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Mike Sousa
 Post subject: Ordering <something>
PostPosted: Tue Apr 10, 2012 2:17 pm 
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Joined: Thu Mar 01, 2012 9:08 pm
Posts: 31
I'm looking to implement the following:

>ORDER something

... where something is hopefully obvious to the player, but I need it to be flexible enough to trap some other responses.

I could have hidden objects in the location and trap the ORDER verb there, but I was wondering if there was a different way to accomplish this, like CONSULT topic.

Any ideas?

Thanks!
-- Mike
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Jim Aikin
 Post subject: Re: Ordering <something>
PostPosted: Tue Apr 10, 2012 2:37 pm 
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Joined: Sun Mar 01, 2009 8:02 pm
Posts: 904
One way to do it ... try searching for "scope" in the docs (using the Search field in the upper right corner of Workbench). You'll find that the Technical Manual has an article called "Redefining Scope." This will show you a way to put any object in the game in scope for purposes of your new verb.

Another way is using Topic objects, which need not be present in the model world at all. The Tech Manual's "How to Create Verbs" article discusses creating verbs that work with Topics.
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bcressey
 Post subject: Re: Ordering <something>
PostPosted: Tue Apr 10, 2012 2:52 pm 
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Joined: Tue Apr 27, 2010 1:02 pm
Posts: 798
I'm not clear on what you're after, but you can use a LiteralAction to capture undirected free-form text from the player. Possibly this is too flexible for your needs.

In the example below, a few special cases are trapped and handled, and the rest are diverted to a secondary action for standard processing.

Code:
VerbRule(Order)
   'order' singleLiteral
   : OrderAction
   verbPhrase = 'order/ordering (what)'
;

VerbRule(OrderThing)
   'orderthing' singleDobj
   : OrderThingAction
   verbPhrase = 'order/ordering (what)'
;

DefineLiteralAction(Order)
   execAction() {
      switch(getLiteral.toLower) {
         case 'lunch':
         case 'sandwich':
            "You place an order for a sandwich. ";
            break;
         case 'launch':
         case 'attack':
         case 'strike':
         case 'nuclear strike':
            "You advise the generals to launch at will. ";
            break;
         default:
            local toks = Tokenizer.tokenize('orderthing ' + getLiteral.toLower);
            executeCommand(gActor, gActor, toks, true);
            break;
      }
   }
;

DefineTAction(OrderThing);

modify Thing
   dobjFor(OrderThing) {
      verify() { illogical('You are not sure how to order that. '); }
   }
;
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Mike Sousa
 Post subject: Re: Ordering <something>
PostPosted: Tue Apr 10, 2012 3:15 pm 
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Joined: Thu Mar 01, 2012 9:08 pm
Posts: 31
Jim, thanks -- I've read that technical article more times than I care to admit, but it wasn't until I read bcressey's response that I realized I was approaching it from the wrong angle.

Bcressey, thanks for that; it's what I'm looking for. Since I plan on lifting most of that code, I will add you to the Credits list. :)

-- Mike
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Jim Aikin
 Post subject: Re: Ordering <something>
PostPosted: Tue Apr 10, 2012 3:40 pm 
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Joined: Sun Mar 01, 2009 8:02 pm
Posts: 904
Please correct me if I'm wrong, but my impression is that Ben Cressey's code for DefineLiteralAction will work correctly for 'order sandwich' but will fail if the player types 'order a sandwich'. The advantage of using Topic objects, I'm pretty sure, is that things like articles and adjectives can be understood and handled.
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bcressey
 Post subject: Re: Ordering <something>
PostPosted: Tue Apr 10, 2012 3:53 pm 
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Joined: Tue Apr 27, 2010 1:02 pm
Posts: 798
Happy to help!

I noticed some artifacts in the output when using UNDO with the above code. Replacing the OrderThing stub with this code should fix it:

Code:
DefineTAction(OrderThing)
   includeInUndo = nil
   actionTime = 0
;


That way the extra action doesn't count against the player's time, and undo will skip over it.

Jim Aikin wrote:
Please correct me if I'm wrong, but my impression is that Ben Cressey's code for DefineLiteralAction will work correctly for 'order sandwich' but will fail if the player types 'order a sandwich'. The advantage of using Topic objects, I'm pretty sure, is that things like articles and adjectives can be understood and handled.


The simple switch statement in the execAction can be replaced with string methods to do more sophisticated matching. Also, the VerbRule can be expanded to handle articles, so you don't have to worry about them when processing the literal.

Code:
VerbRule(Order)
   'order' | ('order' ('a' | 'the' | 'an' | 'some' )) singleLiteral
   : OrderAction
   verbPhrase = 'order/ordering (what)'
;


You're right that this approach is not a good general practice. The alternative approach I came up with - an invisible actor who comes into scope during Order actions, and responds to topics by executing some code - strikes me as too convoluted, though it would leverage the parser rather than doing an end-run around it.
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RealNC
 Post subject: Re: Ordering <something>
PostPosted: Tue Apr 10, 2012 4:02 pm 
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Joined: Tue Apr 20, 2010 2:48 pm
Posts: 695
Does ORDER mean ORDER A BEER? In that case, I think it's more natural to implement it as ASK WAITER FOR BEER (and remapping ORDER to it.) If, however, it means ORDER THE LIEUTENANT TO RETREAT, then bcressey's advice is probably the way to go.
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Mike Sousa
 Post subject: Re: Ordering <something>
PostPosted: Tue Apr 10, 2012 4:20 pm 
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Joined: Thu Mar 01, 2012 9:08 pm
Posts: 31
Good points, considering I was vague in my original post.

Since I only need the command to work one time -- and it's an alternate to the preferred method -- I can certainly use the sample code above.

RealNC wrote:
Does ORDER mean ORDER A BEER? In that case, I think it's more natural to implement it as ASK WAITER FOR BEER (and remapping ORDER to it.) If, however, it means ORDER THE LIEUTENANT TO RETREAT, then bcressey's advice is probably the way to go.


Heh. Well, therein lies the rub. If Sherwin had made the order taker a waiter, or a bartender, or human for that matter, I completely agree with the remapping... ;)

-- Mike
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Mike Sousa
 Post subject: Re: Ordering <something>
PostPosted: Wed Apr 11, 2012 7:51 pm 
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Joined: Thu Mar 01, 2012 9:08 pm
Posts: 31
bcressey wrote:
The simple switch statement in the execAction can be replaced with string methods to do more sophisticated matching. Also, the VerbRule can be expanded to handle articles, so you don't have to worry about them when processing the literal.

Code:
VerbRule(Order)
   'order' | ('order' ('a' | 'the' | 'an' | 'some' )) singleLiteral
   : OrderAction
   verbPhrase = 'order/ordering (what)'
;


Note that this code doesn't work (ORDER LUNCH results in "The story doesn’t understand that command.") and if just ORDER is entered, it sorta crashes. It only works if you type >ORDER A <ENTER> followed by the dobj.

Sorry that I am posting this without the fix; I would if I could, but I can't so I didn't. Or something like that...

In any event, because I need this for an isolated event, I can live with the existing code.

(I figured I would mention the code issue above in case somebody else wanted to use it...)

-- Mike

(EDIT: I felt bad about not really trying to fix it, so I did)

This works instead:
Code:
VerbRule(Order) ('order' singleLiteral) | ('order'  ('a' | 'an' | 'the' | 'some') singleLiteral): OrderAction


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RealNC
 Post subject: Re: Ordering <something>
PostPosted: Wed Apr 11, 2012 8:35 pm 
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Joined: Tue Apr 20, 2010 2:48 pm
Posts: 695
Mike Sousa wrote:
bcressey wrote:
Code:
VerbRule(Order)
   'order' | ('order' ('a' | 'the' | 'an' | 'some' )) singleLiteral
   : OrderAction
   verbPhrase = 'order/ordering (what)'
;


Note that this code doesn't work (ORDER LUNCH results in "The story doesn’t understand that command.")


I believe that's because you forgot to allow "nothing" as a possibility, and also make the single 'order' case depend on the singleLiteral. What you want is:

Code:
  ('order' | ('order' ( /*nothing*/ | 'a' | 'the' | 'an' | 'some'))) singleLiteral


There are many ways to write the above rule, mind you. For examle a cleaner form:

Code:
  ('order' ( /*nothing*/ | 'a' | 'the' | 'an' | 'some')) singleLiteral


(No guarantees though; I didn't actually test this, but I'm sure it should work :))

The above translates to:

ORDER followed by nothing or A or THE or AN or SOME and ending with a singleLiteral.

It's pretty much standard EBNF (it was chosen because it's well known), so the same rules apply.
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