postproc: add the possibility to output a monitor

* src/tgbaalgos/stripacc.cc, src/tgbaalgos/stripacc.hh: New files.
* src/tgbaalgos/Makefile.am: Add them.
* src/tgbaalgos/postproc.cc, src/tgbaalgos/postproc.hh: Add a Monitor
output option.
* src/bin/ltl2tgba.cc: Add a --monitor/-M option.
* NEWS: Mention monitors.
* src/tgba/tgbaexplicit.hh (is_accepting_state): Fix for the
case where the automaton has no acceptance set.

NEWS

@@ -25,17 +25,19 @@ New in spot 0.9.2a:
 	        some simplifications, check whether to formulas are
 	        equivalent, ...
 
-    - ltl2tgba: Translate LTL/PSL formulas into Büchi automata.  A
-                fondamental change to the interface is that you may
-	        now specify the goal of the translation: do you
-	        you favor deterministic or smaller automata?
+    - ltl2tgba: Translate LTL/PSL formulas into Büchi automata (TGBA,
+                BA, or Monitor).  A fondamental change to the
+                interface is that you may now specify the goal of the
+                translation: do you you favor deterministic or smaller
+                automata?
 
     - ltl2tgta: Translate LTL/PSL formulas into Testing Automata.
 
-    - ltlcheck: A tool to find bugs in translators from LTL/PSL to
-                Büchi automata.  This is essentially a Spot-based
-		reimplementation of LBTT that supports PSL in addition
-		to LTL, and that can output more statistics.
+    - ltlcheck: Compare the output of translators from LTL/PSL to
+                Büchi automata, to find bug or for benchmarking.  This
+                is essentially a Spot-based reimplementation of LBTT
+                that supports PSL in addition to LTL, and that can
+                output more statistics.
 
     These binaries are built in the src/bin/ directory.  The former
     test versions of genltl and randltl have been removed from the
@@ -113,7 +115,7 @@ New in spot 0.9.2a:
       automata generated with the web interface.)
 
     - A new class, "postprocessor", makes it easier to apply
-      all availlable simplification algorithms on a TGBA.
+      all availlable simplification algorithms on a TGBA/BA/Monitors.
 
   * Minor changes:
 

src/bin/ltl2tgba.cc

@@ -56,10 +56,12 @@ If multiple formulas are supplied, several automata will be output.";
 static const argp_option options[] =
   {
     /**************************************************/
-    { 0, 0, 0, 0, "Automaton type:", 2 },
+    { 0, 0, 0, 0, "Output automaton type:", 2 },
     { "tgba", OPT_TGBA, 0, 0,
       "Transition-based Generalized Büchi Automaton (default)", 0 },
     { "ba", 'B', 0, 0, "Büchi Automaton", 0 },
+    { "monitor", 'M', 0, 0, "Monitor (accepts all finite prefixes "
+      "of the given formula)", 0 },
     /**************************************************/
     { 0, 0, 0, 0, "Output format:", 3 },
     { "dot", OPT_DOT, 0, 0, "GraphViz's format (default)", 0 },
@@ -116,9 +118,13 @@ parse_opt(int key, char* arg, struct argp_state*)
     case 'B':
       type = spot::postprocessor::BA;
       break;
+    case 'M':
+      type = spot::postprocessor::Monitor;
+      break;
     case 's':
       format = Spin;
-      type = spot::postprocessor::BA;
+      if (type != spot::postprocessor::Monitor)
+	type = spot::postprocessor::BA;
       break;
     case OPT_DOT:
       format = Dot;
@@ -209,7 +215,8 @@ namespace
 	{
 	case Dot:
 	  spot::dotty_reachable(std::cout, aut,
-				type == spot::postprocessor::BA);
+				(type == spot::postprocessor::BA)
+				|| (type == spot::postprocessor::Monitor));
 	  break;
 	case Lbtt:
 	  spot::lbtt_reachable(std::cout, aut);

src/tgba/tgbaexplicit.hh

@@ -710,7 +710,8 @@ namespace spot
       // So we need only to check one to decide
       if (st->successors.empty())
 	return false;
-      return st->successors.front().acceptance_conditions != bddfalse;
+      return (st->successors.front().acceptance_conditions
+	      == this->all_acceptance_conditions_);
     }
 
   private:

src/tgbaalgos/Makefile.am

@@ -63,6 +63,7 @@ tgbaalgos_HEADERS = \
   se05.hh \
   simulation.hh \
   stats.hh \
+  stripacc.hh \
   tau03.hh \
   tau03opt.hh \
   reductgba_sim.hh \
@@ -105,6 +106,7 @@ libtgbaalgos_la_SOURCES = \
   se05.cc \
   simulation.cc \
   stats.cc \
+  stripacc.cc \
   tau03.cc \
   tau03opt.cc \
   reductgba_sim.cc \

src/tgbaalgos/postproc.cc

@@ -23,6 +23,7 @@
 #include "sccfilter.hh"
 #include "degen.hh"
 #include "stats.hh"
+#include "stripacc.hh"
 
 namespace spot
 {
@@ -46,6 +47,49 @@ namespace spot
       a = s;
     }
 
+    if (type_ == Monitor)
+      {
+	if (pref_ == Deterministic)
+	  {
+	    const tgba* m = minimize_monitor(a);
+	    delete a;
+	    return m;
+	  }
+	else
+	  {
+	    const tgba* m = strip_acceptance(a);
+	    delete a;
+	    a = m;
+	  }
+	if (pref_ == Any)
+	  return a;
+
+	const tgba* sim;
+	if (level_ == Low)
+	  sim = simulation(a);
+	else
+	  sim = iterated_simulations(a);
+	if (level_ != High)
+	  {
+	    delete a;
+	    return sim;
+	  }
+	// For Small,High we return the smallest between the output of
+	// the simulation, and that of the deterministic minimization.
+	const tgba* m = minimize_monitor(a);
+	delete a;
+	if (count_states(m) > count_states(sim))
+	  {
+	    delete m;
+	    return sim;
+	  }
+	else
+	  {
+	    delete sim;
+	    return m;
+	  }
+      }
+
     if (pref_ == Any)
       {
 	if (type_ == BA)

src/tgbaalgos/postproc.hh

@@ -27,7 +27,8 @@ namespace spot
   /// \addtogroup tgba_reduction
   /// @{
 
-  /// \brief Wrap TGBA/BA post-processing algorithms in an easy interface.
+  /// \brief Wrap TGBA/BA/Monitor post-processing algorithms in an
+  /// easy interface.
   ///
   /// This class is a shell around scc_filter(),
   /// minimize_obligation(), simulation(), iterated_simulations(), and
@@ -61,7 +62,7 @@ namespace spot
     {
     }
 
-    enum output_type { TGBA, BA };
+    enum output_type { TGBA, BA, Monitor };
     void
     set_type(output_type type)
     {

src/tgbaalgos/stripacc.cc

+// -*- coding: utf-8 -*-
+// Copyright (C) 2012 Laboratoire de Recherche et Développement de
+// l'Epita (LRDE).
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+//
+// Spot is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+// License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "stripacc.hh"
+#include "reachiter.hh"
+
+namespace spot
+{
+  namespace
+  {
+    class strip_iter: public tgba_reachable_iterator_depth_first
+    {
+    public:
+      strip_iter(const tgba* a)
+	: tgba_reachable_iterator_depth_first(a),
+	  out_(new sba_explicit_number(a->get_dict()))
+      {
+      }
+
+      sba_explicit_number*
+      result()
+      {
+	return out_;
+      }
+
+      void
+      process_link(const state*, int in,
+		   const state*, int out,
+		   const tgba_succ_iterator* si)
+      {
+	state_explicit_number::transition* t = out_->create_transition(in, out);
+	out_->add_conditions(t, si->current_condition());
+      }
+
+    private:
+      sba_explicit_number* out_;
+    };
+  }
+
+  sba_explicit_number*
+  strip_acceptance(const tgba* a)
+  {
+    strip_iter si(a);
+    si.run();
+    return si.result();
+  }
+}

src/tgbaalgos/stripacc.hh

+// -*- coding: utf-8 -*-
+// Copyright (C) 2012 Laboratoire de Recherche et Développement de
+// l'Epita (LRDE).
+//
+// This file is part of Spot, a model checking library.
+//
+// Spot is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+//
+// Spot is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+// License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#ifndef SPOT_TGBAALGOS_STRIPACC_HH
+# define SPOT_TGBAALGOS_STRIPACC_HH
+
+# include "tgba/tgbaexplicit.hh"
+
+namespace spot
+{
+  /// \brief Duplicate automaton \a a, removing all acceptance sets.
+  ///
+  /// This is equivalent to marking all states/transitions as accepting.
+  /// \ingroup tgba_misc
+  sba_explicit_number* strip_acceptance(const tgba* a);
+}
+
+#endif // SPOT_TGBAALGOS_STRIPACC_HH