Trait Stream

Source

pub trait Stream<'a> {
    type Item;

    // Required methods
    fn token(&mut self, x: usize) -> StreamResult<Self::Item>;
    fn junk(&mut self, x: usize);
    fn pos(&self) -> usize;
}

Expand description

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);
        } 
    });