Macro try_merge 

macro_rules! try_merge {
    ($res: expr, $errlog: ident) => { ... };
}

Macro to merge_result() and return given ErrorLog if given Result is an Err

Same as

    let mut err_log = ErrorLog::<i32, std::num::ParseIntError>::new();
    match "a1".parse::<i32>() {
        Ok(o) => err_log.set_ok(o),
        Err(e) => {
            err_log.push_err(e);
            return err_log;
        }
    };

Arguments:

1. Result
2. ErrorLog