.isState(m, state)boolwhether a string is a state fsm.isFinal(m, state)boolwhether a state is final
# DrawingFunction Returns Does fsm.mermaid(m)stringa Mermaid stateDiagram-v2 fsm.dot(m)stringa Graphviz digraph