Add a blank heading to the tree. No article so the _navitem only has the article title

Declared in file: hzDissemino.h
Defined in file : hdsNavtree.cpp

Function Logic:

Function body:

hzEcode hdsNavtree::AddHead (hzString& parent)hzString& refname, hzString& title, bool bSlct, 
{
   //  Add a blank heading to the tree. No article so the _navitem only has the article title
   //  
   //  Arguments: 1) parent The parent node to this blank heading
   //     2) refname Unique name of heading
   //     3) title Heading title as visible to user
   //     4) bSlct Show the heading as open/closed in the navtree
   //  
   //  Returns: E_ARGUMENT if either the refname or title is not supplied
   //     E_DUPLICATE if the refname already exists as a tree item (exits)
   //     E_OK  Operation successful
   _hzfunc("hdsNavtree::AddHead(1)") ;
   _navitem    item ;      //  New tree item
   _navitem    parItem ;   //  Parent item
   //  Qualify item
   if (!refname)   return hzerr(E_ARGUMENT, "%s: No item refname supplied", *m_Groupname) ;
   if (!title)     return hzerr(E_ARGUMENT, "%s: No item title supplied", *m_Groupname) ;
   if (m_ItemsByName.Exists(refname))
       hzexit(E_DUPLICATE, "%s: Heading %s (%s) already exists", *m_Groupname, *refname, *title) ;
   if (parent)
   {
       if (!m_ItemsByName.Exists(parent))
           return hzerr(E_NOTFOUND, "%s: Heading %s (%s): Stated parent (%s) does not exist", *m_Groupname, *refname, *title, *parent) ;
       parItem = m_ItemsByName[parent] ;
   }
   item.m_Title = title ;
   if (bSlct)
       item.m_bFlags |= HZ_TREEITEM_OPEN ;
   item.m_bFlags |= HZ_TREEITEM_LINK ;
   if (!parent)
       item.m_nLevel = 0;
   else
       item.m_nLevel = parItem.m_nLevel + 1;
   m_ItemsByParent.Insert(parent, refname) ;
   m_ItemsByName.Insert(refname, item) ;
   return E_OK ;
}