jaq-core 0.7.0

JSON query language interpreter.

This crate allows you to execute jq-like filters.

The example below demonstrates how to use this crate. See the implementation in the jaq crate if you are interested in how to:

• enable usage of the standard library,
• load JSON files lazily,
• handle errors etc.

use jaq_core::{parse, Ctx, Definitions, Error, Val};
use serde_json::{json, Value};

let input = json!(["Hello", "world"]);
let filter = ".[]";

// start out only from core filters,
// which do not include filters in the standard library
// such as `map`, `select` etc.
let defs = Definitions::core();

// parse the filter in the context of the given definitions
let mut errs = Vec::new();
let f = parse::parse(&filter, parse::main()).0.unwrap();
let f = defs.finish(f, Vec::new(), &mut errs);
assert_eq!(errs, Vec::new());

// iterator over the output values
let mut out = f.run(Ctx::new(), Val::from(input));

assert_eq!(out.next(), Some(Ok(Val::from(json!("Hello")))));;
assert_eq!(out.next(), Some(Ok(Val::from(json!("world")))));;
assert_eq!(out.next(), None);;