! ----------------------------------------------------------------------------
!  PARSERM:  Core of parser.
!
!  Supplied for use with Inform 6                         Serial number 991113
!                                                                 Release 6/10
!  (c) Graham Nelson 1993, 1994, 1995, 1996, 1997, 1998, 1999
!      but freely usable (see manuals)
! ----------------------------------------------------------------------------
!  Inclusion of "linklpa"
!                   (which defines properties and attributes)
!  Global variables, constants and arrays
!                1: outside of the parser
!                2: used within the parser
!  Inclusion of natural language definition file
!                   (which creates a compass and direction-objects)
!  Darkness and player objects
!  Definition of grammar token numbering system used by Inform
!
!  The InformParser object
!          keyboard reading
!          level 0: outer shell, conversation, errors
!                1: grammar lines
!                2: tokens
!                3: object lists
!                4: scope and ambiguity resolving
!                5: object comparisons
!                6: word comparisons
!                7: reading words and moving tables about
!          pronoun management
!
!  The InformLibrary object
!          main game loop
!          action processing
!          end of turn sequence
!          scope looping, before/after sequence, sending messages out
!          timers, daemons, time of day, score notification
!          light and darkness
!          changing player personality
!          tracing code (only present if DEBUG is set)
!
!  Status line printing, menu display
!  Printing object names with articles
!  Miscellaneous utility routines
!  Game banner, "version" verb, run-time errors
! ----------------------------------------------------------------------------

System_file;

IFDEF MODULE_MODE;
Constant DEBUG;
Constant Grammar__Version 2;
Include "linklpa";
ENDIF;

! ============================================================================
!   Global variables and their associated Constant and Array declarations
! ----------------------------------------------------------------------------
Global location = InformLibrary;     ! Must be first global defined
Global sline1;                       ! Must be second
Global sline2;                       ! Must be third
                                     ! (for status line display)
! ------------------------------------------------------------------------------
!   Z-Machine and interpreter issues
! ------------------------------------------------------------------------------
#ifdef TARGET_ZCODE;
Global top_object;                   ! Largest valid number of any tree object
Global standard_interpreter;         ! The version number of the Z-Machine
                                     ! Standard which the interpreter claims
                                     ! to support, in form (upper byte).(lower)
! ### these globals are not meaningful... well, maybe standard_interpreter,
! but I'll decide that later.
#endif; ! TARGET_ZCODE
Global undo_flag;                    ! Can the interpreter provide "undo"?
Global just_undone;                  ! Can't have two successive UNDOs
#ifdef TARGET_ZCODE;
Global transcript_mode;              ! true when game scripting is on
IFDEF DEBUG;
Global xcommsdir;                    ! true if command recording is on
ENDIF;
#endif; ! TARGET_ZCODE
#ifdef TARGET_GLULX;
Constant GG_MAINWIN_ROCK  201;
Constant GG_STATUSWIN_ROCK  202;
Constant GG_QUOTEWIN_ROCK  203;
Constant GG_SAVESTR_ROCK 301;
Constant GG_SCRIPTSTR_ROCK 302;
Constant GG_COMMANDWSTR_ROCK 303;
Constant GG_COMMANDRSTR_ROCK 304;
Constant GG_SCRIPTFREF_ROCK 401;
Constant GG_STATUSWIN_SIZE  1; !### make overridable
Array gg_event --> 4;
Array gg_arguments --> 8;
Global gg_mainwin = 0;
Global gg_statuswin = 0;
Global gg_quotewin = 0;
Global gg_scriptfref = 0;
Global gg_scriptstr = 0;
Global gg_savestr = 0;
Global gg_statuswin_cursize = 0;
IFDEF DEBUG;
Global gg_commandstr = 0;
Global gg_command_reading = 0; ! true if gg_commandstr is being replayed
ENDIF;
#endif; ! TARGET_GLULX
! ------------------------------------------------------------------------------
!   Time and score
! (for linkage reasons, the task_* arrays are created not here but in verblib.h)
! ------------------------------------------------------------------------------
Global turns = 1;                    ! Number of turns of play so far
Global the_time = NULL;              ! Current time (in minutes since midnight)
Global time_rate = 1;                ! How often time is updated
Global time_step;                    ! By how much

#ifndef MAX_TIMERS;
Constant MAX_TIMERS  32;             ! Max number timers/daemons active at once
#endif;
Array  the_timers  --> MAX_TIMERS;
Global active_timers;                ! Number of timers/daemons actives

Global score;                        ! The current score
Global last_score;                   ! Score last turn (for testing for changes)
Global notify_mode = true;           ! Score notification
Global places_score;                 ! Contribution to score made by visiting
Global things_score;                 ! Contribution made by acquisition
! ------------------------------------------------------------------------------
!   The player
! ------------------------------------------------------------------------------
Global player;                       ! Which object the human is playing through
Global deadflag;                     ! Normally 0, or false; 1 for dead;
                                     ! 2 for victorious, and higher numbers
                                     ! represent exotic forms of death
! ------------------------------------------------------------------------------
!   Light and room descriptions
! ------------------------------------------------------------------------------
Global lightflag = true;             ! Is there currently light to see by?
Global real_location;                ! When in darkness, location = thedark
                                     ! and this holds the real location
Global visibility_ceiling;           ! Highest object in tree visible from
                                     ! the player's point of view (usually
                                     ! the room, sometimes darkness, sometimes
                                     ! a closed non-transparent container).

Global lookmode = 1;                 ! 1=standard, 2=verbose, 3=brief room descs
Global print_player_flag;            ! If set, print something like "(as Fred)"
                                     ! in room descriptions, to reveal whom
                                     ! the human is playing through
Global lastdesc;                     ! Value of location at time of most recent
                                     ! room description printed out
! ------------------------------------------------------------------------------
!   List writing  (style bits are defined as Constants in "verblibm.h")
! ------------------------------------------------------------------------------
Global c_style;                      ! Current list-writer style
Global lt_value;                     ! Common value of list_together
Global listing_together;             ! Object number of one member of a group
                                     ! being listed together
Global listing_size;                 ! Size of such a group
Global wlf_indent;                   ! Current level of indentation printed by
                                     ! WriteListFrom routine

Global inventory_stage = 1;          ! 1 or 2 according to the context in which
                                     ! "invent" routines of objects are called
Global inventory_style;              ! List-writer style currently used while
                                     ! printing inventories
! ------------------------------------------------------------------------------
!   Menus and printing
! ------------------------------------------------------------------------------
Global pretty_flag = true;           ! Use character graphics, or plain text?
Global menu_nesting;                 ! Level of nesting (0 = root menu)
Global menu_item;                    ! These are used in communicating
Global item_width = 8;               ! with the menu-creating routines
Global item_name = "---";

Global lm_n;                         ! Parameters used by LibraryMessages
Global lm_o;                         ! mechanism

IFDEF DEBUG;
Global debug_flag;                   ! Bitmap of flags for tracing actions,
                                     ! calls to object routines, etc.
Global x_scope_count;                ! Used in printing a list of everything
                                     ! in scope
ENDIF;
! ------------------------------------------------------------------------------
!   Action processing
! ------------------------------------------------------------------------------
Global action;                       ! Action currently being asked to perform
Global inp1;                         ! 0 (nothing), 1 (number) or first noun
Global inp2;                         ! 0 (nothing), 1 (number) or second noun
Global noun;                         ! First noun or numerical value
Global second;                       ! Second noun or numerical value

Global keep_silent;                  ! If true, attempt to perform the action
                                     ! silently (e.g. for implicit takes,
                                     ! implicit opening of unlocked doors)

Global reason_code;                  ! Reason for calling a "life" rule
                                     ! (an action or fake such as ##Kiss)

Global receive_action;               ! Either ##PutOn or ##Insert, whichever
                                     ! is action being tried when an object's
                                     ! "before" rule is checking "Receive"
! ==============================================================================
!   Parser variables: first, for communication to the parser
! ------------------------------------------------------------------------------
Global parser_trace = 0;             ! Set this to 1 to make the parser trace
                                     ! tokens and lines
Global parser_action;                ! For the use of the parser when calling
Global parser_one;                   ! user-supplied routines
Global parser_two;                   !
Array  inputobjs       --> 16;       ! For parser to write its results in
Global parser_inflection;            ! A property (usually "name") to find
                                     ! object names in
! ------------------------------------------------------------------------------
!   Parser output
! ------------------------------------------------------------------------------
Global actor;                        ! Person asked to do something
Global actors_location;              ! Like location, but for the actor
Global meta;                         ! Verb is a meta-command (such as "save")

Array  multiple_object --> 64;       ! List of multiple parameters
Global multiflag;                    ! Multiple-object flag
Global toomany_flag;                 ! Flag for "multiple match too large"
                                     ! (e.g. if "take all" took over 100 things)

Global special_word;                 ! Dictionary address for "special" token
Global special_number;               ! Number typed for "special" token
Global parsed_number;                ! For user-supplied parsing routines
Global consult_from;                 ! Word that a "consult" topic starts on
Global consult_words;                ! ...and number of words in topic
! ------------------------------------------------------------------------------
!   Implicit taking
! ------------------------------------------------------------------------------
Global notheld_mode;                 ! To do with implicit taking
Global onotheld_mode;                !     "old copy of notheld_mode", ditto
Global not_holding;                  ! Object to be automatically taken as an
                                     ! implicit command
Array  kept_results --> 16;          ! Delayed command (while the take happens)
! ------------------------------------------------------------------------------
!   Error numbers when parsing a grammar line
! ------------------------------------------------------------------------------
Global etype;                        ! Error number on current line
Global best_etype;                   ! Preferred error number so far
Global nextbest_etype;               ! Preferred one, if ASKSCOPE_PE disallowed

Constant STUCK_PE     = 1;
Constant UPTO_PE      = 2;
Constant NUMBER_PE    = 3;
Constant CANTSEE_PE   = 4;
Constant TOOLIT_PE    = 5;
Constant NOTHELD_PE   = 6;
Constant MULTI_PE     = 7;
Constant MMULTI_PE    = 8;
Constant VAGUE_PE     = 9;
Constant EXCEPT_PE    = 10;
Constant ANIMA_PE     = 11;
Constant VERB_PE      = 12;
Constant SCENERY_PE   = 13;
Constant ITGONE_PE    = 14;
Constant JUNKAFTER_PE = 15;
Constant TOOFEW_PE    = 16;
Constant NOTHING_PE   = 17;
Constant ASKSCOPE_PE  = 18;
! ------------------------------------------------------------------------------
!   Pattern-matching against a single grammar line
! ------------------------------------------------------------------------------
Array pattern --> 32;                ! For the current pattern match
Global pcount;                       ! and a marker within it
Array pattern2 --> 32;               ! And another, which stores the best match
Global pcount2;                      ! so far
Constant PATTERN_NULL = $ffff;       ! Entry for a token producing no text

Array  line_ttype-->32;              ! For storing an analysed grammar line
Array  line_tdata-->32;
Array  line_token-->32;

Global parameters;                   ! Parameters (objects) entered so far
Global nsns;                         ! Number of special_numbers entered so far
Global special_number1;              ! First number, if one was typed
Global special_number2;              ! Second number, if two were typed
! ------------------------------------------------------------------------------
!   Inferences and looking ahead
! ------------------------------------------------------------------------------
Global params_wanted;                ! Number of parameters needed
                                     ! (which may change in parsing)

Global inferfrom;                    ! The point from which the rest of the
                                     ! command must be inferred
Global inferword;                    ! And the preposition inferred
Global dont_infer;                   ! Another dull flag

Global action_to_be;                 ! (If the current line were accepted.)
Global action_reversed;              ! (Parameters would be reversed in order.)
Global advance_warning;              ! What a later-named thing will be
! ------------------------------------------------------------------------------
!   At the level of individual tokens now
! ------------------------------------------------------------------------------
Global found_ttype;                  ! Used to break up tokens into type
Global found_tdata;                  ! and data (by AnalyseToken)
Global token_filter;                 ! For noun filtering by user routines

Global length_of_noun;               ! Set by NounDomain to no of words in noun
#ifdef TARGET_ZCODE;
Constant REPARSE_CODE = 10000;       ! Signals "reparse the text" as a reply
                                     ! from NounDomain
#ifnot; ! TARGET_GLULX
Constant REPARSE_CODE = $40000000;   ! The parser rather gunkily adds addresses
                                     ! to REPARSE_CODE for some purposes.
                                     ! And expects the result to be greater
                                     ! than REPARSE_CODE (signed comparison).
                                     ! So Glulx Inform is limited to a single
                                     ! gigabyte of storage, for the moment.
#endif; ! TARGET_
Global lookahead;                    ! The token after the one now being matched

Global multi_mode;                   ! Multiple mode
Global multi_wanted;                 ! Number of things needed in multitude
Global multi_had;                    ! Number of things actually found
Global multi_context;                ! What token the multi-obj was accepted for

Global indef_mode;                   ! "Indefinite" mode - ie, "take a brick"
                                     ! is in this mode
Global indef_type;                   ! Bit-map holding types of specification
Global indef_wanted;                 ! Number of items wanted (100 for all)
Global indef_guess_p;                ! Plural-guessing flag
Global indef_owner;                  ! Object which must hold these items
Global indef_cases;                  ! Possible gender and numbers of them
Global indef_possambig;              ! Has a possibly dangerous assumption
                                     ! been made about meaning of a descriptor?
Global indef_nspec_at;               ! Word at which a number like "two" was
                                     ! parsed (for backtracking)
Global allow_plurals;                ! Whether plurals presently allowed or not

Global take_all_rule;                ! Slightly different rules apply to
                                     ! "take all" than other uses of multiple
                                     ! objects, to make adjudication produce
                                     ! more pragmatically useful results
                                     ! (Not a flag: possible values 0, 1, 2)

Global dict_flags_of_noun;           ! Of the noun currently being parsed
                                     ! (a bitmap in #dict_par1 format)
Global pronoun_word;                 ! Records which pronoun ("it", "them", ...)
                                     ! caused an error
Global pronoun_obj;                  ! And what obj it was thought to refer to
Global pronoun__word;                ! Saved value
Global pronoun__obj;                 ! Saved value
! ------------------------------------------------------------------------------
!   Searching through scope and parsing "scope=Routine" grammar tokens
! ------------------------------------------------------------------------------
Constant PARSING_REASON       = 0;   ! Possible reasons for searching scope
Constant TALKING_REASON       = 1;
Constant EACH_TURN_REASON     = 2;
Constant REACT_BEFORE_REASON  = 3;
Constant REACT_AFTER_REASON   = 4;
Constant LOOPOVERSCOPE_REASON = 5;
Constant TESTSCOPE_REASON     = 6;

Global scope_reason = PARSING_REASON; ! Current reason for searching scope

Global scope_token;                  ! For "scope=Routine" grammar tokens
Global scope_error;
Global scope_stage;                  ! 1, 2 then 3

Global ats_flag = 0;                 ! For AddToScope routines
Global ats_hls;                      !

Global placed_in_flag;               ! To do with PlaceInScope

! ------------------------------------------------------------------------------
!   The match list of candidate objects for a given token
! ------------------------------------------------------------------------------
Constant MATCH_LIST_SIZE = 128;
Array  match_list    --> 64;         ! An array of matched objects so far
Array  match_classes --> 64;         ! An array of equivalence classes for them
Array  match_scores --> 64;          ! An array of match scores for them
Global number_matched;               ! How many items in it?  (0 means none)
Global number_of_classes;            ! How many equivalence classes?
Global match_length;                 ! How many words long are these matches?
Global match_from;                   ! At what word of the input do they begin?
Global bestguess_score;              ! What did the best-guess object score?
! ------------------------------------------------------------------------------
!   Low level textual manipulation
! ------------------------------------------------------------------------------
#ifdef TARGET_ZCODE;

Constant INPUT_BUFFER_LEN = 120;     ! Length of buffer array (although we
                                     ! leave an extra byte to allow for
                                     ! interpreter bugs)

Array  buffer    -> 121;             ! Buffer for parsing main line of input
Array  parse     -> 65;              ! Parse table mirroring it
Array  buffer2   -> 121;             ! Buffers for supplementary questions
Array  parse2    -> 65;              !
Array  buffer3   -> 121;             ! Buffer retaining input for "again"

#ifnot; ! TARGET_GLULX

Constant INPUT_BUFFER_LEN = 260;     ! No extra byte necessary
Constant MAX_BUFFER_WORDS = 20;
Constant PARSE_BUFFER_LEN = 244;     ! 4 + MAX_BUFFER_WORDS*4;

Array  buffer    -> INPUT_BUFFER_LEN;
Array  parse     -> PARSE_BUFFER_LEN;
Array  buffer2   -> INPUT_BUFFER_LEN;
Array  parse2    -> PARSE_BUFFER_LEN;
Array  buffer3   -> INPUT_BUFFER_LEN;

#endif; ! TARGET_

Constant comma_word = 'comma,';      ! An "untypeable word" used to substitute
                                     ! for commas in parse buffers

Global wn;                           ! Word number within "parse" (from 1)
Global num_words;                    ! Number of words typed
Global verb_word;                    ! Verb word (eg, take in "take all" or
                                     ! "dwarf, take all") - address in dict
Global verb_wordnum;                 ! its number in typing order (eg, 1 or 3)
Global usual_grammar_after;          ! Point from which usual grammar is parsed
                                     ! (it may vary from the above if user's
                                     ! routines match multi-word verbs)

Global oops_from;                    ! The "first mistake" word number
Global saved_oops;                   ! Used in working this out
Array  oops_workspace -> 64;         ! Used temporarily by "oops" routine

Global held_back_mode;               ! Flag: is there some input from last time
Global hb_wn;                        ! left over?  (And a save value for wn.)
                                     ! (Used for full stops and "then".)
! ----------------------------------------------------------------------------
Array PowersOfTwo_TB                 ! Used in converting case numbers to
  --> $$100000000000                 ! case bitmaps
      $$010000000000
      $$001000000000
      $$000100000000
      $$000010000000
      $$000001000000
      $$000000100000
      $$000000010000
      $$000000001000
      $$000000000100
      $$000000000010
      $$000000000001;
! ============================================================================


! ============================================================================
!  Constants, and one variable, needed for the language definition file
! ----------------------------------------------------------------------------
Constant POSSESS_PK  = $100;
Constant DEFART_PK   = $101;
Constant INDEFART_PK = $102;
Global short_name_case;
! ----------------------------------------------------------------------------
Include "language__";                !  The natural language definition,
                                     !  whose filename is taken from the ICL
                                     !  language_name variable
! ----------------------------------------------------------------------------
#ifndef LanguageCases;
Constant LanguageCases = 1;
#endif;
! ------------------------------------------------------------------------------
!   Pronouns support for the cruder (library 6/2 and earlier) version:
!   only needed in English
! ------------------------------------------------------------------------------
#ifdef EnglishNaturalLanguage;
Global itobj = NULL;                 ! The object which is currently "it"
Global himobj = NULL;                ! The object which is currently "him"
Global herobj = NULL;                ! The object which is currently "her"

Global old_itobj = NULL;             ! The object which is currently "it"
Global old_himobj = NULL;            ! The object which is currently "him"
Global old_herobj = NULL;            ! The object which is currently "her"
#endif;
! ============================================================================


! ============================================================================
! "Darkness" is not really a place: but it has to be an object so that the
!  location-name on the status line can be "Darkness".
! ----------------------------------------------------------------------------
Object thedark "(darkness object)"
  with initial 0,
       short_name DARKNESS__TX,
       description
       [;  return L__M(##Miscellany, 17);
       ];
Object selfobj "(self object)"
  with short_name
       [;  return L__M(##Miscellany, 18);
       ],
       description
       [;  return L__M(##Miscellany, 19);
       ],
       before NULL,   after NULL,    life NULL,    each_turn NULL,
       time_out NULL, describe NULL,
       capacity 100, parse_name 0,
       orders 0, number 0,
  has  concealed animate proper transparent;

! ============================================================================
!  The definition of the token-numbering system used by Inform.
! ----------------------------------------------------------------------------

Constant ILLEGAL_TT        = 0;      ! Types of grammar token: illegal
Constant ELEMENTARY_TT     = 1;      !     (one of those below)
Constant PREPOSITION_TT    = 2;      !     e.g. 'into'
Constant ROUTINE_FILTER_TT = 3;      !     e.g. noun=CagedCreature
Constant ATTR_FILTER_TT    = 4;      !     e.g. edible
Constant SCOPE_TT          = 5;      !     e.g. scope=Spells
Constant GPR_TT            = 6;      !     a general parsing routine

Constant NOUN_TOKEN        = 0;      ! The elementary grammar tokens, and
Constant HELD_TOKEN        = 1;      ! the numbers compiled by Inform to
Constant MULTI_TOKEN       = 2;      ! encode them
Constant MULTIHELD_TOKEN   = 3;
Constant MULTIEXCEPT_TOKEN = 4;
Constant MULTIINSIDE_TOKEN = 5;
Constant CREATURE_TOKEN    = 6;
Constant SPECIAL_TOKEN     = 7;
Constant NUMBER_TOKEN      = 8;
Constant TOPIC_TOKEN       = 9;


Constant GPR_FAIL          = -1;     ! Return values from General Parsing
Constant GPR_PREPOSITION   = 0;      ! Routines
Constant GPR_NUMBER        = 1;
Constant GPR_MULTIPLE      = 2;
Constant GPR_REPARSE       = REPARSE_CODE;
Constant GPR_NOUN          = $ff00;
Constant GPR_HELD          = $ff01;
Constant GPR_MULTI         = $ff02;
Constant GPR_MULTIHELD     = $ff03;
Constant GPR_MULTIEXCEPT   = $ff04;
Constant GPR_MULTIINSIDE   = $ff05;
Constant GPR_CREATURE      = $ff06;

Constant ENDIT_TOKEN       = 15;     ! Value used to mean "end of grammar line"

#Iftrue Grammar__Version == 1;
[ AnalyseToken token m;

    found_tdata = token;

    if (token < 0)   { found_ttype = ILLEGAL_TT; return; }
    if (token <= 8)  { found_ttype = ELEMENTARY_TT; return; }
    if (token < 15)  { found_ttype = ILLEGAL_TT; return; }
    if (token == 15) { found_ttype = ELEMENTARY_TT; return; }
    if (token < 48)  { found_ttype = ROUTINE_FILTER_TT;
                       found_tdata = token - 16;
                       return; }
    if (token < 80)  { found_ttype = GPR_TT;
                       found_tdata = #preactions_table-->(token-48);
                       return; }
    if (token < 128) { found_ttype = SCOPE_TT;
                       found_tdata = #preactions_table-->(token-80);
                       return; }
    if (token < 180) { found_ttype = ATTR_FILTER_TT;
                       found_tdata = token - 128;
                       return; }

    found_ttype = PREPOSITION_TT;
    m=#adjectives_table;
    for (::)
    {   if (token==m-->1) { found_tdata = m-->0; return; }
        m=m+4;
    }
    m=#adjectives_table; RunTimeError(1);
    found_tdata = m;
];
[ UnpackGrammarLine line_address i m;
  for (i = 0 : i < 32 : i++)
  {   line_token-->i = ENDIT_TOKEN;
      line_ttype-->i = ELEMENTARY_TT;
      line_tdata-->i = ENDIT_TOKEN;
  }
  for (i = 0: i <= 5 :i++)
  {   line_token-->i = line_address->(i+1);
      AnalyseToken(line_token-->i);
      if ((found_ttype == ELEMENTARY_TT) && (found_tdata == NOUN_TOKEN)
          && (m == line_address->0))
      {   line_token-->i = ENDIT_TOKEN;
          break;
      }
      line_ttype-->i = found_ttype;
      line_tdata-->i = found_tdata;
      if (found_ttype ~= PREPOSITION_TT) m++;
  }
  action_to_be = line_address->7;
  action_reversed = false;
  params_wanted = line_address->0;
  return line_address + 8;
];
#Ifnot;
[ AnalyseToken token;

    if (token == ENDIT_TOKEN)
    {   found_ttype = ELEMENTARY_TT;
        found_tdata = ENDIT_TOKEN;
        return;
    }

    found_ttype = (token->0) & $$1111;
    found_tdata = (token+1)-->0;
];
#ifdef TARGET_ZCODE;
[ UnpackGrammarLine line_address i;
  for (i = 0 : i < 32 : i++)
  {   line_token-->i = ENDIT_TOKEN;
      line_ttype-->i = ELEMENTARY_TT;
      line_tdata-->i = ENDIT_TOKEN;
  }
  action_to_be = 256*(line_address->0) + line_address->1;
  action_reversed = ((action_to_be & $400) ~= 0);
  action_to_be = action_to_be & $3ff;
  line_address--;
  params_wanted = 0;
  for (i=0::i++)
  {   line_address = line_address + 3;
      if (line_address->0 == ENDIT_TOKEN) break;
      line_token-->i = line_address;
      AnalyseToken(line_address);
      if (found_ttype ~= PREPOSITION_TT) params_wanted++;
      line_ttype-->i = found_ttype;
      line_tdata-->i = found_tdata;
  }
  return line_address + 1;
];
#ifnot; ! TARGET_GLULX
[ UnpackGrammarLine line_address i;
  for (i = 0 : i < 32 : i++)
  {   line_token-->i = ENDIT_TOKEN;
      line_ttype-->i = ELEMENTARY_TT;
      line_tdata-->i = ENDIT_TOKEN;
  }
  @aloads line_address 0 action_to_be;
  action_reversed = (((line_address->2) & 1) ~= 0);
  line_address = line_address - 2;
  params_wanted = 0;
  for (i=0::i++)
  {   line_address = line_address + 5;
      if (line_address->0 == ENDIT_TOKEN) break;
      line_token-->i = line_address;
      AnalyseToken(line_address);
      if (found_ttype ~= PREPOSITION_TT) params_wanted++;
      line_ttype-->i = found_ttype;
      line_tdata-->i = found_tdata;
  }
  return line_address + 1;
];
#endif; ! TARGET_
#Endif;

!  To protect against a bug in early versions of the "Zip" interpreter:
!  Of course, in Glulx, this routine actually performs work.

#ifdef TARGET_ZCODE;

[ Tokenise__ b p; b->(2 + b->1) = 0; @tokenise b p; ];

#endif; ! TARGET_ZCODE

#ifdef TARGET_GLULX;

Array gg_tokenbuf -> DICT_WORD_SIZE;

[ GGWordCompare str1 str2 ix jx;
  for (ix=0 : ix < DICT_WORD_SIZE : ix++) {
    jx = (str1->ix) - (str2->ix);
    if (jx ~= 0)
      return jx;
  }
  return 0;
];

[ Tokenise__ buf tab 
    cx numwords len bx ix wx wpos wlen top bot val res dictlen entrylen;
  len = buf-->0;
  buf = buf+WORDSIZE;

  ! First, split the buffer up into words. We use the standard Infocom
  ! list of word separators (comma, period, double-quote).

  cx = 0;
  numwords = 0;
  while (cx < len) {
    while (cx < len && buf->cx == ' ')
      cx++;
    if (cx >= len)
      break;
    bx = cx;
    if (buf->cx == '.' or ',' or '"') {
      cx++;
    }
    else {
      while (cx < len && buf->cx ~= ' ' or '.' or ',' or '"')
        cx++;
    }
    tab-->(numwords*3+2) = (cx-bx);
    tab-->(numwords*3+3) = WORDSIZE+bx;
    numwords++;
    if (numwords >= MAX_BUFFER_WORDS)
      break;
  }
  tab-->0 = numwords;  

  ! Now we look each word up in the dictionary.

  dictlen = #dictionary_table-->0;
  entrylen = DICT_WORD_SIZE + 7;

  for (wx=0 : wx < numwords : wx++) {
    wlen = tab-->(wx*3+2);
    wpos = tab-->(wx*3+3);

    ! Copy the word into the gg_tokenbuf array, clipping to DICT_WORD_SIZE
    ! characters and lower case.
    if (wlen > DICT_WORD_SIZE)
      wlen = DICT_WORD_SIZE;
    cx = wpos-WORDSIZE;
    for (ix=0 : ix < wlen : ix++) {
      gg_tokenbuf->ix = glk($00A0, buf->(cx+ix));
    }
    for ( : ix < DICT_WORD_SIZE : ix++) {
      gg_tokenbuf->ix = 0;
    }

    ! Perform a simple binary search.
    bot = 0;
    top = dictlen;
    while (1) {
      val = (top+bot) / 2;
      res = #dictionary_table + WORDSIZE + entrylen*val;
      ix = GGWordCompare(res+1, gg_tokenbuf);
      if (ix == 0) {
        break;
      }
      if (bot >= top-1) {
        res = 0;
        break;
      }
      if (ix < 0) {
        bot = val+1;
      }
      else {
        top = val;
      }
    }
    tab-->(wx*3+1) = res;
  }
];

#endif; ! TARGET_GLULX

! ============================================================================
!  The InformParser object abstracts the front end of the parser.
!
!  InformParser.parse_input(results)
!  returns only when a sensible request has been made, and puts into the
!  "results" buffer:
!
!  --> 0 = The action number
!  --> 1 = Number of parameters
!  --> 2, 3, ... = The parameters (object numbers), but
!                  0 means "put the multiple object list here"
!                  1 means "put one of the special numbers here"
!
! ----------------------------------------------------------------------------

Object InformParser "(Inform Parser)"
  with parse_input
       [ results; Parser__parse(results);
       ], has proper;

! ----------------------------------------------------------------------------
!  The Keyboard routine actually receives the player's words,
!  putting the words in "a_buffer" and their dictionary addresses in
!  "a_table".  It is assumed that the table is the same one on each
!  (standard) call.
!
!  It can also be used by miscellaneous routines in the game to ask
!  yes-no questions and the like, without invoking the rest of the parser.
!
!  Return the number of words typed
! ----------------------------------------------------------------------------

#ifdef TARGET_ZCODE;
[ KeyboardPrimitive  a_buffer a_table;
  read a_buffer a_table;
];
#ifnot; ! TARGET_GLULX
[ KeyCharPrimitive win nostat done res ix jx ch;
  ix = jx; ix = ch; ! squash compiler warnings
  if (win == 0)
    win = gg_mainwin;
#IFDEF DEBUG;
  if (gg_commandstr ~= 0 && gg_command_reading ~= false) {
    ! get_line_stream
    done = glk($0091, gg_commandstr, gg_arguments, 31);
    if (done == 0) {
      glk($0044, gg_commandstr, 0); ! stream_close
      gg_commandstr = 0;
      gg_command_reading = false;
      ! fall through to normal user input.
    }
    else {
      ! Trim the trailing newline
      if (gg_arguments->(done-1) == 10)
        done = done-1;
      res = gg_arguments->0;
      if (res == '\') {
        res = 0;
        for (ix=1 : ix<done : ix++) {
          ch = gg_arguments->ix;
          if (ch >= '0' && ch <= '9') {
            @shiftl res 4 res;
            res = res + (ch-'0');
          }
          else if (ch >= 'a' && ch <= 'f') {
            @shiftl res 4 res;
            res = res + (ch+10-'a');
          }
          else if (ch >= 'A' && ch <= 'F') {
            @shiftl res 4 res;
            res = res + (ch+10-'A');
          }
        }
      }
      jump KCPContinue;
    }
  }
#ENDIF;
  done = false;
  glk($00D2, win); ! request_char_event
  while (~~done) {
    glk($00C0, gg_event); ! select
    switch (gg_event-->0) {
      5: ! evtype_Arrange
        if (nostat) {
          glk($00D3, win); ! cancel_char_event
          res = $80000000;
          done = true;
          break;
        }
        DrawStatusLine();
      2: ! evtype_CharInput
        if (gg_event-->1 == win) {
          res = gg_event-->2;
          done = true;
        }
    }
  }
#IFDEF DEBUG;
  if (gg_commandstr ~= 0 && gg_command_reading == false) {
    if (res < 32 || res >= 256 || (res == '\' or ' ')) {
      glk($0081, gg_commandstr, '\'); ! put_buffer_char
      done = 0;
      jx = res;
      for (ix=0 : ix<8 : ix++) {
        @ushiftr jx 28 ch;
        @shiftl jx 4 jx;
        ch = ch & $0F;
        if (ch ~= 0 || ix == 7) done = 1;
        if (done) {
          if (ch >= 0 && ch <= 9)
            ch = ch + '0';
          else
            ch = (ch - 10) + 'A';
          glk($0081, gg_commandstr, ch); ! put_buffer_char
        }
      }
    }
    else {
      glk($0081, gg_commandstr, res); ! put_buffer_char
    }
    glk($0081, gg_commandstr, 10); ! put_char_stream (newline)
  }
#ENDIF;
.KCPContinue;
  return res;
];
[ KeyboardPrimitive  a_buffer a_table done;
#IFDEF DEBUG;
  if (gg_commandstr ~= 0 && gg_command_reading ~= false) {
    ! get_line_stream
    done = glk($0091, gg_commandstr, a_buffer+WORDSIZE,
      (INPUT_BUFFER_LEN-WORDSIZE)-1);
    if (done == 0) {
      glk($0044, gg_commandstr, 0); ! stream_close
      gg_commandstr = 0;
      gg_command_reading = false;
      print "[Command replay complete.]^";
      ! fall through to normal user input.
    }
    else {
      ! Trim the trailing newline
      if ((a_buffer+WORDSIZE)->(done-1) == 10)
        done = done-1;
      a_buffer-->0 = done;
      jump KPContinue;
    }
  }
#ENDIF;
  done = false;
  glk($00D0, gg_mainwin, a_buffer+WORDSIZE, INPUT_BUFFER_LEN-WORDSIZE, 
    0); ! request_line_event
  while (~~done) {
    glk($00C0, gg_event); ! select
    switch (gg_event-->0) {
      5: ! evtype_Arrange
        DrawStatusLine();
      3: ! evtype_LineInput
        if (gg_event-->1 == gg_mainwin)
          done = true;
    }
  }
  a_buffer-->0 = gg_event-->2;
#IFDEF DEBUG;
  if (gg_commandstr ~= 0 && gg_command_reading == false) {
    ! put_buffer_stream
    glk($0085, gg_commandstr, a_buffer+WORDSIZE, a_buffer-->0); 
    glk($0081, gg_commandstr, 10); ! put_char_stream (newline)
  }
#ENDIF;
.KPContinue;
  Tokenise__(a_buffer,a_table);
  ! It's time to close any quote window we've got going.
  if (gg_quotewin) {
    glk($0024, gg_quotewin, 0); ! close_window
    gg_quotewin = 0;
  }
];
#endif; ! TARGET_

[ Keyboard  a_buffer a_table  nw i w w2 x1 x2;

    DisplayStatus();
    .FreshInput;

!  Save the start of the buffer, in case "oops" needs to restore it
!  to the previous time's buffer

    for (i=0:i<64:i++) oops_workspace->i = a_buffer->i;

!  In case of an array entry corruption that shouldn't happen, but would be
!  disastrous if it did:

#ifdef TARGET_ZCODE;
   a_buffer->0 = INPUT_BUFFER_LEN;
   a_table->0 = 15;  ! Allow to split input into this many words
#endif; ! TARGET_

!  Print the prompt, and read in the words and dictionary addresses

    L__M(##Prompt);
    AfterPrompt();
    #IFV5; DrawStatusLine(); #ENDIF;
    KeyboardPrimitive(a_buffer, a_table);
#ifdef TARGET_ZCODE;
    nw=a_table->1;
#ifnot; ! TARGET_GLULX
    nw=a_table-->0;
#endif; ! TARGET_

!  If the line was blank, get a fresh line
    if (nw == 0)
    { L__M(##Miscellany,10); jump FreshInput; }

!  Unless the opening word was "oops", return
!  Conveniently, a_table-->1 is the first word in both ZCODE and GLULX.

    w=a_table-->1;
    if (w == OOPS1__WD or OOPS2__WD or OOPS3__WD) jump DoOops;

#IFV5;
!  Undo handling

!  In Graham's 6/9 code, the following line tests (parse->1==1) instead
!  of (nw==1). I believe that's wrong. In particular, it prevents "undo"
!  from working during "Which do you mean...?" disambiguation, because
!  input at that prompt goes into parse2 instead of parse.

    if ((w == UNDO1__WD or UNDO2__WD or UNDO3__WD) && (nw==1))
    {   if (turns==1)
        {   L__M(##Miscellany,11); jump FreshInput;
        }
        if (undo_flag==0)
        {   L__M(##Miscellany,6); jump FreshInput;
        }
        if (undo_flag==1) jump UndoFailed;
#ifdef TARGET_ZCODE;
        ! The just_undone check shouldn't be done in Glulx, as multiple
        ! undo is possible.
        if (just_undone==1)
        {   L__M(##Miscellany,12); jump FreshInput;
        }
        @restore_undo i;
#ifnot; ! TARGET_GLULX
        @restoreundo i;
        i = (~~i);
#endif; ! TARGET_
        if (i==0)
        {   .UndoFailed;
            L__M(##Miscellany,7);
        }
        jump FreshInput;
    }
#ifdef TARGET_ZCODE;
    @save_undo i;
#ifnot; ! TARGET_GLULX
    @saveundo i;
    if (i == -1) {
        GGRecoverObjects();
        i = 2;
    }
    else {
        i = (~~i);
    }
#endif; ! TARGET_
    just_undone=0;
    undo_flag=2;
    if (i==-1) undo_flag=0;
    if (i==0) undo_flag=1;
    if (i==2)
    {
#ifdef TARGET_ZCODE;
        style bold;
#ifnot; ! TARGET_GLULX
        glk($0086, 4); ! set subheader style
#endif; ! TARGET_
        print (name) location, "^";
#ifdef TARGET_ZCODE;
        style roman;
#ifnot; ! TARGET_GLULX
        glk($0086, 0); ! set normal style
#endif; ! TARGET_
        L__M(##Miscellany,13);
        just_undone=1;
        jump FreshInput;
    }
#ENDIF;

    return nw;

    .DoOops;
    if (oops_from == 0)
    {   L__M(##Miscellany,14); jump FreshInput; }
    if (nw == 1)
    {   L__M(##Miscellany,15); jump FreshInput; }
    if (nw > 2)
    {   L__M(##Miscellany,16); jump FreshInput; }

!  So now we know: there was a previous mistake, and the player has
!  attempted to correct a single word of it.

    for (i=0:i<INPUT_BUFFER_LEN:i++) buffer2->i = a_buffer->i;
#ifdef TARGET_ZCODE;
    x1 = a_table->9; ! Start of word following "oops"
    x2 = a_table->8; ! Length of word following "oops"
#ifnot; ! TARGET_GLULX
    x1 = a_table-->6; ! Start of word following "oops"
    x2 = a_table-->5; ! Length of word following "oops"
#endif; ! TARGET_

!  Repair the buffer to the text that was in it before the "oops"
!  was typed:

    for (i=0:i<64:i++) a_buffer->i = oops_workspace->i;
    Tokenise__(a_buffer,a_table);

!  Work out the position in the buffer of the word to be corrected:

#ifdef TARGET_ZCODE;
    w = a_table->(4*oops_from + 1); ! Start of word to go
    w2 = a_table->(4*oops_from);    ! Length of word to go
#ifnot; ! TARGET_GLULX
    w = a_table-->(3*oops_from);      ! Start of word to go
    w2 = a_table-->(3*oops_from - 1); ! Length of word to go
#endif; ! TARGET_

!  Write spaces over the word to be corrected:

    for (i=0:i<w2:i++) a_buffer->(i+w) = ' ';

    if (w2 < x2)
    {   ! If the replacement is longer than the original, move up...

        for (i=INPUT_BUFFER_LEN-1:i>=w+x2:i--)
            a_buffer->i = a_buffer->(i-x2+w2);

        ! ...increasing buffer size accordingly.

#ifdef TARGET_ZCODE;
        a_buffer->1 = (a_buffer->1) + (x2-w2);
#ifnot; ! TARGET_GLULX
        a_buffer-->0 = (a_buffer-->0) + (x2-w2);
#endif; ! TARGET_

    }

!  Write the correction in:

    for (i=0:i<x2:i++) a_buffer->(i+w) = buffer2->(i+x1);

    Tokenise__(a_buffer,a_table);
#ifdef TARGET_ZCODE;
    nw=a_table->1;
#ifnot; ! TARGET_GLULX
    nw=a_table-->0;
#endif; ! TARGET_

    return nw;
];



! ----------------------------------------------------------------------------
!  To simplify the picture a little, a rough map of the main routine:
!
!  (A)    Get the input, do "oops" and "again"
!  (B)    Is it a direction, and so an implicit "go"?  If so go to (K)
!  (C)    Is anyone being addressed?
!  (D)    Get the verb: try all the syntax lines for that verb
!  (E)    Break down a syntax line into analysed tokens
!  (F)    Look ahead for advance warning for multiexcept/multiinside
!  (G)    Parse each token in turn (calling ParseToken to do most of the work)
!  (H)    Cheaply parse otherwise unrecognised conversation and return
!  (I)    Print best possible error message
!  (J)    Retry the whole lot
!  (K)    Last thing: check for "then" and further instructions(s), return.
!
!  The strategic points (A) to (K) are marked in the commentary.
!
!  Note that there are three different places where a return can happen.
! ----------------------------------------------------------------------------

[ Parser__parse  results   syntax line num_lines line_address i j k
                           token l m;

!  **** (A) ****

!  Firstly, in "not held" mode, we still have a command left over from last
!  time (eg, the user typed "eat biscuit", which was parsed as "take biscuit"
!  last time, with "eat biscuit" tucked away until now).  So we return that.

    if (notheld_mode==1)
    {   for (i=0:i<8:i++) results-->i=kept_results-->i;
        notheld_mode=0; rtrue;
    }

    if (held_back_mode==1)
    {   held_back_mode=0;
        Tokenise__(buffer,parse);
        jump ReParse;
    }

  .ReType;

    Keyboard(buffer,parse);

  .ReParse;

    parser_inflection = name;

!  Initially assume the command is aimed at the player, and the verb
!  is the first word

#ifdef TARGET_ZCODE;
    num_words=parse->1;
#ifnot; ! TARGET_GLULX
    num_words=parse-->0;
#endif; ! TARGET_
    wn=1;
#ifdef LanguageToInformese;
    LanguageToInformese();
#ifv5;
!   Re-tokenise:
    Tokenise__(buffer,parse);
#endif;
#endif;

    BeforeParsing();
#ifdef TARGET_ZCODE;
    num_words=parse->1;
#ifnot; ! TARGET_GLULX
    num_words=parse-->0;
#endif; ! TARGET_

    k=0;
#ifdef DEBUG;
    if (parser_trace>=2)
    {   print "[ ";
        for (i=0:i<num_words:i++)
        {
#ifdef TARGET_ZCODE;
            j=parse-->(i*2 + 1);
#ifnot; ! TARGET_GLULX
            j=parse-->(i*3 + 1);
#endif; ! TARGET_
            k=WordAddress(i+1);
            l=WordLength(i+1);
            print "~"; for (m=0:m<l:m++) print (char) k->m; print "~ ";

            if (j == 0) print "?";
            else
            {
#ifdef TARGET_ZCODE;
                if (UnsignedCompare(j, 0-->4)>=0
                    && UnsignedCompare(j, 0-->2)<0) print (address) j;
                else print j;
#ifnot; ! TARGET_GLULX
                if (j->0 == $60) print (address) j;
                else print j;
#endif; ! TARGET_
            }
            if (i ~= num_words-1) print " / ";
        }
        print " ]^";
    }
#endif;
    verb_wordnum=1;
    actor=player;
    actors_location = ScopeCeiling(player);
    usual_grammar_after = 0;

  .AlmostReParse;

    scope_token = 0;
    action_to_be = NULL;

!  Begin from what we currently think is the verb word

  .BeginCommand;
    wn=verb_wordnum;
    verb_word = NextWordStopped();

!  If there's no input here, we must have something like
!  "person,".

    if (verb_word==-1)
    {   best_etype = STUCK_PE; jump GiveError; }

!  Now try for "again" or "g", which are special cases:
!  don't allow "again" if nothing has previously been typed;
!  simply copy the previous text across

    if (verb_word==AGAIN2__WD or AGAIN3__WD) verb_word=AGAIN1__WD;
    if (verb_word==AGAIN1__WD)
    {   if (actor~=player)
        {   L__M(##Miscellany,20); jump ReType; }
#ifdef TARGET_ZCODE;
        if (buffer3->1==0)
        {   L__M(##Miscellany,21); jump ReType; }
#ifnot; ! TARGET_GLULX
        if (buffer3-->0==0)
        {   L__M(##Miscellany,21); jump ReType; }
#endif; ! TARGET_
        for (i=0:i<INPUT_BUFFER_LEN:i++) buffer->i=buffer3->i;
        jump ReParse;
    }

!  Save the present input in case of an "again" next time

    if (verb_word~=AGAIN1__WD)
        for (i=0:i<INPUT_BUFFER_LEN:i++) buffer3->i=buffer->i;

    if (usual_grammar_after==0)
    {   i = RunRoutines(actor, grammar);
        #ifdef DEBUG;
        if (parser_trace>=2 && actor.grammar~=0 or NULL)
            print " [Grammar property returned ", i, "]^";
        #endif;
        if (i<0) { usual_grammar_after = verb_wordnum; i=-i; }
        if (i==1)
        {   results-->0 = action;
            results-->1 = noun;
            results-->2 = second;
            rtrue;
        }
        if (i~=0) { verb_word = i; wn--; verb_wordnum--; }
        else
        {   wn = verb_wordnum; verb_word=NextWord();
        }
    }
    else usual_grammar_after=0;

!  **** (B) ****

    #ifdef LanguageIsVerb;
    if (verb_word==0)
    {   i = wn; verb_word=LanguageIsVerb(buffer, parse, verb_wordnum);
        wn = i;
    }
    #endif;

!  If the first word is not listed as a verb, it must be a direction
!  or the name of someone to talk to

    if (verb_word==0 || ((verb_word->#dict_par1) & 1) == 0)
    {   

!  So is the first word an object contained in the special object "compass"
!  (i.e., a direction)?  This needs use of NounDomain, a routine which
!  does the object matching, returning the object number, or 0 if none found,
!  or REPARSE_CODE if it has restructured the parse table so the whole parse
!  must be begun again...

        wn=verb_wordnum; indef_mode = false; token_filter = 0;
        l=NounDomain(compass,0,0); if (l==REPARSE_CODE) jump ReParse;

!  If it is a direction, send back the results:
!  action=GoSub, no of arguments=1, argument 1=the direction.

        if (l~=0)
        {   results-->0 = ##Go;
            action_to_be = ##Go;
            results-->1 = 1;
            results-->2 = l;
            jump LookForMore;
        }

!  **** (C) ****

!  Only check for a comma (a "someone, do something" command) if we are
!  not already in the middle of one.  (This simplification stops us from
!  worrying about "robot, wizard, you are an idiot", telling the robot to
!  tell the wizard that she is an idiot.)

        if (actor==player)
        {   for (j=2:j<=num_words:j++)
            {   i=NextWord(); if (i==comma_word) jump Conversation;
            }

            verb_word=UnknownVerb(verb_word);
            if (verb_word~=0) jump VerbAccepted;
        }

        best_etype=VERB_PE; jump GiveError;

!  NextWord nudges the word number wn on by one each time, so we've now
!  advanced past a comma.  (A comma is a word all on its own in the table.)

      .Conversation;
        j=wn-1;
        if (j==1) { L__M(##Miscellany,22); jump ReType; }

!  Use NounDomain (in the context of "animate creature") to see if the
!  words make sense as the name of someone held or nearby

        wn=1; lookahead=HELD_TOKEN;
        scope_reason = TALKING_REASON;
        l=NounDomain(player,actors_location,6);
        scope_reason = PARSING_REASON;
        if (l==REPARSE_CODE) jump ReParse;

        if (l==0) { L__M(##Miscellany,23); jump ReType; }

!  The object addressed must at least be "talkable" if not actually "animate"
!  (the distinction allows, for instance, a microphone to be spoken to,
!  without the parser thinking that the microphone is human).

        if (l hasnt animate && l hasnt talkable)
        {   L__M(##Miscellany, 24, l); jump ReType; }

!  Check that there aren't any mystery words between the end of the person's
!  name and the comma (eg, throw out "dwarf sdfgsdgs, go north").

        if (wn~=j)
        {   L__M(##Miscellany, 25); jump ReType; }

!  The player has now successfully named someone.  Adjust "him", "her", "it":

        PronounNotice(l);

!  Set the global variable "actor", adjust the number of the first word,
!  and begin parsing again from there.

        verb_wordnum=j+1;

!  Stop things like "me, again":

        if (l == player)
        {   wn = verb_wordnum;
            if (NextWordStopped() == AGAIN1__WD or AGAIN2__WD or AGAIN3__WD)
            {   L__M(##Miscellany,20); jump ReType;
            }
        }

        actor=l;
        actors_location=ScopeCeiling(l);
        #ifdef DEBUG;
        if (parser_trace>=1)
            print "[Actor is ", (the) actor, " in ",
                (name) actors_location, "]^";
        #endif;
        jump BeginCommand;
    }


!  **** (D) ****

   .VerbAccepted;

!  We now definitely have a verb, not a direction, whether we got here by the
!  "take ..." or "person, take ..." method.  Get the meta flag for this verb:

    meta=((verb_word->#dict_par1) & 2)/2;

!  You can't order other people to "full score" for you, and so on...

    if (meta==1 && actor~=player)
    {   best_etype=VERB_PE; meta=0; jump GiveError; }

!  Now let i be the corresponding verb number, stored in the dictionary entry
!  (in a peculiar 255-n fashion for traditional Infocom reasons)...

    i=$ff-(verb_word->#dict_par2);

!  ...then look up the i-th entry in the verb table, whose address is at word
!  7 in the Z-machine (in the header), so as to get the address of the syntax
!  table for the given verb...

#ifdef TARGET_ZCODE;
    syntax=(0-->7)-->i;
#ifnot; ! TARGET_GLULX
    syntax=(#grammar_table)-->(i+1);
#endif; ! TARGET_

!  ...and then see how many lines (ie, different patterns corresponding to the
!  same verb) are stored in the parse table...

    num_lines=(syntax->0)-1;

!  ...and now go through them all, one by one.
!  To prevent pronoun_word 0 being misunderstood,

   pronoun_word=NULL; pronoun_obj=NULL;

   #ifdef DEBUG;
   if (parser_trace>=1)
   {    print "[Parsing for the verb '", (address) verb_word,
              "' (", num_lines+1, " lines)]^";
   }
   #endif;

   best_etype=STUCK_PE; nextbest_etype=STUCK_PE;

!  "best_etype" is the current failure-to-match error - it is by default
!  the least informative one, "don't understand that sentence".
!  "nextbest_etype" remembers the best alternative to having to ask a
!  scope token for an error message (i.e., the best not counting ASKSCOPE_PE).


!  **** (E) ****

    line_address = syntax + 1;

    for (line=0:line<=num_lines:line++)
    {   
        for (i = 0 : i < 32 : i++)
        {   line_token-->i = ENDIT_TOKEN;
            line_ttype-->i = ELEMENTARY_TT;
            line_tdata-->i = ENDIT_TOKEN;
        }

!  Unpack the syntax line from Inform format into three arrays; ensure that
!  the sequence of tokens ends in an ENDIT_TOKEN.

        line_address = UnpackGrammarLine(line_address);
            
        #ifdef DEBUG;
        if (parser_trace >= 1)
        {   if (parser_trace >= 2) new_line;
            print "[line ", line; DebugGrammarLine();
            print "]^";
        }
        #endif;

!  We aren't in "not holding" or inferring modes, and haven't entered
!  any parameters on the line yet, or any special numbers; the multiple
!  object is still empty.

        not_holding=0;
        inferfrom=0;
        parameters=0;
        nsns=0; special_word=0; special_number=0;
        multiple_object-->0 = 0;
        multi_context = 0;
        etype=STUCK_PE;

!  Put the word marker back to just after the verb

        wn=verb_wordnum+1;

!  **** (F) ****
!  There are two special cases where parsing a token now has to be
!  affected by the result of parsing another token later, and these
!  two cases (multiexcept and multiinside tokens) are helped by a quick
!  look ahead, to work out the future token now.  We can only carry this
!  out in the simple (but by far the most common) case:
!
!      multiexcept <one or more prepositions> noun
!
!  and similarly for multiinside.

        advance_warning = NULL; indef_mode = false;
        for (i=0,m=false,pcount=0:line_token-->pcount ~= ENDIT_TOKEN:pcount++)
        {   scope_token = 0;

            if (line_ttype-->pcount ~= PREPOSITION_TT) i++;

            if (line_ttype-->pcount == ELEMENTARY_TT)
            {   if (line_tdata-->pcount == MULTI_TOKEN) m=true;
                if (line_tdata-->pcount
                    == MULTIEXCEPT_TOKEN or MULTIINSIDE_TOKEN  && i==1)
                {   !   First non-preposition is "multiexcept" or
                    !   "multiinside", so look ahead.

                    #ifdef DEBUG;
                    if (parser_trace>=2) print " [Trying look-ahead]^";
                    #endif;

                    !   We need this to be followed by 1 or more prepositions.

                    pcount++;
                    if (line_ttype-->pcount == PREPOSITION_TT)
                    {   while (line_ttype-->pcount == PREPOSITION_TT)
                            pcount++;

                        if ((line_ttype-->pcount == ELEMENTARY_TT)
                            && (line_tdata-->pcount == NOUN_TOKEN))
                        {
                            !  Advance past the last preposition

                            while (wn <= num_words)
                            {   if (NextWord() == line_tdata-->(pcount-1))
                                {   l = NounDomain(actors_location, actor,
                                            NOUN_TOKEN);
                                    #ifdef DEBUG;
                                    if (parser_trace>=2)
                                    {   print " [Advanced to ~noun~ token: ";
                                        if (l==REPARSE_CODE)
                                            print "re-parse request]^";
                                        if (l==1) print "but multiple found]^";
                                        if (l==0) print "error ", etype, "]^";
                                        if (l>=2) print (the) l, "]^";
                                    }
                                    #endif;
                                    if (l==REPARSE_CODE) jump ReParse;
                                    if (l>=2) advance_warning = l;
                                }
                            }
                        }
                    }
                    break;
                }
            }
        }

!  Slightly different line-parsing rules will apply to "take multi", to
!  prevent "take all" behaving correctly but misleadingly when there's
!  nothing to take.

        take_all_rule = 0;
        if (m && params_wanted==1 && action_to_be==##Take)
            take_all_rule = 1;

!  And now start again, properly, forearmed or not as the case may be.
!  As a precaution, we clear all the variables again (they may have been
!  disturbed by the call to NounDomain, which may have called outside
!  code, which may have done anything!).

        not_holding=0;
        inferfrom=0;
        parameters=0;
        nsns=0; special_word=0; special_number=0;
        multiple_object-->0 = 0;
        etype=STUCK_PE;
        wn=verb_wordnum+1;

!  **** (G) ****
!  "Pattern" gradually accumulates what has been recognised so far,
!  so that it may be reprinted by the parser later on

        for (pcount=1::pcount++)
        {   pattern-->pcount = PATTERN_NULL; scope_token=0;

            token = line_token-->(pcount-1);
            lookahead = line_token-->pcount;

            #ifdef DEBUG;
            if (parser_trace >= 2)
               print " [line ", line, " token ", pcount, " word ", wn, " : ",
                     (DebugToken) token, "]^";
            #endif;

            if (token ~= ENDIT_TOKEN)
            {   scope_reason = PARSING_REASON;
                parser_inflection = name;
                AnalyseToken(token);
                l = ParseToken__(found_ttype, found_tdata, pcount-1, token);
                while (l<-200) l = ParseToken__(ELEMENTARY_TT, l + 256);
                scope_reason = PARSING_REASON;

                if (l==GPR_PREPOSITION)
                {   if (found_ttype~=PREPOSITION_TT
                        && (found_ttype~=ELEMENTARY_TT
                            || found_tdata~=TOPIC_TOKEN)) params_wanted--;
                    l = true;
                }
                else
                if (l<0) l = false;
                else
                if (l~=GPR_REPARSE)
                {   if (l==GPR_NUMBER)
                    {   if (nsns==0) special_number1=parsed_number;
                        else special_number2=parsed_number;
                        nsns++; l = 1;
                    }
                    if (l==GPR_MULTIPLE) l = 0;
                    results-->(parameters+2) = l;
                    parameters++;
                    pattern-->pcount = l;
                    l = true;
                }

                #ifdef DEBUG;
                if (parser_trace >= 3)
                {   print "  [token resulted in ";
                    if (l==REPARSE_CODE) print "re-parse request]^";
                    if (l==0) print "failure with error type ", etype, "]^";
                    if (l==1) print "success]^";
                }
                #endif;

                if (l==REPARSE_CODE) jump ReParse;
                if (l==false) break;
            }
            else
            {

!  If the player has entered enough already but there's still
!  text to wade through: store the pattern away so as to be able to produce
!  a decent error message if this turns out to be the best we ever manage,
!  and in the mean time give up on this line

!  However, if the superfluous text begins with a comma or "then" then
!  take that to be the start of another instruction

                if (wn <= num_words)
                {   l=NextWord();
                    if (l==THEN1__WD or THEN2__WD or THEN3__WD or comma_word)
                    {   held_back_mode=1; hb_wn=wn-1; }
                    else
                    {   for (m=0:m<32:m++) pattern2-->m=pattern-->m;
                        pcount2=pcount;
                        etype=UPTO_PE; break;
                    }
                }

!  Now, we may need to revise the multiple object because of the single one
!  we now know (but didn't when the list was drawn up).

                if (parameters>=1 && results-->2 == 0)
                {   l=ReviseMulti(results-->3);
                    if (l~=0) { etype=l; break; }
                }
                if (parameters>=2 && results-->3 == 0)
                {   l=ReviseMulti(results-->2);
                    if (l~=0) { etype=l; break; }
                }

!  To trap the case of "take all" inferring only "yourself" when absolutely
!  nothing else is in the vicinity...

                if (take_all_rule==2 && results-->2 == actor)
                {   best_etype = NOTHING_PE; jump GiveError;
                }

                #ifdef DEBUG;
                if (parser_trace>=1)
                    print "[Line successfully parsed]^";
                #endif;

!  The line has successfully matched the text.  Declare the input error-free...

                oops_from = 0;

!  ...explain any inferences made (using the pattern)...

                if (inferfrom~=0)
                {   print "("; PrintCommand(inferfrom); print ")^";
                }

!  ...copy the action number, and the number of parameters...

                results-->0 = action_to_be;
                results-->1 = parameters;

!  ...reverse first and second parameters if need be...

                if (action_reversed && parameters==2)
                {   i = results-->2; results-->2 = results-->3;
                    results-->3 = i;
                    if (nsns == 2)
                    {   i = special_number1; special_number1=special_number2;
                        special_number2=i;
                    }
                }

!  ...and to reset "it"-style objects to the first of these parameters, if
!  there is one (and it really is an object)...

                if (parameters > 0 && results-->2 >= 2)
                    PronounNotice(results-->2);

!  ...and worry about the case where an object was allowed as a parameter
!  even though the player wasn't holding it and should have been: in this
!  event, keep the results for next time round, go into "not holding" mode,
!  and for now tell the player what's happening and return a "take" request
!  instead...

                if (not_holding~=0 && actor==player)
                {   notheld_mode=1;
                    for (i=0:i<8:i++) kept_results-->i = results-->i;
                    results-->0 = ##Take;
                    results-->1 = 1;
                    results-->2 = not_holding;
                    L__M(##Miscellany, 26, not_holding);
                }

!  (Notice that implicit takes are only generated for the player, and not
!  for other actors.  This avoids entirely logical, but misleading, text
!  being printed.)

!  ...and return from the parser altogether, having successfully matched
!  a line.

                if (held_back_mode==1) { wn=hb_wn; jump LookForMore; }
                rtrue;
            }
        }

!  The line has failed to match.
!  We continue the outer "for" loop, trying the next line in the grammar.

        if (etype>best_etype) best_etype=etype;
        if (etype~=ASKSCOPE_PE && etype>nextbest_etype) nextbest_etype=etype;

!  ...unless the line was something like "take all" which failed because
!  nothing matched the "all", in which case we stop and give an error now.

        if (take_all_rule == 2 && etype==NOTHING_PE) break;
   }

!  The grammar is exhausted: every line has failed to match.

!  **** (H) ****

  .GiveError;
        etype=best_etype;

!  Errors are handled differently depending on who was talking.

!  If the command was addressed to somebody else (eg, "dwarf, sfgh") then
!  it is taken as conversation which the parser has no business in disallowing.

    if (actor~=player)
    {   if (usual_grammar_after>0)
        {   verb_wordnum = usual_grammar_after;
            jump AlmostReParse;
        }
        wn=verb_wordnum;
        special_word=NextWord();
        if (special_word==comma_word)
        {   special_word=NextWord();
            verb_wordnum++;
        }
        special_number=TryNumber(verb_wordnum);
        results-->0=##NotUnderstood;
        results-->1=2;
        results-->2=1; special_number1=special_word;
        results-->3=actor;
        consult_from = verb_wordnum; consult_words = num_words-consult_from+1;
        rtrue;
    }

!  **** (I) ****

!  If the player was the actor (eg, in "take dfghh") the error must be printed,
!  and fresh input called for.  In three cases the oops word must be jiggled.

    if (ParserError(etype)~=0) jump ReType;
    pronoun_word = pronoun__word; pronoun_obj = pronoun__obj;

    if (etype==STUCK_PE)   { L__M(##Miscellany, 27); oops_from=1; }
    if (etype==UPTO_PE)    { L__M(##Miscellany, 28);
                             for (m=0:m<32:m++) pattern-->m = pattern2-->m;
                             pcount=pcount2; PrintCommand(0); print ".^";
                           }
    if (etype==NUMBER_PE)  L__M(##Miscellany, 29);
    if (etype==CANTSEE_PE) { L__M(##Miscellany, 30); oops_from=saved_oops; }
    if (etype==TOOLIT_PE)  L__M(##Miscellany, 31);
    if (etype==NOTHELD_PE) { L__M(##Miscellany, 32); oops_from=saved_oops; }
    if (etype==MULTI_PE)   L__M(##Miscellany, 33);
    if (etype==MMULTI_PE)  L__M(##Miscellany, 34);
    if (etype==VAGUE_PE)   L__M(##Miscellany, 35);
    if (etype==EXCEPT_PE)  L__M(##Miscellany, 36);
    if (etype==ANIMA_PE)   L__M(##Miscellany, 37);
    if (etype==VERB_PE)    L__M(##Miscellany, 38);
    if (etype==SCENERY_PE) L__M(##Miscellany, 39);
    if (etype==ITGONE_PE)
    {   if (pronoun_obj == NULL) L__M(##Miscellany, 35);
                            else L__M(##Miscellany, 40);
    }
    if (etype==JUNKAFTER_PE) L__M(##Miscellany, 41);
    if (etype==TOOFEW_PE)  L__M(##Miscellany, 42, multi_had);
    if (etype==NOTHING_PE) { if (multi_wanted==100) L__M(##Miscellany, 43);
                             else L__M(##Miscellany, 44);  }

    if (etype==ASKSCOPE_PE)
    {   scope_stage=3;
        if (indirect(scope_error)==-1)
        {   best_etype=nextbest_etype; jump GiveError;  }
    }

!  **** (J) ****

!  And go (almost) right back to square one...

    jump ReType;

!  ...being careful not to go all the way back, to avoid infinite repetition
!  of a deferred command causing an error.


!  **** (K) ****

!  At this point, the return value is all prepared, and we are only looking
!  to see if there is a "then" followed by subsequent instruction(s).
    
   .LookForMore;

   if (wn>num_words) rtrue;

   i=NextWord();
   if (i==THEN1__WD or THEN2__WD or THEN3__WD or comma_word)
   {   if (wn>num_words)
       {   held_back_mode = false; return; }
       i = WordAddress(verb_wordnum);
       j = WordAddress(wn);
       for (:i<j:i++) i->0 = ' ';
       i = NextWord();
       if (i==AGAIN1__WD or AGAIN2__WD or AGAIN3__WD)
       {   !   Delete the words "then again" from the again buffer,
           !   in which we have just realised that it must occur:
           !   prevents an infinite loop on "i. again"

           i = WordAddress(wn-2)-buffer;
           if (wn > num_words) j = INPUT_BUFFER_LEN-1; 
           else j = WordAddress(wn)-buffer;
           for (:i<j:i++) buffer3->i = ' ';
       }
       Tokenise__(buffer,parse); held_back_mode = true; return;
   }
   best_etype=UPTO_PE; jump GiveError;
];

[ ScopeCeiling person act;
  act = parent(person); if (act == 0) return person;
  if (person == player && location == thedark) return thedark;
  while (parent(act)~=0
         && (act has transparent || act has supporter
             || (act has container && act has open)))
      act = parent(act);
  return act;
];

! ----------------------------------------------------------------------------
!  Descriptors()
!
!  Handles descriptive words like "my", "his", "another" and so on.
!  Skips "the", and leaves wn pointing to the first misunderstood word.
!
!  Allowed to set up for a plural only if allow_p is set
!
!  Returns error number, or 0 if no error occurred
! ----------------------------------------------------------------------------

Constant OTHER_BIT  =   1;     !  These will be used in Adjudicate()
Constant MY_BIT     =   2;     !  to disambiguate choices
Constant THAT_BIT   =   4;
Constant PLURAL_BIT =   8;
Constant LIT_BIT    =  16;
Constant UNLIT_BIT  =  32;

[ ResetDescriptors;
   indef_mode=0; indef_type=0; indef_wanted=0; indef_guess_p=0;
   indef_possambig = false;
   indef_owner = nothing;
   indef_cases = $$111111111111;
   indef_nspec_at = 0;
];

[ Descriptors allow_multiple  o x flag cto type n;

   ResetDescriptors();
   if (wn > num_words) return 0;

   for (flag=true:flag:)
   {   o=NextWordStopped(); flag=false;

       for (x=1:x<=LanguageDescriptors-->0:x=x+4)
           if (o == LanguageDescriptors-->x)
           {   flag = true;
               type = LanguageDescriptors-->(x+2);
               if (type ~= DEFART_PK) indef_mode = true;
               indef_possambig = true;
               indef_cases = indef_cases & (LanguageDescriptors-->(x+1));

               if (type == POSSESS_PK)
               {   cto = LanguageDescriptors-->(x+3);
                   switch(cto)
                   {  0: indef_type = indef_type | MY_BIT;
                      1: indef_type = indef_type | THAT_BIT;
                      default: indef_owner = PronounValue(cto);
                        if (indef_owner == NULL) indef_owner = InformParser;
                   }
               }

               if (type == light)
                   indef_type = indef_type | LIT_BIT;
               if (type == -light)
                   indef_type = indef_type | UNLIT_BIT;
           }

       if (o==OTHER1__WD or OTHER2__WD or OTHER3__WD)
                            { indef_mode=1; flag=1;
                              indef_type = indef_type | OTHER_BIT; }
       if (o==ALL1__WD or ALL2__WD or ALL3__WD or ALL4__WD or ALL5__WD)
                            { indef_mode=1; flag=1; indef_wanted=100;
                              if (take_all_rule == 1)
                                  take_all_rule = 2;
                              indef_type = indef_type | PLURAL_BIT; }
       if (allow_plurals && allow_multiple)
       {   n=TryNumber(wn-1);
           if (n==1)        { indef_mode=1; flag=1; }
           if (n>1)         { indef_guess_p=1;
                              indef_mode=1; flag=1; indef_wanted=n;
                              indef_nspec_at=wn-1;
                              indef_type = indef_type | PLURAL_BIT; }
       }
       if (flag==1
           && NextWordStopped() ~= OF1__WD or OF2__WD or OF3__WD or OF4__WD)
           wn--;  ! Skip 'of' after these
   }
   wn--;
   if ((indef_wanted > 0) && (~~allow_multiple)) return MULTI_PE;
   return 0;
];

! ----------------------------------------------------------------------------
!  CreatureTest: Will this person do for a "creature" token?
! ----------------------------------------------------------------------------

[ CreatureTest obj;
  if (obj has animate) rtrue;
  if (obj hasnt talkable) rfalse;
  if (action_to_be == ##Ask or ##Answer or ##Tell or ##AskFor) rtrue;
  rfalse;
];

[ PrepositionChain wd index;
  if (line_tdata-->index == wd) return wd;
  if ((line_token-->index)->0 & $20 == 0) return -1;
  do
  {   if (line_tdata-->index == wd) return wd;
      index++;
  }
  until ((line_token-->index == ENDIT_TOKEN)
         || (((line_token-->index)->0 & $10) == 0));
  return -1;
];

! ----------------------------------------------------------------------------
!  ParseToken(type, data):
!      Parses the given token, from the current word number wn, with exactly
!      the specification of a general parsing routine.
!      (Except that for "topic" tokens and prepositions, you need to supply
!      a position in a valid grammar line as third argument.)
!
!  Returns:
!    GPR_REPARSE  for "reconstructed input, please re-parse from scratch"
!    GPR_PREPOSITION  for "token accepted with no result"
!    $ff00 + x    for "please parse ParseToken(ELEMENTARY_TT, x) instead"
!    0            for "token accepted, result is the multiple object list"
!    1            for "token accepted, result is the number in parsed_number"
!    object num   for "token accepted with this object as result"
!    -1           for "token rejected"
!
!  (A)            Analyse the token; handle all tokens not involving
!                 object lists and break down others into elementary tokens
!  (B)            Begin parsing an object list
!  (C)            Parse descriptors (articles, pronouns, etc.) in the list
!  (D)            Parse an object name
!  (E)            Parse connectives ("and", "but", etc.) and go back to (C)
!  (F)            Return the conclusion of parsing an object list
! ----------------------------------------------------------------------------

[ ParseToken given_ttype given_tdata token_n x y;
  x = lookahead; lookahead = NOUN_TOKEN;
  y = ParseToken__(given_ttype,given_tdata,token_n);
  if (y == GPR_REPARSE) Tokenise__(buffer,parse);
  lookahead = x; return y;
];

[ ParseToken__ given_ttype given_tdata token_n
             token l o i j k and_parity single_object desc_wn many_flag
             token_allows_multiple;

!  **** (A) ****

   token_filter = 0;

   switch(given_ttype)
   {   ELEMENTARY_TT:
           switch(given_tdata)
           {   SPECIAL_TOKEN:
                   l=TryNumber(wn);
                   special_word=NextWord();
                   #ifdef DEBUG;
                   if (l~=-1000)
                       if (parser_trace>=3)
                           print "  [Read special as the number ", l, "]^";
                   #endif;
                   if (l==-1000)
                   {   #ifdef DEBUG;
                       if (parser_trace>=3)
                         print "  [Read special word at word number ", wn, "]^";
                       #endif;
                       l = special_word;
                   }
                   parsed_number = l; return GPR_NUMBER;

               NUMBER_TOKEN:
                   l=TryNumber(wn++);
                   if (l==-1000) { etype=NUMBER_PE; return GPR_FAIL; } 
                   #ifdef DEBUG;
                   if (parser_trace>=3) print "  [Read number as ", l, "]^";
                   #endif;
                   parsed_number = l; return GPR_NUMBER;

               CREATURE_TOKEN:
                   if (action_to_be==##Answer or ##Ask or ##AskFor or ##Tell)
                       scope_reason = TALKING_REASON;

               TOPIC_TOKEN:
                   consult_from = wn;
                   if ((line_ttype-->(token_n+1) ~= PREPOSITION_TT)
                       && (line_token-->(token_n+1) ~= ENDIT_TOKEN))
                       RunTimeError(13);
                   do o=NextWordStopped();
                   until (o==-1 || PrepositionChain(o, token_n+1) ~= -1);
                   wn--;
                   consult_words = wn-consult_from;
                   if (consult_words==0) return GPR_FAIL;
                   if (action_to_be==##Ask or ##Answer or ##Tell)
                   {   o=wn; wn=consult_from; parsed_number=NextWord();
                       #IFDEF EnglishNaturalLanguage;
                       if (parsed_number=='the' && consult_words>1)
                           parsed_number=NextWord();
                       #ENDIF;
                       wn=o; return 1;
                   }
                   return GPR_PREPOSITION;
           }

       PREPOSITION_TT:
           #Iffalse Grammar__Version==1;
!  Is it an unnecessary alternative preposition, when a previous choice
!  has already been matched?
           if ((token->0) & $10) return GPR_PREPOSITION;
           #Endif;

!  If we've run out of the player's input, but still have parameters to
!  specify, we go into "infer" mode, remembering where we are and the
!  preposition we are inferring...

           if (wn > num_words)
           {   if (inferfrom==0 && parameters<params_wanted)
               {   inferfrom = pcount; inferword = token;
                   pattern-->pcount = REPARSE_CODE + Dword__No(given_tdata);
               }

!  If we are not inferring, then the line is wrong...

               if (inferfrom==0) return -1;

!  If not, then the line is right but we mark in the preposition...

               pattern-->pcount = REPARSE_CODE + Dword__No(given_tdata);
               return GPR_PREPOSITION;
           }

           o = NextWord();

           pattern-->pcount = REPARSE_CODE + Dword__No(o);

!  Whereas, if the player has typed something here, see if it is the
!  required preposition... if it's wrong, the line must be wrong,
!  but if it's right, the token is passed (jump to finish this token).

           if (o == given_tdata) return GPR_PREPOSITION;
           #Iffalse Grammar__Version==1;
           if (PrepositionChain(o, token_n) ~= -1)
               return GPR_PREPOSITION;
           #Endif;
           return -1;

       GPR_TT:
           l=indirect(given_tdata);
           #ifdef DEBUG;
           if (parser_trace>=3)
               print "  [Outside parsing routine returned ", l, "]^";
           #endif;
           return l;

       SCOPE_TT:
           scope_token = given_tdata;
           scope_stage = 1;
           l = indirect(scope_token);
           #ifdef DEBUG;
           if (parser_trace>=3)
               print "  [Scope routine returned multiple-flag of ", l, "]^";
           #endif;
           if (l==1) given_tdata = MULTI_TOKEN; else given_tdata = NOUN_TOKEN;

       ATTR_FILTER_TT:
           token_filter = 1 + given_tdata;
           given_tdata = NOUN_TOKEN;

       ROUTINE_FILTER_TT:
           token_filter = given_tdata;
           given_tdata = NOUN_TOKEN;
   }

   token = given_tdata;

!  **** (B) ****

!  There are now three possible ways we can be here:
!      parsing an elementary token other than "special" or "number";
!      parsing a scope token;
!      parsing a noun-filter token (either by routine or attribute).
!
!  In each case, token holds the type of elementary parse to
!  perform in matching one or more objects, and
!  token_filter is 0 (default), an attribute + 1 for an attribute filter
!  or a routine address for a routine filter.

   token_allows_multiple = false;
   if (token == MULTI_TOKEN or MULTIHELD_TOKEN or MULTIEXCEPT_TOKEN
                or MULTIINSIDE_TOKEN) token_allows_multiple = true;

   many_flag = false; and_parity = true; dont_infer = false;

!  **** (C) ****
!  We expect to find a list of objects next in what the player's typed.

  .ObjectList;

   #ifdef DEBUG;
   if (parser_trace>=3) print "  [Object list from word ", wn, "]^";
   #endif;

!  Take an advance look at the next word: if it's "it" or "them", and these
!  are unset, set the appropriate error number and give up on the line
!  (if not, these are still parsed in the usual way - it is not assumed
!  that they still refer to something in scope)

    o=NextWord(); wn--;

    pronoun_word = NULL; pronoun_obj = NULL;
    l = PronounValue(o);
    if (l ~= 0)
    {   pronoun_word = o; pronoun_obj = l;
        if (l == NULL)
        {   !   Don't assume this is a use of an unset pronoun until the
            !   descriptors have been checked, because it might be an
            !   article (or some such) instead

            for (l=1:l<=LanguageDescriptors-->0:l=l+4)
                if (o == LanguageDescriptors-->l) jump AssumeDescriptor;
            pronoun__word=pronoun_word; pronoun__obj=pronoun_obj;
            etype=VAGUE_PE; return GPR_FAIL; 
        }
    }

    .AssumeDescriptor;

    if (o==ME1__WD or ME2__WD or ME3__WD)
    {   pronoun_word = o; pronoun_obj = player;
    }

    allow_plurals = true; desc_wn = wn;

    .TryAgain;
!   First, we parse any descriptive words (like "the", "five" or "every"):
    l = Descriptors(token_allows_multiple); 
    if (l~=0) { etype=l; return GPR_FAIL; }

    .TryAgain2;

!  **** (D) ****

!  This is an actual specified object, and is therefore where a typing error
!  is most likely to occur, so we set:

    oops_from = wn;

!  So, two cases.  Case 1: token not equal to "held" (so, no implicit takes)
!  but we may well be dealing with multiple objects

!  In either case below we use NounDomain, giving it the token number as
!  context, and two places to look: among the actor's possessions, and in the
!  present location.  (Note that the order depends on which is likeliest.)

    if (token ~= HELD_TOKEN)
    {   i=multiple_object-->0;
        #ifdef DEBUG;
        if (parser_trace>=3)
            print "  [Calling NounDomain on location and actor]^";
        #endif;
        l=NounDomain(actors_location, actor, token);
        if (l==REPARSE_CODE) return l;                  ! Reparse after Q&A
        if (l==0) {   if (indef_possambig)
                      {   ResetDescriptors(); wn = desc_wn; jump TryAgain2; }
                      etype=CantSee(); jump FailToken; } ! Choose best error

        #ifdef DEBUG;
        if (parser_trace>=3)
        {   if (l>1)
                print "  [ND returned ", (the) l, "]^";
            else
            {   print "  [ND appended to the multiple object list:^";
                k=multiple_object-->0;
                for (j=i+1:j<=k:j++)
                    print "  Entry ", j, ": ", (The) multiple_object-->j,
                          " (", multiple_object-->j, ")^";
                print "  List now has size ", k, "]^";
            }
        }
        #endif;

        if (l==1)
        {   if (~~many_flag)
            {   many_flag = true;
            }
            else                                  ! Merge with earlier ones
            {   k=multiple_object-->0;            ! (with either parity)
                multiple_object-->0 = i;
                for (j=i+1:j<=k:j++)
                {   if (and_parity) MultiAdd(multiple_object-->j);
                    else MultiSub(multiple_object-->j);
                }
                #ifdef DEBUG;
                if (parser_trace>=3)
                    print "  [Merging ", k-i, " new objects to the ",
                        i, " old ones]^";
                #endif;
            }
        }
        else
        {   ! A single object was indeed found

            if (match_length == 0 && indef_possambig)
            {   !   So the answer had to be inferred from no textual data,
                !   and we know that there was an ambiguity in the descriptor
                !   stage (such as a word which could be a pronoun being
                !   parsed as an article or possessive).  It's worth having
                !   another go.

                ResetDescriptors(); wn = desc_wn; jump TryAgain2;
            }
        
            if (token==CREATURE_TOKEN && CreatureTest(l)==0)
            {   etype=ANIMA_PE; jump FailToken; } !  Animation is required

            if (~~many_flag)
                single_object = l;
            else
            {   if (and_parity) MultiAdd(l); else MultiSub(l);
                #ifdef DEBUG;
                if (parser_trace>=3)
                    print "  [Combining ", (the) l, " with list]^";
                #endif;
            }
        }
    }

!  Case 2: token is "held" (which fortunately can't take multiple objects)
!  and may generate an implicit take

    else

    {   l=NounDomain(actor,actors_location,token);       ! Same as above...
        if (l==REPARSE_CODE) return GPR_REPARSE;
        if (l==0)
        {   if (indef_possambig)
            {   ResetDescriptors(); wn = desc_wn; jump TryAgain2; }
            etype=CantSee(); return GPR_FAIL;            ! Choose best error
        }

!  ...until it produces something not held by the actor.  Then an implicit
!  take must be tried.  If this is already happening anyway, things are too
!  confused and we have to give up (but saving the oops marker so as to get
!  it on the right word afterwards).
!  The point of this last rule is that a sequence like
!
!      > read newspaper
!      (taking the newspaper first)
!      The dwarf unexpectedly prevents you from taking the newspaper!
!
!  should not be allowed to go into an infinite repeat - read becomes
!  take then read, but take has no effect, so read becomes take then read...
!  Anyway for now all we do is record the number of the object to take.

        o=parent(l);
        if (o~=actor)
        {   if (notheld_mode==1)
            {   saved_oops=oops_from; etype=NOTHELD_PE; jump FailToken;
            }
            not_holding = l;
            #ifdef DEBUG;
            if (parser_trace>=3)
                print "  [Allowing object ", (the) l, " for now]^";
            #endif;
        }
        single_object = l;
    }

!  The following moves the word marker to just past the named object...

    wn = oops_from + match_length;

!  **** (E) ****

!  Object(s) specified now: is that the end of the list, or have we reached
!  "and", "but" and so on?  If so, create a multiple-object list if we
!  haven't already (and are allowed to).

    .NextInList;

    o=NextWord();

    if (o==AND1__WD or AND2__WD or AND3__WD or BUT1__WD or BUT2__WD or BUT3__WD
           or comma_word)
    {
        #ifdef DEBUG;
        if (parser_trace>=3) print "  [Read connective '", (address) o, "']^";
        #endif;

        if (~~token_allows_multiple)
        {   etype=MULTI_PE; jump FailToken;
        }

        if (o==BUT1__WD or BUT2__WD or BUT3__WD) and_parity = 1-and_parity;

        if (~~many_flag)
        {   multiple_object-->0 = 1;
            multiple_object-->1 = single_object;
            many_flag = true;
            #ifdef DEBUG;
            if (parser_trace>=3)
                print "  [Making new list from ", (the) single_object, "]^";
            #endif;
        }
        dont_infer = true; inferfrom=0;           ! Don't print (inferences)
        jump ObjectList;                          ! And back around
    }

    wn--;   ! Word marker back to first not-understood word

!  **** (F) ****

!  Happy or unhappy endings:

    .PassToken;

    if (many_flag)
    {   single_object = GPR_MULTIPLE;
        multi_context = token;
    }
    else
    {   if (indef_mode==1 && indef_type & PLURAL_BIT ~= 0)
        {   if (indef_wanted<100 && indef_wanted>1)
            {   multi_had=1; multi_wanted=indef_wanted;
                etype=TOOFEW_PE;
                jump FailToken;
            }
        }
    }
    return single_object;

    .FailToken;

!  If we were only guessing about it being a plural, try again but only
!  allowing singulars (so that words like "six" are not swallowed up as
!  Descriptors)

    if (allow_plurals && indef_guess_p==1)
    {   allow_plurals=false; wn=desc_wn; jump TryAgain;
    }
    return -1;
];

! ----------------------------------------------------------------------------
!  NounDomain does the most substantial part of parsing an object name.
!
!  It is given two "domains" - usually a location and then the actor who is
!  looking - and a context (i.e. token type), and returns:
!
!   0    if no match at all could be made,
!   1    if a multiple object was made,
!   k    if object k was the one decided upon,
!   REPARSE_CODE if it asked a question of the player and consequently rewrote
!        the player's input, so that the whole parser should start again
!        on the rewritten input.
!
!   In the case when it returns 1<k<REPARSE_CODE, it also sets the variable
!   length_of_noun to the number of words in the input text matched to the
!   noun.
!   In the case k=1, the multiple objects are added to multiple_object by
!   hand (not by MultiAdd, because we want to allow duplicates).
! ----------------------------------------------------------------------------

[ NounDomain domain1 domain2 context    first_word i j k l
                                        answer_words marker;

#ifdef DEBUG;
  if (parser_trace>=4)
  {   print "   [NounDomain called at word ", wn, "^";
      print "   ";
      if (indef_mode)
      {   print "seeking indefinite object: ";
          if (indef_type & OTHER_BIT)  print "other ";
          if (indef_type & MY_BIT)     print "my ";
          if (indef_type & THAT_BIT)   print "that ";
          if (indef_type & PLURAL_BIT) print "plural ";
          if (indef_type & LIT_BIT)    print "lit ";
          if (indef_type & UNLIT_BIT)  print "unlit ";
          if (indef_owner ~= 0) print "owner:", (name) indef_owner;
          new_line;
          print "   number wanted: ";
          if (indef_wanted == 100) print "all"; else print indef_wanted;
          new_line;
          print "   most likely GNAs of names: ", indef_cases, "^";
      }
      else print "seeking definite object^";
  }
#endif;

  match_length=0; number_matched=0; match_from=wn; placed_in_flag=0;

  SearchScope(domain1, domain2, context);

#ifdef DEBUG;
  if (parser_trace>=4) print "   [ND made ", number_matched, " matches]^";
#endif;

  wn=match_from+match_length;

!  If nothing worked at all, leave with the word marker skipped past the
!  first unmatched word...

  if (number_matched==0) { wn++; rfalse; }

!  Suppose that there really were some words being parsed (i.e., we did
!  not just infer).  If so, and if there was only one match, it must be
!  right and we return it...

  if (match_from <= num_words)
  {   if (number_matched==1) { i=match_list-->0; return i; }

!  ...now suppose that there was more typing to come, i.e. suppose that
!  the user entered something beyond this noun.  If nothing ought to follow,
!  then there must be a mistake, (unless what does follow is just a full
!  stop, and or comma)

      if (wn<=num_words)
      {   i=NextWord(); wn--;
          if (i ~=  AND1__WD or AND2__WD or AND3__WD or comma_word
                 or THEN1__WD or THEN2__WD or THEN3__WD
                 or BUT1__WD or BUT2__WD or BUT3__WD)
          {   if (lookahead==ENDIT_TOKEN) rfalse;
          }
      }
  }

!  Now look for a good choice, if there's more than one choice...

  number_of_classes=0;
  
  if (number_matched==1) i=match_list-->0;
  if (number_matched>1)
  {   i=Adjudicate(context);
      if (i==-1) rfalse;
      if (i==1) rtrue;       !  Adjudicate has made a multiple
                             !  object, and we pass it on
  }

!  If i is non-zero here, one of two things is happening: either
!  (a) an inference has been successfully made that object i is
!      the intended one from the user's specification, or
!  (b) the user finished typing some time ago, but we've decided
!      on i because it's the only possible choice.
!  In either case we have to keep the pattern up to date,
!  note that an inference has been made and return.
!  (Except, we don't note which of a pile of identical objects.)

  if (i~=0)
  {   if (dont_infer) return i;
      if (inferfrom==0) inferfrom=pcount;
      pattern-->pcount = i;
      return i;
  }

!  If we get here, there was no obvious choice of object to make.  If in
!  fact we've already gone past the end of the player's typing (which
!  means the match list must contain every object in scope, regardless
!  of its name), then it's foolish to give an enormous list to choose
!  from - instead we go and ask a more suitable question...

  if (match_from > num_words) jump Incomplete;

!  Now we print up the question, using the equivalence classes as worked
!  out by Adjudicate() so as not to repeat ourselves on plural objects...

  if (context==CREATURE_TOKEN)
      L__M(##Miscellany, 45); else L__M(##Miscellany, 46);

  j=number_of_classes; marker=0;
  for (i=1:i<=number_of_classes:i++)
  {   
      while (((match_classes-->marker) ~= i)
             && ((match_classes-->marker) ~= -i)) marker++;
      k=match_list-->marker;

      if (match_classes-->marker > 0) print (the) k; else print (a) k;

      if (i<j-1)  print ", ";
      if (i==j-1) print (string) OR__TX;
  }
  print "?^";

!  ...and get an answer:

  .WhichOne;
#ifdef TARGET_ZCODE;
  for (i=2:i<INPUT_BUFFER_LEN:i++) buffer2->i=' ';
#endif; ! TARGET_ZCODE
  answer_words=Keyboard(buffer2, parse2);

!  Conveniently, parse2-->1 is the first word in both ZCODE and GLULX.
  first_word=(parse2-->1);

!  Take care of "all", because that does something too clever here to do
!  later on:

  if (first_word == ALL1__WD or ALL2__WD or ALL3__WD or ALL4__WD or ALL5__WD)
  {   
      if (context == MULTI_TOKEN or MULTIHELD_TOKEN or MULTIEXCEPT_TOKEN
                     or MULTIINSIDE_TOKEN)
      {   l=multiple_object-->0;
          for (i=0:i<number_matched && l+i<63:i++)
          {   k=match_list-->i;
              multiple_object-->(i+1+l) = k;
          }
          multiple_object-->0 = i+l;
          rtrue;
      }
      L__M(##Miscellany, 47);
      jump WhichOne;
  }

!  If the first word of the reply can be interpreted as a verb, then
!  assume that the player has ignored the question and given a new
!  command altogether.
!  (This is one time when it's convenient that the directions are
!  not themselves verbs - thus, "north" as a reply to "Which, the north
!  or south door" is not treated as a fresh command but as an answer.)

  #ifdef LanguageIsVerb;
  if (first_word==0)
  {   j = wn; first_word=LanguageIsVerb(buffer2, parse2, 1); wn = j;
  }
  #endif;
  if (first_word ~= 0)
  {   j=first_word->#dict_par1;
      if ((0~=j&1) && (first_word ~= 'long' or 'short' or 'normal'
                                     or 'brief' or 'full' or 'verbose'))
      {   CopyBuffer(buffer, buffer2);
          return REPARSE_CODE;
      }
  }

!  Now we insert the answer into the original typed command, as
!  words additionally describing the same object
!  (eg, > take red button
!       Which one, ...
!       > music
!  becomes "take music red button".  The parser will thus have three
!  words to work from next time, not two.)

#ifdef TARGET_ZCODE;

  k = WordAddress(match_from) - buffer; l=buffer2->1+1; 
  for (j=buffer + buffer->0 - 1: j>= buffer+k+l: j--)
      j->0 = 0->(j-l);
  for (i=0:i<l:i++) buffer->(k+i) = buffer2->(2+i);
  buffer->(k+l-1) = ' ';
  buffer->1 = buffer->1 + l;
  if (buffer->1 >= (buffer->0 - 1)) buffer->1 = buffer->0;

#ifnot; ! TARGET_GLULX

  k = WordAddress(match_from) - buffer;
  l = (buffer2-->0) + 1;
  for (j=buffer+INPUT_BUFFER_LEN-1 : j >= buffer+k+l : j--)
      j->0 = j->(-l);
  for (i=0:i<l:i++) 
      buffer->(k+i) = buffer2->(WORDSIZE+i);
  buffer->(k+l-1) = ' ';
  buffer-->0 = buffer-->0 + l;
  if (buffer-->0 > (INPUT_BUFFER_LEN-WORDSIZE)) 
      buffer-->0 = (INPUT_BUFFER_LEN-WORDSIZE);

#endif; ! TARGET_

!  Having reconstructed the input, we warn the parser accordingly
!  and get out.

  return REPARSE_CODE;

!  Now we come to the question asked when the input has run out
!  and can't easily be guessed (eg, the player typed "take" and there
!  were plenty of things which might have been meant).

  .Incomplete;

  if (context==CREATURE_TOKEN)
      L__M(##Miscellany, 48); else L__M(##Miscellany, 49);

#ifdef TARGET_ZCODE;
  for (i=2:i<INPUT_BUFFER_LEN:i++) buffer2->i=' ';
#endif; ! TARGET_ZCODE
  answer_words=Keyboard(buffer2, parse2);

  first_word=(parse2-->1);
  #ifdef LanguageIsVerb;
  if (first_word==0)
  {   j = wn; first_word=LanguageIsVerb(buffer2, parse2, 1); wn = j;
  }
  #endif;

!  Once again, if the reply looks like a command, give it to the
!  parser to get on with and forget about the question...

  if (first_word ~= 0)
  {   j=first_word->#dict_par1;
      if (0~=j&1)
      {   CopyBuffer(buffer, buffer2);
          return REPARSE_CODE;
      }
  }

!  ...but if we have a genuine answer, then:
!
!  (1) we must glue in text suitable for anything that's been inferred.

  if (inferfrom ~= 0)
  {   for (j = inferfrom: j<pcount: j++)
      {   if (pattern-->j == PATTERN_NULL) continue;
#ifdef TARGET_ZCODE;
          i=2+buffer->1; (buffer->1)++; buffer->(i++) = ' ';
#ifnot; ! TARGET_GLULX
          i = WORDSIZE + buffer-->0;
          (buffer-->0)++; buffer->(i++) = ' ';
#endif; ! TARGET_
    
          if (parser_trace >= 5)
          print "[Gluing in inference with pattern code ", pattern-->j, "]^";

! Conveniently, parse2-->1 is the first word in both ZCODE and GLULX.

          parse2-->1 = 0;

          ! An inferred object.  Best we can do is glue in a pronoun.
          ! (This is imperfect, but it's very seldom needed anyway.)
    
          if (pattern-->j >= 2 && pattern-->j < REPARSE_CODE)
          {   PronounNotice(pattern-->j);
              for (k=1: k<=LanguagePronouns-->0: k=k+3)
                  if (pattern-->j == LanguagePronouns-->(k+2))
                  {   parse2-->1 = LanguagePronouns-->k;
                      if (parser_trace >= 5)
                      print "[Using pronoun '", (address) parse2-->1, "']^";
                      break;
                  }
          }
          else
          {   ! An inferred preposition.
              parse2-->1 = No__Dword(pattern-->j - REPARSE_CODE);
              if (parser_trace >= 5)
                  print "[Using preposition '", (address) parse2-->1, "']^";
          }
    
          ! parse2-->1 now holds the dictionary address of the word to glue in.

          if (parse2-->1 ~= 0)
          {   k = buffer + i;
#ifdef TARGET_ZCODE;
              @output_stream 3 k;
              print (address) parse2-->1;
              @output_stream -3;
              k = k-->0;
              for (l=i:l<i+k:l++) buffer->l = buffer->(l+2);
              i = i + k; buffer->1 = i-2;
#ifnot; ! TARGET_GLULX
              k = PrintAnyToArray(buffer+i, INPUT_BUFFER_LEN-i, parse2-->1);
              i = i + k; buffer-->0 = i - WORDSIZE;
#endif; ! TARGET_
          }
      }
  }

!  (2) we must glue the newly-typed text onto the end.

#ifdef TARGET_ZCODE;
  i=2+buffer->1; (buffer->1)++; buffer->(i++) = ' ';
  for (j=0: j<buffer2->1: i++, j++)
  {   buffer->i = buffer2->(j+2);
      (buffer->1)++;
      if (buffer->1 == INPUT_BUFFER_LEN) break;
  }    
#ifnot; ! TARGET_GLULX
  i = WORDSIZE + buffer-->0;
  (buffer-->0)++; buffer->(i++) = ' ';
  for (j=0: j<buffer2-->0: i++, j++)
  {   buffer->i = buffer2->(j+WORDSIZE);
      (buffer-->0)++;
      if (buffer-->0 == INPUT_BUFFER_LEN) break;
  }    
#endif; ! TARGET_

#ifdef TARGET_ZCODE;

!  (3) we fill up the buffer with spaces, which is unnecessary, but may
!      help incorrectly-written interpreters to cope.

  for (:i<INPUT_BUFFER_LEN:i++) buffer->i = ' ';

#endif; ! TARGET_ZCODE
 
  return REPARSE_CODE;
];

! ----------------------------------------------------------------------------
!  The Adjudicate routine tries to see if there is an obvious choice, when
!  faced with a list of objects (the match_list) each of which matches the
!  player's specification equally well.
!
!  To do this it makes use of the context (the token type being worked on).
!  It counts up the number of obvious choices for the given context
!  (all to do with where a candidate is, except for 6 (animate) which is to
!  do with whether it is animate or not);
!
!  if only one obvious choice is found, that is returned;
!
!  if we are in indefinite mode (don't care which) one of the obvious choices
!    is returned, or if there is no obvious choice then an unobvious one is
!    made;
!
!  at this stage, we work out whether the objects are distinguishable from
!    each other or not: if they are all indistinguishable from each other,
!    then choose one, it doesn't matter which;
!
!  otherwise, 0 (meaning, unable to decide) is returned (but remember that
!    the equivalence classes we've just worked out will be needed by other
!    routines to clear up this mess, so we can't economise on working them
!    out).
!
!  Returns -1 if an error occurred
! ----------------------------------------------------------------------------
Constant SCORE__CHOOSEOBJ = 1000;
Constant SCORE__IFGOOD = 500;
Constant SCORE__UNCONCEALED = 100;
Constant SCORE__BESTLOC = 60;
Constant SCORE__NEXTBESTLOC = 40;
Constant SCORE__NOTCOMPASS = 20;
Constant SCORE__NOTSCENERY = 10;
Constant SCORE__NOTACTOR = 5;
Constant SCORE__GNA = 1;
Constant SCORE__DIVISOR = 20;

[ Adjudicate context i j k good_flag good_ones last n flag offset sovert;

#ifdef DEBUG;
  if (parser_trace>=4)
  {   print "   [Adjudicating match list of size ", number_matched,
          " in context ", context, "^";
      print "   ";
      if (indef_mode)
      {   print "indefinite type: ";
          if (indef_type & OTHER_BIT)  print "other ";
          if (indef_type & MY_BIT)     print "my ";
          if (indef_type & THAT_BIT)   print "that ";
          if (indef_type & PLURAL_BIT) print "plural ";
          if (indef_type & LIT_BIT)    print "lit ";
          if (indef_type & UNLIT_BIT)  print "unlit ";
          if (indef_owner ~= 0) print "owner:", (name) indef_owner;
          new_line;
          print "   number wanted: ";
          if (indef_wanted == 100) print "all"; else print indef_wanted;
          new_line;
          print "   most likely GNAs of names: ", indef_cases, "^";
      }
      else print "definite object^";
  }
#endif;

  j=number_matched-1; good_ones=0; last=match_list-->0;
  for (i=0:i<=j:i++)
  {   n=match_list-->i;
      match_scores-->i = 0;

      good_flag = false;

      switch(context) {
          HELD_TOKEN, MULTIHELD_TOKEN:
              if (parent(n)==actor) good_flag = true;
          MULTIEXCEPT_TOKEN:
              if (advance_warning == -1) {
                  good_flag = true;
              } else {
                  if (n ~= advance_warning) good_flag = true;
              }
          MULTIINSIDE_TOKEN:
              if (advance_warning == -1) {
                  if (parent(n) ~= actor) good_flag = true;
              } else {
                  if (n in advance_warning) good_flag = true;
              }
          CREATURE_TOKEN: if (CreatureTest(n)==1) good_flag = true;
          default: good_flag = true;
      }

      if (good_flag) {
          match_scores-->i = SCORE__IFGOOD;
          good_ones++; last = n;
      }
  }
  if (good_ones==1) return last;

  ! If there is ambiguity about what was typed, but it definitely wasn't
  ! animate as required, then return anything; higher up in the parser
  ! a suitable error will be given.  (This prevents a question being asked.)
  !
  if (context==CREATURE_TOKEN && good_ones==0) return match_list-->0;

  if (indef_mode==0) indef_type=0;

  ScoreMatchL(context);
  if (number_matched == 0) return -1;

  if (indef_mode == 0)
  {   !  Is there now a single highest-scoring object?
      i = SingleBestGuess();
      if (i >= 0)
      {   
#ifdef DEBUG;
          if (parser_trace>=4)
              print "   Single best-scoring object returned.]^";
#endif;
          return i;
      }
  }

  if (indef_mode==1 && indef_type & PLURAL_BIT ~= 0)
  {   if (context ~= MULTI_TOKEN or MULTIHELD_TOKEN or MULTIEXCEPT_TOKEN
                     or MULTIINSIDE_TOKEN)
      {   etype=MULTI_PE; return -1; }
      i=0; offset=multiple_object-->0; sovert = -1;
      for (j=BestGuess():j~=-1 && i<indef_wanted
           && i+offset<63:j=BestGuess())
      {   flag=0;
          if (j hasnt concealed && j hasnt worn) flag=1;
          if (sovert == -1) sovert = bestguess_score/SCORE__DIVISOR;
          else {
              if (indef_wanted == 100
                  && bestguess_score/SCORE__DIVISOR < sovert) flag=0;
          }
          if (context==MULTIHELD_TOKEN or MULTIEXCEPT_TOKEN
              && parent(j)~=actor) flag=0;
          if (action_to_be == ##Take or ##Remove && parent(j)==actor) flag=0;
          k=ChooseObjects(j,flag);
          if (k==1) flag=1; else { if (k==2) flag=0; }
          if (flag==1)
          {   i++; multiple_object-->(i+offset) = j;
#ifdef DEBUG;
              if (parser_trace>=4) print "   Accepting it^";
#endif;
          }
          else
          {   i=i;
#ifdef DEBUG;
              if (parser_trace>=4) print "   Rejecting it^";
#endif;
          }
      }
      if (i<indef_wanted && indef_wanted<100)
      {   etype=TOOFEW_PE; multi_wanted=indef_wanted;
          multi_had=i;
          return -1;
      }
      multiple_object-->0 = i+offset;
      multi_context=context;
#ifdef DEBUG;
      if (parser_trace>=4)
          print "   Made multiple object of size ", i, "]^";
#endif;
      return 1;
  }

  for (i=0:i<number_matched:i++) match_classes-->i=0;

  n=1;
  for (i=0:i<number_matched:i++)
      if (match_classes-->i==0)
      {   match_classes-->i=n++; flag=0;
          for (j=i+1:j<number_matched:j++)
              if (match_classes-->j==0
                  && Identical(match_list-->i, match_list-->j)==1)
              {   flag=1;
                  match_classes-->j=match_classes-->i;
              }
          if (flag==1) match_classes-->i = 1-n;
      }
  n--; number_of_classes = n;

#ifdef DEBUG;
  if (parser_trace>=4)
  {   print "   Grouped into ", n, " possibilities by name:^";
      for (i=0:i<number_matched:i++)
          if (match_classes-->i > 0)
              print "   ", (The) match_list-->i,
                  " (", match_list-->i, ")  ---  group ",
                  match_classes-->i, "^";
  }
#endif;

  if (indef_mode == 0)
  {   if (n > 1)
      {   k = -1;
          for (i=0:i<number_matched:i++)
          {   if (match_scores-->i > k)
              {   k = match_scores-->i;
                  j = match_classes-->i; j=j*j;
                  flag = 0;
              }
              else
              if (match_scores-->i == k)
              {   if ((match_classes-->i) * (match_classes-->i) ~= j)
                      flag = 1;
              }
          }
          if (flag)
          {
#ifdef DEBUG;
              if (parser_trace>=4)
                  print "   Unable to choose best group, so ask player.]^";
#endif;
              return 0;
          }
#ifdef DEBUG;
          if (parser_trace>=4)
              print "   Best choices are all from the same group.^";
#endif;          
      }
  }

!  When the player is really vague, or there's a single collection of
!  indistinguishable objects to choose from, choose the one the player
!  most recently acquired, or if the player has none of them, then
!  the one most recently put where it is.

  if (n==1) dont_infer = true;
  return BestGuess();
];

! ----------------------------------------------------------------------------
!  ReviseMulti  revises the multiple object which already exists, in the
!    light of information which has come along since then (i.e., the second
!    parameter).  It returns a parser error number, or else 0 if all is well.
!    This only ever throws things out, never adds new ones.
! ----------------------------------------------------------------------------

[ ReviseMulti second_p  i low;

#ifdef DEBUG;
  if (parser_trace>=4)
      print "   Revising multiple object list of size ", multiple_object-->0,
            " with 2nd ", (name) second_p, "^";
#endif;

  if (multi_context==MULTIEXCEPT_TOKEN or MULTIINSIDE_TOKEN)
  {   for (i=1, low=0:i<=multiple_object-->0:i++)
      {   if ( (multi_context==MULTIEXCEPT_TOKEN
                && multiple_object-->i ~= second_p)
               || (multi_context==MULTIINSIDE_TOKEN
                   && multiple_object-->i in second_p))
          {   low++; multiple_object-->low = multiple_object-->i;
          }
      }
      multiple_object-->0 = low;
  }

  if (multi_context==MULTI_TOKEN && action_to_be == ##Take)
  {   for (i=1, low=0:i<=multiple_object-->0:i++)
          if (ScopeCeiling(multiple_object-->i)==ScopeCeiling(actor))
              low++;
#ifdef DEBUG;
      if (parser_trace>=4)
          print "   Token 2 plural case: number with actor ", low, "^";
#endif;
      if (take_all_rule==2 || low>0)
      {   for (i=1, low=0:i<=multiple_object-->0:i++)
          {   if (ScopeCeiling(multiple_object-->i)==ScopeCeiling(actor))
              {   low++; multiple_object-->low = multiple_object-->i;
              }
          }
          multiple_object-->0 = low;
      }
  }

  i=multiple_object-->0;
#ifdef DEBUG;
  if (parser_trace>=4)
      print "   Done: new size ", i, "^";
#endif;
  if (i==0) return NOTHING_PE;
  return 0;
];

! ----------------------------------------------------------------------------
!  ScoreMatchL  scores the match list for quality in terms of what the
!  player has vaguely asked for.  Points are awarded for conforming with
!  requirements like "my", and so on.  Remove from the match list any
!  entries which fail the basic requirements of the descriptors.
! ----------------------------------------------------------------------------

[ ScoreMatchL context its_owner its_score obj i j threshold met a_s l_s;

!  if (indef_type & OTHER_BIT ~= 0) threshold++;
  if (indef_type & MY_BIT ~= 0)    threshold++;
  if (indef_type & THAT_BIT ~= 0)  threshold++;
  if (indef_type & LIT_BIT ~= 0)   threshold++;
  if (indef_type & UNLIT_BIT ~= 0) threshold++;
  if (indef_owner ~= nothing)      threshold++;

#ifdef DEBUG;
  if (parser_trace>=4) print "   Scoring match list: indef mode ", indef_mode,
      " type ", indef_type,
      ", satisfying ", threshold, " requirements:^";
#endif;

  a_s = SCORE__NEXTBESTLOC; l_s = SCORE__BESTLOC;
  if (context == HELD_TOKEN or MULTIHELD_TOKEN or MULTIEXCEPT_TOKEN) {
      a_s = SCORE__BESTLOC; l_s = SCORE__NEXTBESTLOC;
  }

  for (i=0: i<number_matched: i++) {
      obj = match_list-->i; its_owner = parent(obj); its_score=0;

!      if (indef_type & OTHER_BIT ~=0
!          &&  obj~=itobj or himobj or herobj) met++;
      if (indef_type & MY_BIT ~=0  &&  its_owner==actor) met++;
      if (indef_type & THAT_BIT ~=0  &&  its_owner==actors_location) met++;
      if (indef_type & LIT_BIT ~=0  &&  obj has light) met++;
      if (indef_type & UNLIT_BIT ~=0  &&  obj hasnt light) met++;
      if (indef_owner~=0 && its_owner == indef_owner) met++;

      if (met < threshold)
      {
#ifdef DEBUG;
          if (parser_trace >= 4)
              print "   ", (The) match_list-->i,
                    " (", match_list-->i, ") in ", (the) its_owner,
                    " is rejected (doesn't match descriptors)^";
#endif;
          match_list-->i=-1;
      }
      else
      {   its_score = 0;
          if (obj hasnt concealed) its_score = SCORE__UNCONCEALED;

          if (its_owner==actor)   its_score = its_score + a_s;
          else
          if (its_owner==actors_location) its_score = its_score + l_s;
          else
          if (its_owner~=compass) its_score = its_score + SCORE__NOTCOMPASS;

          its_score = its_score + SCORE__CHOOSEOBJ * ChooseObjects(obj, 2);

          if (obj hasnt scenery) its_score = its_score + SCORE__NOTSCENERY;
          if (obj ~= actor) its_score = its_score + SCORE__NOTACTOR;

          !   A small bonus for having the correct GNA,
          !   for sorting out ambiguous articles and the like.

          if (indef_cases & (PowersOfTwo_TB-->(GetGNAOfObject(obj))))
              its_score = its_score + SCORE__GNA;

          match_scores-->i = match_scores-->i + its_score;
#ifdef DEBUG;
          if (parser_trace >= 4)
              print "     ", (The) match_list-->i,
                    " (", match_list-->i, ") in ", (the) its_owner,
                    " : ", match_scores-->i, " points^";
#endif;
      }
  }

  for (i=0:i<number_matched:i++)
  {   while (match_list-->i == -1)
      {   if (i == number_matched-1) { number_matched--; break; }
          for (j=i:j<number_matched:j++)
          {   match_list-->j = match_list-->(j+1);
              match_scores-->j = match_scores-->(j+1);              
          }
          number_matched--;
      }
  }
];

! ----------------------------------------------------------------------------
!  BestGuess makes the best guess it can out of the match list, assuming that
!  everything in the match list is textually as good as everything else;
!  however it ignores items marked as -1, and so marks anything it chooses.
!  It returns -1 if there are no possible choices.
! ----------------------------------------------------------------------------

[ BestGuess  earliest its_score best i;

  earliest=0; best=-1;
  for (i=0:i<number_matched:i++)
  {   if (match_list-->i >= 0)
      {   its_score=match_scores-->i;
          if (its_score>best) { best=its_score; earliest=i; }
      }
  }
#ifdef DEBUG;
  if (parser_trace>=4)
  {   if (best<0)
          print "   Best guess ran out of choices^";
      else
          print "   Best guess ", (the) match_list-->earliest,
                " (", match_list-->earliest, ")^";
  }
#endif;
  if (best<0) return -1;
  i=match_list-->earliest;
  match_list-->earliest=-1;
  bestguess_score = best;
  return i;
];

! ----------------------------------------------------------------------------
!  SingleBestGuess returns the highest-scoring object in the match list
!  if it is the clear winner, or returns -1 if there is no clear winner
! ----------------------------------------------------------------------------

[ SingleBestGuess  earliest its_score best i;

  earliest=-1; best=-1000;
  for (i=0:i<number_matched:i++)
  {   its_score=match_scores-->i;
      if (its_score==best) { earliest = -1; }
      if (its_score>best) { best=its_score; earliest=match_list-->i; }
  }
  bestguess_score = best;
  return earliest;
];

! ----------------------------------------------------------------------------
!  Identical decides whether or not two objects can be distinguished from
!  each other by anything the player can type.  If not, it returns true.
! ----------------------------------------------------------------------------

[ Identical o1 o2 p1 p2 n1 n2 i j flag;

  if (o1==o2) rtrue;  ! This should never happen, but to be on the safe side
  if (o1==0 || o2==0) rfalse;  ! Similarly
  if (parent(o1)==compass || parent(o2)==compass) rfalse; ! Saves time

!  What complicates things is that o1 or o2 might have a parsing routine,
!  so the parser can't know from here whether they are or aren't the same.
!  If they have different parsing routines, we simply assume they're
!  different.  If they have the same routine (which they probably got from
!  a class definition) then the decision process is as follows:
!
!     the routine is called (with self being o1, not that it matters)
!       with noun and second being set to o1 and o2, and action being set
!       to the fake action TheSame.  If it returns -1, they are found
!       identical; if -2, different; and if >=0, then the usual method
!       is used instead.

  if (o1.parse_name~=0 || o2.parse_name~=0)
  {   if (o1.parse_name ~= o2.parse_name) rfalse;
      parser_action=##TheSame; parser_one=o1; parser_two=o2;
      j=wn; i=RunRoutines(o1,parse_name); wn=j;
      if (i==-1) rtrue; if (i==-2) rfalse;
  }

!  This is the default algorithm: do they have the same words in their
!  "name" (i.e. property no. 1) properties.  (Note that the following allows
!  for repeated words and words in different orders.)

  p1 = o1.&1; n1 = (o1.#1)/WORDSIZE;
  p2 = o2.&1; n2 = (o2.#1)/WORDSIZE;

!  for (i=0:i<n1:i++) { print (address) p1-->i, " "; } new_line;
!  for (i=0:i<n2:i++) { print (address) p2-->i, " "; } new_line;

  for (i=0:i<n1:i++)
  {   flag=0;
      for (j=0:j<n2:j++)
          if (p1-->i == p2-->j) flag=1;
      if (flag==0) rfalse;
  }

  for (j=0:j<n2:j++)
  {   flag=0;
      for (i=0:i<n1:i++)
          if (p1-->i == p2-->j) flag=1;
      if (flag==0) rfalse;
  }

!  print "Which are identical!^";
  rtrue;
];

! ----------------------------------------------------------------------------
!  PrintCommand reconstructs the command as it presently reads, from
!  the pattern which has been built up
!
!  If from is 0, it starts with the verb: then it goes through the pattern.
!  The other parameter is "emptyf" - a flag: if 0, it goes up to pcount:
!  if 1, it goes up to pcount-1.
!
!  Note that verbs and prepositions are printed out of the dictionary:
!  and that since the dictionary may only preserve the first six characters
!  of a word (in a V3 game), we have to hand-code the longer words needed.
!
!  (Recall that pattern entries are 0 for "multiple object", 1 for "special
!  word", 2 to REPARSE_CODE-1 are object numbers and REPARSE_CODE+n means the
!  preposition n)
! ----------------------------------------------------------------------------

[ PrintCommand from i k spacing_flag;

  if (from==0)
  {   i=verb_word;
      if (LanguageVerb(i) == 0)
          if (PrintVerb(i) == 0)
              print (address) i;
      from++; spacing_flag = true;
  }

  for (k=from:k<pcount:k++)
  {   i=pattern-->k;
      if (i == PATTERN_NULL) continue;
      if (spacing_flag) print (char) ' ';
      if (i==0) { print (string) THOSET__TX; jump TokenPrinted; }
      if (i==1) { print (string) THAT__TX; jump TokenPrinted; }
      if (i>=REPARSE_CODE) print (address) No__Dword(i-REPARSE_CODE);
      else print (the) i;
      .TokenPrinted;
      spacing_flag = true;
  }
];

! ----------------------------------------------------------------------------
!  The CantSee routine returns a good error number for the situation where
!  the last word looked at didn't seem to refer to any object in context.
!
!  The idea is that: if the actor is in a location (but not inside something
!  like, for instance, a tank which is in that location) then an attempt to
!  refer to one of the words listed as meaningful-but-irrelevant there
!  will cause "you don't need to refer to that in this game" rather than
!  "no such thing" or "what's 'it'?".
!  (The advantage of not having looked at "irrelevant" local nouns until now
!  is that it stops them from clogging up the ambiguity-resolving process.
!  Thus game objects always triumph over scenery.)
! ----------------------------------------------------------------------------

[ CantSee  i w e;
    saved_oops=oops_from;

    if (scope_token~=0) { scope_error = scope_token; return ASKSCOPE_PE; }

    wn--; w=NextWord();
    e=CANTSEE_PE;
    if (w==pronoun_word)
    {   pronoun__word=pronoun_word; pronoun__obj=pronoun_obj;
        e=ITGONE_PE;
    }
    i=actor; while (parent(i) ~= 0) i = parent(i);
    if (i has visited && Refers(i,wn-1)==1) e=SCENERY_PE;
    if (etype>e) return etype;
    return e;
];

! ----------------------------------------------------------------------------
!  The MultiAdd routine adds object "o" to the multiple-object-list.
!
!  This is only allowed to hold 63 objects at most, at which point it ignores
!  any new entries (and sets a global flag so that a warning may later be
!  printed if need be).
! ----------------------------------------------------------------------------

[ MultiAdd o i j;
  i=multiple_object-->0;
  if (i==63) { toomany_flag=1; rtrue; }
  for (j=1:j<=i:j++)
      if (o==multiple_object-->j) 
          rtrue;
  i++;
  multiple_object-->i = o;
  multiple_object-->0 = i;
];

! ----------------------------------------------------------------------------
!  The MultiSub routine deletes object "o" from the multiple-object-list.
!
!  It returns 0 if the object was there in the first place, and 9 (because
!  this is the appropriate error number in Parser()) if it wasn't.
! ----------------------------------------------------------------------------

[ MultiSub o i j k et;
  i=multiple_object-->0; et=0;
  for (j=1:j<=i:j++)
      if (o==multiple_object-->j)
      {   for (k=j:k<=i:k++)
              multiple_object-->k = multiple_object-->(k+1);
          multiple_object-->0 = --i;
          return et;
      }
  et=9; return et;
];

! ----------------------------------------------------------------------------
!  The MultiFilter routine goes through the multiple-object-list and throws
!  out anything without the given attribute "attr" set.
! ----------------------------------------------------------------------------

[ MultiFilter attr  i j o;
  .MFiltl;
  i=multiple_object-->0;
  for (j=1:j<=i:j++)
  {   o=multiple_object-->j;
      if (o hasnt attr) { MultiSub(o); jump Mfiltl; }
  }
];

! ----------------------------------------------------------------------------
!  The UserFilter routine consults the user's filter (or checks on attribute)
!  to see what already-accepted nouns are acceptable
! ----------------------------------------------------------------------------

[ UserFilter obj;

  if (token_filter > 0 && token_filter < 49)
  {   if (obj has (token_filter-1)) rtrue;
      rfalse;
  }
  noun = obj;
  return indirect(token_filter);
];

! ----------------------------------------------------------------------------
!  MoveWord copies word at2 from parse buffer b2 to word at1 in "parse"
!  (the main parse buffer)
! ----------------------------------------------------------------------------

#ifdef TARGET_ZCODE;

[ MoveWord at1 b2 at2 x y;
  x=at1*2-1; y=at2*2-1;
  parse-->x++ = b2-->y++;
  parse-->x = b2-->y;
];

#ifnot; ! TARGET_GLULX

[ MoveWord at1 b2 at2 x y;
  x=at1*3-2; y=at2*3-2;
  parse-->x++ = b2-->y++;
  parse-->x++ = b2-->y++;
  parse-->x = b2-->y;
];

#endif; ! TARGET_

! ----------------------------------------------------------------------------
!  SearchScope  domain1 domain2 context
!
!  Works out what objects are in scope (possibly asking an outside routine),
!  but does not look at anything the player has typed.
! ----------------------------------------------------------------------------

[ SearchScope domain1 domain2 context i;

  i=0;
!  Everything is in scope to the debugging commands

#ifdef DEBUG;
  if (scope_reason==PARSING_REASON
      && verb_word == 'purloin' or 'tree' or 'abstract'
                       or 'gonear' or 'scope' or 'showobj')
  {
#ifdef TARGET_ZCODE;
      for (i=selfobj:i<=top_object:i++)
          if (i ofclass Object && (parent(i)==0 || parent(i) ofclass Object))
              PlaceInScope(i);
#ifnot; ! TARGET_GLULX
      objectloop (i)
          if (i ofclass Object && (parent(i)==0 || parent(i) ofclass Object))
              PlaceInScope(i);
#endif; ! TARGET_
      rtrue;
  }
#endif;

!  First, a scope token gets priority here:

  if (scope_token ~= 0)
  {   scope_stage=2;
      if (indirect(scope_token)~=0) rtrue;
  }

!  Next, call any user-supplied routine adding things to the scope,
!  which may circumvent the usual routines altogether if they return true:

  if (actor==domain1 or domain2 && InScope(actor)~=0) rtrue;

!  Pick up everything in the location except the actor's possessions;
!  then go through those.  (This ensures the actor's possessions are in
!  scope even in Darkness.)

  if (context==MULTIINSIDE_TOKEN && advance_warning ~= -1)
  {   if (IsSeeThrough(advance_warning)==1)
          ScopeWithin(advance_warning, 0, context);
  }
  else
  {   if (domain1~=0 && domain1 has supporter or container)
          ScopeWithin_O(domain1, domain1, context);
      ScopeWithin(domain1, domain2, context);
      if (domain2~=0 && domain2 has supporter or container)
          ScopeWithin_O(domain2, domain2, context);
      ScopeWithin(domain2, 0, context);
  }

!  A special rule applies:
!  in Darkness as in light, the actor is always in scope to himself.

  if (thedark == domain1 or domain2)
  {   ScopeWithin_O(actor, actor, context);
      if (parent(actor) has supporter or container)
          ScopeWithin_O(parent(actor), parent(actor), context);
  }
];

! ----------------------------------------------------------------------------
!  IsSeeThrough is used at various places: roughly speaking, it determines
!  whether o being in scope means that the contents of o are in scope.
! ----------------------------------------------------------------------------

[ IsSeeThrough o;
  if (o has supporter
      || (o has transparent)
      || (o has container && o has open))
      rtrue;
  rfalse;
];

! ----------------------------------------------------------------------------
!  PlaceInScope is provided for routines outside the library, and is not
!  called within the parser (except for debugging purposes).
! ----------------------------------------------------------------------------

[ PlaceInScope thing;
   if (scope_reason~=PARSING_REASON or TALKING_REASON)
   {   DoScopeAction(thing); rtrue; }
   wn=match_from; TryGivenObject(thing); placed_in_flag=1;
];

! ----------------------------------------------------------------------------
!  DoScopeAction
! ----------------------------------------------------------------------------

[ DoScopeAction thing s p1;
  s = scope_reason; p1=parser_one;
#ifdef DEBUG;
  if (parser_trace>=6)
  {   print "[DSA on ", (the) thing, " with reason = ", scope_reason,
      " p1 = ", parser_one, " p2 = ", parser_two, "]^";
  }
#endif;
  switch(scope_reason)
  {   REACT_BEFORE_REASON:
          if (thing.react_before==0 or NULL) return;
#ifdef DEBUG;
          if (parser_trace>=2)
          {   print "[Considering react_before for ", (the) thing, "]^"; }
#endif;
          if (parser_one==0) parser_one = RunRoutines(thing,react_before);
      REACT_AFTER_REASON:
          if (thing.react_after==0 or NULL) return;
#ifdef DEBUG;
          if (parser_trace>=2)
          {   print "[Considering react_after for ", (the) thing, "]^"; }
#endif;
          if (parser_one==0) parser_one = RunRoutines(thing,react_after);
      EACH_TURN_REASON:
          if (thing.each_turn == 0 or NULL) return;
#ifdef DEBUG;
          if (parser_trace>=2)
          {   print "[Considering each_turn for ", (the) thing, "]^"; }
#endif;
          PrintOrRun(thing, each_turn);
      TESTSCOPE_REASON:
          if (thing==parser_one) parser_two = 1;
      LOOPOVERSCOPE_REASON:
          indirect(parser_one,thing); parser_one=p1;
  }
  scope_reason = s;
];

! ----------------------------------------------------------------------------
!  ScopeWithin looks for objects in the domain which make textual sense
!  and puts them in the match list.  (However, it does not recurse through
!  the second argument.)
! ----------------------------------------------------------------------------

[ ScopeWithin domain nosearch context x y;

   if (domain==0) rtrue;

!  Special rule: the directions (interpreted as the 12 walls of a room) are
!  always in context.  (So, e.g., "examine north wall" is always legal.)
!  (Unless we're parsing something like "all", because it would just slow
!  things down then, or unless the context is "creature".)

   if (indef_mode==0 && domain==actors_location
       && scope_reason==PARSING_REASON && context~=CREATURE_TOKEN)
           ScopeWithin(compass);

!  Look through the objects in the domain, avoiding "objectloop" in case
!  movements occur, e.g. when trying each_turn.

   x = child(domain);
   while (x ~= 0)
 