From e44f1b89978ca291c63aa8302ddff118f00bfec6 Mon Sep 17 00:00:00 2001
From: Alexandre Duret-Lutz <adl@lrde.epita.fr>
Date: Sun, 8 Nov 2009 19:36:35 +0100
Subject: [PATCH] Make it possible to clone const formulae.

* src/ltlast/formula.hh, src/ltlast/formula.cc (clone): Declare
as const.
---
 ChangeLog             | 7 +++++++
 src/ltlast/formula.cc | 6 +++---
 src/ltlast/formula.hh | 2 +-
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index e5e44a709..e5d7390fe 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2009-11-08  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
+
+	Make it possible to clone const formulae.
+
+	* src/ltlast/formula.hh, src/ltlast/formula.cc (clone): Declare
+	as const.
+
 2009-11-08  Alexandre Duret-Lutz  <adl@lrde.epita.fr>
 
 	Rename formula::ref and formula::unref as formula::clone
diff --git a/src/ltlast/formula.cc b/src/ltlast/formula.cc
index c0c498e78..7cee80f7f 100644
--- a/src/ltlast/formula.cc
+++ b/src/ltlast/formula.cc
@@ -27,10 +27,10 @@ namespace spot
   namespace ltl
   {
     formula*
-    formula::clone()
+    formula::clone() const
     {
-      ref_();
-      return this;
+      const_cast<formula*>(this)->ref_();
+      return const_cast<formula*>(this);
     }
 
     formula::~formula()
diff --git a/src/ltlast/formula.hh b/src/ltlast/formula.hh
index 1667d7d1c..fb92a119a 100644
--- a/src/ltlast/formula.hh
+++ b/src/ltlast/formula.hh
@@ -80,7 +80,7 @@ namespace spot
       ///
       /// This increments the reference counter of this node (if one is
       /// used).
-      formula* clone();
+      formula* clone() const;
       /// \brief release this node
       ///
       /// This decrements the reference counter of this node (if one is