Crate xpath_eval 

A pure-Rust XPath 1.0 expression parser and evaluator, generic over the document model.

Phase 02: lexer + recursive-descent parser producing a structured AST. Phase 03: the generic document/node data model and the 13 XPath axes. Phase 04: the value model, type conversions, operators, and full location-path/predicate evaluation — see plan/ for the roadmap.

Structs

EvaluationContext

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.

ExpandedName

An expanded name (namespace URI + local name), §5.2/§5.3/§5.4/§5.5.

FilterExpr

[20] FilterExpr — a PrimaryExpr with zero or more predicates.

FunctionCall

[16] FunctionCall — name plus argument expressions. Not validated against the core function library in this phase; any syntactically valid QName is accepted.

LocationPath

[1]/[2]/[3] LocationPath — // is desugared into an explicit descendant-or-self::node() step prepended to (or inserted into) steps.

ParseError

A structured parse error: a byte offset into the input expression plus a human-readable description (not a bare string error).

QName

A qualified name (NCName (':' NCName)?, XML Namespaces §3).

Step

[4] Step — AxisSpecifier NodeTest Predicate*, with AbbreviatedStep (. / ..) desugared into the equivalent self/parent axis step.

Enums

AdditiveOp

Axis

The 13 XPath axes ([6] AxisName). Abbreviated forms (@, ., ..) are represented as their equivalent explicit axis, not as a separate variant.

EqualityOp

EvalError

An evaluation-time error. Distinct from ParseError (parser.rs), which covers syntax — this covers semantic failures once a well-formed Expr is evaluated against a concrete context.

Expr

[14] Expr and the full operator-precedence chain [18]/[21]-[27] in a single flat enum: each precedence level either produces a node here or, when its operator is absent, simply returns the inner expression from the next-tighter level (standard precedence-climbing shortcut).

MultiplicativeOp

NodeKind

An XPath 1.0 node type (§5).

NodeTest

[7] NodeTest — includes the NameTest alternatives (*, prefix:*, QName) and the NodeType/processing-instruction(Literal) forms.

PathExpr

[19] PathExpr.

PrimaryExpr

[15] PrimaryExpr.

RelationalOp

Value

An XPath 1.0 value: one of the four object types (§3.1) — “node-set (an unordered collection of nodes without duplicates), boolean, number … [or] string”.

Traits

Document

An XPath 1.0 document: gives access to the root node.

Node

A node in the caller’s tree, viewed as an XPath 1.0 data-model node.

Functions

ancestor

ancestor axis (reverse): “contains the ancestors of the context node; … the parent of the context node and the parent’s parent and so on; thus, the ancestor axis will always include the root node, unless the context node is the root node”. Results are nearest-ancestor-first (reverse document order).

ancestor_or_self

ancestor-or-self axis (reverse): “contains the context node and the ancestors of the context node”. Results are context-node-first, then nearest ancestor first (reverse document order).

attribute

attribute axis: “contains the attributes of the context node; the axis will be empty unless the context node is an element”.

child

child axis: “contains the children of the context node”.

descendant

descendant axis: “contains the descendants of the context node; … thus the descendant axis never contains attribute or namespace nodes”.

descendant_or_self

descendant-or-self axis: “contains the context node and the descendants of the context node”.

evaluate

Evaluates expr against ctx, producing an XPath 1.0 value.

following

following axis: “contains all nodes in the same document as the context node that are after the context node in document order, excluding any descendants and excluding attribute nodes and namespace nodes”.

following_sibling

following-sibling axis: “contains all the following siblings of the context node; if the context node is an attribute node or namespace node, the following-sibling axis is empty”.

namespace

namespace axis: “contains the namespace nodes of the context node; the axis will be empty unless the context node is an element”.

parent

parent axis: “contains the parent of the context node, if there is one”.

parse

Parses an XPath 1.0 expression string into a structured Expr AST.

preceding

preceding axis (reverse): “contains all nodes in the same document as the context node that are before the context node in document order, excluding any ancestors and excluding attribute nodes and namespace nodes”.

preceding_sibling

preceding-sibling axis (reverse): “contains all the preceding siblings of the context node; if the context node is an attribute node or namespace node, the preceding-sibling axis is empty”. Results are nearest-preceding-sibling-first (reverse document order).

self_axis

self axis: “contains just the context node itself”.