It's the first time I have used a parser combinator, so maybe I just have a misunderstanding about how I should use a parser combinator.
I have the following code which works in general:
The problem is, I don't understand how I can get rid of the .unwrap() in my parse_method and parse_url functions and use the ? operator instead. I have already read https://github.com/rust-bakery/nom/blob/main/doc/error_management.md but absolutely don't understand how to apply it in this case.
I think I have to create a custom Error Enum and implement the ParseError trait. I tried that, but without any success. Unfortunately, the nom crate does not have many examples, and the ones that are there never use the ? operator.
This leads me to think that I misunderstood how I should use a parser combinator. Is the idea that I just parse the parts and assemble the parts later where I do not return IResult or is the idea that I should use .map_err and return noms own error types? I am really lost. Any help is appreciated.
Use map_res combinator:
fn parse_method(input: &[u8]) -> IResult<&[u8], Method> {
let (input, method) = map_res(
terminated(take_till(is_space), multispace0),
Method::from_bytes,
)(input)?;
Ok((input, method))
}
In general, you should prefer using combinators over manually successively calling parsers: full example