| Chapter 17: Activities |

| 17.23. Asking which do you mean

1. When it happens. When the player has typed an ambiguous noun reference, and Inform has not been able to decide what was meant.

2. The default behaviour. A question such as "Which do you mean, the laminated mahogany box or the boom box?" is printed. (This activity shapes the question: it is not responsible for parsing the answer. It would be very mysterious to write rules for this activity such that nothing is printed, because the player would then have no idea what to type.)

3. Examples. The question is harder to print than may first appear, since one must not simply list the options, but also take into account collections of plural objects ("Which do you mean, the gold-tipped pen or a gold coin?''). It is probably better not to try to rewrite this.

(a) But we can place notes before or after: here is a verbose explanation for beginners to IF.

> Before asking which do you mean: say "Okay, so I'm going to have to ask a question now: you've typed something ambiguous, and I don't know which noun you're referring to."

> After asking which do you mean: say "(Just type a word or two to give me more information.)"

(b) We can also use this activity as a context for other activities. For instance:

> The Champs du Mars is a room. The great Eiffel Tower is here. "The great Tower stands high over you." The souvenir model Eiffel Tower is here. "Comparatively tiny is the souvenir version." The great Eiffel Tower is fixed in place. Understand "actual" as the great Tower.

> Rule for printing the name of the great Tower while asking which do you mean: say "actual Tower". Rule for printing the name of the souvenir tower while asking which do you mean: say "souvenir".

causes TAKE TOWER (for instance) to produce a nice tidy question in reply: "Which do you mean, the actual Tower or the souvenir?"

4. A note about actions. This activity takes place during the process of understanding the player's command, when the action that will take place is not fully known. So if the player types "TAKE SHOEBOX", this activity would happen when SHOEBOX is being examined for meaning. Inform knows that the action will be taking, but nothing else. That means attaching a proviso like "... while taking a container" to a rule for this activity will cause the rule to have no effect - whereas "... while taking" would be fine.

271
| Example Apples Prompting the player on how to disambiguate otherwise similar objects.

Inform by default detects whether two objects can be disambiguated by any vocabulary available to the player. If so, it asks a question; if not, it picks one of the identical objects at random. Generally this produces good behavior. Occasionally, though, two objects have some distinguishing characteristic that doesn't appear in the object name. For instance, suppose we've created a class of apples that can be told apart depending one whether they've been bitten or not: An apple is a kind of thing. Consumption is a kind of value. The consumptions are pristine and bitten. An apple has a consumption. The description of an apple is "It is [consumption]." Understand the consumption property as describing an apple. The player can meaningfully type >EAT BITTEN APPLE or >EAT PRISTINE APPLE but if he types >EAT APPLE Inform will, annoyingly, ask Which do you mean, an apple or the apple? This gives the player no indication of why Inform is making a distinction. So here we add a special "printing the name" rule to get around that situation: "Apples" Orchard is a room. An apple is a kind of thing. Consumption is a kind of value. The consumptions are pristine and bitten. An apple has a consumption. The description of an apple is "It is [consumption]." Understand the consumption property as describing an apple. Before printing the name of an apple while asking which do you mean: say "[consumption] ". Before printing the plural name of an apple while asking which do you mean: say "[consumption] ". The player carries three apples. Instead of eating a pristine apple: say "You take a satisfying bite."; now the noun is bitten. Instead of eating a bitten apple: say "You consume the apple entirely."; remove the noun from play. Inform will also separate the bitten from the pristine apples in inventory listings and room descriptions, even though it's not clear why; we can improve on that behavior thus: Before listing contents: group apples together. Rule for grouping together an apple (called target): let source be the holder of the target; say "[number of apples held by the source in words] apple[s], some bitten". Before printing the plural name of an apple (called target): let source be the holder of the target; if every apple held by the source is bitten, say "bitten "; if every apple held by the source is pristine, say "pristine ". Test me with "i / eat apple / i / eat apple / pristine / i / eat apple / pristine / i".

272
| Example Walls and Noses Responding to "EXAMINE WALL" with "In which direction?", and to "EXAMINE NOSE" with "Whose nose do you mean, Frederica's, Betty's, Wilma's or your own?"

Previous | Contents | Next