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combine 2.3.0

Fast parser combinators on arbitrary streams with zero-copy support.
Documentation 
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// The feature `buffered_stream` must be enabled to run these tests
extern crate combine;
use combine::primitives::{BufferedStream, Error};
use combine::char::{char, digit, spaces, string};
use combine::{StreamOnce, Parser, choice, from_iter, many, many1, sep_by, try};

#[test]
fn shared_stream_buffer() {
    // Iterator that can't be cloned
    let text = "10,222,3,44".chars().map(|c| {
        if c.is_digit(10) {
            (c as u8 + 1) as char
        } else {
            c
        }
    });
    let buffer = BufferedStream::new(from_iter(text), 1);
    let int: &mut Parser<Input = _, Output = _> = &mut many(digit())
        .map(|s: String| s.parse::<i64>().unwrap());
    let result = sep_by(int, char(','))
        .parse(buffer.as_stream())
        .map(|t| t.0);
    assert_eq!(result, Ok(vec![21, 333, 4, 55]));
}

#[test]
fn shared_stream_backtrack() {
    let text = "apple,apple,ananas,orangeblah";
    let mut iter = text.chars();
    // Iterator that can't be cloned
    let buffer = BufferedStream::new(from_iter(&mut iter), 2);
    let stream = buffer.as_stream();

    let value: &mut Parser<Input = _, Output = _> =
        &mut choice([try(string("apple")), try(string("orange")), try(string("ananas"))]);
    let mut parser = sep_by(value, char(','));
    let result = parser.parse(stream)
        .map(|t| t.0);
    assert_eq!(result, Ok(vec!["apple", "apple", "ananas", "orange"]));
}

#[test]
fn shared_stream_insufficent_backtrack() {
    let text = "apple,apple,ananas,orangeblah";
    let mut iter = text.chars();
    // Iterator that can't be cloned
    let buffer = BufferedStream::new(from_iter(&mut iter), 1);
    let stream = buffer.as_stream();

    let value: &mut Parser<Input = _, Output = _> =
        &mut choice([try(string("apple")), try(string("orange")), try(string("ananas"))]);
    let mut parser = sep_by(value, char(','));
    let result: Result<Vec<&str>, _> = parser.parse(stream)
        .map(|t| t.0);
    assert!(result.is_err());
    assert!(result.unwrap_err()
        .errors
        .iter()
        .any(|err| *err == Error::Message("Backtracked to far".into())));
}

/// Test which checks that a stream which has ended does not repeat the last token in some cases in
/// which case this test would loop forever
#[test]
fn always_output_end_of_input_after_end_of_input() {
    let text = "10".chars();
    let buffer = BufferedStream::new(from_iter(text), 1);
    let int = many1(digit()).map(|s: String| s.parse::<i64>().unwrap());
    let result = many(spaces().with(int))
        .parse(buffer.as_stream())
        .map(|t| t.0);
    assert_eq!(result, Ok(vec![10]));
}

#[test]
fn position() {
    let text = "10abc".chars();
    let buffer = BufferedStream::new(from_iter(text), 3);
    let stream = buffer.as_stream();
    println!("{:?}", stream);
    assert_eq!(stream.position(), 0);
    let result = many1::<Vec<_>, _>(digit()).parse(stream.clone());
    println!("{:?}", stream);
    assert_eq!(stream.position(), 0);
    assert!(result.is_ok());
    assert_eq!(result.unwrap().1.position(), 2);
}