!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!       DOORS           An INFORM 6.10 library creating easy-to-code doors
!                       By L. Ross Raszewski <rraszews@skipjack.bluecrab.org>
!
!  According to "The Inform Designer's Manual, 3rd edition" (reprinted 
! without permission)
! To set up a door:
!
!   (a) give the object the door attribute;
!   (b) set its door_to property to the destination;
!   (c) set its door_dir property to the direction which that would be,
!       such as n_to;
!   (d) make the room's map connection in that direction point to the door
!       itself.
!
! Yeah, right.  The majority of doors you'll meet in real life are two-sided
! and anyone who's tried to code up a two-sided door in Inform knows what 
! they're in for. You'll need something like a
!       door_to [; if (location == shrine) return jungle; return shrine;],
! and a 
!       door_dir [; if (location == shrine) return u_to; return d_to;],
! Now, I'll agree this isn't all that bad, but I'm sure you've wished it 
! was easier.  Many a newbie has died trying to code up something lke this.
!
! Not anymore.
!
! Observe if you will the Connector class.
!
! Suppose you need a door between roomA and roomB, where roomA is to the east 
! of roomB.
!
!
!  Connector door "door"
!        with name "door",
!             e_to roomA,
!             w_to roomB,
!             when_open "The door is open",  
!             when_closed "The door is closed",
!        has openable;
!
! Voila!  This simple syntax is equivalent to the conventional syntax:
!
! Object door "door"
!        with name "door",
!             door_to [; if (location == roomA) return roomB; return roomA;],
!             door_dir [; if (location == roomB) return e_to; return w_to;],
!             when_open "The door is open",  
!             when_closed "The door is closed",
!             found_in roomA roomB;
!        has openable door static;
!
! I can hear you now.  "What?  I save three lousy lines?"  Well, yeah, but in
! a game with a lot of doors, you've saved yourself some syntax. And it 
! certaintly is more intuitive.
! 
! The only catch, for the sake of economy, is that you have to call the 
! function InitDoors(); in your initialise.
!
! Also by the author:
!               The AltMenuing system
!       Center          Centers a line of text in either window.
!       Domenu          Improved menuing with multiple description lines
!       Altmenu         Object oriented menuing system
!       Hints           Altmenu hint system
!       Sound           The Inform Sound System
!       YesNo           pseudo-rhetorical Yes or no questions
!       Date            Datekeeping and printing
!       Footnote        Autonumbering footnotes
!       Locktest        Default key selection
!       Newlock         Key-side lock definition
!       Ordinal         Ordinal number printing
!       Whatis          "What is a" questions
!       Senses          Recursive sensory perception
!       Pmove           Move objects into the tree as the youngest object
!       Movie           Non-interactive cut-scenes
!       Manual          inform "instruction manual" system
!       
!  Coming soon:
!       Converse        Hit-word based conversation
!       MenuTalk        Menu-based Conversation
!       UniCursr        Unicursor- Text adventures with the contol simplicity
!                       of omnifunction click graphic games (ie. Type "clock" 
!                       to examine, take, or manipulate the clock)
!
!       Please write me and tell me what you think.

Class Connector
            with door_dir [; if (location==self.sidea) 
                                                return self.dira;
                                                return self.dirb;
                       ],
             door_to  [; if (location==self.sidea) 
                                                return self.sideb;
                                                return self.sidea;
                       ],
             
             sidea 0,
             dira 0,
             sideb 0,
             dirb 0,
             found_in 0 0,
        has door static;

[ InitDoors o i j;
        objectloop (j ofclass Connector) { 
                objectloop (o in compass)
                                { i=o.door_dir;
                                  if (j provides i)
                                        { j.sidea=j.i;
                                          j.dirb=i;
                                        };
                                  };
                            objectloop (o in compass)
                                { i=o.door_dir;
                                  if ((j provides i) && (j.dirb~=i))
                                        { j.sideb=j.i;
                                          j.dira=i;
                                        };
                                  };
                            j.&found_in-->0=j.sidea;
                            j.&found_in-->1=j.sideb;
        };
];