New style const capable visitors

25 files changed, 367 insertions, 465 deletions

diff --git a/paludis/all_dep_atom.cc b/paludis/all_dep_atom.cc
index 4db11fe..1e73d78 100644
--- a/paludis/all_dep_atom.cc
+++ b/paludis/all_dep_atom.cc
@@ -22,7 +22,6 @@
 #include "use_dep_atom.hh"
 #include "package_dep_atom.hh"
 #include "dep_atom_visitor.hh"
-#include "visitor_pattern-impl.hh"
 
 using namespace paludis;
 
diff --git a/paludis/all_dep_atom.hh b/paludis/all_dep_atom.hh
index 9d499e5..500786c 100644
--- a/paludis/all_dep_atom.hh
+++ b/paludis/all_dep_atom.hh
@@ -37,8 +37,9 @@ namespace paludis
      *
      * \ingroup DepResolver
      */
-    class AllDepAtom : public CompositeDepAtom,
-                       public Visitable<AllDepAtom, DepAtomVisitor>
+    class AllDepAtom :
+        public CompositeDepAtom,
+        public Visitable<AllDepAtom, DepAtomVisitorTypes>
     {
         public:
             /**
diff --git a/paludis/any_dep_atom.cc b/paludis/any_dep_atom.cc
index e2432b6..730b836 100644
--- a/paludis/any_dep_atom.cc
+++ b/paludis/any_dep_atom.cc
@@ -22,7 +22,6 @@
 #include "use_dep_atom.hh"
 #include "package_dep_atom.hh"
 #include "dep_atom_visitor.hh"
-#include "visitor_pattern-impl.hh"
 
 using namespace paludis;
 
diff --git a/paludis/any_dep_atom.hh b/paludis/any_dep_atom.hh
index 002471b..32412c2 100644
--- a/paludis/any_dep_atom.hh
+++ b/paludis/any_dep_atom.hh
@@ -21,6 +21,7 @@
 #define PALUDIS_GUARD_PALUDIS_ANY_DEP_ATOM_HH 1
 
 #include <paludis/composite_dep_atom.hh>
+#include <paludis/dep_atom_visitor.hh>
 
 /** \file
  * Declarations for AnyDepAtom.
@@ -30,15 +31,14 @@
 
 namespace paludis
 {
-    class DepAtomVisitor;
-
     /**
      * Represents a "|| ( )" dependency block.
      *
      * \ingroup DepResolver
      */
-    class AnyDepAtom : public CompositeDepAtom,
-                       public Visitable<AnyDepAtom, DepAtomVisitor>
+    class AnyDepAtom :
+        public CompositeDepAtom,
+        public Visitable<AnyDepAtom, DepAtomVisitorTypes>
     {
         public:
             /**
diff --git a/paludis/block_dep_atom.cc b/paludis/block_dep_atom.cc
index e0e94b4..b76947b 100644
--- a/paludis/block_dep_atom.cc
+++ b/paludis/block_dep_atom.cc
@@ -23,7 +23,6 @@
 #include "block_dep_atom.hh"
 #include "package_dep_atom.hh"
 #include "dep_atom_visitor.hh"
-#include "visitor_pattern-impl.hh"
 
 using namespace paludis;
 
diff --git a/paludis/block_dep_atom.hh b/paludis/block_dep_atom.hh
index 8709bcf..e515f45 100644
--- a/paludis/block_dep_atom.hh
+++ b/paludis/block_dep_atom.hh
@@ -22,6 +22,7 @@
 
 #include <paludis/dep_atom.hh>
 #include <paludis/package_dep_atom.hh>
+#include <paludis/dep_atom_visitor.hh>
 
 /** \file
  * Declarations for the BlockDepAtom class.
@@ -38,8 +39,9 @@ namespace paludis
      *
      * \ingroup DepResolver
      */
-    class BlockDepAtom : public DepAtom,
-                         public Visitable<BlockDepAtom, DepAtomVisitor>
+    class BlockDepAtom :
+        public DepAtom,
+        public Visitable<BlockDepAtom, DepAtomVisitorTypes>
     {
         private:
             PackageDepAtom::ConstPointer _atom;
diff --git a/paludis/dep_atom.hh b/paludis/dep_atom.hh
index 3100851..1029d47 100644
--- a/paludis/dep_atom.hh
+++ b/paludis/dep_atom.hh
@@ -20,7 +20,8 @@
 #ifndef PALUDIS_GUARD_PALUDIS_DEP_ATOM_HH
 #define PALUDIS_GUARD_PALUDIS_DEP_ATOM_HH 1
 
-#include <paludis/visitor_pattern.hh>
+#include <paludis/visitor.hh>
+#include <paludis/dep_atom_visitor.hh>
 #include <paludis/composite_pattern.hh>
 #include <paludis/instantiation_policy.hh>
 #include <paludis/counted_ptr.hh>
@@ -33,7 +34,6 @@
 
 namespace paludis
 {
-    class DepAtomVisitor;
     class CompositeDepAtom;
 
     /**
@@ -42,7 +42,7 @@ namespace paludis
      * \ingroup DepResolver
      */
     class DepAtom :
-        public virtual VisitableInterface<DepAtomVisitor>,
+        public virtual VisitableInterface<DepAtomVisitorTypes>,
         public virtual Composite<DepAtom, CompositeDepAtom>,
         private InstantiationPolicy<DepAtom, instantiation_method::NonCopyableTag>,
         public InternalCounted<DepAtom>
diff --git a/paludis/dep_atom_dumper.cc b/paludis/dep_atom_dumper.cc
index dd81d82..5eaa96c 100644
--- a/paludis/dep_atom_dumper.cc
+++ b/paludis/dep_atom_dumper.cc
@@ -25,9 +25,6 @@
 #include "dep_atom_visitor.hh"
 #include "dep_atom_dumper.hh"
 
-#include "visitor_pattern-impl.hh"
-#include "composite_visitor_pattern-impl.hh"
-
 using namespace paludis;
 
 DepAtomDumper::DepAtomDumper(std::ostream * const o) :
@@ -36,39 +33,33 @@ DepAtomDumper::DepAtomDumper(std::ostream * const o) :
 }
 
 void
-DepAtomDumper::enter(const AllDepAtom * const)
+DepAtomDumper::visit(const AllDepAtom * const a)
 {
     *_o << "<all>";
-}
-
-void
-DepAtomDumper::leave(const AllDepAtom * const)
-{
+    for (CompositeDepAtom::Iterator i(a->begin()), i_end(a->end()) ;
+            i != i_end ; ++i)
+        (*i)->accept(this);
     *_o << "</all>";
 }
 
 void
-DepAtomDumper::enter(const AnyDepAtom * const)
+DepAtomDumper::visit(const AnyDepAtom * const a)
 {
     *_o << "<any>";
-}
-
-void
-DepAtomDumper::leave(const AnyDepAtom * const)
-{
+    for (CompositeDepAtom::Iterator i(a->begin()), i_end(a->end()) ;
+            i != i_end ; ++i)
+        (*i)->accept(this);
     *_o << "</any>";
 }
 
 void
-DepAtomDumper::enter(const UseDepAtom * const f)
-{
-    *_o << "<use flag=\"" << f->flag() << "\" inverse=\""
-        << (f->inverse() ? "true" : "false") << "\">";
-}
-
-void
-DepAtomDumper::leave(const UseDepAtom * const)
+DepAtomDumper::visit(const UseDepAtom * const a)
 {
+    *_o << "<use flag=\"" << a->flag() << "\" inverse=\""
+        << (a->inverse() ? "true" : "false") << "\">";
+    for (CompositeDepAtom::Iterator i(a->begin()), i_end(a->end()) ;
+            i != i_end ; ++i)
+        (*i)->accept(this);
     *_o << "</use>";
 }
 
diff --git a/paludis/dep_atom_dumper.hh b/paludis/dep_atom_dumper.hh
index e8f9b3a..fbf20d3 100644
--- a/paludis/dep_atom_dumper.hh
+++ b/paludis/dep_atom_dumper.hh
@@ -33,11 +33,9 @@ namespace paludis
     /**
      * Dump dependency atoms to a stream in pseudo-XML form, for testing.
      */
-    class DepAtomDumper : public DepAtomVisitor,
-                          public VisitsComposite<DepAtomDumper, AllDepAtom>,
-                          public VisitsComposite<DepAtomDumper, AnyDepAtom>,
-                          public VisitsComposite<DepAtomDumper, UseDepAtom>,
-                          private InstantiationPolicy<DepAtomDumper, instantiation_method::NonCopyableTag>
+    class DepAtomDumper :
+        public DepAtomVisitorTypes::ConstVisitor,
+        private InstantiationPolicy<DepAtomDumper, instantiation_method::NonCopyableTag>
     {
         private:
             std::ostream * const _o;
@@ -48,14 +46,11 @@ namespace paludis
              */
             DepAtomDumper(std::ostream * const o);
 
-            void enter(const AllDepAtom * const);
-            void leave(const AllDepAtom * const);
+            void visit(const AllDepAtom * const);
 
-            void enter(const AnyDepAtom * const);
-            void leave(const AnyDepAtom * const);
+            void visit(const AnyDepAtom * const);
 
-            void enter(const UseDepAtom * const);
-            void leave(const UseDepAtom * const);
+            void visit(const UseDepAtom * const);
 
             void visit(const PackageDepAtom * const);
 
diff --git a/paludis/dep_atom_visitor.cc b/paludis/dep_atom_visitor.cc
index 404b795..3ed873f 100644
--- a/paludis/dep_atom_visitor.cc
+++ b/paludis/dep_atom_visitor.cc
@@ -21,10 +21,3 @@
 
 using namespace paludis;
 
-DepAtomVisitor::DepAtomVisitor()
-{
-}
-
-DepAtomVisitor::~DepAtomVisitor()
-{
-}
diff --git a/paludis/dep_atom_visitor.hh b/paludis/dep_atom_visitor.hh
index d241bab..ff12c45 100644
--- a/paludis/dep_atom_visitor.hh
+++ b/paludis/dep_atom_visitor.hh
@@ -20,15 +20,7 @@
 #ifndef PALUDIS_GUARD_PALUDIS_DEP_ATOM_VISITOR_HH
 #define PALUDIS_GUARD_PALUDIS_DEP_ATOM_VISITOR_HH 1
 
-#include <paludis/dep_atom.hh>
-#include <paludis/visitor_pattern.hh>
-#include <paludis/composite_visitor_pattern.hh>
-
-/** \file
- * Declarations for the DepAtomVisitor base class.
- *
- * \ingroup DepResolver
- */
+#include <paludis/visitor.hh>
 
 namespace paludis
 {
@@ -38,28 +30,8 @@ namespace paludis
     class UseDepAtom;
     class BlockDepAtom;
 
-    /**
-     * A DepAtomVisitor is a generic base class for traversing a DepAtom
-     * collection.
-     */
-    class DepAtomVisitor : public virtual Visits<PackageDepAtom>,
-                           public virtual Visits<AllDepAtom>,
-                           public virtual Visits<AnyDepAtom>,
-                           public virtual Visits<UseDepAtom>,
-                           public virtual Visits<BlockDepAtom>
-    {
-        protected:
-            /**
-             * Constructor.
-             */
-            DepAtomVisitor();
-
-        public:
-            /**
-             * Destructor.
-             */
-            virtual ~DepAtomVisitor();
-    };
+    typedef VisitorTypes<PackageDepAtom *, AllDepAtom *, AnyDepAtom *,
+            UseDepAtom *, BlockDepAtom *> DepAtomVisitorTypes;
 }
 
 #endif
diff --git a/paludis/dep_list.cc b/paludis/dep_list.cc
index c879c18..486ae6f 100644
--- a/paludis/dep_list.cc
+++ b/paludis/dep_list.cc
@@ -25,8 +25,6 @@
 #include "no_resolvable_option_error.hh"
 #include "circular_dependency_error.hh"
 #include "internal_error.hh"
-#include "visitor_pattern-impl.hh"
-#include "composite_visitor_pattern-impl.hh"
 #include "all_dep_atom.hh"
 #include "any_dep_atom.hh"
 #include "block_dep_atom.hh"
@@ -145,13 +143,11 @@ DepList::end() const
 }
 
 void
-DepList::enter(const AllDepAtom * const)
-{
-}
-
-void
-DepList::leave(const AllDepAtom * const)
+DepList::visit(const AllDepAtom * const v)
 {
+    for (CompositeDepAtom::Iterator i(v->begin()), i_end(v->end()) ;
+            i != i_end ; ++i)
+        (*i)->accept(this);
 }
 
 struct DepListEntryMatcher :
diff --git a/paludis/dep_list.hh b/paludis/dep_list.hh
index 5baaa1e..7bfc6e5 100644
--- a/paludis/dep_list.hh
+++ b/paludis/dep_list.hh
@@ -58,11 +58,8 @@ namespace paludis
     class DepList :
         private InstantiationPolicy<DepList, instantiation_method::NonCopyableTag>,
         private PrivateImplementationPattern<DepList>,
-        protected DepAtomVisitor,
-        protected VisitsComposite<DepList, AllDepAtom>
+        protected DepAtomVisitorTypes::ConstVisitor
     {
-        friend class VisitsComposite<DepList, AllDepAtom>;
-
         private:
             void _add_in_role(DepAtom::ConstPointer, const std::string & role);
 
@@ -71,9 +68,7 @@ namespace paludis
             void visit(const UseDepAtom * const);
             void visit(const AnyDepAtom * const);
             void visit(const BlockDepAtom * const);
-
-            void enter(const AllDepAtom * const);
-            void leave(const AllDepAtom * const);
+            void visit(const AllDepAtom * const);
 
         public:
             /**
diff --git a/paludis/files.m4 b/paludis/files.m4
index c62bf8c..361e2a6 100644
--- a/paludis/files.m4
+++ b/paludis/files.m4
@@ -19,7 +19,6 @@ add(`circular_dependency_error',         `hh', `cc')
 add(`comparison_policy',                 `hh', `cc', `test')
 add(`composite_dep_atom',                `hh', `cc')
 add(`composite_pattern',                 `hh', `cc')
-add(`composite_visitor_pattern',         `hh', `cc', `impl')
 add(`config_file',                       `hh', `cc', `test')
 add(`config_file_error',                 `hh', `cc')
 add(`container_entry',                   `hh', `cc', `test')
@@ -116,5 +115,5 @@ add(`version_metadata',                  `hh', `cc')
 add(`version_operator',                  `hh', `cc', `test')
 add(`version_spec',                      `hh', `cc', `test')
 add(`version_spec_collection',           `hh', `cc')
-add(`visitor_pattern',                   `hh', `cc', `impl', `test')
+add(`visitor',                           `hh', `cc', `test')
 
diff --git a/paludis/package_dep_atom.cc b/paludis/package_dep_atom.cc
index abc2d50..fa4f732 100644
--- a/paludis/package_dep_atom.cc
+++ b/paludis/package_dep_atom.cc
@@ -26,8 +26,6 @@
 #include "package_dep_atom.hh"
 #include "dep_atom_visitor.hh"
 
-#include "visitor_pattern-impl.hh"
-
 using namespace paludis;
 
 PackageDepAtom::PackageDepAtom(const QualifiedPackageName & package) :
diff --git a/paludis/package_dep_atom.hh b/paludis/package_dep_atom.hh
index 1b3b7a6..8dc4936 100644
--- a/paludis/package_dep_atom.hh
+++ b/paludis/package_dep_atom.hh
@@ -25,6 +25,7 @@
 #include <paludis/version_operator.hh>
 #include <paludis/slot_name.hh>
 #include <paludis/version_spec.hh>
+#include <paludis/dep_atom_visitor.hh>
 #include <ostream>
 
 /** \file
@@ -42,8 +43,9 @@ namespace paludis
      *
      * \ingroup DepResolver
      */
-    class PackageDepAtom : public DepAtom,
-                           public Visitable<PackageDepAtom, DepAtomVisitor>
+    class PackageDepAtom :
+        public DepAtom,
+        public Visitable<PackageDepAtom, DepAtomVisitorTypes>
     {
         private:
             QualifiedPackageName _package;
diff --git a/paludis/use_dep_atom.cc b/paludis/use_dep_atom.cc
index a9de5f4..3448b64 100644
--- a/paludis/use_dep_atom.cc
+++ b/paludis/use_dep_atom.cc
@@ -23,8 +23,6 @@
 #include "package_dep_atom.hh"
 #include "dep_atom_visitor.hh"
 
-#include "visitor_pattern-impl.hh"
-
 using namespace paludis;
 
 UseDepAtom::UseDepAtom(const UseFlagName & flag, bool inverse) :
diff --git a/paludis/use_dep_atom.hh b/paludis/use_dep_atom.hh
index 37de86e..c1dc54b 100644
--- a/paludis/use_dep_atom.hh
+++ b/paludis/use_dep_atom.hh
@@ -22,6 +22,7 @@
 
 #include <paludis/composite_dep_atom.hh>
 #include <paludis/use_flag_name.hh>
+#include <paludis/dep_atom_visitor.hh>
 
 /** \file
  * Declarations for the UseDepAtom class.
@@ -31,15 +32,14 @@
 
 namespace paludis
 {
-    class DepAtomVisitor;
-
     /**
      * Represents a use? ( ) dependency atom.
      *
      * \ingroup DepResolver
      */
-    class UseDepAtom : public CompositeDepAtom,
-                       public Visitable<UseDepAtom, DepAtomVisitor>
+    class UseDepAtom :
+        public CompositeDepAtom,
+        public Visitable<UseDepAtom, DepAtomVisitorTypes>
     {
         private:
             const UseFlagName _flag;
diff --git a/paludis/visitor.cc b/paludis/visitor.cc
new file mode 100644
index 0000000..ffeab02
--- /dev/null
+++ b/paludis/visitor.cc
@@ -0,0 +1,4 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+#include "visitor.hh"
+
diff --git a/paludis/visitor.hh b/paludis/visitor.hh
new file mode 100644
index 0000000..639c0e7
--- /dev/null
+++ b/paludis/visitor.hh
@@ -0,0 +1,158 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2006 Ciaran McCreesh <ciaranm@gentoo.org>
+ *
+ * This file is part of the Paludis package manager. Paludis 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
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Paludis 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, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef PALUDIS_GUARD_PALUDIS_VISITOR_HH
+#define PALUDIS_GUARD_PALUDIS_VISITOR_HH 1
+
+namespace paludis
+{
+    template <typename NodePtrType_>
+    class Visits;
+
+    namespace visitor_internals
+    {
+        template <unsigned n_>
+        struct NoType
+        {
+        };
+
+        template <typename>
+        struct MakePointerToConst;
+
+        template <typename T_>
+        struct MakePointerToConst<T_ *>
+        {
+            typedef const T_ * Type;
+        };
+    }
+
+    template <typename VisitorType_>
+    class VisitableInterface
+    {
+        protected:
+            virtual ~VisitableInterface()
+            {
+            }
+
+        public:
+            virtual void accept(typename VisitorType_::Visitor * const) = 0;
+
+            virtual void accept(typename VisitorType_::ConstVisitor * const) const = 0;
+    };
+
+    template <typename OurType_, typename VisitorType_>
+    class Visitable :
+        public virtual VisitableInterface<VisitorType_>
+    {
+        protected:
+            ~Visitable()
+            {
+            }
+
+        public:
+            virtual void accept(typename VisitorType_::Visitor * const v)
+            {
+                static_cast<Visits<OurType_ *> *>(v)->visit(
+                        static_cast<OurType_ *>(this));
+            }
+
+            virtual void accept(typename VisitorType_::ConstVisitor * const v) const
+            {
+                static_cast<Visits<const OurType_ *> *>(v)->visit(
+                        static_cast<const OurType_ *>(this));
+            }
+    };
+
+    template <typename NodePtrType_>
+    class Visits
+    {
+        protected:
+            virtual ~Visits()
+            {
+            }
+
+        public:
+            virtual void visit(NodePtrType_ const) = 0;
+    };
+
+    template <unsigned n_>
+    class Visits<const visitor_internals::NoType<n_> * >
+    {
+        protected:
+            virtual ~Visits()
+            {
+            }
+    };
+
+    template <unsigned n_>
+    class Visits<visitor_internals::NoType<n_> * >
+    {
+        protected:
+            virtual ~Visits()
+            {
+            }
+    };
+
+    template <
+        typename N1_,
+        typename N2_ = visitor_internals::NoType<2> *,
+        typename N3_ = visitor_internals::NoType<3> *,
+        typename N4_ = visitor_internals::NoType<4> *,
+        typename N5_ = visitor_internals::NoType<5> *,
+        typename N6_ = visitor_internals::NoType<6> *,
+        typename N7_ = visitor_internals::NoType<7> *,
+        typename N8_ = visitor_internals::NoType<8> *,
+        typename N9_ = visitor_internals::NoType<9> *>
+    class VisitorTypes
+    {
+        private:
+            VisitorTypes();
+
+
+        public:
+            class ConstVisitor :
+                public Visits<typename visitor_internals::MakePointerToConst<N1_>::Type>,
+                public Visits<typename visitor_internals::MakePointerToConst<N2_>::Type>,
+                public Visits<typename visitor_internals::MakePointerToConst<N3_>::Type>,
+                public Visits<typename visitor_internals::MakePointerToConst<N4_>::Type>,
+                public Visits<typename visitor_internals::MakePointerToConst<N5_>::Type>,
+                public Visits<typename visitor_internals::MakePointerToConst<N6_>::Type>,
+                public Visits<typename visitor_internals::MakePointerToConst<N7_>::Type>,
+                public Visits<typename visitor_internals::MakePointerToConst<N8_>::Type>,
+                public Visits<typename visitor_internals::MakePointerToConst<N9_>::Type>
+            {
+            };
+
+            class Visitor :
+                public Visits<N1_>,
+                public Visits<N2_>,
+                public Visits<N3_>,
+                public Visits<N4_>,
+                public Visits<N5_>,
+                public Visits<N6_>,
+                public Visits<N7_>,
+                public Visits<N8_>,
+                public Visits<N9_>
+            {
+            };
+    };
+}
+
+#endif
diff --git a/paludis/visitor_TEST.cc b/paludis/visitor_TEST.cc
new file mode 100644
index 0000000..a5dbbce
--- /dev/null
+++ b/paludis/visitor_TEST.cc
@@ -0,0 +1,153 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2006 Ciaran McCreesh <ciaranm@gentoo.org>
+ *
+ * This file is part of the Paludis package manager. Paludis 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
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Paludis 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, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "visitor.hh"
+#include "deleter.hh"
+#include "indirect_iterator.hh"
+#include <test/test_framework.hh>
+#include <test/test_runner.hh>
+#include <vector>
+#include <algorithm>
+
+using namespace paludis;
+using namespace test;
+
+class Node;
+class FooNode;
+class BarNode;
+
+typedef VisitorTypes<FooNode *, BarNode *> NodeVisitorTypes;
+
+struct Node :
+    virtual VisitableInterface<NodeVisitorTypes>
+{
+};
+
+struct FooNode :
+    Node,
+    Visitable<FooNode, NodeVisitorTypes>
+{
+    std::string c_foo() const
+    {
+        return "c_foo";
+    }
+
+    std::string foo()
+    {
+        return "foo";
+    }
+};
+
+struct BarNode :
+    Node,
+    Visitable<BarNode, NodeVisitorTypes>
+{
+    std::string c_bar() const
+    {
+        return "c_bar";
+    }
+
+    std::string bar()
+    {
+        return "bar";
+    }
+};
+
+struct NodeCVisitor :
+    NodeVisitorTypes::ConstVisitor
+{
+    std::string r;
+
+    virtual void visit(const FooNode * const f)
+    {
+        r.append(f->c_foo());
+    }
+
+    virtual void visit(const BarNode * const b)
+    {
+        r.append(b->c_bar());
+    }
+};
+
+struct NodeVisitor :
+    NodeVisitorTypes::Visitor
+{
+    std::string r;
+
+    virtual void visit(FooNode * const f)
+    {
+        r.append(f->foo());
+    }
+
+    virtual void visit(BarNode * const b)
+    {
+        r.append(b->bar());
+    }
+};
+
+namespace test_cases
+{
+    struct ConstVisitorTest : TestCase
+    {
+        ConstVisitorTest() : TestCase("const visitor") { }
+
+        void run()
+        {
+            std::vector<Node *> v;
+
+            v.push_back(new FooNode);
+            v.push_back(new BarNode);
+            v.push_back(new FooNode);
+
+            NodeCVisitor c;
+            TEST_CHECK_EQUAL(c.r, "");
+            for (IndirectIterator<std::vector<Node *>::const_iterator, Node>
+                    i(v.begin()), i_end(v.end()) ; i != i_end ; ++i)
+                i->accept(&c);
+            TEST_CHECK_EQUAL(c.r, "c_fooc_barc_foo");
+
+            std::for_each(v.begin(), v.end(), Deleter());
+        }
+    } test_const_visitor;
+
+    struct VisitorTest : TestCase
+    {
+        VisitorTest() : TestCase("visitor") { }
+
+        void run()
+        {
+            std::vector<Node *> v;
+
+            v.push_back(new FooNode);
+            v.push_back(new BarNode);
+            v.push_back(new FooNode);
+
+            NodeVisitor c;
+            TEST_CHECK_EQUAL(c.r, "");
+            for (IndirectIterator<std::vector<Node *>::iterator, Node>
+                    i(v.begin()), i_end(v.end()) ; i != i_end ; ++i)
+                i->accept(&c);
+            TEST_CHECK_EQUAL(c.r, "foobarfoo");
+
+            std::for_each(v.begin(), v.end(), Deleter());
+        }
+    } test_visitor;
+}
+
diff --git a/paludis/visitor_pattern-impl.hh b/paludis/visitor_pattern-impl.hh
deleted file mode 100644
index e1f5392..0000000
--- a/paludis/visitor_pattern-impl.hh
+++ /dev/null
@@ -1,34 +0,0 @@
-/* vim: set sw=4 sts=4 et foldmethod=syntax : */
-
-/*
- * Copyright (c) 2005, 2006 Ciaran McCreesh <ciaranm@gentoo.org>
- *
- * This file is part of the Paludis package manager. Paludis is free software;
- * you can redistribute it and/or modify it under the terms of the GNU General
- * Public License version 2, as published by the Free Software Foundation.
- *
- * Paludis 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, write to the Free Software Foundation, Inc., 59 Temple
- * Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#ifndef PALUDIS_GUARD_PALUDIS_VISITOR_PATTERN_IMPL_HH
-#define PALUDIS_GUARD_PALUDIS_VISITOR_PATTERN_IMPL_HH 1
-
-namespace paludis
-{
-    template <typename VOurType_, typename VVisitorType_>
-    void
-    Visitable<VOurType_, VVisitorType_>::accept(VVisitorType_ * const v) const
-    {
-        static_cast<Visits<VOurType_> *>(v)->visit(
-                static_cast<const VOurType_ *>(this));
-    }
-}
-
-#endif
diff --git a/paludis/visitor_pattern.cc b/paludis/visitor_pattern.cc
deleted file mode 100644
index f069ab1..0000000
--- a/paludis/visitor_pattern.cc
+++ /dev/null
@@ -1,21 +0,0 @@
-/* vim: set sw=4 sts=4 et foldmethod=syntax : */
-
-/*
- * Copyright (c) 2005, 2006 Ciaran McCreesh <ciaranm@gentoo.org>
- *
- * This file is part of the Paludis package manager. Paludis is free software;
- * you can redistribute it and/or modify it under the terms of the GNU General
- * Public License version 2, as published by the Free Software Foundation.
- *
- * Paludis 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, write to the Free Software Foundation, Inc., 59 Temple
- * Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#include "visitor_pattern.hh"
-
diff --git a/paludis/visitor_pattern.hh b/paludis/visitor_pattern.hh
deleted file mode 100644
index c4091ac..0000000
--- a/paludis/visitor_pattern.hh
+++ /dev/null
@@ -1,105 +0,0 @@
-/* vim: set sw=4 sts=4 et foldmethod=syntax : */
-
-/*
- * Copyright (c) 2005, 2006 Ciaran McCreesh <ciaranm@gentoo.org>
- *
- * This file is part of the Paludis package manager. Paludis is free software;
- * you can redistribute it and/or modify it under the terms of the GNU General
- * Public License version 2, as published by the Free Software Foundation.
- *
- * Paludis 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, write to the Free Software Foundation, Inc., 59 Temple
- * Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#ifndef PALUDIS_GUARD_PALUDIS_VISITOR_PATTERN_HH
-#define PALUDIS_GUARD_PALUDIS_VISITOR_PATTERN_HH 1
-
-/** \file
- * Declarations for the Visits, Visitable and VisitableInterface
- * class templates. You must also include visitor_pattern-impl.hh in
- * any implementation files that define subclasses of VisitsComposite
- * or Visitable.
- *
- * \ingroup Utility
- */
-
-namespace paludis
-{
-    /**
-     * Declares that a class can visit a node of type NodeType_.
-     *
-     * \ingroup Utility
-     */
-    template <typename NodeType_>
-    class Visits
-    {
-        public:
-            /**
-             * Interface: visit a node.
-             */
-            virtual void visit(const NodeType_ * const) = 0;
-
-            /**
-             * Destructor.
-             */
-            virtual ~Visits()
-            {
-            }
-    };
-
-    /**
-     * Declare a class visitable by VIVisitorType_. Used in abstract base
-     * classes that define a visitable interface but are not themselves
-     * visitable. Should be inherited virtually.
-     *
-     * \ingroup Utility
-     */
-    template <typename VIVisitorType_>
-    class VisitableInterface
-    {
-        public:
-            /**
-             * Interface: accept a visitor.
-             */
-            virtual void accept(VIVisitorType_ * const) const = 0;
-
-            /**
-             * Destructor
-             */
-            virtual ~VisitableInterface()
-            {
-            }
-    };
-
-    /**
-     * Declare a class of type VOurType_ visitable by VVisitorType_. Should
-     * not use virtual inheritance. Can be used in child classes of an
-     * abstract base class that uses VisitableInterface.
-     *
-     * \ingroup Utility
-     */
-    template <typename VOurType_, typename VVisitorType_>
-    class Visitable : public virtual VisitableInterface<VVisitorType_>
-    {
-        public:
-            /**
-             * Accept a visitor.
-             */
-            virtual void accept(VVisitorType_ * const v) const;
-
-            /**
-             * Destructor.
-             */
-            virtual ~Visitable()
-            {
-            }
-    };
-}
-
-#endif
diff --git a/paludis/visitor_pattern_TEST.cc b/paludis/visitor_pattern_TEST.cc
deleted file mode 100644
index 7d663d8..0000000
--- a/paludis/visitor_pattern_TEST.cc
+++ /dev/null
@@ -1,192 +0,0 @@
-/* vim: set sw=4 sts=4 et foldmethod=syntax : */
-
-/*
- * Copyright (c) 2005, 2006 Ciaran McCreesh <ciaranm@gentoo.org>
- *
- * This file is part of the Paludis package manager. Paludis is free software;
- * you can redistribute it and/or modify it under the terms of the GNU General
- * Public License version 2, as published by the Free Software Foundation.
- *
- * Paludis 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, write to the Free Software Foundation, Inc., 59 Temple
- * Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-#include "visitor_pattern.hh"
-#include "visitor_pattern-impl.hh"
-#include "deleter.hh"
-#include <test/test_runner.hh>
-#include <test/test_framework.hh>
-#include <list>
-#include <algorithm>
-#include <sstream>
-
-using namespace test;
-using namespace paludis;
-
-/** \file
- * Tests for visitor_pattern.hh .
- *
- * \ingroup Test
- */
-
-#ifndef DOXYGEN
-
-class MyVisitorBase;
-
-class MyBaseClass : public virtual VisitableInterface<MyVisitorBase>
-{
-    protected:
-        MyBaseClass()
-        {
-        }
-};
-
-class MyClassOne : public MyBaseClass,
-                   public Visitable<MyClassOne, MyVisitorBase>
-{
-    public:
-        MyClassOne()
-        {
-        }
-
-        int get_one_thing() const
-        {
-            return 1;
-        }
-};
-
-class MyClassTwo : public MyBaseClass,
-                   public Visitable<MyClassTwo, MyVisitorBase>
-{
-    public:
-        MyClassTwo()
-        {
-        }
-
-        std::string get_two_thing() const
-        {
-            return "two";
-        }
-};
-
-class MyClassThree : public MyBaseClass,
-                     public Visitable<MyClassThree, MyVisitorBase>
-{
-    public:
-        MyClassThree()
-        {
-        }
-};
-
-class MyVisitorBase : public Visits<MyClassOne>,
-                      public Visits<MyClassTwo>,
-                      public Visits<MyClassThree>
-{
-    protected:
-        MyVisitorBase()
-        {
-        }
-};
-
-class MyStringifyVisitor : public MyVisitorBase
-{
-    private:
-        std::stringstream s;
-
-    public:
-        MyStringifyVisitor()
-        {
-        }
-
-        void visit(const MyClassOne * const one)
-        {
-            s << one->get_one_thing();
-        }
-
-        void visit(const MyClassTwo * const two)
-        {
-            s << two->get_two_thing();
-        }
-
-        void visit(const MyClassThree * const)
-        {
-            s << "---";
-        }
-
-        std::string value() const
-        {
-            return s.str();
-        }
-};
-
-class MyCountingVisitor : public MyVisitorBase
-{
-    private:
-        int _value;
-
-    public:
-        MyCountingVisitor() :
-            _value(0)
-        {
-        }
-
-        void visit(const MyClassOne * const)
-        {
-            _value += 1;
-        }
-
-        void visit(const MyClassTwo * const)
-        {
-            _value += 2;
-        }
-
-        void visit(const MyClassThree * const)
-        {
-            _value += 3;
-        }
-
-        int value() const
-        {
-            return _value;
-        }
-};
-
-#endif
-
-namespace test_cases
-{
-    /**
-     * \test Test visitor pattern.
-     *
-     * \ingroup Test
-     */
-    struct VisitorTest : TestCase
-    {
-        VisitorTest() : TestCase("visitor") { }
-
-        void run()
-        {
-            std::list<MyBaseClass *> items;
-            items.push_back(new MyClassOne);
-            items.push_back(new MyClassTwo);
-            items.push_back(new MyClassThree);
-            items.push_back(new MyClassOne);
-
-            MyStringifyVisitor v;
-            std::for_each(items.begin(), items.end(), std::bind2nd(std::mem_fun(&MyBaseClass::accept), &v));
-            TEST_CHECK_EQUAL(v.value(), "1two---1");
-
-            MyCountingVisitor c;
-            std::for_each(items.begin(), items.end(), std::bind2nd(std::mem_fun(&MyBaseClass::accept), &c));
-            TEST_CHECK_EQUAL(c.value(), 1 + 2 + 3 + 1);
-
-            std::for_each(items.begin(), items.end(), Deleter());
-        }
-    } test_visitor;
-}