evaluator_rs

Build codecov License:MIT

A evaluation engine library for Rust.

Usage

Please see the Documentation for more details.

Add to your Cargo.toml:

toml [dependencies] evaluator_rs = "0.1"

Examples:

```rust extern crate evaluator_rs;

use std::collections::HashMap;

use evaluatorrs::{evaluate, parseexprfromstr, parseexprfrom_json, Value};

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

} ```

Data types

| Type | Examples | |----------|-------------| | Number | 1 | | String | 'hello world' | | Bool | true | | Array | [1, 2, 3] |

Supported operators

| Operator | Precedence | Description | |----------|-------------|-------------| | && | 1 | And | | \|\| | 1 | Or | | == | 2 | Equal | | > | 2 | Greater than | | >= | 2 | Greater than or equal | | < | 2 | Lower than | | <= | 2 | Lower than or equal | | in | 2 | Array contains | | * | 3 | Product | | / | 3 | Division | | + | 4 | Sum | | - | 4 | Sub |

Identifier

Identifiers are wrapped by curly brace. When expression is evaluated, parameters must be provided identifier value.

Examples:

rust let expr = parse_expr("{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));

License