# evaluroll

Evaluroll is a dice roll evaluator for tabletop games.
It supports dice notation and basic arithmetic,
as specified in the [roll20 spec](https://wiki.roll20.net/Dice_Reference#Roll20_Dice_Specification).
It also supports keeping and dropping dice, as well as parenthesized expressions.

It also supports parsing into an AST, which can be used to evaluate the expression multiple times.

## Examples

Parsing an expression into an AST:

```rust
let ast = evaluroll::parse("1d20")?;
```

Evaluating an AST:

```rust
use evaluroll::Eval;

let ast = evaluroll::parse("1d20")?;

let mut rng = rand::thread_rng();
let output = ast.eval(&mut rng)?;

assert_eq!(1, output.rolls.len());
assert!((1..=20).contains(&output.total));
```

Evaluating an expression directly:

```rust
let mut rng = rand::thread_rng();
let output = evaluroll::eval(&mut rng, "1d20")?;

assert_eq!(1, output.rolls.len());
assert!((1..=20).contains(&output.total));
```
## Features

Evaluroll has the following features:

- `trace`: Enables tracing of the AST and the output of the parser.

License: MIT