23.2 Creating a new tree iterator

Constructor function: Marpa_Tree marpa_t_new (Marpa_Order o)

On success, does the following:

• Creates a new tree iterator, with a reference count of 1.
• Increases the reference count of its parent ordering object, o, by 1.
• Positions the new tree iterator before the first parse tree.

Return value: On success, a newly created tree. On hard failure, NULL.