bdddict: remove now/next variables.

These were only used by the BDD-based implementation of TGBA, which has
been removed.

* src/tgba/bdddict.cc, src/tgba/bdddict.hh, src/tgba/bddprint.cc: Remove
support for now/next variables.

src/tgba/bdddict.cc

@@ -85,17 +85,13 @@ namespace spot
   bdd_dict::bdd_dict()
     // Initialize priv_ first, because it also initializes BuDDy
     : priv_(new bdd_dict_priv()),
-      bdd_map(bdd_varnum()),
-      next_to_now(bdd_newpair()),
-      now_to_next(bdd_newpair())
+      bdd_map(bdd_varnum())
   {
   }
 
   bdd_dict::~bdd_dict()
   {
     assert_emptiness();
-    bdd_freepair(next_to_now);
-    bdd_freepair(now_to_next);
     delete priv_;
   }
 
@@ -138,35 +134,6 @@ namespace spot
     register_propositions(bdd_low(f), for_me);
   }
 
-  int
-  bdd_dict::register_state(const ltl::formula* f, const void* for_me)
-  {
-    int num;
-    // Do not build a state that already exists.
-    fv_map::iterator sii = now_map.find(f);
-    if (sii != now_map.end())
-      {
-	num = sii->second;
-      }
-    else
-      {
-	f = f->clone();
-	num = priv_->allocate_variables(2);
-	now_map[f] = num;
-	bdd_map.resize(bdd_varnum());
-	bdd_map[num].type = now;
-	bdd_map[num].f = f;
-	bdd_map[num + 1].type = next;
-	bdd_map[num + 1].f = f;
-	// Record that num+1 should be renamed as num when
-	// the next state becomes current.
-	bdd_setpair(next_to_now, num + 1, num);
-	bdd_setpair(now_to_next, num, num + 1);
-      }
-    bdd_map[num].refs.insert(for_me); // Keep only references for now.
-    return num;
-  }
-
   int
   bdd_dict::register_acceptance_variable(const ltl::formula* f,
 					const void* for_me)
@@ -315,7 +282,7 @@ namespace spot
 
     // ME was the last user of this variable.
     // Let's free it.  First, we need to find
-    // if this is a Now, a Var, or an Acc variable.
+    // if this is a Var or an Acc variable.
     int n = 1;
     const ltl::formula* f = 0;
     switch (bdd_map[v].type)
@@ -324,15 +291,6 @@ namespace spot
 	f = bdd_map[v].f;
 	var_map.erase(f);
 	break;
-      case now:
-	f = bdd_map[v].f;
-	now_map.erase(f);
-	bdd_setpair(now_to_next, v, v);
-	bdd_setpair(next_to_now, v + 1, v + 1);
-	n = 2;
-	break;
-      case next:
-	break;
       case acc:
 	f = bdd_map[v].f;
 	acc_map.erase(f);
@@ -388,16 +346,6 @@ namespace spot
     return s.find(by_me) != s.end();
   }
 
-  bool
-  bdd_dict::is_registered_state(const ltl::formula* f, const void* by_me)
-  {
-    fv_map::iterator fi = now_map.find(f);
-    if (fi == now_map.end())
-      return false;
-    ref_set& s = bdd_map[fi->second].refs;
-    return s.find(by_me) != s.end();
-  }
-
   bool
   bdd_dict::is_registered_acceptance_variable(const ltl::formula* f,
 					      const void* by_me)
@@ -423,12 +371,6 @@ namespace spot
 	  case anon:
 	    os << (r.refs.empty() ? "Free" : "Anon");
 	    break;
-	  case now:
-	    os << "Now[" << to_string(r.f) << ']';
-	    break;
-	  case next:
-	    os << "Next[" << to_string(r.f) << ']';
-	    break;
 	  case acc:
 	    os << "Acc[" << to_string(r.f) << ']';
 	    break;
@@ -467,8 +409,6 @@ namespace spot
 
     bool var_seen = false;
     bool acc_seen = false;
-    bool now_seen = false;
-    bool next_seen = false;
     bool refs_seen = false;
     unsigned s = bdd_map.size();
     for (unsigned i = 0; i < s; ++i)
@@ -481,36 +421,18 @@ namespace spot
 	  case acc:
 	    acc_seen = true;
 	    break;
-	  case now:
-	    now_seen = true;
-	    break;
-	  case next:
-	    next_seen = true;
-	    break;
 	  case anon:
 	    break;
 	  }
 	refs_seen |= !bdd_map[i].refs.empty();
       }
-    if (var_map.empty()
-	&& now_map.empty()
-	&& acc_map.empty())
+    if (var_map.empty() && acc_map.empty())
       {
 	if (var_seen)
 	  {
 	    std::cerr << "var_map is empty but Var in map" << std::endl;
 	    fail = true;
 	  }
-	if (now_seen)
-	  {
-	    std::cerr << "now_map is empty but Now in map" << std::endl;
-	    fail = true;
-	  }
-	else if (next_seen)
-	  {
-	    std::cerr << "Next variable seen (without Now) in map" << std::endl;
-	    fail = true;
-	  }
 	if (acc_seen)
 	  {
 	    std::cerr << "acc_map is empty but Acc in map" << std::endl;

src/tgba/bdddict.hh

 // -*- coding: utf-8 -*-
-// Copyright (C) 2011, 2012, 2013 Laboratoire de Recherche et Développement
-// de l'Epita (LRDE).
+// Copyright (C) 2011, 2012, 2013, 2014 Laboratoire de Recherche et
+// Développement de l'Epita (LRDE).
 // Copyright (C) 2003, 2004, 2006  Laboratoire d'Informatique de Paris 6 (LIP6),
 // département Systèmes Répartis Coopératifs (SRC), Université Pierre
 // et Marie Curie.
@@ -42,9 +42,7 @@ namespace spot
   /// The BDD library uses integers to designate Boolean variables in
   /// its decision diagrams.  This class is used to map such integers
   /// to objects actually used in Spot.  These objects are usually
-  /// atomic propositions, but they can also be acceptance conditions,
-  /// or "Now/Next" variables (although the latter should be
-  /// eventually removed).
+  /// atomic propositions, but they can also be acceptance conditions.
   ///
   /// When a BDD variable is registered using a bdd_dict, it is always
   /// associated to a "user" (or "owner") object.  This is done by
@@ -72,14 +70,13 @@ namespace spot
     /// BDD-variable-to-formula maps.
     typedef std::map<int, const ltl::formula*> vf_map;
 
-    fv_map now_map;		///< Maps formulae to "Now" BDD variables
     fv_map var_map;		///< Maps atomic propositions to BDD variables
     fv_map acc_map;		///< Maps acceptance conditions to BDD variables
 
     /// BDD-variable reference counts.
     typedef std::set<const void*> ref_set;
 
-    enum var_type { anon = 0, now, next, var, acc };
+    enum var_type { anon = 0, var, acc };
     struct bdd_info {
       bdd_info() : type(anon) {}
       var_type type;
@@ -91,15 +88,6 @@ namespace spot
     // Map BDD variables to their meaning.
     bdd_info_map bdd_map;
 
-    /// \brief Map Next variables to Now variables.
-    ///
-    /// Use with BuDDy's bdd_replace() function.
-    bddPair* next_to_now;
-    /// \brief Map Now variables to Next variables.
-    ///
-    /// Use with BuDDy's bdd_replace() function.
-    bddPair* now_to_next;
-
     /// \brief Register an atomic proposition.
     ///
     /// Return (and maybe allocate) a BDD variable designating formula
@@ -121,19 +109,6 @@ namespace spot
     /// automaton).
     void register_propositions(bdd f, const void* for_me);
 
-    /// \brief Register a couple of Now/Next variables
-    ///
-    /// Return (and maybe allocate) two BDD variables for a state
-    /// associated to formula \a f.  The \a for_me argument should point
-    /// to the object using this BDD variable, this is used for
-    /// reference counting.  It is perfectly safe to call this
-    /// function several time with the same arguments.
-    ///
-    /// \return The first variable number.  Add one to get the second
-    /// variable.  Use bdd_ithvar() or bdd_nithvar() to convert this
-    /// to a BDD.
-    int register_state(const ltl::formula* f, const void* for_me);
-
     /// \brief Register an atomic proposition.
     ///
     /// Return (and maybe allocate) a BDD variable designating an
@@ -215,7 +190,6 @@ namespace spot
     /// @{
     /// Check whether formula \a f has already been registered by \a by_me.
     bool is_registered_proposition(const ltl::formula* f, const void* by_me);
-    bool is_registered_state(const ltl::formula* f, const void* by_me);
     bool is_registered_acceptance_variable(const ltl::formula* f,
 					   const void* by_me);
     /// @}

src/tgba/bddprint.cc

@@ -72,14 +72,6 @@ namespace spot
 	    print_ltl(ref.f, o) << '"';
 	  }
 	break;
-      case bdd_dict::now:
-	o << "Now[";
-	print_ltl(ref.f, o) << ']';
-	break;
-      case bdd_dict::next:
-	o << "Next[";
-	print_ltl(ref.f, o) << ']';
-	break;
       case bdd_dict::anon:
 	o << '?' << v;
       }