Implement nested id support

Now the 'id' specifier can optionally include the data member path
to the id inside the composite value. For example:

#pragma db id(first)
std::pair<int, int> p;

Note that one somewhat counter-intuitive aspect of this new feature
is that the whole member marked with id ('p' in the above example)
and not just the actual id member ('p.first' in the above example)
is treated as readonly.

Such nested id also cannot be automatically assigned (auto specifier).

1 files changed, 4 insertions, 4 deletions

diff --git a/odb/header.cxx b/odb/header.cxx
index 0a01311..2155ed8 100644
--- a/odb/header.cxx
+++ b/odb/header.cxx
@@ -60,9 +60,10 @@ traverse_object (type& c)
 {
   using semantics::data_member;
 
-  data_member* id (id_member (c));
+  data_member_path* id (id_member (c));
+  data_member* idf (id ? id->front () : 0);
   bool auto_id (id && auto_ (*id));
-  bool base_id (id && &id->scope () != &c); // Comes from base.
+  bool base_id (id && &idf->scope () != &c); // Comes from base.
 
   data_member* opt (context::optimistic (c));
 
@@ -157,8 +158,7 @@ traverse_object (type& c)
   {
     if (base_id)
     {
-      semantics::class_& b (
-        dynamic_cast<semantics::class_&> (id->scope ()));
+      semantics::class_& b (dynamic_cast<semantics::class_&> (idf->scope ()));
       string const& type (class_fq_name (b));
 
       os << "typedef object_traits< " << type << " >::id_type id_type;";