From 60a6fbbee332277c5b60e2dd45dfac9c64328de3 Mon Sep 17 00:00:00 2001
From: John Fletcher <J.P.Fletcher@aston.ac.uk>
Date: Wed, 4 Feb 2015 10:59:15 +0000
Subject: [PATCH] core/is_value and value.  Identify val() at run time

---
 include/boost/phoenix/core/is_value.hpp | 3 ++-
 include/boost/phoenix/core/value.hpp    | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/boost/phoenix/core/is_value.hpp b/include/boost/phoenix/core/is_value.hpp
index 4bd6a12..501d7e0 100644
--- a/include/boost/phoenix/core/is_value.hpp
+++ b/include/boost/phoenix/core/is_value.hpp
@@ -45,12 +45,13 @@ namespace boost { namespace phoenix
         : is_value<T>
     {};
 
+    // This does not seem to work.
+    // There is an alternative in value.hpp which does work.
     template <typename T>
     struct is_value< expression::value<T> >
         : mpl::true_
     {};
 
-
     template <typename T>
     bool is_val(T const &t)
     {
diff --git a/include/boost/phoenix/core/value.hpp b/include/boost/phoenix/core/value.hpp
index 30e1344..d2e8ce9 100644
--- a/include/boost/phoenix/core/value.hpp
+++ b/include/boost/phoenix/core/value.hpp
@@ -52,6 +52,12 @@ namespace boost { namespace phoenix
         return expression::value<T>::make(t);
     }
 
+    // Identifies this Expr as a value.
+    template <typename Expr>
+    struct is_value<actor<Expr>  >
+        : mpl::true_
+    {};
+
     // Call out actor for special handling
     template<typename Expr>
     struct is_custom_terminal<actor<Expr> >