From 9da5febf1d9af9f5cb62d5d35fc87136e6e4cd60 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Mon, 11 Apr 2016 09:20:49 +0200
Subject: Add basic support for variable value inheritance

Currently, only abs_dir_path inherits from dir_path.
---
 build2/variable.ixx | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

(limited to 'build2/variable.ixx')

diff --git a/build2/variable.ixx b/build2/variable.ixx
index e52a150..9b29608 100644
--- a/build2/variable.ixx
+++ b/build2/variable.ixx
@@ -81,17 +81,27 @@ namespace build2
   inline const T&
   cast (const value& v)
   {
-    assert (!v.null () && v.type == &value_traits<T>::value_type);
+    assert (!v.null ());
+
+    // Find base if any.
+    //
+    const value_type* b (v.type);
+    for (; b != nullptr && b != &value_traits<T>::value_type; b = b->base) ;
+    assert (b != nullptr);
+
     return *static_cast<const T*> (v.type->cast == nullptr
                                    ? static_cast<const void*> (&v.data_)
-                                   : v.type->cast (v));
+                                   : v.type->cast (v, b));
   }
 
   template <typename T>
   inline T&
   cast (value& v)
   {
-    return const_cast<T&> (cast<T> (static_cast<const value&> (v)));
+    assert (!v.null () && v.type == &value_traits<T>::value_type);
+    return *static_cast<T*> (v.type->cast == nullptr
+                             ? static_cast<void*> (&v.data_)
+                             : const_cast<void*> (v.type->cast (v, v.type)));
   }
 
   template <typename T>
-- 
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