Node-set ordering previously recomputed both nodes' root paths on every
precedes comparison (treePath is O(depth x siblings), so sorts were
O(n log n x depth)). Add decorate-sort-undecorate helpers,
sortedByDocumentOrder() and firstInDocumentOrder(), that compute each node's
order key once, and switch the evaluator's order-and-dedup, the EXSLT set
functions, string-value coercion, and NodeFunctions' target lookup to them.
set:leading/trailing also decorate once, reusing the keys for the pivot
filter and the final sort. precedes stays for pairwise use, sharing the
key comparator (Node.ordered). Behavior unchanged, all suites green.
Closes#113
Compile and evaluate full XPath 1.0 expressions, not just location paths.
Add the four-type Value (node-set, boolean, number, string) with the spec's
coercion rules and canonical number formatting, a recursive-descent parser
for the operator grammar (or/and, equality, relational, additive,
multiplicative, unary minus, union) whose grammatical position disambiguates
* and the operator keywords, function calls, variable references, and filter
expressions. Predicates are now arbitrary expressions (a numeric predicate
is a position test). Comparison follows the node-set quantification rules.
Query gains value/number/string/boolean accessors and a $variable binding
map; the core functions last, position, count, not, true, false, boolean,
number, and string ship with it.
Closes#42
Rebuild the XPath engine on the parent-aware tree. Add an XPath node
abstraction (tree, attribute, namespace) with document order, and navigate
all thirteen axes: child, descendant, parent, ancestor, following-sibling,
preceding-sibling, following, preceding, attribute, namespace, self,
descendant-or-self, ancestor-or-self. Support the ./../@/// abbreviations
and processing-instruction() node tests. Reverse axes number nearest-first
for positional predicates; results return de-duplicated in document order.
The attribute axis excludes xmlns declarations; the namespace axis surfaces
in-scope namespace nodes.
Closes#40
