class norm_system_id :Normalizes the SYSTEM ID, and forwards the open request to the passed resolver.resolver ->
resolver
Normalization includes:
"http://h/p1", ...;
"http://h/p2", ...;
)
First, the catalog now even works if the URL is written in an
unsual way, e.g. http://h/p1/../p2, or http://h/p%31.
Second, relative URLs can be used. For instance, the document
referred to as http://h/p1 can now refer to the other document
as p2.