tl: mp_class() and --format=%[vw]h

Tools for deciding the class of a formula.

* spot/tl/hierarchy.cc, spot/tl/hierarchy.hh: New files.
* spot/tl/Makefile.am: Add them.
* bin/common_output.cc, bin/common_output.hh: Implement --format=%h.
* tests/core/hierarchy.test: More tests.
* NEWS: Update.

spot/tl/Makefile.am

@@ -1,6 +1,6 @@
 ## -*- coding: utf-8 -*-
-## Copyright (C) 2015, 2016 Laboratoire de Recherche et Développement de
-## l'Epita (LRDE).
+## Copyright (C) 2015, 2016, 2017 Laboratoire de Recherche et
+## Développement de l'Epita (LRDE).
 ##
 ## This file is part of Spot, a model checking library.
 ##
@@ -31,6 +31,7 @@ tl_HEADERS =					\
   environment.hh				\
   exclusive.hh					\
   formula.hh					\
+  hierarchy.hh					\
   length.hh					\
   ltlf.hh					\
   mutation.hh					\
@@ -53,6 +54,7 @@ libtl_la_SOURCES =				\
   dot.cc					\
   exclusive.cc					\
   formula.cc					\
+  hierarchy.cc					\
   length.cc					\
   ltlf.cc					\
   mark.cc					\

spot/tl/hierarchy.cc

@@ -0,0 +1,85 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2017 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 <spot/tl/hierarchy.hh>
+#include <spot/twaalgos/isdet.hh>
+#include <spot/twaalgos/ltl2tgba_fm.hh>
+#include <spot/twaalgos/minimize.hh>
+#include <spot/twaalgos/postproc.hh>
+#include <spot/twaalgos/remfin.hh>
+#include <spot/twaalgos/strength.hh>
+#include <spot/twaalgos/totgba.hh>
+
+
+namespace spot
+{
+  namespace
+  {
+    static bool is_recurrence(formula f, const twa_graph_ptr& aut)
+    {
+      if (f.is_syntactic_recurrence() || is_deterministic(aut))
+        return true;
+      // If aut is a non-deterministic TGBA, we do
+      // TGBA->DPA->DRA->(D?)BA.  The conversion from DRA to
+      // BA will preserve determinism if possible.
+      spot::postprocessor p;
+      p.set_type(spot::postprocessor::Generic);
+      p.set_pref(spot::postprocessor::Deterministic
+                 | spot::postprocessor::SBAcc);
+      p.set_level(spot::postprocessor::Low);
+      auto dra = p.run(aut);
+      if (dra->acc().is_generalized_buchi())
+        {
+          return true;
+        }
+      else
+        {
+          auto ba = rabin_to_buchi_maybe(to_generalized_rabin(dra));
+          assert(ba);
+          return is_deterministic(ba);
+        }
+    }
+  }
+
+  char mp_class(formula f)
+  {
+    if (f.is_syntactic_safety() && f.is_syntactic_guarantee())
+      return 'B';
+    auto dict = make_bdd_dict();
+    auto aut = ltl_to_tgba_fm(f, dict, true);
+    auto min = minimize_obligation(aut, f);
+    if (aut != min) // An obligation.
+      {
+        bool g = is_terminal_automaton(min);
+        bool s = is_safety_mwdba(min);
+        if (g)
+          return s ? 'B' : 'G';
+        else
+          return s ? 'S' : 'O';
+      }
+    // Not an obligation.  Could by 'P', 'R', or 'T'.
+    if (is_recurrence(f, aut))
+      return 'R';
+    f = formula::Not(f);
+    aut = ltl_to_tgba_fm(f, dict, true);
+    if (is_recurrence(f, aut))
+      return 'P';
+    return 'T';
+  }
+}

spot/tl/hierarchy.hh

@@ -0,0 +1,40 @@
+// -*- coding: utf-8 -*-
+// Copyright (C) 2017 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/>.
+
+#pragma once
+
+#include <spot/tl/formula.hh>
+
+namespace spot
+{
+  /// \brief Return the class of \a f in the temporal hierarchy of Manna
+  /// and Pnueli (PODC'90).
+  ///
+  /// The class is indicated using a character among:
+  /// - 'B' (bottom) safety properties that are also guarantee properties
+  /// - 'G' guarantee properties that are not also safety properties
+  /// - 'S' safety properties that are not also guarantee properties
+  /// - 'O' obligation properties that are not safety or guarantee
+  ///       properties
+  /// - 'P' persistence properties that are not obligations
+  /// - 'R' recurrence properties that are not obligations
+  /// - 'T' (top) properties that are not persistence or recurrence
+  ///   properties
+  SPOT_API char mp_class(formula f);
+}