proper way to check inclusion among DocIterator ?

[Tommaso Cucinotta]

Hi,

is there an easy way to check whether a DocIterator d is positioned within two 
others a and b ?
(that is, going through the document using forwardPos(), one encounters a, then 
d, then b).

AFAIU, DocIterator::operator() just compares nesting levels, but no pos() nor 
pit() etc.

Thanks,

        T.