Attribute known_about;                 ! Player has seen this spell somewhere
Attribute reversed;                    ! Effect of this known spell reversed

Attribute is_spell;
Class  Spell
  with name "spell" "spells", article "the",
       number 0,
       word_name
       [;  print (address) (self.&name)-->0;
       ],
       short_name
       [;  self.word_name(); print " spell"; give self known_about; rtrue;
       ],
       specification
       [;  self.short_name();
           print ": ", (string) self.purpose;
       ],
       before
       [;  Examine: self.specification(); ".";
       ],
  has  is_spell;

Object memory
  with capacity 5,
       number_known 1,
       describe_contents
       [ i j k;
           objectloop (i in self) if (i.number==100) j++;
           if (j>0)
           {   print "The ";
               objectloop (i in self)
                   if (i.number==100)
                   {   k++; i.word_name();
                       if (k==j-1) print " and ";
                       if (k<j-1) print ", ";
                   }
               if (j==1) print " spell is"; else print " spells are";
               print " yours forever.  Other than that, y";
           }
           else print "Y";
           print "ou have ";
           j=0; k=0;
           objectloop (i in self) if (i.number<100) j++;
           if (j>0)
           {   print "the ";
               objectloop (i in self)
                   if (i.number<100)
                   {   k++;
                       print (name) i;
                       if (i.number==2) print " (twice)";
                       if (i.number==3) print " (thrice)";
                       if (i.number==4) print " (four times)";
                       if (i.number>=5) print " (many times)";
                       if (k==j-1) print " and ";
                       if (k<j-1) print ", ";
                   }
           }
           else print "no spells";
           " memorised.";
       ],
       learn_spell
       [ sp;
           if (sp.number==100) "You always know that spell.";
           print "Using your best study habits, you commit the ";
           sp.word_name();
           print " spell to memory";
           if (sp notin self) sp.number=0;
           move sp to self;
           self.number_known++;
           sp.number++;
           if (sp.number==1) print ".";
           if (sp.number==2) print " once again.";
           if (sp.number==3) print " a third time.";
           if (sp.number>3) print " yet another time.";
           if (self.number_known <= self.capacity) { new_line; rtrue; }
           self.forget_spell(sibling(child(self)));
           "  You have so much buzzing around in your head, though,
              that it's likely something may have been forgotten
              in the shuffle.";
       ],
       forget_spell
       [ sp;
           if (sp notin self || sp.number==100) rtrue;
           self.number_known--;
           sp.number--;
           if (sp.number==0) remove sp;
           rtrue;
       ];

Spell -> gnusto_spell
  with name "gnusto",
       purpose "copy a scroll into your spell book",
       number 100,
       magic
       [ i a_book;
            if (second ofclass SpellBook)
               "Unlike scrolls, spell books are magically guarded against
                the 'theft' of their lore.";
            if (second==0 || ~~(second ofclass Scroll))
               "Your spell fizzles vaguely out.";
            if (second notin player)
                "A gnusto spell would require close scrutiny of the scroll
                 it is to copy: which you do not seem to be holding.";
            objectloop (i in player)
                if (i ofclass SpellBook) a_book=i;
            if (a_book==0)
                "Your spell fails, as you have no spell book.";
            i=child(second);
            if (i==0 || ~~(i ofclass Spell))
            {   print_ret "Your spell fails, as ", (the) second,
                   " is illegible.";
            }
            a_book.learn_spell(i); remove second;
            print_ret
               "Your spell book begins to glow softly.  Slowly, ornately,
                the words of ", (the) i, " are inscribed,
                glowing even more brightly then the book itself. 
                The book's brightness fades, but the spell remains! 
                However, the scroll on which it was written vanishes as
                the last word is copied.";
       ];

Class SpellBook
  with array_of_spells 0 0 0 0  0 0 0 0  0 0 0 0  0 0 0 0,
       capacity 16,
       learn_spell
       [ sp p i;
              p = self.&array_of_spells;
              for (i=0:i<self.capacity && (p-->i)~=0:i++) ;
              if (i==self.capacity) rtrue;
              p-->i = sp;
       ],
       before
       [; Open, Close:
              print_ret
              (The) self, " is always open to the right place, but it
              is also always closed. This eliminates tedious leafing and
              hunting for spells.  Many lives have been saved by this
              magical innovation.";
          Attack:
              print_ret "When you are done, ", (the) self, " remains unmarred.";
       ],
       after
       [ p i j; Examine:
              p = self.&array_of_spells;
              for (i=0:i<self.capacity && (p-->i)~=0:i++)
              {   j=p-->i; <Examine j>;
              }
              rtrue;
       ];

Class Scroll
  with parse_name
       [ i j k; j=-1;
              if (self has general)
              {   if (child(self)~=0 && child(self) ofclass Spell)
                      j=(child(self).&name)-->0; else j='illegible';
              }
              for (::)
              {   k=NextWord();
                  if (k=='scrolls') parser_action=##PluralFound;
                  if ((k=='scrolls' or 'scroll' or j) || k==(self.&name)-->0)
                      i++;
                  else return i;
              }
       ],
       before
       [ i; Examine:
            i=child(self);
            give self general;
            if (i==0 || ~~(i ofclass Spell))
                "The scroll has faded, and you cannot read it.";
            print "The scroll reads ~"; i.specification(); "~.";
       ],
       invent
       [;   if (inventory_stage==2 && self has general)
            {   if (child(self)==0 || ~~(child(self) ofclass Spell))
                    print " (which is illegible)";
                else
                {   print " (of ", (the) child(self), ")"; }
            }
       ];

[ ReadableSpell i j k;
  if (scope_stage==1)
  {   if (action_to_be==##Examine) rfalse;
      rtrue;
  }
  if (scope_stage==2)
  {   objectloop (i in player)
          if (i ofclass SpellBook)
          {   for (k=0:k<i.capacity && (i.&array_of_spells)-->k~=0:k++)
              {   j=(i.&array_of_spells)-->k; PlaceInScope(j);
              }
          }
      rtrue;
  }
  ! No need for scope_stage 3 (the error stage), because our
  ! ParserError routine handles that case instead
];

[ CopyableSpell i j k;
  if (scope_stage==1) return 1;
  if (scope_stage==2)
  {   objectloop (i in player)
          if (i ofclass SpellBook)
          {   for (k=0:k<i.capacity && (i.&array_of_spells)-->k~=0:k++)
              {   j=(i.&array_of_spells)-->k; PlaceInScope(j);
              }
          }
      rfalse;
  }
  ! No need for scope_stage 3 (the error stage), because our
  ! ParserError routine handles that case instead
];

[ SpellsSub; memory.describe_contents(); ];

[ LearnSub; if (location==thedark)
                print "(The magic writing of the spells casts enough light
                        that you can read them.)^";
            memory.learn_spell(noun);
];

Global the_spell_was = gnusto_spell;

[ CastOneSub; <Cast the_spell_was noun>; ];

[ CastSub;
  the_spell_was = noun; memory.forget_spell(noun);

  if (noun has reversed)
  {   give noun ~reversed;
      if (noun.unmagic() ~= 0) return;
      "Nothing happens.";
  }

  if (second ~= 0)
  {   ResetVagueWords(second);                     ! Set "it", "him", "her"
      if (second provides before
          && second.before() ~= 0) return;         ! Run before routine(s)
  }
  if (noun.magic() ~= 0) return;
  "Nothing happens.";
];

[ InScope i;
  if (verb_word=='c,cast' or 'cast')
      objectloop (i in memory) PlaceInScope(i);
  rfalse;
];

[ ParserError x i flag vb;
  if (etype==VERB_PE or ASKSCOPE_PE)
  {   if (etype==ASKSCOPE_PE)
      {   if (verb_word=='cast') vb=1;
          if (verb_word=='learn' or 'memorise' or 'memorize') vb=2;
          if (verb_word=='copy') vb=3;
          if (vb==0) { etype=CANTSEE_PE; rfalse; }
      }
      wn=verb_wordnum; if (vb~=0) wn++;
      x=NextWordStopped();
      for (i=player+1:i<=top_object:i++)
          if (i ofclass Spell && Refers(i,x)==1
              && i has known_about) flag=1;
      if (flag==1)
      {   if (vb==0 or 1)
             "You haven't got that spell committed to memory.  [Type ~spells~
              to see what you do remember.]";
          if (vb==2)
             "Your training is such that you can only memorise such a spell
              with the aid of a spell book containing it.";
          if (vb==3)
             "You have no text of that spell to copy.";
      }
      if (vb==1)
         "You haven't learned that spell, if indeed it is a spell.";
      if (vb==2 or 3)
         "You haven't access to that spell, if indeed it is a spell.";
  }
  rfalse;
];

[ ChooseObjects obj code;
  if (code<2) rfalse;
  if (action_to_be==##WriteOn && obj in player) return 9;
  return 0;
];

[ UnknownVerb word i;
  objectloop (i in memory)
      if (word==(i.&name)-->0) { the_spell_was = i; return 'c,cast'; }
  rfalse;
];

[ PrintVerb v;
  if (v=='c,cast') { print "cast a spell at"; rtrue; }
  rfalse;
];