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[prop.git] / lib-src / automata / treegen.cc

///////////////////////////////////////////////////////////////////////////////
//  This file is generated automatically using Prop (version 2.3.3),
//  last updated on Mar 30, 1997.
//  The original source file is "treegen.pcc".
///////////////////////////////////////////////////////////////////////////////

#line 1 "treegen.pcc"
//////////////////////////////////////////////////////////////////////////////
// NOTICE:
//
// ADLib, Prop and their related set of tools and documentation are in the 
// public domain.   The author(s) of this software reserve no copyrights on 
// the source code and any code generated using the tools.  You are encouraged
// to use ADLib and Prop to develop software, in both academic and commercial
// settings, and are welcomed to incorporate any part of ADLib and Prop into
// your programs.
//
// Although you are under no obligation to do so, we strongly recommend that 
// you give away all software developed using our tools.
//
// We also ask that credit be given to us when ADLib and/or Prop are used in 
// your programs, and that this notice be preserved intact in all the source 
// code.
//
// This software is still under development and we welcome(read crave for)
// any suggestions and help from the users.
//
// Allen Leung 
// 1994
//////////////////////////////////////////////////////////////////////////////

#include <assert.h>
#include <iostream>
#include <AD/automata/treegram.h>  // tree grammar
#include <AD/automata/treegen.h>    // tree automata compiler
#include <AD/contain/bitset.h>      // bit set
#include <AD/hash/dchash.h>         // direct chaining hash map
#include <AD/contain/vararray.h>    // variable sized array
#include <AD/contain/slnklist.h>    // linked list
#include <AD/memory/mempool.h>      // memory pool

//////////////////////////////////////////////////////////////////////////////
//  Make hidden types visible
//////////////////////////////////////////////////////////////////////////////
typedef TreeGrammar::TreeProduction TreeProduction;
typedef TreeGrammar::Functor        Functor;
typedef TreeGrammar::Arity          Arity;
typedef TreeGrammar::Variable       Variable;
typedef TreeGrammar::State          State;
typedef TreeGrammar::Rule           Rule;
typedef TreeAutomaton::Equiv        Equiv;
typedef SLinkList<State>            StateList;

//////////////////////////////////////////////////////////////////////////////
//  Class TreeGenerator represents the internals of the automata compiler.
//  This stuff is completely hidden from the interface.
//////////////////////////////////////////////////////////////////////////////
class TreeGenerator {

   TreeGenerator(const TreeGenerator&);    // no copy constructor
   void operator = (const TreeGenerator&); // no assignment

public:

   ///////////////////////////////////////////////////////////////////////////
   //  Internal data structures
   ///////////////////////////////////////////////////////////////////////////

   TreeGen&                        treegen;
   TreeGrammar&                    G;             // the grammar
   MemPool                         mem;           // memory pool
   BitSet **                       ruleset_map;   // non-terminal -> rule set
   Rule *                          rule_map;      // non-terminal -> rule set
   DCHashTable<TreeTerm, Variable> non_terminals; // term -> non-terminals map
   VarArray <TreeTerm>             n_states;      // non-terminals -> term map
   DCHashTable<BitSet *, State>    state_labels;  // non-terminal set -> state mapping
   DCHashTable<TreeTerm, BitSet *> delta;         // term -> non-terminals mapping
   VarArray <BitSet *>             d_states;      // state -> non-terminal set
   VarArray <TreeTerm>             d_terms;       // state -> term map
   BitSet                      *** proj;          // projections
   BitSet                       ** closure0;      // transitive closure of each non-terminal
   Variable                        max_non_terminal;
   State                           number_of_states;
   StateList                   *** representers;

   ///////////////////////////////////////////////////////////////////////////
   //  Constructor
   ///////////////////////////////////////////////////////////////////////////
   TreeGenerator(TreeGen& gen, TreeGrammar& g) : 
      treegen(gen), G(g), mem(4096), non_terminals(1037),  
      state_labels(1037), delta(1037) {} 

   ///////////////////////////////////////////////////////////////////////////
   //  Methods to process various phases of the compilation.
   ///////////////////////////////////////////////////////////////////////////
   void     assign_non_terminals   ();
   TreeTerm assign_non_terminal    ( TreeTerm );
   void     compute_closures       (); 
   void     compute_projections    ();
   void     compute_representers   ();
   void     compute_initial_states ();
   void     compute_transitions    ();
   BitSet * compute_transition (BitSet *, TreeTerm, int, int, const BitSet&, State [], int []);
   void     compute_delta      (BitSet *, TreeTerm, int, int, const State []);
   void     compute_accept_rules (State);
   std::ostream& print_report (std::ostream&) const;
   std::ostream& print_state (std::ostream&, State) const;
};

//////////////////////////////////////////////////////////////////////////////
//  The following method is used to assign non-terminal symbols 
//  to each distinct term within the grammar
//////////////////////////////////////////////////////////////////////////////
void TreeGenerator::assign_non_terminals()
{
   ///////////////////////////////////////////////////////////////////////////
   //  The grammar may already have user defined variable names.
   //  New non-terminals will have encodings right after these variables. 
   ///////////////////////////////////////////////////////////////////////////
   max_non_terminal = G.max_variable() + 1; 
   non_terminals.insert(wild_term,0);
   {  for (Variable v = max_non_terminal - 1; v >= 0; v--)
         n_states.At(v) = wild_term;
   }

   ///////////////////////////////////////////////////////////////////////////
   //  Traverse thru the grammar and compute the non-terminal numbers.
   //  The tree grammar *IS* destructively altered.
   ///////////////////////////////////////////////////////////////////////////
   {  for (int i = G.size() - 1; i >= 0; i--) 
         G.update(i,assign_non_terminal( G[i].term ));
   }

   ///////////////////////////////////////////////////////////////////////////
   //  Compute the mapping from non-terminal -> accept rule
   ///////////////////////////////////////////////////////////////////////////
   ruleset_map = (BitSet **)mem.c_alloc(sizeof(BitSet *) * max_non_terminal);
   rule_map    = (Rule *)   mem.c_alloc(sizeof(Rule) * max_non_terminal);
   {  int i;
      for (i = max_non_terminal - 1; i >= 0; i--) rule_map[i] = -1;
      for (i = G.size() - 1; i >= 0; i--) { 
         Variable v = non_terminals[G[i].term];
         if (ruleset_map[v] == 0) 
            ruleset_map[v] = new (mem, max_non_terminal) BitSet;
         ruleset_map[v]->add(i);
         rule_map[v] = i;
      }
   } 
}

//////////////////////////////////////////////////////////////////////////////
//  Method to assign non-terminal numbers for a tree term.  This is
//  defined inductive as: 
//////////////////////////////////////////////////////////////////////////////
TreeTerm TreeGenerator::assign_non_terminal( TreeTerm t )
{  
   ///////////////////////////////////////////////////////////////////////////
   //  Step (a) recursively fold the terms.
   ///////////////////////////////////////////////////////////////////////////
   
#line 153 "treegen.pcc"
#line 163 "treegen.pcc"
{
   if (t) {
      switch (t->tag__) {
         case a_TreeTerm::tag_tree_term: {
#line 160 "treegen.pcc"
            
            for (int i = _tree_term(t)->_2 - 1; i >= 0; i--)
               _tree_term(t)->_3[i] = assign_non_terminal(_tree_term(t)->_3[i]);
            
#line 163 "treegen.pcc"
            } break;
         case a_TreeTerm::tag_var_term: {
#line 155 "treegen.pcc"
       // skip
            
#line 156 "treegen.pcc"
            } break;
         case a_TreeTerm::tag_and_term: {
#line 157 "treegen.pcc"
          _and_term(t)->_1 = assign_non_terminal(_and_term(t)->_1); _and_term(t)->_2 = assign_non_terminal(_and_term(t)->_2);
            
#line 158 "treegen.pcc"
            } break;
         case a_TreeTerm::tag_or_term: {
#line 158 "treegen.pcc"
         _or_term(t)->_1 = assign_non_terminal(_or_term(t)->_1); _or_term(t)->_2 = assign_non_terminal(_or_term(t)->_2);
            
#line 159 "treegen.pcc"
            } break;
         case a_TreeTerm::tag_not_term: {
#line 159 "treegen.pcc"
        _not_term(t)->not_term = assign_non_terminal(_not_term(t)->not_term); 
            
#line 160 "treegen.pcc"
            } break;
         default: {
#line 156 "treegen.pcc"
       // skip
            
#line 157 "treegen.pcc"
            } break;
      }
   } else {
#line 154 "treegen.pcc"
// skip
      
#line 155 "treegen.pcc"
   }
}
#line 163 "treegen.pcc"
#line 163 "treegen.pcc"


   ///////////////////////////////////////////////////////////////////////////
   //  Look it up from the ``non_terminal'' map.
   ///////////////////////////////////////////////////////////////////////////
   Ix p = non_terminals.lookup(t);
   if (p == 0) {  // not found!
      ////////////////////////////////////////////////////////////////////////
      //  Step (b) if it is not found, assign a new non-terminal number.
      //  Notice that ``wild_term'' always gets the non-terminal number of 0.
      ////////////////////////////////////////////////////////////////////////
      Variable var;
      
#line 175 "treegen.pcc"
#line 179 "treegen.pcc"
{
   if (t) {
      switch (t->tag__) {
         case a_TreeTerm::tag_var_term: {
#line 177 "treegen.pcc"
          var = _var_term(t)->var_term;
            
#line 178 "treegen.pcc"
            } break;
         default: {
#line 178 "treegen.pcc"
 var = max_non_terminal++;
            
#line 179 "treegen.pcc"
            } break;
      }
   } else {
#line 176 "treegen.pcc"
   var = 0;
      
#line 177 "treegen.pcc"
   }
}
#line 179 "treegen.pcc"
#line 179 "treegen.pcc"

      non_terminals.insert(t,var);  // update map
      n_states.At(var) = t;            // update inverse map
   } else { 
      t = non_terminals.key(p);
   }
   return t;
}

//////////////////////////////////////////////////////////////////////////////
//  This is the method for computing transitive closure on a non-terminal
//  set.   Transitive closures apply in the presence of single reductions
//       X -> Y
//  or logical connectives:
//       X -> Y and Z 
//       X -> Y or  Z
//
//  We don't support negation yet since it is anti-monotonic.
//////////////////////////////////////////////////////////////////////////////
void TreeGenerator::compute_closures()
{  
   ///////////////////////////////////////////////////////////////////////////
   //  Allocate the array closure0, which maps each non-terminal to
   //  its transitive closure.  Closure set are allocated only if
   //  they are non-trivial (i.e. closure0[v] is something other than
   //  { 0, v }.
   ///////////////////////////////////////////////////////////////////////////
   closure0 = (BitSet**)mem.c_alloc(sizeof(BitSet*) * max_non_terminal); 

   ///////////////////////////////////////////////////////////////////////////
   //  Allocate closures for user defined non-terminals
   ///////////////////////////////////////////////////////////////////////////
   {  for (Variable v = G.min_variable(); v <= G.max_variable(); v++) {
         closure0[v] = new (mem, max_non_terminal) BitSet;
         closure0[v]->add(0);
         closure0[v]->add(v);
      }
   }

   ///////////////////////////////////////////////////////////////////////////
   //  Now compute the transitive closure
   ///////////////////////////////////////////////////////////////////////////
   Bool changed;
   BitSet& temp = *new(mem, max_non_terminal) BitSet; // temporary set buffer
   do {
      changed = false;

      /////////////////////////////////////////////////////////////////////////
      //  Propagate closure information.
      /////////////////////////////////////////////////////////////////////////
      foreach (p, non_terminals) {
         TreeTerm term = non_terminals.key(p);
         Variable var  = non_terminals.value(p);

         /////////////////////////////////////////////////////////////////////
         //  Allocate a new closure set if necessary.
         /////////////////////////////////////////////////////////////////////
         
#line 236 "treegen.pcc"
#line 243 "treegen.pcc"
{
   if (term) {
      switch (term->tag__) {
         case a_TreeTerm::tag_tree_term:
         case a_TreeTerm::tag_not_term:
         case a_TreeTerm::tag_set_term: {
            L1:; 
#line 242 "treegen.pcc"
            
            
#line 243 "treegen.pcc"
            } break;
         default: {
            if (
#line 237 "treegen.pcc"
            (closure0[var] == 0)
#line 237 "treegen.pcc"
) {
               
               L2:; 
#line 237 "treegen.pcc"
               
               closure0[var] = new (mem, max_non_terminal) BitSet;
               closure0[var]->add(0);
               closure0[var]->add(var);
               changed = true;
               
#line 242 "treegen.pcc"
            } else {
                goto L1; }
            } break;
      }
   } else { goto L1; }
}
#line 243 "treegen.pcc"
#line 243 "treegen.pcc"


         /////////////////////////////////////////////////////////////////////
         //  Propagate closures sets.
         /////////////////////////////////////////////////////////////////////
         
#line 248 "treegen.pcc"
#line 266 "treegen.pcc"
{
   if (term) {
      switch (term->tag__) {
         case a_TreeTerm::tag_var_term: {
            if (
#line 259 "treegen.pcc"
            (var != _var_term(term)->var_term)
#line 259 "treegen.pcc"
) {
               
#line 259 "treegen.pcc"
               
               if (closure0[_var_term(term)->var_term]) { 
                  if (closure0[var]->Union_if_changed(*closure0[_var_term(term)->var_term])) changed = true;
               } else { 
                  if (closure0[var]->add_if_changed(_var_term(term)->var_term)) changed = true;
               }
               
#line 265 "treegen.pcc"
            } else {
               
               L3:; 
#line 265 "treegen.pcc"
             // skip
               
#line 266 "treegen.pcc"
            }
            } break;
         case a_TreeTerm::tag_and_term: {
#line 249 "treegen.pcc"
            
            BitSet * s1 = closure0[ non_terminals[_and_term(term)->_1] ];
            BitSet * s2 = closure0[ non_terminals[_and_term(term)->_2] ];
            temp.Intersect(*s1,*s2);
            if (closure0[var]->Union_if_changed(temp)) changed = true;
            
#line 254 "treegen.pcc"
            } break;
         case a_TreeTerm::tag_or_term: {
#line 254 "treegen.pcc"
            
            BitSet * s1 = closure0[ non_terminals[_or_term(term)->_1] ];
            BitSet * s2 = closure0[ non_terminals[_or_term(term)->_2] ];
            if (closure0[var]->Union_if_changed(*s1)) changed = true;
            if (closure0[var]->Union_if_changed(*s2)) changed = true;
            
#line 259 "treegen.pcc"
            } break;
         default: { goto L3; } break;
      }
   } else { goto L3; }
}
#line 266 "treegen.pcc"
#line 266 "treegen.pcc"

      }

      /////////////////////////////////////////////////////////////////////////
      //  Propagate closure information to user non-terminals
      /////////////////////////////////////////////////////////////////////////
      for (int i = G.size() - 1; i >= 0; i--) {
         Variable v1 = G[i].var;
         Variable v2 = non_terminals[G[i].term];
         // cerr << "[" << v1 << " ";
         // G.print_variable(cerr,v1) << " <= " << v2 << " "; 
         // G.print(cerr,G[i].term) << "]\n";
         if (v1 == 0) continue;
         if (closure0[v2]) {
            if (closure0[v1]->Union_if_changed(*closure0[v2])) changed = true;
         } else {
            if (closure0[v1]->add_if_changed(v2)) changed = true;
         }
      }
   } while (changed);
}

//////////////////////////////////////////////////////////////////////////////
//  This is the method for computing projections.
//  A projection on functor f and arity i (written as proj[f][i]) is
//  the set of non-terminals that can appear in that position.
//////////////////////////////////////////////////////////////////////////////
void TreeGenerator::compute_projections()
{   
   ///////////////////////////////////////////////////////////////////////////
   //  Allocate the projection array.
   ///////////////////////////////////////////////////////////////////////////
   {  proj = (BitSet***)mem.c_alloc(sizeof(BitSet**) * (G.max_functor() + 1));
      for (Functor f = G.min_functor(); f <= G.max_functor(); f++) {
         if (G.arity(f) == 0) continue;
         proj[f] = (BitSet**)mem.c_alloc(sizeof(BitSet*) * G.arity(f));
         for (int i = G.arity(f) - 1; i >= 0; i--) {
            proj[f][i] = new (mem, max_non_terminal) BitSet;
            proj[f][i]->add(0);
         }
      }
   }

   ///////////////////////////////////////////////////////////////////////////
   //  Compute the projections by going over the terms and
   //  looking up the non-terminals at each argument.
   ///////////////////////////////////////////////////////////////////////////
   {  foreach (p, non_terminals) {
         
#line 314 "treegen.pcc"
#line 322 "treegen.pcc"
{
   TreeTerm _V1 = non_terminals.key(p);
   if (_V1) {
      switch (_V1->tag__) {
         case a_TreeTerm::tag_tree_term: {
#line 315 "treegen.pcc"
            
            for (int i = _tree_term(_V1)->_2 - 1; i >= 0; i--) {
               Variable v = non_terminals[ _tree_term(_V1)->_3[i] ];
               if (closure0[v]) proj[_tree_term(_V1)->_1][i]->Union(*closure0[v]);
               else             proj[_tree_term(_V1)->_1][i]->add(v);
            }
            
#line 321 "treegen.pcc"
            } break;
         default: {
            L4:; 
#line 321 "treegen.pcc"
          // skip
            
#line 322 "treegen.pcc"
            } break;
      }
   } else { goto L4; }
}
#line 322 "treegen.pcc"
#line 322 "treegen.pcc"

      }
   }
}

//////////////////////////////////////////////////////////////////////////////
// Method to allocate the representer state list for each functor at
// each arity.  ``Representers'' are simply interesting states.
//////////////////////////////////////////////////////////////////////////////
void TreeGenerator::compute_representers()
{  representers = (StateList***)mem.c_alloc(sizeof(StateList**) * (G.max_functor() + 1));
   for (Functor f = G.min_functor(); f <= G.max_functor(); f++) 
      representers[f] = 
         (StateList**)mem.c_alloc(sizeof(StateList*) * G.arity(f));
}

//////////////////////////////////////////////////////////////////////////////
//  Method to compute the accept rules of a state
//////////////////////////////////////////////////////////////////////////////
void TreeGenerator::compute_accept_rules (State s)
{  register const BitSet& vars     = *d_states.Get( s );
   register BitSet&       rules    = treegen.accept_rules(s);
   register Rule          min_rule = G.size();
   register int v;
   foreach_bit_fast(v,vars) {
      Rule r = rule_map[v];
      if (r >= 0 && r < min_rule) min_rule = r;
      const BitSet * r_set = ruleset_map[v];
      if (r_set) rules.Union(*r_set);
   }
   if (min_rule == G.size()) min_rule = -1;
   treegen.set_accept1(s, min_rule);
}

//////////////////////////////////////////////////////////////////////////////
//  Method to compute the initial states.
//  These are the ``wildcard'' or no-information state, state 0.
//  Followed by a state for each unit functor.
//////////////////////////////////////////////////////////////////////////////
void TreeGenerator::compute_initial_states()
{
   ///////////////////////////////////////////////////////////////////////////
   //  Create the first state corresponding to the wildcard.
   ///////////////////////////////////////////////////////////////////////////
   number_of_states = 0;
   {  BitSet * state_zero = new (mem, max_non_terminal) BitSet;
      state_zero->add (0);
      state_labels.insert(state_zero, number_of_states);
      d_states.At( number_of_states ) = state_zero;
      d_terms .At( number_of_states ) = new(mem)
#line 371 "treegen.pcc"
TreeTerm_set_term
#line 371 "treegen.pcc"
(state_zero);
      treegen.new_state(0);
      compute_accept_rules(0);
      number_of_states++;
   }

   ///////////////////////////////////////////////////////////////////////////
   //  Generate the rest of the terminal states formed by unit functors.
   ///////////////////////////////////////////////////////////////////////////
   {  foreach (i, non_terminals) {
         
#line 381 "treegen.pcc"
#line 396 "treegen.pcc"
{
   TreeTerm _V2 = non_terminals.key(i);
   if (_V2) {
      switch (_V2->tag__) {
         case a_TreeTerm::tag_tree_term: {
            switch (_tree_term(_V2)->_2) {
               case 0: {
#line 382 "treegen.pcc"
                // use terms with arity 0 only
                  BitSet * new_state = new (mem, max_non_terminal) BitSet;
                  Variable v         = non_terminals.value(i);
                  new_state->add(0);
                  if (closure0[v]) new_state->Union(*closure0[v]);
                  else             new_state->add(v);
                  state_labels.insert(new_state, number_of_states);
                  d_states.At( number_of_states ) = new_state;
                  d_terms .At( number_of_states ) =
#line 390 "treegen.pcc"
#line 390 "treegen.pcc"
                  new (mem) TreeTerm_set_term(new_state)
#line 390 "treegen.pcc"
#line 390 "treegen.pcc"
                  ;
                  treegen.new_state(number_of_states);
                  treegen.add_delta(_tree_term(_V2)->_1,number_of_states);
                  compute_accept_rules(number_of_states);
                  number_of_states++;
                  
#line 395 "treegen.pcc"
               } break;
               default: {
                  L5:; 
#line 395 "treegen.pcc"
                  
                  
#line 396 "treegen.pcc"
               }
            }
            } break;
         default: { goto L5; } break;
      }
   } else { goto L5; }
}
#line 396 "treegen.pcc"
#line 396 "treegen.pcc"
 
      }
   }
}

//////////////////////////////////////////////////////////////////////////////
//  Method to compute transitions.
//////////////////////////////////////////////////////////////////////////////
void TreeGenerator::compute_transitions()
{   
   ///////////////////////////////////////////////////////////////////////////
   //  Some temporary buffers used during this process.
   ///////////////////////////////////////////////////////////////////////////
   BitSet * projected   [256];            // projected states of arity i
   Bool     is_relevant [256];            // is arity i relevant?
   State    inputs      [256];            // input state of arity i
   int      equiv_class [256];            // equivalence class of above.
   BitSet * T    = 0;                     // current result non-terminal set
   TreeTerm term = new_term(mem, 0, 255); // current term 

   {  for (int i = G.max_arity() - 1; i >= 0; i--)
         projected[i] = new (mem, max_non_terminal) BitSet;
   }

   ///////////////////////////////////////////////////////////////////////////
   //  Compute the transitions of the states.  We'll start from state 0.
   ///////////////////////////////////////////////////////////////////////////
   for (State current = 0; current < number_of_states; current++) {
      const BitSet& S = *d_states.Get(current);

      ////////////////////////////////////////////////////////////////////////
      // Iterate over all the non-unit functors and compute their transition
      // function on this new state ``current.''
      ////////////////////////////////////////////////////////////////////////
      for (Functor f = G.min_functor(); f <= G.max_functor(); f++) {
         int n; // arity
         if ((n = G.arity(f)) == 0) continue; 

         
#line 434 "treegen.pcc"
#line 436 "treegen.pcc"
{
   if (term) {
      switch (term->tag__) {
         case a_TreeTerm::tag_tree_term: {
#line 435 "treegen.pcc"
          _tree_term(term)->_1 = f; _tree_term(term)->_2 = n; 
#line 435 "treegen.pcc"
            } break;
         default: {
            L6:; 
#line 436 "treegen.pcc"
          assert("bug"); 
#line 436 "treegen.pcc"
            } break;
      }
   } else { goto L6; }
}
#line 437 "treegen.pcc"
#line 437 "treegen.pcc"


         /////////////////////////////////////////////////////////////////////
         //  Compute the projections on the arguments.
         //  If the intersection of S with the ith projection is an old state T,
         //  then the transition with respect to arity ith must be the same
         //  as the state T.
         /////////////////////////////////////////////////////////////////////
         for (int i = n - 1; i >= 0; i--) {
            projected[i]->Intersect(S, *proj[f][i]); 
            projected[i]->add(0);
            Ix old = state_labels.lookup(projected[i]);
            State mapped = current;
            if (old && (mapped = state_labels.value(old)) < current) {  
               is_relevant[i] = false;
            } else {  
               representers[f][i] = new (mem, mapped, representers[f][i]) StateList;
               is_relevant[i] = true;
            }
            //////////////////////////////////////////////////////////////////
            // Update the index map ``mu.'' 
            //////////////////////////////////////////////////////////////////
            treegen.add_mu(f,i,current,mapped);
         }
         
         /////////////////////////////////////////////////////////////////////
         // Now compute the transition function of functor f with respect
         // to the state ``current.''  Check only the arities that can
         // produce new information.  This is done by fixing all ``relevant''
         // arities to state ``current'' and the rest to the rest of the
         // representer states.
         /////////////////////////////////////////////////////////////////////
         for (int fix = n - 1; fix >= 0; fix--) {
            if (! is_relevant[fix]) continue;
            inputs      [ fix ] = current;
            equiv_class [ fix ] = treegen.index_map(f,fix,current);
            T = compute_transition(T, term, 0, fix, *projected[fix], inputs, equiv_class);
         }
      }
   }
}

//////////////////////////////////////////////////////////////////////////////
//  Method to compute a set of transitions functions.
//  We iterate over all the representer states.
//////////////////////////////////////////////////////////////////////////////
BitSet * TreeGenerator::compute_transition
   ( BitSet *      T,        // temporary bitset 
     TreeTerm      term,     // temporary term
     int           i,        // current arity to consider
     int           fixed,    // the fixed arity
     const BitSet& S,        // input state of the fixed arity
     State         inputs[], // input states
     int           equiv []  // equiv class of above
   )
{
   if (i == fixed) i++;  // skip the fixed arity.
   
#line 494 "treegen.pcc"
#line 552 "treegen.pcc"
{
   if (term) {
      switch (term->tag__) {
         case a_TreeTerm::tag_tree_term: {
#line 496 "treegen.pcc"
            
            if (i < _tree_term(term)->_2) {
               ////////////////////////////////////////////////////////////////////////
               //  Try arity i == wildcard first
               ////////////////////////////////////////////////////////////////////////
               _tree_term(term)->_3[i] = wild_term; 
               inputs[i]   = 0;
               equiv [i]   = 0;
               T = compute_transition(T, term, i+1, fixed, S, inputs, equiv);
            
               //////////////////////////////////////////////////////////////////////
               // Try arity i == a representer state next.
               ////////////////////////////////////////////////////////////////////////
               for (StateList * r = representers[_tree_term(term)->_1][i]; r; r = r->tail) {
                  inputs[i]   = r->head;
                  equiv [i]   = treegen.index_map(_tree_term(term)->_1,i,r->head);
                  _tree_term(term)->_3[i] = d_terms.Get( r->head );
                  T = compute_transition(T, term, i+1, fixed, S, inputs, equiv);
               }
            } else {
               ////////////////////////////////////////////////////////////////////////
               //  Compute the non-terminal set corresponding to the new state.
               ////////////////////////////////////////////////////////////////////////
               if (T == 0) T = new (mem, max_non_terminal) BitSet;
               else        T->clear();
               T->add(0);
               int v;
               foreach_bit_fast (v, S) {
                  _tree_term(term)->_3[ fixed ] = n_states[v];
                  compute_delta(T, term, 0, fixed, inputs);
               }
            
               ////////////////////////////////////////////////////////////////////////
               //  Now, lookup the new state to see if it is a new one.
               //  If so, create a new state.  
               ////////////////////////////////////////////////////////////////////////
               Ix s;
               State mapped;
               if ((s = state_labels.lookup(T))) { // old state
                  mapped = state_labels.value(s);
               } else {                      // new state
                  d_states.At( number_of_states ) = T;
                  d_terms .At( number_of_states ) = new(mem)
#line 538 "treegen.pcc"
TreeTerm_set_term
#line 538 "treegen.pcc"
            (T);
            state_labels.insert(T, number_of_states);
            treegen.new_state(number_of_states);
            compute_accept_rules(number_of_states);
            T = 0;
            mapped = number_of_states++;
            }
            
            ////////////////////////////////////////////////////////////////////////
            //  Update the delta table.
            ////////////////////////////////////////////////////////////////////////
            treegen.add_delta(_tree_term(term)->_1, equiv, mapped);
            }
            
#line 551 "treegen.pcc"
            } break;
         default: {
            L7:; 
#line 552 "treegen.pcc"
           assert("bug"); 
#line 552 "treegen.pcc"
            } break;
      }
   } else { goto L7; }
}
#line 553 "treegen.pcc"
#line 553 "treegen.pcc"

   return T;
}

//////////////////////////////////////////////////////////////////////////////
//  Method to compute one delta function
//////////////////////////////////////////////////////////////////////////////
void TreeGenerator::compute_delta
   ( BitSet *      T,        // temporary bitset 
     TreeTerm      term,     // temporary term
     int           i,        // current arity to consider
     int           fixed,    // the fixed arity
     const State   inputs[]  // input states
   )
{  Bool first = i == 0;
   if (i == fixed) i++;
   Ix p;

   if ((p = non_terminals.lookup(term))) { 
      ////////////////////////////////////////////////////////////////////////
      // Found! use the info from the grammar.
      ////////////////////////////////////////////////////////////////////////
      Variable v = non_terminals.value(p);
      if (closure0[v]) T->Union(*closure0[v]);
      else T->add(v);
   } else if ((p = delta.lookup(term))) {
      ////////////////////////////////////////////////////////////////////////
      // Found! use the info from the delta map.
      ////////////////////////////////////////////////////////////////////////
      T->Union(* delta.value(p)); 
   } else {
      ////////////////////////////////////////////////////////////////////////
      // Split input state s into subcases and compute the union of all of 
      // them.  Memorize individual cases into the map ``delta.''
      ////////////////////////////////////////////////////////////////////////
      
#line 588 "treegen.pcc"
#line 612 "treegen.pcc"
{
   if (term) {
      switch (term->tag__) {
         case a_TreeTerm::tag_tree_term: {
#line 590 "treegen.pcc"
          
            if (i < _tree_term(term)->_2) {
               const BitSet& U = *d_states.Get( inputs[i] );
               TreeTerm save = _tree_term(term)->_3[i];  
               BitSet * V;
               if (first) V = T;
               else { V = new (mem, max_non_terminal) BitSet; V->add(0); }
            
               int v;
               foreach_bit_fast (v, U) { 
                  _tree_term(term)->_3 [i] = n_states[v];
                  compute_delta(V, term, i + 1, fixed, inputs);
               }
               _tree_term(term)->_3[i] = save;
            
               if (! first) {
                  TreeTerm n_term = new_term(mem, _tree_term(term)->_1, _tree_term(term)->_2, _tree_term(term)->_3);
                  delta.insert(n_term,V);
                  T->Union(*V);
               }
            }
            
#line 611 "treegen.pcc"
            } break;
         default: {
            L8:; 
#line 612 "treegen.pcc"
           assert ("bug"); 
#line 612 "treegen.pcc"
            } break;
      }
   } else { goto L8; }
}
#line 613 "treegen.pcc"
#line 613 "treegen.pcc"

   }
}

//////////////////////////////////////////////////////////////////////////////
//  Method to print a report of the generated tables. 
//////////////////////////////////////////////////////////////////////////////
std::ostream& TreeGenerator::print_report(std::ostream& log) const
{
   ///////////////////////////////////////////////////////////////////////////
   //  (1) Print the item set.
   ///////////////////////////////////////////////////////////////////////////
   {  log << "\nItems:\n";
      for (Variable v = 0; v < max_non_terminal; v++) {
         log << '{' << v << "}\t";
         G.print(log, n_states.Get(v)) << '\n';
      }
   }   

   ///////////////////////////////////////////////////////////////////////////
   //  (2) Print each state
   ///////////////////////////////////////////////////////////////////////////
   {  log << "\nStates:\n";
      for (State s = 0; s < number_of_states; s++) {
         print_state(log,s);
      }
   }
   return log;
}

//////////////////////////////////////////////////////////////////////////////
//  Method to print a state 
//////////////////////////////////////////////////////////////////////////////
std::ostream& TreeGenerator::print_state(std::ostream& log, State s) const
{
   log << '<' << s << '>';
   const BitSet& S = *d_states.Get(s);
   Variable v;
   foreach_bit(v,S) G.print(log << '\t', n_states.Get(v)) << '\n';
   if (treegen.is_accept_state(s)) 
      log << "\t[accept " << treegen.accept1_rule(s) << "]\n";
   return log;
}

//////////////////////////////////////////////////////////////////////////////
//  Client visible methods follow.
//  All the work has been down by the class TreeGenerator.
//  Class TreeGen simply ties things up together.
//////////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////
//  Constructors and destructor of the class TreeGen.
//////////////////////////////////////////////////////////////////////////////
TreeGen:: TreeGen(Mem& m) : TreeAutomaton(m), impl(0) {}
TreeGen:: TreeGen(Mem& m, TreeGrammar& Gram)  
   : TreeAutomaton(m), impl(0) { compile(Gram); }
TreeGen::~TreeGen() { delete impl; }

//////////////////////////////////////////////////////////////////////////////
//  This is the top level method to compile a tree grammar.
//////////////////////////////////////////////////////////////////////////////
void TreeGen::compile (TreeGrammar& Gram)
{  
   ///////////////////////////////////////////////////////////////////////////
   //  Let our superclass do its stuff first.
   ///////////////////////////////////////////////////////////////////////////
   Super::compile(Gram);

   ///////////////////////////////////////////////////////////////////////////
   //  The internal representation is defined here.
   ///////////////////////////////////////////////////////////////////////////
   delete impl;
   impl = new TreeGenerator(*this,Gram);

   ///////////////////////////////////////////////////////////////////////////
   //  Now carry out the various steps.
   ///////////////////////////////////////////////////////////////////////////
   impl->assign_non_terminals();   // assign unique non-terminal names.
   impl->compute_closures();       // compute transitive closures of non-terminals.
   impl->compute_projections();    // compute the projections on functors.
   impl->compute_representers();   // allocate the representor states.
   impl->compute_initial_states(); // compute the initial states first.
   impl->compute_transitions();    // compute the rest of the transitions.
}

//////////////////////////////////////////////////////////////////////////////
//  Method to print a report of the generated tables.
//////////////////////////////////////////////////////////////////////////////
std::ostream& TreeGen::print_report(std::ostream& log) const
{  Super::print_report(log);
   if (impl) impl->print_report(log);
   return log;
}

//////////////////////////////////////////////////////////////////////////////
//  Method to print a state of the generated tables.
//////////////////////////////////////////////////////////////////////////////
std::ostream& TreeGen::print_state(std::ostream& log, State s) const
{  if (impl) impl->print_state(log,s);
   return log;
}

//////////////////////////////////////////////////////////////////////////////
//  Algorithm name
//////////////////////////////////////////////////////////////////////////////
const char * TreeGen::algorithm() const { return "TreeGen"; }
#line 719 "treegen.pcc"
/*
------------------------------- Statistics -------------------------------
Merge matching rules         = yes
Number of DFA nodes merged   = 52
Number of ifs generated      = 11
Number of switches generated = 10
Number of labels             = 8
Number of gotos              = 10
Adaptive matching            = disabled
Fast string matching         = disabled
Inline downcasts             = disabled
--------------------------------------------------------------------------
*/