Struct XPathContext 

pub struct XPathContext<'doc> {
    pub index: DocIndex<'doc>,
    /* private fields */
}

Reusable XPath context for an arena-allocated ArenaDocument.

Build once, evaluate many times. Internally the XPath evaluator is generic over DocIndexLike.

Fields

index: DocIndex<'doc>

The flat index used by the evaluator. Exposed so external adapters (e.g. the libxml2 C-ABI shim in sup-xml-compat) can build their own result-object wrappers without rebuilding the index.

Implementations

impl<'doc> XPathContext<'doc>

pub fn new(doc: &'doc Document) -> XPathContext<'doc>

Build a strict-mode evaluation context for doc. O(n) in the number of nodes. Equivalent to new_with with default XPathOptions.

pub fn new_with( doc: &'doc Document, options: XPathOptions, ) -> XPathContext<'doc>

Build an evaluation context for doc with explicit options. Use this to opt into libxml2-compatible behaviour for the three spec deviations called out on XPathOptions.

pub fn eval(&self, src: &str) -> Result<Value, XmlError>

pub fn eval_at(&self, src: &str, context_node: usize) -> Result<Value, XmlError>

Evaluate src against a specific context node. XPath 1.0 allows the context-node to be any node in the document; the libxml2 ABI exposes this via xmlXPathContext.node.

pub fn eval_with( &self, src: &str, context_node: usize, bindings: &dyn XPathBindings, ) -> Result<Value, XmlError>

Evaluate src against context_node, consulting bindings for user-registered functions (extensions= in lxml), variables ($varname), and namespace prefix resolution. This is the entry point the libxml2 C-ABI shim (sup-xml-compat::xpath) uses when its xmlXPathContext carries registered namespaces, functions, or variables.

pub fn id_for_element(&self, ptr: *const Node<'_>) -> Option<usize>

Find the index ID for a node identified by its arena pointer. Returns None if the pointer doesn’t match any indexed node. Linear scan; O(n) in document size — call once per evaluation, not per expression step.

Handles attribute pointers too: libxslt sets the XPath context node to an xmlAttr* while iterating @* (<xsl:for-each select="@*">), and the C-ABI layer hands that pointer here cast to *const Node. The match is by raw address, so comparing the indexed &Attribute against ptr is sound regardless of the nominal pointer type.

pub fn eval_bool(&self, src: &str) -> Result<bool, XmlError>

pub fn eval_str(&self, src: &str) -> Result<String, XmlError>

pub fn eval_num(&self, src: &str) -> Result<f64, XmlError>

pub fn eval_strings(&self, src: &str) -> Result<Vec<String>, XmlError>

pub fn eval_count(&self, src: &str) -> Result<usize, XmlError>

pub fn eval_node_xml(&self, src: &str) -> Result<Vec<String>, XmlError>

Evaluate src and return each matched node serialized as XML (the XPath equivalent of xmllint --xpath’s default output).

• Element / Text / Comment / CData / PI nodes serialize to their subtree XML form, identical to [crate::serialize_node_to_string] with default options.
• Attribute nodes render as name="value" with the value attribute-escaped.
• Namespace nodes render as xmlns:prefix="uri" (or xmlns="…" for the default namespace).
• The synthetic Document node (returned by /) serializes as the whole document via crate::serialize_to_string.

Non-NodeSet results (string / number / boolean) collapse to a single-element vec containing their XPath 1.0 string form, matching Self::eval_strings.