Re: [Libxmlplusplus-general] dom_parser example using Visitor pattern

[Stefan Seefeld <seefeld sympatico ca>]

Murray Cumming wrote:
> On Tue, 2003-02-04 at 08:21, Stefan Seefeld wrote:
>
> > * add a 'Visitor' class to get rid of all the dynamic_casts in the existing
> >   examples
>
>
> I read that chapter in the Design Patterns book yesterday. It would be
> interesting, but I think it should be a separate example (maybe
> dom_parser_visitor) because we still need a simple example of the API.

I don't quite see the link between a parser (a document factory), and
a visitor.

I agree that this is quite independent of the rest. It merely addresses
the type safety issue, i.e. it helps us recover the exact type of a
child node.

In terms of API complexity it requires all nodes to have an 'accept'
method, to be implemented as

void Element::accept(Visitor *v) { v->visit_element(this);}

plus a 'Visitor' base class that has one 'visit' method per node type.
(to be implemented by users)

Stefan