Crates.io | evaluator_rs |
lib.rs | evaluator_rs |
version | 0.1.5 |
source | src |
created_at | 2022-05-30 17:45:50.078589 |
updated_at | 2024-11-27 16:41:21.303311 |
description | A evaluation engine library for Rust |
homepage | https://github.com/tuyentv96/evaluator_rs |
repository | https://github.com/tuyentv96/evaluator_rs.git |
max_upload_size | |
id | 597093 |
size | 477,118 |
A evaluation engine library for Rust.
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, ¶meters).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, ¶meters).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, ¶meters).unwrap();
assert_eq!(rs, Value::from(true));
}
Type | Examples |
---|---|
Number | 1 |
String | 'hello world' |
Bool | true |
Array | [1, 2, 3] |
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 |
Identifiers are wrapped by curly brace. When expression is evaluated, parameters must be provided identifier value.
Examples:
let expr = parse_expr("{a} in [1, 2 , 3]").unwrap();
let parameters = HashMap::from([("a", Value::from(1))]);
let rs = evaluate(&expr, ¶meters).unwrap();
assert_eq!(rs, Value::from(true));