-- Cet exemple est clairement trop compliqué.


node diff(incr, decr: bool) returns (diff: int)
let
    diff = (0 -> pre diff) +
        (if incr and not decr then 1
        else if not incr and decr then -1
        else 0);
tel

node train(beacon, second: bool) returns (early, late: bool)
var probe advance: int;
let
    advance = diff(beacon, second);

    automaton
        initial state NotEarly
        unless if advance > 10 resume Early;
        let early = false; tel

        state Early
        unless if advance = 0 resume NotEarly;
        let early = true; tel
    returns early;

    automaton
        initial state NotLate
        unless if advance < -10 resume Late;
        let late = false; tel

        state Late
        unless if advance = 0 resume NotLate;
        let late = true; tel
    returns late;
tel

node observer(early, late: bool) returns (alarm: bool)
var ontime: bool;
let
    ontime = not (late or early);
    automaton
        initial state Ok
        unless if early resume Early;
        let alarm = false; tel

        state Early
        unless if ontime resume Ok;
        let alarm = late; tel
    returns alarm;
tel

node train_check(beacon, second: bool) returns (early, late, alarm: bool)
let
    early, late = train(beacon, second);
    alarm = observer(early, late);
    guarantee ok : not alarm;
tel

node test(i: int) returns(a, b, c: int; exit: bool)
var early, late, alarm: bool;
let
    exit = i >= 100;
    early, late, alarm = train_check((i+1) mod 2 = 0, i mod 3 = 0);
    c = if alarm then 1 else 0;
    a = if early then 1 else 0;
    b = if late then 1 else 0;
tel