scc_info: add Python bindings

Related to #172, where we discussed that scc_info bindings were
missing.

* spot/twaalgos/sccinfo.hh (spot::scc_info::scc_node): Move...
(spot::scc_info_node): ... here to help Swig.
* python/spot/impl.i: Add bindings for scc_info.
* tests/python/sccinfo.py: New file.
* tests/Makefile.am: Add it.

python/spot/impl.i

@@ -133,6 +133,7 @@
 #include <spot/twaalgos/neverclaim.hh>
 #include <spot/twaalgos/randomize.hh>
 #include <spot/twaalgos/remfin.hh>
+#include <spot/twaalgos/sccinfo.hh>
 #include <spot/twaalgos/strength.hh>
 #include <spot/twaalgos/sccfilter.hh>
 #include <spot/twaalgos/stats.hh>
@@ -533,6 +534,9 @@ def state_is_accepting(self, src) -> "bool":
 %include <spot/twaalgos/neverclaim.hh>
 %include <spot/twaalgos/randomize.hh>
 %include <spot/twaalgos/remfin.hh>
+%traits_swigtype(spot::scc_info_node);
+%fragment(SWIG_Traits_frag(spot::scc_info_node));
+%include <spot/twaalgos/sccinfo.hh>
 %include <spot/twaalgos/strength.hh>
 %include <spot/twaalgos/sccfilter.hh>
 %include <spot/twaalgos/stats.hh>
@@ -778,6 +782,14 @@ def state_is_accepting(self, src) -> "bool":
       throw std::runtime_error
         ("universal destinations should be explored with univ_dest()");
   }
+ }
+
+%extend spot::scc_info {
+  swig::SwigPyIterator* __iter__(PyObject **PYTHON_SELF)
+   {
+      return swig::make_forward_iterator(self->begin(), self->begin(),
+                                         self->end(), *PYTHON_SELF);
+   }
 }
 
 %extend spot::acc_cond::acc_code {

spot/twaalgos/sccinfo.hh

@@ -1,6 +1,6 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2014, 2015, 2016 Laboratoire de Recherche et
+// Copyright (C) 2014-2017 Laboratoire de Recherche et Développement
-// Développement de l'Epita.
+// de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
 //
@@ -24,6 +24,79 @@
 
 namespace spot
 {
+
+  /// Storage for SCC related information.
+  class SPOT_API scc_info_node
+  {
+  public:
+    typedef std::vector<unsigned> scc_succs;
+    friend class scc_info;
+  protected:
+    scc_succs succ_;
+    acc_cond::mark_t acc_;
+    std::vector<unsigned> states_; // States of the component
+    bool trivial_:1;
+    bool accepting_:1;        // Necessarily accepting
+    bool rejecting_:1;        // Necessarily rejecting
+    bool useful_:1;
+  public:
+    scc_info_node():
+      acc_(0U), trivial_(true), accepting_(false),
+      rejecting_(false), useful_(false)
+    {
+    }
+
+    scc_info_node(acc_cond::mark_t acc, bool trivial):
+      acc_(acc), trivial_(trivial), accepting_(false),
+      rejecting_(false), useful_(false)
+    {
+    }
+
+    bool is_trivial() const
+    {
+      return trivial_;
+    }
+
+    /// \brief True if we are sure that the SCC is accepting
+    ///
+    /// Note that both is_accepting() and is_rejecting() may return
+    /// false if an SCC interesects a mix of Fin and Inf sets.
+    bool is_accepting() const
+    {
+      return accepting_;
+    }
+
+    // True if we are sure that the SCC is rejecting
+    ///
+    /// Note that both is_accepting() and is_rejecting() may return
+    /// false if an SCC interesects a mix of Fin and Inf sets.
+    bool is_rejecting() const
+    {
+      return rejecting_;
+    }
+
+    bool is_useful() const
+    {
+      return useful_;
+    }
+
+    acc_cond::mark_t acc_marks() const
+    {
+      return acc_;
+    }
+
+    const std::vector<unsigned>& states() const
+    {
+      return states_;
+    }
+
+    const scc_succs& succ() const
+    {
+      return succ_;
+    }
+  };
+
+
   /// \brief Compute an SCC map and gather assorted information.
   ///
   /// This takes twa_graph as input and compute its SCCs.  This
@@ -39,75 +112,10 @@ namespace spot
   class SPOT_API scc_info
   {
   public:
-    typedef std::vector<unsigned> scc_succs;
+    // scc_node used to be an inner class, but Swig 3.0.10 does not
-
+    // support that yet.
-    class scc_node
+    typedef scc_info_node scc_node;
-    {
+    typedef scc_info_node::scc_succs scc_succs;
-      friend class scc_info;
-    protected:
-      scc_succs succ_;
-      acc_cond::mark_t acc_;
-      std::vector<unsigned> states_; // States of the component
-      bool trivial_:1;
-      bool accepting_:1;        // Necessarily accepting
-      bool rejecting_:1;        // Necessarily rejecting
-      bool useful_:1;
-    public:
-      scc_node():
-        acc_(0U), trivial_(true), accepting_(false),
-        rejecting_(false), useful_(false)
-      {
-      }
-
-      scc_node(acc_cond::mark_t acc, bool trivial):
-        acc_(acc), trivial_(trivial), accepting_(false),
-        rejecting_(false), useful_(false)
-      {
-      }
-
-      bool is_trivial() const
-      {
-        return trivial_;
-      }
-
-      /// \brief True if we are sure that the SCC is accepting
-      ///
-      /// Note that both is_accepting() and is_rejecting() may return
-      /// false if an SCC interesects a mix of Fin and Inf sets.
-      bool is_accepting() const
-      {
-        return accepting_;
-      }
-
-      // True if we are sure that the SCC is rejecting
-      ///
-      /// Note that both is_accepting() and is_rejecting() may return
-      /// false if an SCC interesects a mix of Fin and Inf sets.
-      bool is_rejecting() const
-      {
-        return rejecting_;
-      }
-
-      bool is_useful() const
-      {
-        return useful_;
-      }
-
-      acc_cond::mark_t acc_marks() const
-      {
-        return acc_;
-      }
-
-      const std::vector<unsigned>& states() const
-      {
-        return states_;
-      }
-
-      const scc_succs& succ() const
-      {
-        return succ_;
-      }
-    };
 
   protected:
 
@@ -146,18 +154,35 @@ namespace spot
       return sccof_[st];
     }
 
-    auto begin() const
+    std::vector<scc_node>::const_iterator begin() const
-      SPOT_RETURN(node_.begin());
+    {
-    auto end() const
+      return node_.begin();
-      SPOT_RETURN(node_.end());
+    }
-    auto cbegin() const
+
-      SPOT_RETURN(node_.cbegin());
+    std::vector<scc_node>::const_iterator end() const
-    auto cend() const
+    {
-      SPOT_RETURN(node_.cend());
+      return node_.end();
-    auto rbegin() const
+    }
-      SPOT_RETURN(node_.rbegin());
+
-    auto rend() const
+    std::vector<scc_node>::const_iterator cbegin() const
-      SPOT_RETURN(node_.rend());
+    {
+      return node_.cbegin();
+    }
+
+    std::vector<scc_node>::const_iterator cend() const
+    {
+      return node_.cend();
+    }
+
+    std::vector<scc_node>::const_reverse_iterator rbegin() const
+    {
+      return node_.rbegin();
+    }
+
+    std::vector<scc_node>::const_reverse_iterator rend() const
+    {
+      return node_.rend();
+    }
 
     const std::vector<unsigned>& states_of(unsigned scc) const
     {

tests/Makefile.am

@@ -331,6 +331,7 @@ TESTS_python = \
   python/alternating.py \
   python/bddnqueen.py \
   python/bugdet.py \
+  python/sccinfo.py \
   python/implies.py \
   python/interdep.py \
   python/ltl2tgba.test \

tests/python/sccinfo.py

@@ -0,0 +1,66 @@
+#!/usr/bin/python3
+# -*- mode: python; coding: utf-8 -*-
+# Copyright (C) 2017 Laboratoire de Recherche et Développement de
+# l'EPITA.
+#
+# 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/>.
+
+import spot
+
+a = spot.translate('(Ga -> Gb) W c')
+
+si = spot.scc_info(a)
+n = si.scc_count()
+assert n == 4
+
+acc = 0
+rej = 0
+triv = 0
+for i in range(n):
+    acc += si.is_accepting_scc(i)
+    rej += si.is_rejecting_scc(i)
+    triv += si.is_trivial(i)
+assert acc == 3
+assert rej == 1
+assert triv == 0
+
+for scc in si:
+    acc -= scc.is_accepting()
+    rej -= scc.is_rejecting()
+    triv -= scc.is_trivial()
+assert acc == 0
+assert rej == 0
+assert triv == 0
+
+l0 = si.states_of(0)
+l1 = si.states_of(1)
+l2 = si.states_of(2)
+l3 = si.states_of(3)
+l = sorted(list(l0) + list(l1) + list(l2) + list(l3))
+assert l == [0, 1, 2, 3, 4]
+
+i = si.initial()
+todo = {i}
+seen = {i}
+while todo:
+    e = todo.pop()
+    for s in si.succ(e):
+        if s not in seen:
+            seen.add(s)
+            todo.add(s)
+assert seen == {0, 1, 2, 3}
+
+assert not spot.is_weak_automaton(a, si)