* src/ltlvisit/clone.cc (clone): New const version.

* src/ltlvisit/clone.hh (clone): Likewise.
* src/ltlvisit/destroy.cc (destroy): New const version.
* src/ltlvisit/destroy.hh (destroy): Likewise.
* src/tgba/tgbabddconcretefactory.cc
(tgba_bdd_concrete_factory::create_state,
tgba_bdd_concrete_factory::create_atomic_prop,
tgba_bdd_concrete_factory::promise): Clone new formulae.
* src/tgba/tgbabdddict.cc (tgba_bdd_dict::tgba_bdd_dict,
tgba_bdd_dict::~tgba_bdd_dict, tgba_bdd_dict::operator=): New methods
that clone and destroy formulae.
* src/tgbatest/ltl2tgba.test, src/tgbatest/ltl2tgba.cc: New files.
* src/tgbatest/Makefile.am (check_PROGRAMS): Add ltl2tgba.
(ltl2tgba_SOURCES): New variable.
(TESTS): Add ltl2tgba.test.

src/ltlvisit/clone.cc

@@ -70,5 +70,10 @@ namespace spot
       return v.result();
     }
 
+    formula*
+    clone(const formula* f)
+    {
+      return clone(const_cast<formula*>(f));
+    }
   }
 }

src/ltlvisit/clone.hh

@@ -36,6 +36,8 @@ namespace spot
 
     /// \brief Clone a formula.
     formula* clone(formula* f);
+    /// \brief Clone a formula.
+    formula* clone(const formula* f);
   }
 }
 

src/ltlvisit/destroy.cc

@@ -16,10 +16,16 @@ namespace spot
     };
 
     void
-    destroy(formula *f)
+    destroy(formula* f)
     {
       destroy_visitor v;
       f->accept(v);
     }
+
+    void
+    destroy(const formula* f)
+    {
+      destroy(const_cast<formula*>(f));
+    }
   }
 }

src/ltlvisit/destroy.hh

@@ -9,6 +9,8 @@ namespace spot
   {
     /// \brief Destroys a formula
     void destroy(formula *f);
+    /// \brief Destroys a formula
+    void destroy(const formula *f);
   }
 }