Ytukyg

The parser works as expected until I want to parse the h: digit which is always the last digit in the string and the compiler gives me

^ expected &str, found struct `nom::types::CompleteStr`

I assume it's because the parser is looking ahead. How do I stop that, or how can I signify it's done?

#[macro_use]

extern crate nom;



use nom::digit;

use nom::types::CompleteStr;

use std::str::FromStr;



#[derive(Debug, PartialEq)]

pub struct Order {

    pub l: u64,

    pub w: u64,

    pub h: u64,

}



named!(order_parser<CompleteStr, Order>,

    do_parse!(

        l: map_res!(digit, u64::from_str) >>

        tag!("x") >>

        w: map_res!(digit, u64::from_str) >>

        tag!("x") >>

        h: map_res!(digit, u64::from_str) >>

        (Order {l:  l, w: w, h: h })

    )

);



pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<&str>> {

    order_parser(order)

}



#[test]

fn test_order_parser() {

    assert_eq!(

        wrap_order(CompleteStr("2x3x4")),

        Ok((CompleteStr(""), Order { l: 2, w: 3, h: 4 }))

    );

}

The error is not on the last digit parser, it's on each of them (Rust 1.30.0 prints the error three times). That's because u64::from_str works on &str, not CompleteStr.

You can fix your parsers to use u64::from_str correctly this way:

do_parse!(

    l: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>

    tag!("x") >>

    w: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>

    tag!("x") >>

    h: map_res!(digit, |CompleteStr(s)| u64::from_str(s)) >>

    (Order { l: l, w: w, h: h })

)

There are also some unrelated error with the next function, which can be fixed by using the appropriate types in the signature:

pub fn wrap_order(order: &str) -> Result<(CompleteStr, Order), nom::Err<CompleteStr>> {

    order_parser(CompleteStr(order))

}