infocom/compilers/inform5/examples/thief.inf

!--------------------------------------------------------------------------
! THE THIEF: an interactive demonstration by Gareth Rees
! 
! The Inform designer's manual has a brief example of a thief who can walk
! around the map like the player does.  However, that example didn't really
! exploit the full complexities of Inform movement rules, so here's an
! example game in which the thief can walk through doors, pick locks, cross
! bridges and so on, and change his actions as the map changes.
! 
! There are various subtleties.  First of all, some movement routines print
! messages when the player travels (e.g. "You duck your head as you go
! through the door.").  Clearly, these should be modified or omitted when
! the thief moves, so we provide a global variable `moving_thief' which is
! set to 1 when the thief is moving so that the movement routines can
! modify their behaviour appropriately.
! 
! Second, doors report their destination and direction by checking to see
! which room they are in, for example:
! 
!       door_dir [;
!           if (self in EastSide) return w_to;
!           return e_to;
!       ],
! 
! If you want this to work with the thief you should be careful to avoid
! the following, which although apparently equivalent, doesn't quite work:
! 
!       door_dir [;
!           if (location == EastSide) return w_to;
!           return e_to;
!       ],
! 
! The problem is that `location' always refers to where the player is, and
! the thief might be somewhere else entirely.  Even in the first case, we
! still have to take care to move the door to where the thief is (it might
! have been moved elsewhere by `MoveFloatingObjects').
!--------------------------------------------------------------------------

Constant DEBUG;
Constant Story "THE THIEF";
Constant Headline "^An interactive demonstration^by Gareth Rees^";
Global moving_thief = 0;

Include "parser";
Include "verblib";

[ Initialise;
    location = EastSide;
    StartDaemon(Thief);
    "^^^^^The question is, who's going to get the treasure, you or that \
    pesky thief?^^";
];


!--------------------------------------------------------------------------
! PEOPLE WHO CARRY/WEAR OBJECTS
! 
! People who are members of CarryingClass can wear clothing and carry
! objects, and (unless concealed) they will be listed (in two lists, one
! for clothing, one for everything else) when the person is examined.
! 
! Note: any object of this class should not print a new-line after their
! description, because the listing of their inventory follows directly.
!--------------------------------------------------------------------------

Class   CarryingClass
 has    animate transparent
 with   before [ i j k;
         Examine:
            if (location == thedark) return L__M(##Examine,1);
            PrintOrRun(self,description,1);
            objectloop (k in self) {
                if (k hasnt worn && k hasnt concealed) {
                    give k workflag;
                    i++;
                }
                else give k ~workflag;
            }
            if (i > 0) {
                print " ", (CPronounNom) self, " is carrying ";
                WriteListFrom(child(self), FULLINV_BIT + ENGLISH_BIT +
                    WORKFLAG_BIT + CONCEAL_BIT);
            }
            objectloop (k in self) {
                if (k has worn && k hasnt concealed) {
                    give k workflag;
                    j++;
                }
                else give k ~workflag;
            }
            if (j > 0) {
                if (i == 0) {
                    print " ", (CPronounNom) self, " is";
                }
                else print ", and";
                print " wearing ";
                WriteListFrom(child(self), ENGLISH_BIT + WORKFLAG_BIT);
            }
            if (i > 0 || j > 0) print ".";
            new_line;
            rtrue;
        ];


!--------------------------------------------------------------------------
! THINGS THAT CAN BE FOLLOWED
! 
! Members of FollowClass can be followed when they travel from the player's
! current room into another room. The code maintains the room that the
! object just left (in just_visited) and the direction that it went (in
! follow_dir). When the player types "follow thing", FollowScope adds to
! scope all objects that are is_followable, and which have just_visited
! equal to the location. If a match is made, the player is moved in the
! follow_dir direction. This copes with, e.g. the object going through a
! door and locking it.
! 
! The various properties are maintained by MoveNPC() and MovePrintNPC() -
! the latter describing the movement of the object, though it has to assume
! that map connections never twist and turn in order to print the direction
! of arrival.
! 
! The entry point NewRoom() is used to clear the just_visited property,
! otherwise you could follow objects you never even saw move.
!--------------------------------------------------------------------------

Property follow_dir 0;
Property just_visited 0;
Attribute is_followable;

Class   FollowClass
 has    is_followable
 with   just_visited 0,
        follow_dir 0;

[ NewRoom i;
    for (i = selfobj + 1: i <= top_object: i++)
        if (i has is_followable)
            i.just_visited = 0;
];

[ FollowScope i;
    if (scope_stage == 1) rfalse;
    if (scope_stage == 2) {
        for (i = selfobj + 1: i <= top_object: i++) {
            if (i has is_followable && i.just_visited == location)
                PlaceInScope(i);
        }
        rfalse;
    }
    "You've no idea where that is.";
];

[ FollowSub;
    if (noun == player) "You can't follow yourself.";
    if (noun in location) "No need!";
    if (noun.follow_dir == 0)
        print_ret "You start after ", (the) noun, " but you can't find ",
            (PronounAcc) noun, ". As far as you're concerned, ",
            (PronounNom) noun, " has vanished into thin air.";
    <Enter noun.follow_dir>;
];

[ NoFollowSub;
    if (noun == player) "You can't follow yourself.";
    print_ret (The) noun, " is right here.";    
];

[ PronounAcc i;
    if (i hasnt animate) print "it";
    else { if (i has female) print "her"; else print "him"; } ];

[ PronounNom i;
    if (i hasnt animate) print "it";
    else { if (i has female) print "she"; else print "he"; } ];

[ CPronounNom i;
    if (i hasnt animate) print "It";
    else { if (i has female) print "She"; else print "He"; } ];

[ MoveNPC n dest dir;
    if (n has is_followable) {
        n.just_visited = parent(n);
        n.follow_dir = dir;
    }
    if (dest == 0) remove n;
    else move n to dest;
];

[ MovePrintNPC n dest dir;
    if (n in location) {
        print "^", (The) n, " stalks away";
        if (dir ~= in_obj or out_obj or u_obj && dir ~= d_obj)
            print "to the ", (DirectionName) dir.door_dir;
        print ".^";
    }
    MoveNPC(n, dest, dir);
    if (n in location)
        print "^", (The) n, " stalks in.^";
];

Include "grammar";

Verb "follow" "chase" "pursue" "trail"
    * scope=FollowScope                 -> Follow
    * "after" scope=FollowScope         -> Follow
    * noun                              -> NoFollow
    * "after" noun                      -> NoFollow;


!--------------------------------------------------------------------------
! THE DUNGEON
! 
! Some scenery for the thief to wander round, with changing exits and
! entrances.
!--------------------------------------------------------------------------

Constant TooWide "The fissure is too wide to cross.";

Object  EastSide "East side of the fissure"
 has    light
 with   name "fissure",
        description "Mist rises from the gaping fissure to the west, and \
            passages lead north and east.",
        n_to [;
            if (moving_thief == 0)
                print "The passage turns to the right.^";
            return PassageA;
        ],
        e_to PassageB,
        w_to TooWide,
        s_to 0,
        before [;
         Jump:
            deadflag = 1;
            "You plunge to your doom.";
         Wave:
            if (noun == BlackRod) {
                if (CrystalBridge hasnt absent) {
                    remove CrystalBridge;
                    give CrystalBridge absent;
                    self.w_to = TooWide;
                    WestSide.e_to = TooWide;
                    "The crystal bridge shimmers and then fades away \
                    completely.";
                }
                move CrystalBridge to self;
                give CrystalBridge ~absent;
                self.w_to = CrystalBridge;
                WestSide.e_to = CrystalBridge;
                "There is a shimmering to the west and a crystal bridge \
                appears, spanning the fissure.";
            }
        ];

Object  CrystalBridge "crystal bridge"
 has    static door open absent
 with   name "crystal" "bridge",
        initial "A crystal bridge spans the fissure.",
        found_in WestSide EastSide,
        door_dir [;
            if (self in EastSide) return w_to;
            return e_to;
        ],
        door_to [;
            if (self in EastSide) return WestSide;
            return EastSide;
        ];

Object  Mist "mist"
 has    scenery
 with   name "mist",
        description "cold and clammy",
        found_in WestSide EastSide;

Object  Fissure "fissure"
 has    scenery
 with   name "fissure" "pit" "chasm" "gaping",
        description "Very deep.",
        found_in WestSide EastSide;

Object  WestSide "West Side of the Fissure"
 has    light
 with   description "Mist coils and writhes from a gaping fissure to the \
            east. There are no other exits.",
        e_to TooWide;

Object  PassageA "Twisty Passage"
 has    light
 with   description "Little twisty passages lead west and south, and there \
            is an exit to daylight to the north.",
        w_to [;
            if (moving_thief == 0)
                print "The passage turns to the left.^";
            return EastSide;
        ],
        n_to [;
            if (moving_thief == 1) rfalse;
            if (GoldCoin notin player)
                "You're not leaving without the treasure.";
            deadflag = 2;
            rtrue;
        ],
        s_to PassageB;

Nearby  Lever "lever"
 has    static
 with   name "lever",
        initial "There is a lever here.",
        before [;
         Push,Pull:
            if (self has general) "Nothing happens.";
            give self general;
            give SecretDoor ~absent;
            EastSide.s_to = SecretDoor;
            "You hear a grinding sound away to the southwest.";
        ];

Nearby  BlackRod "black rod"
 with   name "black" "rod" "star",
        initial "There is a black rod with a star on the end here.";

Object  PassageB "Twisty Passage"
 has    light
 with   description "Little twisty passages lead west and north.",
        w_to EastSide,
        n_to PassageA;

Nearby  ShinyKey "shiny key"
 with   name "shiny" "key";

Object  TreasureChamber "Treasure Chamber"
 has    light
 with   description "The secret treasure chamber of Zork, once the legend \
            that all adventurers sought after; now it seems a bit \
            depleted. There is an exit to the north.",
        n_to SecretDoor;

Nearby  GoldCoin "gold coin"
 with   name "treasure" "gold" "coin",
        initial "A single gold coin is all that remains of the treasure \
            of the Flatheads.";

Object  SecretDoor "secret door"
 has    static locked lockable openable door absent
 with   name "secret" "door",
        found_in EastSide TreasureChamber,
        with_key ShinyKey,
        describe [ i;
            i = RunRoutines(self,door_dir);
            print_ret "^There is a secret door here, leading ",
                (DirectionName) i, "!";
        ],
        door_dir [;
            if (self in TreasureChamber) return n_to;
            return s_to;
        ],
        door_to [;
            if (self in TreasureChamber) return EastSide;
            return TreasureChamber;
        ];


!--------------------------------------------------------------------------
! THE THIEF HIMSELF
! 
! As of library 5/11, it's possible to steal things from thief using "get
! object from thief"; this is because of a bug in `RemoveSub' in
! `verblib.h' that will be corrected in 5/12.
!--------------------------------------------------------------------------

Object  Thief "thief" PassageA
 class  FollowClass CarryingClass
 with   name "thief" "gentleman" "distinguished",
        initial "There is a distinguished gentleman here.",
        description "A distinguished gentleman.",
        life [;
         Attack: deadflag = 1; "He skewers you with his stiletto.";
         Ask,Answer,Order,Tell: "The thief only laughs.";
         ThrowAt: "He dodges your missile with ease.";
        ],
        daemon [ i j k;
            ! The thief steals the gold coin if possible
            if (GoldCoin in parent(self)) {
                move GoldCoin to self;
                if (self in location)
                    print "^~My, what an interesting gold coin,~ says the \
                        thief, picking it up.^";
            }
            if (GoldCoin in player && self in location) {
                move GoldCoin to self;
                print "^The thief steals the gold coin from you.^";
            }

            ! Count the available exits quickly
            objectloop(i in Compass)
                if (ZRegion(parent(self).(i.door_dir)) == 1 or 2)
                    k ++;
            if (k == 0) rtrue;

            ! Pick an exit at random and attempt to travel that way
            j = random(k); k = 0;
            objectloop(i in Compass) {
                if (ZRegion(parent(self).(i.door_dir)) == 1 or 2) {
                    k ++;
                    if (k == j) {
                        MoveThief(i);
                        rtrue;
                    }
                }
            }
        ];

Nearby  Stiletto "stiletto dagger"
 with   name "stiletto" "dagger" "knife";

Nearby  Cloak "black cloak"
 has    clothing worn
 with   name "cloak" "black";

! Returns 1 if it moved the thief successfully
! Returns 0 if it couldn't move the thief in the requested direction

[ MoveThief
    dir   ! the direction to move the thief (n_obj, s_obj etc)
    dest  ! the room in which the thief ends up
    p     ! the room in which the thief starts out
    zr    ! the ZRegion of the destination
    o     ! the door the thief is trying to go through
    po;   ! the parent of the door

    ! Find out what's in the requested direction.  This code won't work if
    ! the thief can enter vehicles, but in this demo he can't, so this is
    ! OK.
    p = parent(Thief);
    dest = p.(dir.door_dir);
    zr = ZRegion(dest);

    ! It might be a string which would be printed to the player.
    ! Assume that this means that the thief can't go in that direction.
    if (zr == 3) rfalse;

    ! It might be a routine which is activated when the player tries to 
    ! move in that direction.  We'll set moving_thief to 1 and hope that
    ! the routine does the right thing (it should return the
    ! destination if possible, or else 0 or 1 if there is no exit).
    if (zr == 2) {
        moving_thief = 1;
        dest = RunRoutines(p, (dir.door_dir));
        moving_thief = 0;
        if (dest == 0 or 1) rfalse;
    }

    ! If there's no exit in the given direction
    if (zr == 0 || dest == 0) rfalse;

    ! If the destination has the `door' attribute, then it's a door
    if (dest has door) {
        ! Find out where the door goes. Make sure the door is (temporarily)
        ! in the same room as the thief, otherwise the code will go wrong
        ! (see discussion at top of file).
        o = dest;
        po = parent(o);
        move o to p;
        dest = ValueOrRun(o,door_to);
        move o to po;
        if (dest == 0) rfalse; ! It might not lead anywhere.

        if (o has locked) {
            ! Need a check here to see if the thief has the keys or
            ! lockpicks required to open this door.  In the demo, he always
            ! succeeds.
            give o ~locked;
            if (p == location)
                print "^", (The) Thief, " picks the lock of ", (the) o, ".^";
        }
        if (o hasnt open && o has openable && o hasnt locked) {
            ! The thief can open closed doors. Here, he leaves then open
            ! behind him.
            give o open;
            if (p == location)
                print "^", (The) Thief, " opens ", (the) o, ".^";
            if (dest == location)
                print "^", (The) o, " opens.^";
        }
        if (o hasnt open) rfalse;
    }

    ! Now dest contains the destination room, so move the thief
    MovePrintNPC(Thief,dest,dir);
    rtrue;
];

End;