Feature request: Fixed-length string parsing

[adammw]

Add fixed length string parsing support with documentation. Tried a combination of Take and Map but couldn't get anything to compile.

For example, a format that has a fixed length name field of [u8, 16] that gets parsed as ASCII/UTF8.

[chifflier]

Hi,

The following should work (it compiles):

#[derive(Nom)]
pub struct FixedLengthString<'a> {
    #[nom(Parse = "map_res(take(3_usize), core::str::from_utf8)")]
    pub s: &'a str,
}

That said, I will think of an attribute to make it easier and do that without having to map_res manually.