Finalize Kripke interface.

* src/kripke/fairkripke.hh, src/kripke/fairkripke.cc,
* src/kripke/kripke.hh, src/kripke/kripke.cc: Finalize and
document the Kripke interface.  I have tested it by updating
checkpn to use it.

src/kripke/kripke.hh

@@ -1,4 +1,4 @@
-// Copyright (C) 2009 Laboratoire de Recherche et Developpement de l'Epita
+// Copyright (C) 2009, 2010 Laboratoire de Recherche et Developpement de l'Epita
 //
 // This file is part of Spot, a model checking library.
 //
@@ -25,14 +25,67 @@
 namespace spot
 {
 
-  typedef fair_kripke_succ_iterator kripke_succ_iterator;
+  /// \brief Iterator code for Kripke structure
+  /// \ingroup kripke
+  ///
+  /// This iterator can be used to simplify the writing
+  /// of an iterator on a Kripke structure (or lookalike).
+  ///
+  /// If you inherit from this iterator, you should only
+  /// redefine
+  ///
+  ///   - kripke_succ_iterator::first()
+  ///   - kripke_succ_iterator::next()
+  ///   - kripke_succ_iterator::done()
+  ///   - kripke_succ_iterator::current_state()
+  ///
+  /// This class implements kripke_succ_iterator::current_condition(),
+  /// and kripke_succ_iterator::current_acceptance_conditions().
+  class kripke_succ_iterator : public tgba_succ_iterator
+  {
+  public:
+    /// \brief Constructor
+    ///
+    /// The \a cond argument will be the one returned
+    /// by kripke_succ_iterator::current_condition().
+    kripke_succ_iterator(const bdd& cond);
+    virtual ~kripke_succ_iterator();
 
+    virtual bdd current_condition() const;
+    virtual bdd current_acceptance_conditions() const;
+  protected:
+    bdd cond_;
+  };
+
+  /// \brief Interface for a Kripke structure
+  /// \ingroup kripke
+  ///
+  /// A Kripke structure is a graph in which each node (=state) is
+  /// labeled by a conjunction of atomic proposition.
+  ///
+  /// Such a structure can be seen as spot::tgba without
+  /// any acceptance condition.
+  ///
+  /// A programmer that develops an instance of Kripke structure needs
+  /// just provide an implementation for the following methods:
+  ///
+  ///   - kripke::get_init_state()
+  ///   - kripke::succ_iter()
+  ///   - kripke::state_condition()
+  ///   - kripke::format_state()
+  ///   - and optionally kripke::transition_annotation()
+  ///
+  /// The other methods of the tgba interface (like those dealing with
+  /// acceptance conditions) are supplied by this kripke class and
+  /// need not be defined.
+  ///
+  /// See also spot::kripke_succ_iterator.
   class kripke: public fair_kripke
   {
   public:
     virtual ~kripke();
 
-    virtual bdd acceptance_conditions_of_state(const state* s) const;
+    virtual bdd state_acceptance_conditions(const state*) const;
     virtual bdd neg_acceptance_conditions() const;
     virtual bdd all_acceptance_conditions() const;
   };