HierarchyPath parser now returns nil when
the path is empty (instead of a string slice with one
EmptyString element).
If isAbsolute is set to true, when calling the AsString
method on a nil HierarchyPath, only the separator will
be returned. Alternatively, if isAbsolute is false, it
will just return . to signal that the path currently
being processed is the one required.This avoids a nil
expr error coming from the xmlquery library.
Use the Query and QueryAll functions from the xmlquery
package to be able to handle the errors ourselves and
avoid panics.
Remove config default value for xmlRootPath. The field
will remain commented in config_defaults for reference.
Add tests for HierarchyPath.AsString function.
Add comments for XmlProvider and xmlRootPath opt.
Update XmlProvider String() func based on the comment
which specifies that it should display the already
parsed values out of cache.
