[−][src]Trait streams_rs::Stream

pub trait Stream<'a> {
    type Item;
    fn token(&mut self, x: usize) -> StreamResult<Self::Item>;

    fn junk(&mut self, x: usize);

    fn pos(&self) -> usize;
}

Suppose you need to process each line of a text file. One way to do this is to read the file in as a single large string and use something like split to turn it into a list. This works when the file is small, but because the entire file is loaded into memory, it does not scale well when the file is large.

More commonly, the read_line function can be used to read one line at a time from a channel. This typically looks like:

    // LineReadStream is just example, you can implement your own stream for reading files.
    use streams_rs::*;
    use io_stream::*;
    let mut c = std::io::Cursor::new(b"a\n b\n c");
    let mut stream = LineReadStream::new(&mut c);
    let _ = smatch!(match (stream) {
        [a=> b=> c =>] => {
            println!("{:?} {:?} {:?}",a,b,c);
        } 
    });

Associated Types

type Item

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Required methods

fn token(&mut self, x: usize) -> StreamResult<Self::Item>

Returns token at x. It's possible to cache values. FnStream for example caches all tokens returned from getter.

fn junk(&mut self, x: usize)

Basucally same as truncating vector.

fn pos(&self) -> usize

Return stream position, does not used by macro or streams-rs, but might be usefull for someone.

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Implementors

impl<'a, T: Clone> Stream<'a> for FnStream<'a, T>[src]

type Item = T

impl<'b, 'a: 'b, T: BufRead> Stream<'a> for LineReadStream<'a, T>[src]

type Item = Option<String>

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