use estring::{EString, SepVec};
type PlusVec<T> = SepVec<T, '+'>;
type MulVec<T> = SepVec<T, '*'>;
fn main() -> estring::Result<()> {
let res = EString::from("10+5*2+3")
.parse::<PlusVec<MulVec<f32>>>()?
.iter()
.map(|m| m.iter().product::<f32>())
.sum::<f32>();
assert_eq!(res, 23.0);
Ok(())
}