Chapter 9: Time
9.11. Future events

We often want to arrange for something to happen at some point in the future. Here is yet another timepiece:

An egg-timer is in the Chamber. "A plastic egg timer in the shape of a chicken can be pressed to set it going."

Instead of pushing the egg-timer:
    say "It begins to mark time.";
    the egg-timer clucks in four turns from now.

At the time when the egg-timer clucks:
    say "Cluck! Cluck! Cluck! says the egg-timer."

The event here is called "the egg-timer clucks". It only happens if we instruct so, using one of the following phrases:

(rule) in (time) from now

This phrase causes the given rule to be run at a given time offset from the current time of day. Example:

the egg-timer clucks in 18 minutes from now;

(rule) in (number) turn/turns from now

This phrase causes the given rule to be run at a given number of turns after the current one. Example:

the egg-timer clucks in four turns from now;

(rule) at (time)

This phrase causes the given rule to be run at a given time of day. Example:

the egg-timer clucks at 11:35 AM;

If we know in advance what time we want something to happen, we can more simply write:

At 4 PM: say "The great bells of the clock tower chime four."

(Note that in either case such rules begin with the word "at": they are the only rules allowed to begin with the word "at".)


143
* Example  MRE
Hunger that eventually kills the player, and foodstuffs that can delay the inevitable by different amounts of time.

RB
144
** Example  Totality
To schedule an eclipse of the sun, which involves a number of related events.

RB

First we define the events, and then we create a phrase to schedule them:

"Totality"

At the time when the penumbra appears:
    say "The sunlight dies away to an eerie, brownish penumbra."

At the time when the eclipse begins:
    say "The moon passes across the disc of the sun, plunging the world into darkness.";
    now the Chamber is dark.

At the time when the eclipse ends:
    say "The moon passes away from the sun, and a gloomy penumbral light returns.";
    now the Chamber is lighted.

At the time when normal sunlight returns:
    say "The sun shines once more bright in the sky, not to be eclipsed again on this spot for another thirty-seven years."

To schedule an eclipse for (totality - a time):
    the penumbra appears at two minutes before totality;
    the eclipse begins at totality;
    the eclipse ends at three minutes after totality;
    normal sunlight returns at five minutes after totality.

Now we make use of the new phrase:

When play begins, schedule an eclipse for 3:27 PM.

The Chamber is a room.

The time of day is 3:25 PM.

Test me with "z / z / z / z / z / z / z / z / z".

We shall see much more about creating phrases later. Their advantage is that they enable a complicated sequence of operations to be given a meaningful name, and that they can be re-used many times as needed.

145
** Example  Empire
A train which follows a schedule, stopping at a number of different locations.

RB
146
*** Example  Hour of the Wren
Allowing the player to make an appointment, which is then kept.

RB


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