As we have seen, a well-written understand rule will often solve the problem of allowing the player to apply specific actions to objects not normally in scope. When we need to adjust scope for some other reason than reading the player's command, though, "deciding the scope of..." may come in handy.
For instance, suppose we wanted to extend Four Stars 1 to add a tomcat on the balcony that will be heard whenever the player listens from the next room, as in:
>listen
You hear the soothing whalesong from the Bose speaker and the yowling from the tomcat.
To this end, we're going to change the way we assess scope, but only during the listening action. Otherwise the tomcat remains in the other room and off-limits. The new source text is marked out below:
The Waning Moon Resort is a dark room. "A spacious room with a flagstone floor, and a dreamcatcher hung over the king-size bed." The dreamcatcher is scenery in the Resort. The description is "The usual web of threads and crystals, feathers and beads." Instead of taking the dreamcatcher, say "Ah, ah -- you might be tempted to take it as a souvenir, except that the price list in the minibar clearly states they charge $65 apiece if you walk off with one. Cheaper than stealing the Frette bathrobes, but still probably not a good idea."
{**}The Balcony is outside from the Resort. In the Balcony is a tomcat. The sound of the tomcat is "yowling". After printing the name of the tomcat when the tomcat is not visible: say " outside on the balcony".
From here we continue with the same scenario as before:
{**}The king-size bed is an enterable supporter in the Resort. The description is "200-thread-count Egyptian cotton sheets, according to the website. You would make fun, only they really are extraordinarily comfortable." The player is on the bed. A Lindt chocolate is on the bed. It is edible. The scent of the chocolate is "chocolate-hazelnut smell".
Instead of exiting: say "You are too weary to move."
An electric light is a kind of device. Carry out switching on an electric light: now the noun is lit. Carry out switching off an electric light: now the noun is unlit. Understand "light" as an electric light.
The solar lamp is an electric light in Waning Moon Resort. The description is "Specially designed to give light in a spectrum resembling sunlight, to improve the mood and make a person energetic." The lamp is switched on and lit.
An electric noisemaker is a kind of device. An electric noisemaker has some text called usual sound. The usual sound of an electric noisemaker is usually "beepbeepbeep". Carry out switching on an electric noisemaker: now the sound of the noun is the usual sound of the noun. Report switching on an electric noisemaker: say "[The noun] goes [usual sound of the noun]!" instead. Report switching off an electric noisemaker: say "You switch off [the noun], silencing the [usual sound of the noun]." instead.
Carry out switching off an electric noisemaker: now the sound of the noun is "silence".
The bedside table is in the Resort. The table supports a potted plant and a Bose speaker. The scent of the potted plant is "rosemary"
The Bose speaker is an electric noisemaker. The usual sound of the speaker is "soothing whalesong". The sound of the speaker is "soothing whalesong". The speaker is switched on.
Instead of touching a device: say "You feel the surface of [the noun] and discover the switch."
Instead of touching a scented thing: say "The brush of your fingers stirs loose a fresh cloud of [scent of the noun] smell."
Instead of examining an audible thing while in darkness: try listening to the noun. Instead of examining something while in darkness: try touching the noun.
say "You unceremoniously dump [the noun] into [the second noun], hoping it sustains no important damage thereby."
Before printing the name of a dark room: if the player can touch an audible thing, say "Noisy "; if the player can touch a scented thing, say "Perfumed ".
Visibility rule when in darkness:
if examining something, there is sufficient light;
say "You have at last escaped from the airport and gotten through customs; survived an unnerving taxi ride over icy highways; stared down the impertinent concierge; endured the bellhop's catalog of features in your room; and achieved, finally, a moment of peace. Time for a good night's slumber!"
Test me with "listen / x dreamcatcher / switch lamp off / look / sleep / eat chocolate / sleep / get plant / examine plant / open suitcase / put plant in suitcase / close suitcase / sleep / look / examine bose / switch bose off / sleep".