array/varray: allow construction from containers

array/varray.hpp

@@ -40,13 +40,22 @@ namespace cruft {
           : m_data (std::data (rhs))
         { ; }
 
+
         varray (std::array<T,S> &&) = delete;
 
+
         //-------------------------------------------------------------------------
         varray (T (&_data)[S])
           : m_data (_data)
         { ; }
 
+
+        template <typename ContainerT>
+        varray (ContainerT &_container)
+          : varray (_container.data ())
+        { CHECK_GE (_container.size (), size ()); }
+
+
         //---------------------------------------------------------------------
         std::size_t size (void) const { return S; }