This crate implements shell arithmetic expansion.

Arithmetic expansion evaluates an expression that may contain some operators that perform basic maths. The expression is given as a string and parsed like an expression in C. The expression can include variables that interact with the environment.

To evaluate an expression, you call the [eval()] function with a string and an environment.

use std::collections::HashMap;
use yash_arith::{eval, Value};
let mut env = HashMap::new();
env.insert("a".to_owned(), "2".to_owned());
let result = eval("1 + a", &mut env);
assert_eq!(result, Ok(Value::Integer(3)));

Yash-arith

yash-arith is a Rust library crate for performing the POSIX shell's arithmetic expansion. This crate is part of yash but can be used independently.

• Changelog

Usage

Add yash-arith as a dependency in your Cargo.toml.

use std::collections::HashMap;
use yash_arith::{eval, Value};
let mut env = HashMap::new();
env.insert("a".to_owned(), "2".to_owned());
let result = eval("1 + a", &mut env);
assert_eq!(result, Ok(Value::Integer(3)));

License

This crate is distributed under GPLv3.