Unlike what I thought before syntax such as "node()" is not a function call.
Instead this is a special node test that tests the *types* of nodes, not their
names.
The lexer doesn't lex things correctly due to "//" and "/" both being separate
rules. As a result the lexer emits two T_SLASH tokens for queries such as
".//foo".
This separates namespace handling into namespace names and namespace objects.
The namespace objects are retrieved from the element an attribute belongs to.
Once retrieved the namespace is cached, due to the overhead of retrieving
namespaces in large documents.
The old code used for generating Object#inspect values has been ripped out (for
the most part). The result is a non indented but far more compact #inspect
output. The code for this is also easier and doesn't break the signature of
Object#inspect.
Oga won't be handling URIs any time soon. The rationale is that they server zero
purpose when it comes to just parsing XML. Another goal of Oga is to make it
easy to modify and reserialize documents back to XML. If namespaces would also
store the URIs this would make this process more difficult.
This also comes with some small cleanups regarding
XPath::Evaluator#node_matches?. This change removes the need to, every time,
also use can_match_node?() to prevent NoMethodError errors from popping up.
This still uses a stack but at least no longer relies on the call stack. I
decided not to go with the Morris in-order algorithm [1] as it modifies the tree
during a search. This would not work well if a document were to be accessed from
multiple threads at once (which should be possible for read-only operations).
I might change this method to actually perform a search (opposed to just
returning everything). This will require some closer inspection of the
available XPath axes to determine if this is needed.
Tests will also be added once I've taken care of the above.
[1]: http://en.wikipedia.org/wiki/Tree_traversal#Morris_in-order_traversal_using_threading
The previous commit was nonsense as I didn't understand XPath's "following" axis
properly. This commit introduces proper tests and a note for future me so that I
can implement it properly.
The evaluation of axes has been fixed by changing the initial context as well as
the behaviour of some of the handler methods.
The initial context has been changed so that it's simply a NodeSet of whatever
the root object is, either a Document or an Element instance. Previously this
would be set to the child nodes of a Document in case the root object was a
Document. This in turn would prevent "child" axes from operating correctly.
When parsing a bare node test such as "A" this is now parsed as following:
(axis "child" (test nil "A"))
Instead of this:
(test nil "A")
According to the XPath specification both are identical and this simplifies some
of the code in the XPath evaluator.
Yorick Peterse