# Documentation
Simplified shunting library for evaluating math expressions in cosmwasm smart contracts.
The original crate https://crates.io/crates/shunting could not be used directly for cosmwasm (rand library can not be used directly for wasm-unknonw-unknown target).
## Using the library
```rust
fn main() {
let input = "sin(0.2)^2 + cos(0.2)^2";
let expr = ShuntingParser::parse_str(input).unwrap();
let result = MathContext::new().eval(&expr).unwrap();
println!("{} = {}", expr, result);
}
```
## A MathContext
`MathContext` allows keeping context across multiple invocations to parse and evaluate. You can do this via the `setvar` method.
## The tool in the crate
The crate also ship with the `tox` binary with a math repl.
```
$ tox
>> 4!
24
>> a = sin(0.2)^2 + cos(0.2)^2
>> a
1
>> (-3)!
NaN
>> (84 % (5/2)) !
1.32934
>> pi * 2.1^2 / cbrt(-(6+3))
-6.660512
```