How "fsm" should work

[tcr]

The current "sequence" blocks are designed to convert sequential code into a state machine. This makes state machines easy to write, but hard to leverage their full expressive power.

A complementary "fsm" block may make it easy to author states:

fsm my_state {
    IDLE => {
        led <= 0;
        if start_condition {
            my_state <= ACTIVE;
        }
    }
    ACTIVE => {
        led <= 1;
        if some_condition {
            my_state <= IDLE; // maybe "next IDLE;" or "fsm <= IDLE;" for anonymous
        }
    }
}

Some questions:

1. Can we elide my_state in most cases?
2. Can we reference my_state outside of the fsm? Can we change (or check) its value from other blocks?
3. Is an explicit my_state <= {value} allowed inside the fsm?
4. How do you declare the initial state; is it just the first state?
5. How does scoping of states work inside of fsm?
6. Can we nest fsms?