auto operator()() const noexcept {

using namespace sml;

const auto guard = [](const dependency& d) { /// more dependencies might be passed

return !d.i;

};

const auto action = [](dependency& d,

const auto& event) { /// event is deduced, order is not important

d.i = event.i + 42;

};

// clang-format off

return make_transition_table(

*"idle"_s + event<e1> [ guard ] / action = "s1"_s

, "s1"_s + event<e1> [ ([](const auto& event, const dependency& d) { return d.i == event.i; }) ] = X

);

// clang-format on

}

using namespace sml;

dependency d;

sm<dependencies> sm{d}; /// pass all dependencies (from guards, actions) via

/// constructor (order is not important)

assert(sm.is("idle"_s));

sm.process_event(e1{0});

assert(sm.is("s1"_s)); /// action sets dependency.i to 42

sm.process_event(e1{0});

assert(sm.is("s1"_s)); /// not satisfied, dependency.i(42) != event.i(0)

sm.process_event(e1{42});

assert(sm.is(X)); /// transition to X