Struct Document 

pub struct Document { /* private fields */ }

A JSON document in jlens’s internal representation.

Every evaluate call converts the parts of its input document that the expression reads from serde_json::Value, one level at a time. An expression that reads most of a large document can spend more on that than on the evaluation itself. To evaluate several expressions (a set of rules, say) or the same one several times against one document, convert it once into a Document and use Expression::evaluate_document.

use jlens_core::{Bindings, Document, Expression, Options};

let doc = Document::parse(r#"{"items": [{"price": 2}, {"price": 3}]}"#).unwrap();
let rules = ["$sum(items.price) > 4", "$count(items) < 10"];
for rule in rules {
    let expr = Expression::compile(rule).unwrap();
    let result = expr.evaluate_document(&doc, &Bindings::new(), &Options::default());
    assert_eq!(result.unwrap(), Some(serde_json::json!(true)));
}

Evaluations never modify the document. The one exception is a transform (|...|) whose expression rebinds $clone to a function that does not copy its argument.

A Document is not Send. Convert it on the thread that evaluates against it.

Implementations

impl Document

pub fn new(json: &JsonValue) -> Self

Converts a serde_json value.

pub fn parse(text: &str) -> Result<Self>

Parses JSON text straight into the internal representation. This is faster than parsing into a serde_json::Value and converting it.

pub fn to_json(&self) -> JsonValue

The document as JSON.

Trait Implementations

impl Debug for Document

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<&Value> for Document

fn from(json: &JsonValue) -> Self

Converts to this type from the input type.