Timers

A define timer counts turns by name. You never write a number: you name the turns, the timer steps through them one per turn once started, and it ends in the one state every timer shares, expired, which is never written. It is the second kind of counter beside a tally: a tally counts things and moves only when you raise, lower, or set it; a timer counts turns and takes only the timer verbs. The compiler rejects each kind's verbs on the other.

define timer waiting for the player
  pausing
  loitering
  interrupted one chance in 2
end timer

define timer search for the wandering mercenaries
  arriving
  lingering
    Those mercenaries are getting uncomfortably close. You'd better get going
    before they notice you!
  meanwhile, one chance in 5
    phrase merc-idle
end timer

define timer lunge for the wandering mercenaries
end timer

for <owner> hangs the timer on an entity or the player; with no for it belongs to the story. Each line before end timer is one of three things. A state name is one turn, and it may carry an indented text body spoken the turn that state is reached, exactly as a phrase line does. meanwhile — at most one — holds statements that run on every turn the timer is running, alongside the turn's state; with , one chance in N they run occasionally, on the story's seeded stream. interrupted one chance in N — at most one — gives each running turn that chance of expiring right then instead of stepping. A timer with no state lines is legal: one turn, then expired.

A timer knows nothing but turns. It is not bound to a room, a state, or a condition; the conditions under which it runs are the ordinary conditions of the clauses that start and reset it.

The verbs

start search        ## begins; first named state next turn
stop search         ## holds where it is
restart search      ## back to the first state and running
reset search        ## back to not-started
interrupt search    ## expires now — `when … expires` fires as if it had run out

Inside the owner's block a timer is named bare (start lunge); elsewhere by possessive (restart the player's waiting, reset the mercenaries' search). start on a running timer is a no-op; restart is the explicit form. A stopped timer never expires on its own — interrupt is the one verb that acts from any started state, and on a not-started timer it is a no-op, like reset.

Reading a timer

is reads the named turn and has reads the lifecycle; the two do not overlap:

while search is lingering        ## the named turn
while search has started         ## running or expired
while search has expired         ## over — the only spelling; `is expired` is rejected

A timer state and an entity state may share a word: the subject disambiguates, and the analyzer checks each against its own subject's list.

Expiry is an event

Expiry gets a clause head on the owner, parallel to define sequence's when <owner> becomes <state>:

create the wandering mercenaries
  a person, plural
  states, reversible: approaching, searching

  when search expires
    change the wandering mercenaries to approaching
    start lunge
    phrase merc-spotted
  end when

From outside the owner the head is possessive — when the player's waiting expires, when the mercenaries' search expires — and a , while <condition> modifier is legal on it as on every clause head.

A timer started during turn T is in its first named state on T+1 and expires the turn after its last named state; one with no states expires on T+1. expires fires exactly once per run, whether the timer ran out, was interrupted by chance, or by the verb. meanwhile never runs on the expiring turn. A timer's position is ordinary world state on its owner, so it rides save, restore, and undo like a counter does — and it is one of the moments a chapter can begin on.