fn main() -> syn::Result<()> {
use macro_rules_rt::Rule;
let from = "$e:literal".parse()?;
let to = "$e * 5".parse()?;
let rule = Rule::new(from, to)?;
let source = "1 + 2";
let expect = "1 * 5 + 2 * 5";
let result = rule.replace_all(source)?;
assert_eq!(result, expect);
Ok(())
}