# doer.t | documentation

    #charset "us-ascii"
    #include "advlite.h"

    /*
     *   **************************************************************************
     *   doer.t
     *
     *   This module forms part of the adv3Lite library (c) 2012-13 Eric Eve, but is
     *   heavily based on parts of the Mercury library (c) 2012 Michael J. Roberts.
     */

    /*
     *   A Redirector is an object that can redirect one action to another via a
     *   doInstead wrapper method that provides a common interface. Subclasses are
     *   responsible for implementing the redirect method.
     *
     *   We begin this module by defing the Redirector class since in adv3Lite
     *   (though not in Mercury) Redirector is the base class for Doer.
     */
    class Redirector: object

        /*
         *   doInstead() turns the current action into altAction with the objects
         *   specified in args, and executes altAction as a replacement for the
         *   current action.
         */
        doInstead(altAction, [args])
        {
            doOtherAction(true, altAction, args...);
        }

        /*
         *   doNested() executes altAction with the objects specified in args,
         *   executins altAction as part of the current action.
         */
        doNested(altAction, [args])
        {
            doOtherAction(nil, altAction, args...);
        }

        /*
         *   Execute altAction on the objects specified in the args parameter. If
         *   isReplacement is true make altAction a replacement for the current
         *   action.
         */
        doOtherAction(isReplacement, altAction, [args])
        {

            /* Extract our dobj and our iobj from the args parameter. */
            local dobj = args.element(1);
            local iobj = args.element(2);
            local aobj = args.element(3);

            /*
             *   If the action involves a Literal argument and one of the arguments
             *   is supplied as a single-quoted string, wrap it in a LiteralObject
             *   before passing it.
             */
            if(altAction.ofKind(LiteralAction) || altAction.ofKind(LiteralTAction)
               || aobj != nil)
            {
                if(dataType(dobj) == TypeSString)
                    dobj = new LiteralObject(dobj);
                if(dataType(iobj) == TypeSString)
                    iobj = new LiteralObject(iobj);
                if(dataType(aobj) == TypeSString)
                    aobj = new LiteralObject(aobj);
            }

            /*
             *   If the action involves a Topic object and one of the argumnets is
             *   supplied as a single-quoted string, wrap it in a Topic before using
             *   it.
             */
            if(altAction.ofKind(TopicAction) || altAction.ofKind(TopicTAction)
               || aobj != nil)
            {
                if(dataType(dobj) == TypeSString)
                    dobj = new Topic(dobj);
                if(dataType(iobj) == TypeSString)
                    iobj = new Topic(iobj);
                if(dataType(aobj) == TypeSString)
                    aobj = new Topic(aobj);
            }

            /*
             *   If the action is a TopicTAction check that the appropriate object
             *   (usually but not necessarily the indirect object) has been passed
             *   as a ResolvedTopic; if not, wrap it in a new Resolved Topic object.
             */
            if(altAction.ofKind(TopicTAction))
            {
                if(altAction.topicIsGrammaticalIobj && !iobj.ofKind(ResolvedTopic))
                    iobj = new ResolvedTopic([iobj], iobj.name.split(' '));

                if(!altAction.topicIsGrammaticalIobj && !dobj.ofKind(ResolvedTopic))
                    dobj = new ResolvedTopic([dobj], dobj.name.split(' '));

    //            if(!altAction.topicIsGrammaticalAobj && !aobj.ofKind(ResolvedTopic))
    //                dobj = new ResolvedTopic([aobj], aobj.name.split(' '));
            }

            /*
             *   If the new action is of a kind that requires two objects, call the
             *   redirect method with both objects
             */
            if(altAction.ofKind(TIAction) || altAction.ofKind(LiteralTAction) ||
               altAction.ofKind(TopicTAction))
            {
                redirect(gCommand, altAction, dobj: dobj, iobj: iobj, aobj: aobj,
                         isReplacement: isReplacement);
                return;
            }

            /*
             *   If the action is a TopicAction check that its object has been
             *   passed as a ResolvedTopic; if not, wrap it in a new Resolved Topic
             *   object.
             */
            if(altAction.ofKind(TopicAction) && !dobj.ofKind(ResolvedTopic))
            {
                dobj = new ResolvedTopic([dobj], dobj.name.split(' '));
            }

            /*
             *   If the new action requires a single object, call redirect with the
             *   direct object.
             */
            if(altAction.ofKind(TAction) || altAction.ofKind(LiteralAction) ||
               altAction == Go || altAction.ofKind(TopicAction))
            {
                redirect(gCommand, altAction, dobj: dobj, isReplacement:
                         isReplacement);
                return;
            }

            /*
             *   Otherwise call redirect with the new action alone (it's some form
             *   of intransitve action).
             */
            redirect(gCommand, altAction, isReplacement: isReplacement);
        }

    ;

    /* ------------------------------------------------------------------------ */
    /*
     *   A Doer is a command handler for a specific action acting on particular
     *   objects under a given set of conditions.  We use these for all of the
     *   levels of customization in command handling.
     *
     *   Doer objects are inherently static.  All Doer objects should be
     *   defined at compile time; they're not designed to be created
     *   dynamically during execution.  Rather than creating and removing Doer
     *   objects as conditions in the game change, use the Doer conditions to
     *   define when a given Doer is active and when it's dormant.
     */
    class Doer: Redirector
        /*
         *   The command that the object handles.  This is a string describing
         *   the action and object combination that this handler recognizes.
         *
         *   The command string specifies a verb and its objects, generally
         *   using the same verb phrase syntax that a player would use to enter
         *   a command to the game.  The exact verb syntax is up to the
         *   language library to define; for English, we replicate the same
         *   verb phrases used to parse command input.
         *
         *   The verb phrase syntax is generally the same as for regular player
         *   commands, but the noun syntax is different.  Each noun is written
         *   as the SOURCE CODE name of a game object or class.  That is, not a
         *   noun-and-adjective phrase as the player would type it, but the
         *   program symbol name as it appears in the source code.  If you use
         *   a class name, the command matches any object of the class.  For
         *   example, to handle putting any treasure in any container:
         *
         *.    cmd = 'put Treasure in Container'
         *
         *   You can match multiple objects or classes in a single noun slot
         *   (and you can freely mix objects and classes).  For example, to
         *   handle putting any treasure or magic item in a container:
         *
         *.    cmd = 'put Treasure|Magical in Container'
         *
         *   You can't use the '|' syntax with verbs, because the verb syntax
         *   covers the entire phrase.  You can match multiple verbs by writing
         *   out the entire phrasing for each verb, separating each phrase with
         *   a semicolon:
         *
         *.    cmd = 'take skull; put skull in Thing'
         *
         *   You can also write a command that matches ANY verb, by using "*"
         *   as the verb.  You can follow the "*" with any number of objects;
         *   the first is the direct object, the second is the indirect, and
         *   the third is the accessory.  This phrasing will match any verb
         *   that matches the given objects AND the given number of objects.
         *   For example, '* Thing' will match any verb with a direct object
         *   that's of class Thing, but it won't match verbs without any
         *   objects or verbs with an indirect object.  Using "*" as a noun
         *   will match any object as well as no object at all.  So to write a
         *   handler for every possible command, you'd write:
         *
         *.    cmd = '* * * *'
         *
         *   That is, match any verb, with or without any direct object,
         *   indirect object, and accessory object.
         */
        cmd = ''

        /*
         *   The priority of this handler.  You can use this when it's
         *   necessary to override the default precedence order, which is
         *   figured according to the specialization rules described below.
         *
         *   Most of the time, you shouldn't need to set a priority manually.
         *   If you don't, the library determines the precedence automatically
         *   according to the degree of specialization.  However, the way the
         *   library figures specialization is a heuristic, so it's not always
         *   right.  In cases where the heuristic produces the wrong results,
         *   you can bypass the rules by setting a priority manually.  A manual
         *   priority takes precedence over all of the standard rules.
         *
         *   Our basic approach is to process Doers in order from most specific
         *   to most general.  This creates a natural hierarchy of handlers
         *   where more specific rules override the generic, default handlers.
         *   Here are the degrees of specialization, in order of importance:
         *
         *   1. A Doer with a higher 'priority' value takes precedence over one
         *   with a lower value.
         *
         *   2. A Doer with a 'when' condition is more specific than a Doer
         *   without one.  A 'when' condition means that the Doer is designed
         *   to operate only at specific times, so it's inherently more
         *   specialized than one that always operates.
         *
         *   3. A Doer with a 'where' condition is more specific than a Doer
         *   without one.  A 'where' condition means that the Doer only applies
         *   to a limited geographical area.
         *
         *   4. A Doer that matches a particular Action is more specific than
         *   one that matches any Action.
         *
         *   5. If two Doer commands are for the same Action, the Doer that
         *   matches a more specialized subclass (or just a single object
         *   instance) for a noun phrase is more specific than one that matches
         *   a base class for the same noun phrase.  For example, 'take
         *   Container' is more specific than 'take Thing', because Container
         *   is a subclass of Thing, and 'take backpack' (where the 'backpack'
         *   is a Container) is more specific than either.  This type of
         *   specialization applies in the canonical object role order: direct
         *   object, indirect object, accessory.  For example, we consider 'put
         *   Container in Thing' to be more specific than 'put Thing in
         *   Container', because we look at the direct object by itself before
         *   we even consider the indirect object.  This rule only applies when
         *   the Action is the same: 'put Thing in Container' and 'open Door'
         *   are equal for the purposes of this rule.
         *
         *   It's important to understand that each degree of specialization is
         *   considered independently of the others, in the order above.  For
         *   example, if you have a Doer with just a 'when' condition, and
         *   another with only a 'where' condition, the one with the 'when'
         *   condition has higher priority.  This is because we look at the
         *   presence of a 'when' condition first, before even considering
         *   whether there's a 'where' condition.
         *
         *   The library has no way to gauge the specificity of a 'when' or
         *   'where' condition, so there's no finer-grained priority to the
         *   conditions than simply their presence or absence.
         *
         *   If two Doers have the same priority based on the rules above, the
         *   one that's defined LATER in the source code has priority.  This
         *   means that Doers defined in the game take priority over library
         *   definitions.
         */
        priority = 100

        /*
         *   Execute the command.
         */

        /*
         *   ECSE ADDED a curCmd parameter (the command being added) to give the Doer
         *   access to what it's meant to be acting on, together with a default
         *   handling (execute the action associated with the current command).
         */
        exec(curCmd)
        {
            /*
             *   If the command specifies a direction, check that the direction is
             *   valid for the actor's location. This will rule out meaningless
             *   commands like THROW BALL PORT, GO AFT or PUSH TROLLEY STARBOARD
             *   when we're not aboard a vessel.
             */
            if(curCmd.verbProd && curCmd.verbProd.dirMatch != nil)
                checkDirection(curCmd);

            /*
             *   Temporarily set gDobj and gIobj to the dobj and iobj of the curCmd
             *   so that they're available to be passed as parameters
             */
            gAction.curDobj = curCmd.dobj;
            gAction.curIobj = curCmd.iobj;
            gAction.curAobj = curCmd.acc;

            /*
             *   If the command is an action to be carried out by the player
             *   character, execute the action in the normal manner.
             */
            if(curCmd.actor == gPlayerChar)
            {
                /*
                 *   If our execAction() method is going to handle the action in
                 *   some non-standard way, instead of simply stopping it or
                 *   replacing it with another one, we need to perform some
                 *   housekeeping to ensure everything works properly.
                 */
                if(handleAction)
                {
                    /*
                     *   If we specified an object on the handleAction property,
                     *   it's the action we're going to simulate. We don't need to
                     *   specify a different action if we're notionally handling the
                     *   one we've just matched.
                     */
                    if(propType(&handleAction) == TypeObject)
                    {
                        /*
                         *   Change the current action to the one we're notionally
                         *   handling.
                         */
                        gAction = handleAction;

                        /*
                         *   Set the objects of the new gAction in case we need them
                         */
                        gAction.curDobj = curCmd.dobj;
                        gAction.curIobj = curCmd.iobj;
                        gAction.curAobj = curCmd.acc;
                    }

                    /* Send the beforeAction notifications. */
                    gAction.beforeAction();

                }

                execAction(curCmd);
            }

            /*
             *   If the command is directed to another actor (or object) let the
             *   actor or object in question handle it.
             */
            else
                curCmd.actor.handleCommand(curCmd.action);
        }

        /*
         *   If this Doer is handling a complete action (instead of stopping one or
         *   replacing it with another) this should either be true (if it's the same
         *   action that we've matched) or some other action (if that's the one
         *   we're simulating and it's not the one we matched).
         */
        handleAction = nil

        /*
         *   We separate out execAction() as a separate method from exec() so that
         *   custom Doers can readily override this for the player character while
         *   leaving commands directed to other actors (or objects) to be handle by
         *   their handleCommand() method.     */

        execAction(curCmd)
        {
            /*
             *   Our default behaviour is to let the current action handle the
             *   command.
             */
            curCmd.action.exec(curCmd);
        }

        /*
         *   Check whether the direction associatated with this command is valid for
         *   the actor's current location.
         */
        checkDirection(curCmd)
        {
            local dirn = curCmd.verbProd.dirMatch.dir;
            local loc = curCmd.actor.getOutermostRoom();

            /*
             *   Rule out a command involving a shipboard direction where shipboard
             *   directions aren't allowed.
             */
            if(dirn.ofKind(ShipboardDirection) && !loc.allowShipboardDirections())
            {
                DMsg(no shipboard directions, 'Shipboard directions {plural} {have}
                    no meaning {here}, ');
                abort;
            }

            /*
             *   Rule out a command involving a compass direction where compass
             *   directions aren't allowed.
             */
            if(dirn.ofKind(CompassDirection) && !loc.allowCompassDirections)
            {
                DMsg(no compass directions, 'Compass directions {plural} {have}
                    no meaning {here}, ');
                abort;
            }

            /*
             *   Set the direction property of the current Command's association
             *   Action object to the direction determined by its
             *   verbProd.dirMatch.dir property in case the game author tries to use
             *   action.direction to get at the direction entered.
             */
            curCmd.action.direction = dirn;

        }

        /*
         *   Utility method that can be called from execAction() to redirect the
         *   command to a new action with the same (or new) objects. This will
         *   normally be called via the doInstead()/doNested() interface defined on
         *   our Redirector superclass.
         */
        redirect(curCmd, altAction, dobj: = 0, iobj: = 0, aobj: = 0,
                 isReplacement: = true)
        {

            /*
             *   We use a default value of 0 for the dobj and iobj parameters to
             *   mean 'keep the current value' so that we can explicitly pass nil
             *   values if we want to.
             */
            dobj = dobj == 0 ? curCmd.dobj : dobj;
            iobj = iobj == 0 ? curCmd.iobj : iobj;
            aobj = iobj == 0 ? curCmd.acc : aobj;

            /*
             *   Get the current command to change its current action to altAction
             *   performed on dobj and iobj. Note that this will change gAction to
             *   altAction.
             */
            curCmd.changeAction(altAction, dobj, iobj, aobj);

            /* Execute the command on our new action. */
            gAction.exec(curCmd);
        }

        /*
         *   Set this property to true for this Doer to match only if the wording
         *   corresponds (and not just the action). At the moment the check is
         *   only on the first word of the command, but this may usually be enough
         */

        strict = nil

        /*
         *   Flag, do we want to ignore (i.e. not report) an error in the
         *   construction of this Doer. We may want to do this when the error is
         *   simply due to the exclusion of a module like extras.t
         */
        ignoreError = nil
    ;

    /* Define isHappening as a property in case the scenes module is not included */
    property isHappening;

    /* ------------------------------------------------------------------------ */
    /*
     *   A DoerCmd is a helper object that stores a single command match
     *   template for a Doer object.  A given Doer can match multiple commands;
     *   each match is represented by one of these objects.
     */
    class DoerCmd: object
        /* construction */
        construct(d, c)
        {
            doer = d;
            cmd = c;
        }

        /* the Doer I'm associated with */
        doer = nil

        /*
         *   The parsed command template.  This is a list consisting of the
         *   Action we match plus the objects or classes we match for the noun
         *   phrases, in the canonical order (direct object, indirect object,
         *   accessory).  The action can also be the Action class itself, to
         *   indicate that we match all actions.  We only match a command with
         *   the same number of noun phrases as in the template.
         */
        cmd = []

        /*
         *   My global sequence number.  During initialization, we set this to
         *   reflect our position in the global list of DoerCmd objects after
         *   the list is sorted into priority order.  This makes it easy to
         *   sort a new list of DoerCmd objects into the original priority
         *   order.
         */
        seqno = 0

        /*
         *   Class member: the master table of DoerCmd objects.  The library
         *   builds this automatically during preinitialization.  This is a
         *   lookup table indexed by Action.  Each Action entry has a list of
         *   DoerCmd objects associated with that Action.  Note that the
         *   generic all-verb handlers are listed under Action.
         */
        doerTab = nil

        /*
         *   Class method: Get a list of Doer objects matching the given
         *   command.  'cmdLst' is the command's action and object list in
         *   canonical format: [action, dobj, iobj, accessory].
         */
        findDoers(cmdLst)
        {
            /*
             *   Start with a list of the DoerCmd objects that could *possibly*
             *   match this command.  This includes all of the DoerCmds listed
             *   in the master table under the command's action, plus all of
             *   the wildcard "any action" DoerCmds, which are listed in the
             *   table under Action.
             */
            local lst = nilToList(doerTab[cmdLst[1]])
                + nilToList(doerTab[Action]);

            /* keep only the elements that match the command's objects */
            lst = lst.subset({ d: d.matchCmd(cmdLst) });

            /*
             *   keep only the elements whose where and when conditions don't
             *   exclude them.
             */

            lst = lst.subset({ d: d.matchConditions() } );

            /* sort the combined list into the original priority order */
            lst = lst.sort(SortAsc, { a, b: a.seqno - b.seqno });

            /* pull out the list of Doers that the DoerCmds map to */
            lst = lst.mapAll({ d: d.doer });

            /*
             *   It's conceivable that a given Doer is listed more than once,
             *   since the same Doer could have more than one matching command
             *   template.  In such cases we'd still only want to process each
             *   Doer once, so eliminate any duplicates.
             */
            lst = lst.getUnique();

            /* return the result */
            return lst;
        }

        /*
         *   Check for a match to a command list.  'cmdLst' is the command
         *   object list in canonical format: [action, dobj, iobj, ...].  This
         *   routine determines if our Doer is a handler for the given command.
         */
        matchCmd(cmdLst)
        {
            /*
             *   The first element of the template is the action.  For the
             *   template to match, the Command's action must either exactly
             *   match the template action, or it must be an instance of the
             *   template action class.
             */
            if (cmdLst[1] != cmd[1] && !cmdLst[1].ofKind(cmd[1]))
                return nil;

            /*
             *   If the strict property is set we want the doer to match not only
             *   the command but the wording of the command, or rather, at least the
             *   first word, so that, for example, 'go through junk' would not be
             *   treated as matching 'walk through junk' (in English idiom the first
             *   but not the second might be treated as meaning 'search junk').
             */

            if (gCommand != nil && doer.strict && gCommand.verbProd.tokenList !=
                nil)
            {
                local cmdToks = gCommand.verbProd.tokenList.mapAll( {x:
                    getTokVal(x) });
                local doerToks = doer.cmd.split(' ');

                if(cmdToks[1] != doerToks[1])
                    return nil;
            }

            /*
             *   The rest of the template is the list of noun roles, in
             *   canonical order (direct object, indirect object, accessory).
             *   The Command must have the same number of objects, and each
             *   object in the Command must match the corresponding template
             *   object or be an instance of the template object class.
             *   (There's one special case: if the template object is nil, we
             *   match anything.)
             *
             *   First, check that we have the same number of objects.
             */
            if (cmdLst.length() != cmd.length())
                return nil;

            /* now check each object */
            for (local i = 2, local len = cmd.length() ; i <= len ; ++i)
            {
                /* get the object from the Command and template */
                local cobj = cmdLst[i];
                local tobj = cmd[i];

                /*
                 *   if the template object is non-nil, we have to match the
                 *   object or class
                 */
                if (tobj != nil && cobj != tobj && !cobj.ofKind(tobj)
                    && cobj.lexicalParent != tobj)
                    return nil;
            }

            /* everything matches, so this Command matches this template */
            return true;
        }

        /*
         *   Get the processing priority sorting order relative to another
         *   DoerCmd.  (See Doer.priority for a discussion of the priority
         *   rules.)
         */
        compareTo(other)
        {
            local p, a, b;

            /* the explicitly priority takes precedence over all other rules */
            if (doer.priority != other.doer.priority)
                return doer.priority - other.doer.priority;

            /* a 'when' has priority over no 'when' */
            p = doer.propDefined(&when);
            if (p != other.doer.propDefined(&when))
                return p ? 1 : -1;

            /* a 'where' has priority over no 'where' */
            p = doer.propDefined(&where);
            if (p != other.doer.propDefined(&where))
                return p ? 1 : -1;

             /* a 'who' has priority over no 'where' */
            p = doer.propDefined(&who);
            if (p != other.doer.propDefined(&who))
                return p ? 1 : -1;

            /* a 'during' has priority over no 'during' */
            p = doer.propDefined(&during);
                if (p != other.doer.propDefined(&during))
                return p ? 1 : -1;

            /* get each command's Action */
            a = cmd[1];
            b = other.cmd[1];

            /*
             *   a 'direction' has priority over no 'direction' for a Travel
             *   command.
             */
            if(a == Travel)
            {
                p = doer.propDefined(&direction);
                if (p != other.doer.propDefined(&direction))
                    return p ? 1 : -1;
            }

            /*
             *   if one is a specific Action and the other is the generic
             *   'Action' class (a wildcard that matches all actions), the
             *   specific action takes precedence
             */
            if (a != Action && b == Action)
                return 1;
            if (a == Action && b != Action)
                return -1;

            /* if the actions are the same, compare the objects */
            if (a == b && cmd.length() == other.cmd.length())
            {
                /*
                 *   Check each object role in turn, in canonical order.  The
                 *   first one where the precedence differs determines the
                 *   overall precedence.
                 */
                for (local i = 2 ; i < cmd.length() ; ++i)
                {
                    /* get the two objects */
                    a = cmd[i];
                    b = other.cmd[i];

                    /*
                     *   if one is a subclass of the other, the subclass takes
                     *   precedence because it's more specialized
                     */
                    if (a == nil || b == nil)
                    {
                        if (a != nil)
                            return 1;
                        if (b != nil)
                            return -1;
                    }
                    else
                    {
                        if (a.ofKind(b))
                            return 1;
                        if (b.ofKind(a))
                            return -1;
                    }
                }
            }

            /*
             *   Failing all else, go by the relative location of the source
             *   code definitions: the definition that appears later in the
             *   source code takes precedence.  If the two are defined in
             *   different modules, the one in the later module takes
             *   precedence.
             */
            if (doer.sourceTextGroup != other.doer.sourceTextGroup)
                return doer.sourceTextGroup.sourceTextGroupOrder
                - other.doer.sourceTextGroup.sourceTextGroupOrder;

            /* they're in the same module, so the later one takes precedence */
            return doer.sourceTextOrder - other.doer.sourceTextOrder;
        }

        /* Check whether a Doer matches its where, when, who and during conditions. */
        matchConditions()
        {
            /* first check the where condition, if there is one. */
            if(doer.propDefined(&where))
            {
                local whereLst = valToList(doer.where);

                /*
                 *   if we can't match any item in the where list to the player
                 *   char's current location, we don't meet the where condition, so
                 *   return nil
                 */
                if(whereLst.indexWhich( {loc: gPlayerChar.isIn(loc)}) == nil)
                    return nil;
            }

            /*
             *   Interpret 'when' as simply a routine that returns true or nil
             *   aocording to some condition defined by the author; so we simply
             *   test whether doer.when returns nil if the property is defined.
             */
            if(doer.propDefined(&when) && doer.when() == nil)
                return nil;

             /* check the who condition, if there is one. */
            if(doer.propDefined(&who))
            {
                local whoLst = valToList(doer.who);

                /*
                 *   If we can't match any item in the who list to the current
                 *   actor, we don't meet the who condition, so return nil
                 */
                if(whoLst.indexOf(gCommand.actor) == nil)
                    return nil;
            }

            /*
             *   if we're using the scene manager and a during condition is
             *   specified, test whether the scene is currently happening.
             */
            if(defined(sceneManager) && doer.propDefined(&during))
            {
                local duringList = valToList(doer.during);

                if(duringList.indexWhich({s: s.isHappening}) == nil)
                    return nil;
            }

            /*
             *   If the command is a travel action and a direction has been
             *   specified, check that we match the direction.
             */
            if(doer.propDefined(&direction) && cmd[1] is in (Travel,
                PushTravelDir, ThrowDir))
                return valToList(doer.direction).indexOf(
                    gCommand.verbProd.dirMatch.dir) != nil;

            /*
             *   If we haven't failed any of the conditions, we're okay to match, so
             *   return true.
             */
            return true;
        }
    ;

    /* ------------------------------------------------------------------------ */
    /*
     *   A DoerParser is a helper object we use during initialization for
     *   parsing Doer 'cmd' strings and turning them into action description
     *   lists.  The language-specific library creates these for us based on
     *   the language grammar.
     *
     *   These objects are only used during initialization, since they're only
     *   needed to set up the internal representation of a Doer command
     *   template string.  During normal play we only need that internal
     *   representation.
     */
    class DoerParser: object
        /*
         *   Construction.  The language library should create one of these
         *   objects for each verb phrasing it wants to define for use in
         *   writing Doer 'cmd' strings.
         */
        construct(action, v, pat, roles)
        {
            action_ = action;
            verb_ = v;
            pat_ = new RexPattern('<space>*' + pat + '<space>*$');
            roles_ = roles;
        }

        /* The Action object for the verb. */
        action_ = nil

        /*
         *   The main verb word.  This is simply the first word of the verb's
         *   token list.  This is essentially a hash, to reduce the number of
         *   regular expressions we have to test individually.  This saves us a
         *   lot of compute time, since it's very quick to pull out the first
         *   word and get a list of the small set of rules with the same first
         *   word.  We then test each of those potential matches by doing the
         *   full regular expression comparison.
         */
        verb_ = nil

        /*
         *   The regular expression for the verb rule.  The verb initializer
         *   sets this up to contain the literal text of the verb rule's
         *   literal tokens, and to substitute a parenthesized group wildcard
         *   pattern for each noun slot.  For example, for English, a Give To
         *   rule might look like 'give (.+) to (.+)'.
         */
        pat_ = nil

        /*
         *   The list of object roles.  This is a list of NounRole objects.
         *   The list entries correspond positionally to the parenthesized
         *   groups in the regular expression string, so roles_[1] is the noun
         *   role for the first parenthesized group, roles_[2] is the noun role
         *   for the second group, and so on.
         */
        roles_ = []
    ;

    /* ------------------------------------------------------------------------ */
    /*
     *   DoerParser Table.  This stores a lookup table of DoerParser objects,
     *   indexed by the first word (the verb) of the command template.
     */
    class DoerParserTable: object
        /* add a parser to the table */
        addParser(p)
        {
            /* get the verb from the parser */
            local v = p.verb_;

            /* make sure there's a list at the verb entry */
            if (ptab[v] == nil)
                ptab[v] = [];

            /* add this parser to the list for its verb */
            ptab[v] += p;
        }

        /* get the list of parsers for a given verb word */
        getParsers(v)
        {
            /* look up the list */
            local lst = ptab[v];

            /* return the list, or an empty list if the verb is unknown */
            return (lst != nil ? lst : []);
        }

        /* the lookup table */
        ptab = perInstance(new LookupTable(64, 128))
    ;

    /*
     *   Initialize the Doer objects.  This parses each Doer's command string
     *   to generate a list of command templates.
     */
    doerPreinit: PreinitObject
        execute()
        {

            /* initialize the DoerParser objects */
            local ptab = new DoerParserTable();
            initDoerParsers(ptab);

            /* get the global symbols */
            local gtab = t3GetGlobalSymbols();

            /* get the predicate noun phrase list */
            local roles = NounRole.allPredicate;

            /*
             *   Add the special "any verb" wildcard verbs.  Add one for each
             *   subset of the roles list.  (The role subsets are always
             *   cumulative, because we don't ever have a later role without
             *   also including all of the earlier roles.  E.g., if a verb
             *   takes an indirect object, it must take a direct object as
             *   well.)
             */
            local pat = '<star>';
            local npat = ' (<alphanum|_|vbar|star>+)';
            for (local i = 0 ; i <= roles.length() ; ++i, pat += npat)
            {
                ptab.addParser(new DoerParser(
                    Action, '*', pat, roles.sublist(1, i)));
            }

            /* set up an empty list of command template (DoerCmd) objects */
            local tlst = new Vector(100);

            /* call the language-specific parser for each Doer's command string */
            forEachInstance(Doer, new function(d)
            {
                /* get the string to parse */
                local c = d.cmd;

                /*
                 *   split it into commands - a given Doer might match multiple
                 *   commands
                 */
                local clst = c.split(';');

                /* process each command */
                foreach (c in clst)
                {
                    /* check for direction names in the command */
                    local tokList = c.split(R'<space|vbar>');

                    foreach(local tok in tokList)
                    {
                        local dir = Direction.nameTab[tok];
                        if(dir != nil)
                        {
                            d.direction = valToList(d.direction) + dir;
                        }
                    }

                    /* pull out the first word of the command */
                    rexMatch(R'<space>*(<alphanum|star>+)', c);

                    /* match it against each template with the same first word */
                    local found = nil;
                    foreach (local p in ptab.getParsers(rexGroup(1)[3]))
                    {
                        /* if we match this item's template, this is the one */
                        if (rexMatch(p.pat_, c))
                        {
                            /*
                             *   It matches.  Set up the initial action template
                             *   with just the action.
                             */
                            local tpl = [p.action_];

                            /*
                             *   Add each noun slot.  Note that we need to add
                             *   the nouns in the canonical order: dobj, iobj,
                             *   accessory.  This might differ from the order
                             *   of the noun phrases in the verb; for example,
                             *   Give To in English can be phrased as "give
                             *   dobj to iobj" or as "give iobj dobj" - the
                             *   second form uses the reverse of the canonical
                             *   order.  We must always use the canonical
                             *   ordering for the template, regardless of how
                             *   the verb is phrased.
                             */
                            foreach (local r in roles)
                            {
                                /*
                                 *   find this role in the template list order
                                 *   - this tells us which parenthesized group
                                 *   it matches in the regular expression for
                                 *   the verb template
                                 */
                                local idx = p.roles_.indexOf(r);

                                /*
                                 *   If the role isn't in the verb, we're done.
                                 *   A verb with an indirect object always has
                                 *   a direct object, and a verb with an
                                 *   accessory always has direct and indirect
                                 *   objects, so if this role isn't in the
                                 *   verb's list, we know there are no more
                                 *   roles to find.
                                 */
                                if (idx == nil)
                                    break;

                                /* get the regular expression match */
                                local n = rexGroup(idx)[3];

                                /* add it to the template list */
                                tpl += n;
                            }

                            /* expand "noun|noun" constructions */
                            expandNounLists(gtab, d, tlst, tpl, 2);

                            /* we found a match, so we can stop looking */
                            found = true;
                            break;
                        }
                    }

                    /* if we didn't a match, note the error */
                    if (!found && d.ignoreError == nil)
                    {
                        "Error in Doer command phrase \"<<d.cmd>>\": this
                        command syntax doesn't match any known verb grammar.";
                    }
                }
            });

            /* sort the DoerCmd list by descending precedence */
            tlst.sort(SortDesc, { a, b: a.compareTo(b) });

            /* build the master table of DoerCmd objects */
            local dtab = DoerCmd.doerTab = new LookupTable(64, 128);
            local seqno = 1;
            foreach (local d in tlst)
            {
                /*
                 *   Set this item's global sequence number.  This lets us
                 *   quickly sort into the original priority order when we
                 *   combine two lists.
                 */
                d.seqno = seqno++;

                /* get this item's Action - it's the first template item */
                local action = d.cmd[1];

                /* make sure this entry has a list */
                if (dtab[action] == nil)
                    dtab[action] = [];

                /* add this item to this action entry's list */
                dtab[action] += d;
            }
        }

        /*
         *   Expand an initial template list.  This takes a list of the form
         *   [action, 'a|b|c', 'd|e|f'], and converts it into multiple lists
         *   with an individual noun in each slot.
         */
        expandNounLists(gtab, d, tlst, tpl, idx)
        {
            /*
             *   if we've run out of slots, we have a fully expanded template,
             *   so simply add the current template to the results and return
             */
            if (idx > tpl.length())
            {
                tlst.append(new DoerCmd(d, tpl));
                return;
            }

            /* process the list of elements for the current item */
            foreach (local item in tpl[idx].split('|'))
            {
                /* look up the object name in the symbol table */
                local obj = gtab[item];

                /* if we didn't find it, note the error */
                if (obj == nil && item != '*')
                {
                    /* explain the problem */
                    if(!d.ignoreError)
                        "Error in Doer command phrase \"<<d.cmd>>\": the word \"<<
                          item>>\" is not a known object or class name.
                        Each noun must be the source code name of an object
                        or class.\n";

                    /* abort processing this template */
                    return;
                }

                /* build the simplified list with the current single item */
                local stpl = tpl;
                stpl[idx] = obj;

                /* recursively process the rest of the list */
                expandNounLists(gtab, d, tlst, stpl, idx + 1);
            }
        }

    ;

    /*
     *   Define four DefaultDoers that between them will match any command unless a
     *   more specialized Doer intervenes. This allows most commands to be executed
     *   by the appropriate action.
     */

    default4Doer: Doer
        cmd = '* * * *'
    ;

    default3Doer: Doer
        cmd = '* * *'
    ;

    default2Doer: Doer
        cmd = '* *'
    ;

    default1Doer: Doer
        cmd = '*'
    ;

Adv3Lite Library Reference Manual
Generated on 12/09/2014 from adv3Lite version 1.4