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hfsm.dev API Cheat Sheet

Globals

Machine and MachineT<>

Using default settings:

using M = hfsm2::Machine;

Customizable version:

using M = hfsm2::MachineT<
              TContext,                // data shared between states and external code
              Config<>,                // optional: config, see below
              TPayload                 // optional: transition payload
          >;

Config<>

hfsm2::Config<
    TUtility,                          // optional: customizable Expected Utility Value type (default: float)
    NMaxPlanTasks,                     // optional: max number of plans' entries across the entire FSM
                                       //                   (default: 2x number of sub-states in all regions)
    NMaxSubstitutions = 4              // optional: max number of guard substitutions
>

Regions

Abbreviations:

• H => Head
• SS => SubStates

Type	Root	Headless Root	Region	Headless Region
Composite	M::Root<H, SS>	M::PeerRoot<SS>	M::Composite<H, SS>	M::CompositePeers<SS>
Resumable	M::ResumableRoot<H, SS>	M::ResumablePeerRoot<SS>	M::Resumable<H, SS>	M::ResumablePeers<SS>
Utilitarian	M::UtilitarianRoot<H, SS>	M::UtilitarianPeerRoot<SS>	M::Utilitarian<H, SS>	M::UtilitarianPeers<SS>
Orthogonal	M::OrthogonalRoot<H, SS>	M::OrthogonalPeerRoot<SS>	M::Orthogonal<H, SS>	M::OrthogonalPeers<SS>

FSM Stucture Declaration

#define S(s) struct s

using FSM = M::Root<S(..),
               ..
            >;

#undef S

States

Overridable M::State Methods

Group	Methods
Pre-Conditions	Config::Utility utility(const Control&)
Guards	void entryGuard(GuardControl&) void exitGuard(GuardControl&)
Transition Events	void enter(PlanControl&) void exit(PlanControl&)
Periodic Updates	void update(FullControl&)
Event Reactions	void react(const TEvent&, FullControl&)
Plan Events	void planSucceeded(FullControl&) void planFailed(FullControl&)

Additional Overridable Region Head M::State Methods

Group	Methods
Plan Events	void planSucceeded(FullControl&) void planFailed(FullControl&)

State Bases

Default:

struct UserState
    : FSM::State
{}

Inject shared code (see Injections below for more details)

struct UserState
    : FSM::StateT<TInjection1, TInjection2>
{}

Injections

struct UserInjection
    : FSM::Bare
{}

Overridable Injection Methods

Group	Methods
Guards	void preEntryGuard(Context&) void preExitGuard(Context&)
Bounds	void preEnter(Context&) void postExit(Context&)
Periodic Updates	void preUpdate(Context&)
Event Reactions	void preReact(const TEvent&, Context&)

Controls

Control Inheritance Graph

GuardControl -> FullControl -> PlanControl -> Control

Functional Overview

Type	Additional Functionality
Control	Inspect
PlanControl	Modify plans
FullControl	Issue transitions Succeed and fail plans
GuardControl	Cancel in-flight transitions

Control Interface

Used in:

• M::State::utility()

Group	Methods
Inspect Structure	StateID stateId<TState>() RegionID regionId<TRegion>()
Access Context	Context& _() Context& context()
Query State Activity	bool isActive<TState>() bool isResumable<TState>() bool isScheduled<TState>()	bool isActive(StateID) bool isResumable(StateID) bool isScheduled(StateID)
Inspect Own Plan	ConstPlan plan()
Inspect Plans	ConstPlan plan<TRegion>()	ConstPlan plan(RegionID)

Additional PlanControl Interface

Used in:

• void enter(PlanControl&)
• void exit(PlanControl&)

Group	Methods
Modify Own Plan	Plan plan()
Modify Plans	Plan plan<TRegion>()	Plan plan(RegionID)

Additional FullControl Interface

Used in:

• void update(FullControl&)
• void react(const TEvent&, FullControl&)
• void planSucceeded(FullControl&)
• void planFailed(FullControl&)

Group	Methods
Initiate Transitions	void changeTo<TState>() void restart<TState>() void resume<TState>() void utilize<TState>() void schedule<TState>()	void changeTo(StateID) void restart(StateID) void resume(StateID) void utilize(StateID) void schedule(StateID)
Succeed / Fail Plans	void succeed() void fail()

Additional GuardControl Interface

Used in:

• void entryGuard(GuardControl&)
• void exitGuard(GuardControl&)

Group	Methods
Cancel In-Flight Transitions	void cancel()