Crate xrust[−][src]
Expand description
A Rust implementation of the XQuery and XPath Data Model 3.1.
The library separates parsing from evaluation. An expression is compiled to create a ‘Sequence Constructor’. This constructor is then applied to a source document to produce a Sequence.
A Sequence is an ordered collection of zero or more Items, implemented as a Rust Vector. An Item is a Node, Function or atomic Value.
let mut dc = DynamicContext::new();
let p = Parser::default();
let doc = p.parse_string("<Test/>").expect("parsing XML failed");
let rgdoc = Rc::new(doc) as Rc<dyn Document>;
dc.set_doc(Rc::clone(&rgdoc));
let s = vec![Rc::new(Item::Document(Rc::clone(&rgdoc)))];
let xpath = parse("/child::Test").expect("XPath parsing failed");
let seq = evaluate(
&dc,
Some(s), Some(0),
&xpath
).expect("evaluation failed");
assert_eq!(seq.len(), 1);
assert_eq!(seq[0].to_name().get_localname(), "Test");An explanation of the above example:
- The libxml crate is used to create an XML document.
- The libxml Document is cast to a generic Document.
- The Document is set as the context document in the DynamicContext.
- A Sequence is created with one item: the document we just created.
- Parse an XPath expression. This results in a sequence constructor.
- Evaluate the sequence constructor.
- The DynamicContext created earlier is used.
- The Sequence created earlier is provided as the initial context for the evaluation.
- The evaluation should return a sequence with one item.
- That item is the root element of the original XML document.
See the xslt module for an example of how to evaluate an XSL stylesheet.
Status
The project, so far, is a proof-of-concept.
For XPath it provides most of v1.0 functionality, with some v2.0 and v3.1 features.
For XSLT, the implementation has barely started. To begin with it only supports literal result elements and literal text.
The library has not been extensively tested.
Plan
- Implement a v3.1 XSLT engine.
Goals / Future Work
- The library should always return errors, i.e. it should not panic
- Make the library more idiomatically Rust
Contributions
We need your help!
- Download the crate and try it out. Tell us what you like or don’t like. How can it be improved?
- Let us know what doesn’t work. Submit a bug report.
- Do you need more documentation? There can never be enough!
- Add some tests.
- Write some code.
- Donate resources (i.e. $$$)
Re-exports
pub use xdmerror::Error;pub use xdmerror::ErrorKind;pub use item::Sequence;pub use item::SequenceTrait;pub use item::Item;pub use item::Value;pub use item::Document;pub use item::Node;pub use xpath::parse;pub use evaluate::StaticContext;pub use evaluate::static_analysis;pub use evaluate::DynamicContext;pub use evaluate::evaluate;pub use evaluate::Constructor;pub use xslt::from_document;