urpose graph description languages can specify an arbitrary
number of edge and vertex properties, using strings to represent the
key-value pairs.  A graph reader function should capture these
arbitrary properties, but since function templates can only be
parameterized on a fixed number of property maps, the traditional
techniques for handling property maps do not suffice to implement them.</p>
<p>Dynamic property maps specifically address the need for an interface
to property maps whose checking is delayed 