Crate mate_rs

This crate provides a library for parsing and calculating arithmetic expressions inputted as &str(string). Uses Lexer structure to parse string input in to token list, and Calculator structure to calculate final result from token list. Has also a general wrapper structure that implements Lexer and Calculator inside of it. And makes it easy to calculate arithmetic expression’s result directly without dealing with parsing and calculating manually.

Usage

This crate is on crates.io and can be used by adding mate-rs to your dependencies in your project’s Cargo.toml.

[dependencies]
mate-rs = "0.1.4"

Example: with Mate

Mate is general wrapper structure for Lexer and Calculator. has only one method that used to calculate result via string(&str) input.

use mate_rs::mate::Mate;

let result = Mate::calculate("6 * 7");
match result {
    Ok(v) => assert_eq!(v, 42.0),
    Err(_) => {
        // Do something ...
    }
};

Example: with Lexer and Calculator

Lexer is the main structure that parses string-input to token-list. Calculator is the structure that used to calculate final result via Lexer’s result.

use mate_rs::{calculator::Calculator, lexer::Lexer};

// Generated tokens gonna be something like:
//  |
//  | Token(
//  |   type: SUBEXP,
//  |   tokens: [
//  |        Token(
//  |          type: SUBEXP,
//  |          tokens: [
//  |               Token(type: NUMBER,  literal: "2")
//  |               Token(type: PLUS,    literal: "+")
//  |               Token(type: NUMBER,  literal: "5")
//  |          ],
//  |        ),
//  |        Token(type: PRODUCT, literal: "*"),
//  |        Token(
//  |          type: SUBEXP,
//  |          tokens: [
//  |               Token(type: NUMBER,  literal: "5")
//  |               Token(type: MINUS,   literal: "-")
//  |               Token(type: NUMBER,  literal: "9")
//  |               Token(type: PLUS,    literal: "+")
//  |               Token(
//  |                 type: SUBEXP,
//  |                 tokens: [
//  |                      Token(type: NUMBER,  literal: "8")
//  |                      Token(type: PLUS,    literal: "-")
//  |                      Token(type: NUMBER,  literal: "5")
//  |                 ],
//  |               ),
//  |          ],
//  |        ),
//  |   ],
//  | ),
//  | Token(type: PLUS,    literal: "+")
//  | Token(type: NUMBER,  literal: "35")
//  |
let input = "[ (2 + 5) * (5 - 9 + (8 - 5)) ] + 35";
let tokens = Lexer::lex(input.clone()).unwrap(); // should handle error case also

// Result will be calculated from tokens, by X/O/Y algorithm.
//
//  ╭────────╮ ╭───────────╮ ╭────────╮
//  │ NUMBER │ │ OPERATION │ │ NUMBER │
//  ╰────────╯ ╰───────────╯ ╰────────╯
//       ╰───╮       │        ╭───╯
//           ▼       ▼        ▼
//           X  [+, -, *, /]  Y
//
let result = Calculator::calculate(tokens, input.clone());

match result {
    Ok(v) => assert_eq!(v, 42.0),
    Err(_) => {
        // Do something ...
    }
};

For details refer to repository.

Modules

calculator

errors

lexer

mate

monitor

token

utils