Struct EvaluationContext 

pub struct EvaluationContext<'ctx, 'hook, N: Node<'ctx>> {
    pub node: N,
    pub position: usize,
    pub size: usize,
    pub variables: Option<&'hook (dyn Fn(&QName) -> Option<Value<N>> + 'hook)>,
    pub namespaces: Option<&'hook (dyn Fn(&str) -> Option<String> + 'hook)>,
    /* private fields */
}

The context an Expr is evaluated against (§2.2/§2.4): the context node, its 1-based proximity position and the context size within whatever node-set it was drawn from, a variable-binding lookup hook, and a namespace-prefix resolution hook.

None in variables means “no variables are bound” — every PrimaryExpr::Variable lookup then fails with EvalError::UnboundVariable. Nothing in this phase binds variables yet (that is a schematron-engine <let> concern), but PrimaryExpr::Variable still needs this real, clearly-erroring path rather than a panic or a silently-wrong default.

None in namespaces means “no namespace bindings are declared” — prefixed name tests then never match any node (see resolve_prefix’s doc comment for the full rationale).

'ctx is the node/document borrow lifetime (N: Node<'ctx>); 'hook is an independent lifetime for the variables/namespaces hook references. The two are deliberately decoupled (see plan/05b-decouple-hook-lifetime.md): a hook built locally within a single evaluate() call (e.g. a closure over a temporary namespace-binding table) does not need to live as long as the document itself, and there is no 'hook: 'ctx (or reverse) bound between them — nothing here ever stores the hook and the node together in a way that would require one.

_ctx is a zero-sized marker: 'ctx is only used in the N: Node<'ctx> bound above, not in any field type on its own, and Rust requires every declared lifetime parameter of a struct to appear in a field (E0392 otherwise) — this PhantomData satisfies that without adding any real state.

Fields

node: N

position: usize

size: usize

variables: Option<&'hook (dyn Fn(&QName) -> Option<Value<N>> + 'hook)>

namespaces: Option<&'hook (dyn Fn(&str) -> Option<String> + 'hook)>

Implementations

impl<'ctx, 'hook, N: Node<'ctx>> EvaluationContext<'ctx, 'hook, N>

pub fn new(node: N) -> Self

A context whose node is both the sole member and the first member of its own (size-1) context node-set, with no variable bindings and no namespace context.

Trait Implementations

impl<'ctx, 'hook, N: Clone + Node<'ctx>> Clone for EvaluationContext<'ctx, 'hook, N>

fn clone(&self) -> EvaluationContext<'ctx, 'hook, N>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'ctx, 'hook, N: Copy + Node<'ctx>> Copy for EvaluationContext<'ctx, 'hook, N>