Crate evaluator_rs

evaluator_rs

A evaluation engine library for Rust.

Usage

Please see the Documentation for more details.

Add to your Cargo.toml:

[dependencies]
evaluator_rs = "0.1"

Examples:

extern crate evaluator_rs;

use std::collections::HashMap;

use evaluator_rs::{evaluate, parse_expr_from_str, parse_expr_from_json, Value};

fn main() {
    // from str expression
    let expr = parse_expr_from_str("{a} + 2 + 3").unwrap();
    let parameters = HashMap::from([("a", Value::from(1))]);
    let rs = evaluate(&expr, &parameters).unwrap();
    assert_eq!(rs, Value::from(6));

    let expr = parse_expr_from_str("{a} in [1, 2 , 3]").unwrap();
    let parameters = HashMap::from([("a", Value::from(1))]);
    let rs = evaluate(&expr, &parameters).unwrap();
    assert_eq!(rs, Value::from(true));

    // from json expression
    let json_expr = r#"{
        "lhs": "{a}",
        "op": "in",
        "rhs": [4, 5, 6]
    }"#;
    let expr = parse_expr_from_json(json_expr).unwrap();
    let parameters = HashMap::from([("a", Value::from(4))]);
    let rs = evaluate(&expr, &parameters).unwrap();
    assert_eq!(rs, Value::from(true));
}

Enums

EvaluatorError

Expr

ParserError

Value

Value used by by the parser and evaluator.

Functions

evaluate

evaluate expresstion with parameters

parse_expr_from_json

Parse expression from json

parse_expr_from_str

Parse expression from str