Documentation for Visitor concepts in graph library

From: Kevin S. Van Horn (kevin_vanhorn_at_[hidden])
Date: 2001-03-28 18:33:18

The documentation for the various Visitor concepts does not require that
visitors be copyable.  This strikes me as a bit odd, given that the
algorithms that use them take parameters passed by value, and not by
reference.  In fact, taking a look at variant (3) of the
dijkstra_shortest_paths algorithm, the last argument (UniformCostVisitor
visit) is in fact copied to provide the last argument of a nested call to
variant (4).

So I think that either you need to eliminate any copying of visitors, and
mention in the documentation that visitors are not required to be
copyable, or the visitor concepts should require that visitors be
copyable, and the documentation should mention that visitors are intended
to be lightweight objects that are inexpensive to pass by value.