Add a 'Base' type to RecursiveASTVisitor to make recursing easier and document

how you're supposed to use it.

llvm-svn: 103993

1 files changed, 7 insertions, 4 deletions

diff --git a/clang/include/clang/AST/RecursiveASTVisitor.h b/clang/include/clang/AST/RecursiveASTVisitor.h
index 36b151ddf34..1b2f3a79ddb 100644
--- a/clang/include/clang/AST/RecursiveASTVisitor.h
+++ b/clang/include/clang/AST/RecursiveASTVisitor.h
@@ -40,14 +40,17 @@ return static_cast<Derived*>(this)->Visit ## NAME(static_cast<CLASS*>(Var))
    *
    * Clients of this visitor should subclass the visitor (providing themselves
    * as the template argument, using the curiously recurring template pattern)
-   * and override any of the Visit* methods for declaration, type, statement, 
-   * expression, or other AST nodes where the visitor should customize 
-   * behavior. Returning "true" from one of these overridden functions will
-   * abort the traversal.
+   * and override any of the Visit* methods for declaration, type, statement,
+   * expression, or other AST nodes where the visitor should customize
+   * behavior.  Returning "true" from one of these overridden functions will
+   * abort the entire traversal.  An overridden Visit* method will not descend
+   * further into the AST for that node unless Base::Visit* is called.
    */
   template<typename Derived>
   class RecursiveASTVisitor {
   public:
+    typedef RecursiveASTVisitor<Derived> Base;
+
     /// \brief Return a reference to the derived class.
     Derived &getDerived() { return *static_cast<Derived*>(this); }