v_eval

```rust use v_eval::{Value, Eval};

fn main() -> Result<(), ()> { let e = Eval::default() .insert("foo", "true")? .insert("bar", "false")?;

assert_eq!(e.eval("foo != bar").unwrap(), Value::Bool(true));
assert_eq!(
    e.eval("true && foo != bar && true").unwrap(),
    Value::Bool(true)
);
assert_eq!(e.eval("1 == 1 != bar").unwrap(), Value::Bool(true));
assert_eq!(e.eval("1 == 1 + 1 == bar").unwrap(), Value::Bool(true));

Ok(())

} ```