[Boost-users] walk thru multi_index

From: Dmitriy Bure (borech_at_[hidden])
Date: 2006-02-01 12:49:01

Hello,
I'm very interested to use multi_index container in my work. But didn't 
found much documentation and\or examples. Maybe anyone could suggest a 
place to find it?
Basically now I'm trying to implement probably very simple thing. There 
is basic structure:

struct AvNode
{
  CNode* var;
  int context;
  MemoryPlace location;
  ...
};

And I'd like to have multi_index container with such nodes (all fields 
are non-equal). Something like this:

typedef multi_index_container<
  AvNode,
  indexed_by<
    ordered_non_unique<
      tag<varNcontextIndex>,
      composite_key<
        AvNode,
        BOOST_MULTI_INDEX_MEMBER(AvNode,CNode*,var),
        BOOST_MULTI_INDEX_MEMBER(AvNode,int,context)
      >
    >
  >
 > AvNodeSet;

And then I need to iterate on this container. Better to say that I'd 
like to group elements in container by first two fields. Could you help 
me in this problem? In fact I have one solution but it's too large and 
non-fine:

AvNodeSet avNodes;

typedef index<AvNodeSet, varNcontextIndex>::type AvNodesSet2VarNcontext;
AvNodesSet2VarNcontext& avNodes2VarNcontext = 
boost::multi_index::get<varNcontextIndex>(avNodes);

AvNodesSet2VarNcontext::iterator it = avNodes2VarNcontext.begin();
while(it != avNodes2VarNcontext.end())
{
    CNode* var = it->var;
  
    AvNodesSet2VarNcontext::iterator it2Var = it;
    while( (it2Var != avNodes2VarNcontext.end()) && (it2Var ->var== var) )
    {
        int context = it2Var->context;

        FOO(make_pair(var, context));

        AvNodesSet2VarNcontext::iterator it2Context = it2Var;
        while( (it2Context != avNodes2VarNcontext.end()) && 
(it2Context->context == context) )
        {
            ++it2Context;
        }
        it2Var = it2Context;
    }
    it = it2Var;
}

Hope for your help...
-- 
Best regards,
Dmitriy Bure mailto:borech_at_[hidden]