X-Git-Url: https://jxself.org/git/?p=ibg.git;a=blobdiff_plain;f=chapters%2F12.rst;fp=chapters%2F12.rst;h=0260f67233a9f16e37de7eb10843fdd3d762af46;hp=f7009c6a04789ce1257e369e840f45bc349ac553;hb=fb8b7c14f10733e913e2b87f9a82e5b44c0dc7be;hpb=54830106a3ef48c411e0346f54bfb56f3072b8a2 diff --git a/chapters/12.rst b/chapters/12.rst index f7009c6..0260f67 100644 --- a/chapters/12.rst +++ b/chapters/12.rst @@ -20,7 +20,10 @@ owner of Benny's café to be developed in full. Too many toilets ================ -If you check the ``name`` properties of the toilet door, the toilet key +.. index:: + single: ambiguous objects + +If you check the :prop:`name` properties of the toilet door, the toilet key and the toilet room, you’ll see that the dictionary word ``'toilet'`` occurs in all of them. There won't be any problems if players mention the words DOOR or KEY, but we reach a strange impasse should they try to @@ -78,21 +81,21 @@ some routines at the heart of the standard library; these may not be identical in other Inform versions. The introduction explains what ``pname.h`` does for you; namely, it lets -you avoid using complicated ``parse_name`` routines to disambiguate the +you avoid using complicated :prop:`parse_name` routines to disambiguate the player's input when the same dictionary word refers to more than one -item. A ``parse_name`` routine would have been the solution to our +item. A :prop:`parse_name` routine would have been the solution to our problem before the existence of this file, and it qualifies as an advanced programming topic, difficult to master on a first approach. Fortunately, we don't need to worry. Neil Cerutti explains: The ``pname.h`` package defines a new object property, ``pname`` (short for phrase name), with a similar look and feel to the standard - ``name`` property: both contain a list of dictionary words. However, + :prop:`name` property: both contain a list of dictionary words. However, in a ``pname`` property the order of the words is significant, and special operators ``'.p'`` ``'.or'`` and ``'.x'`` enable you to embed some intelligence into the list. In most cases where the standard - ``name`` property isn't enough, you can now just replace it with a - ``pname`` property, rather than write a ``parse_name`` property + :prop:`name` property isn't enough, you can now just replace it with a + ``pname`` property, rather than write a :prop:`parse_name` property routine. We'll soon see how it works. Let's take a look at the installation @@ -147,7 +150,7 @@ providing replacements for some standard routines. Now our source code is ready to benefit from the library package. How does it work? We have acquired a new property -- ``pname`` -- which can be added to some of our objects, and which works pretty much like a -``name`` property. In fact, it should be used *instead* of a ``name`` +:prop:`name` property. In fact, it should be used *instead* of a :prop:`name` property where we have a disambiguation problem. Let’s change the relevant lines for the toilet door and the toilet key: @@ -229,7 +232,7 @@ code. Remember Benny's basic definition from the previous chapter: strikes him.", has scenery animate male proper transparent; -We can now add some complexity, beginning with a ``life`` property. In +We can now add some complexity, beginning with a :prop:`life` property. In generic form: .. code-block:: inform @@ -296,9 +299,9 @@ capability), is more local property variables: live [; ... -Now we are ready to tackle the ``Give`` action of the ``life`` property, +Now we are ready to tackle the ``Give`` action of the :prop:`life` property, which deals with commands like GIVE THE KEY TO BENNY (in a moment, we'll -come to the ``Give`` action of the ``orders`` property, which deals with +come to the ``Give`` action of the :prop:`orders` property, which deals with commands like BENNY, GIVE ME THE KEY): .. code-block:: inform @@ -326,7 +329,7 @@ commands like BENNY, GIVE ME THE KEY): back anytime,~ he says."; } -The Give action in the ``life`` property holds the variable ``noun`` as +The Give action in the :prop:`life` property holds the variable :var:`noun` as the object offered to the NPC. Remember that we can use the ``switch`` statement as shorthand for: @@ -340,7 +343,7 @@ We won't let players give away their clothes or their costume (yes, an improbable action, but you never know). The toilet key and the coin are successfully transferred. The property ``key_not_returned`` will be set to true when we receive the toilet key from Benny (we have not coded that bit -yet), and now, when we give it back, it's reset to ``false``. The ``move`` +yet), and now, when we give it back, it's reset to :const:`false`. The ``move`` statement is in charge of the actual transfer of the object from the player's inventory to Benny, and we finally display a confirmation message. With the coin, we find a new statement: ``remove``. This extracts @@ -350,7 +353,7 @@ object permanently -- and indeed you could return it to the object tree using the ``move`` statement); as far as the player is concerned, there isn’t a COIN to be found anywhere. The ``coffee_not_paid`` property will be set to true when Benny serves us the cup of coffee (again, we’ll see that -in a moment); now we reset it to ``false``, which liberates the player from +in a moment); now we reset it to :const:`false`, which liberates the player from debt. This culminates with the ``"..."`` print-and-return statement, telling the player that the action was successful. In passing, remember that in :ref:`homely-atmos` we defined the counter such that PUT KEY ON @@ -366,11 +369,11 @@ indulge in caffeine. Once the coin is paid, it disappears for good, supposedly into Benny's greedy pockets. No need to worry about it any more. -The benny object needs also an ``orders`` property, just to take care of +The benny object needs also an :prop:`orders` property, just to take care of the player's requests for coffee and the key, and to fend off any other -demands. The ``Give`` action in an ``orders`` property deals with inputs +demands. The ``Give`` action in an :prop:`orders` property deals with inputs like ASK BENNY FOR THE KEY or BENNY, GIVE ME THE KEY. The syntax is -similar to that of the ``life`` property: +similar to that of the :prop:`life` property: .. code-block:: inform @@ -412,7 +415,7 @@ similar to that of the ``life`` property: } ], -* We test the value of ``second`` in order to trap over-generous +* We test the value of :var:`second` in order to trap over-generous gestures such as BENNY, GIVE COFFEE TO CUSTOMERS . Then we consider potential requests. @@ -425,9 +428,9 @@ similar to that of the ``life`` property: possessions -- a perverse player could get the key, then drop it somewhere and ask for it again; if this should happen, we indicate that Benny is nobody's fool with the message ``"~Last place I saw - that key..."``. Once all these fitting conditions are ``true``, + that key..."``. Once all these fitting conditions are :const:`true`, players will get the key, which means that they have to return it -- - the ``key_not_returned`` property becomes ``true`` -- and we display + the ``key_not_returned`` property becomes :const:`true` -- and we display a suitable message. However, if the player didn't ask for a coffee, Benny refuses to oblige, mentioning for the first time the menu board where players will be able to see a picture of a cup of coffee when @@ -437,9 +440,9 @@ similar to that of the ``life`` property: * **Coffee:** we check whether players have already asked for a coffee, by testing the ``coffee_asked_for`` property, and refuse to serve - another one if ``true``. If ``false``, we place the coffee on the + another one if :const:`true`. If :const:`false`, we place the coffee on the counter, and set the properties ``coffee_asked_for`` and - ``coffee_not_paid`` to ``true``. The message bit you know about. + ``coffee_not_paid`` to :const:`true`. The message bit you know about. * **Food:** we'll provide an object to deal with all of the delicious comestibles to be found in the café, specifically those (such as @@ -520,13 +523,13 @@ description: we could have assigned a new value to the ``player.description`` variable, but opted to use the ``LibraryMessages`` object instead. This is a similar case. The code causing Benny to intercept the forgetful player could have been added, -perhaps, to a ``daemon`` property in Benny’s definition. However, since +perhaps, to a :prop:`daemon` property in Benny’s definition. However, since the action to be intercepted is always the same one and happens to be a movement action when the player tries to leave the café room, it is also possible to code it by trapping the ``Go`` action of the room object. Both would have been right, but this is somewhat simpler. -We have added a ``before`` property to the room object (albeit a longish +We have added a :prop:`before` property to the room object (albeit a longish one), just dealing with the ``Go`` action. As we mentioned in an earlier chapter, this technique lets you trap the player who is about to exit a room before the movement actually takes place, a good moment to @@ -559,9 +562,9 @@ The first three are covered by the test: if (benny.coffee_not_paid == true || benny.key_not_returned == true) ... that is, if either the coffee is not paid for *or* if the key is not -returned. When this condition is ``false``, it means that both +returned. When this condition is :const:`false`, it means that both misdemeanours have been avoided and that the player is free to go. -However, when this condition is ``true``, the hand of Benny falls on the +However, when this condition is :const:`true`, the hand of Benny falls on the player's shoulder and then the game displays a different message according to which fault or faults the player has committed.