Crates.io | stap |
lib.rs | stap |
version | 0.1.1 |
source | src |
created_at | 2024-05-25 08:27:46.729173 |
updated_at | 2024-06-01 08:38:02.589439 |
description | Stateful parser |
homepage | |
repository | https://github.com/hatoo/stap |
max_upload_size | |
id | 1251833 |
size | 49,094 |
stap
(stateful parser) is a library of stateful parser for streaming input using async
syntax.
When a input isn't enough for parsing, stap
remembers the curent state and waits to more inputs and parses them when the input is supplied.
use futures::FutureExt;
use stap::{many1, Anchor, Cursor, Input, Parsing};
fn main() {
let mut input = Input::new(Cursor {
buf: Vec::<u8>::new(),
index: 0,
});
let mut parsing = Parsing::new(&mut input, |mut iref| {
async move {
// anchoring the current index
// restoring the index if parsing fails (= when dropped)
let mut anchor = Anchor::new(&mut iref);
let num = many1(&mut anchor, |b| b.is_ascii_digit()).await?;
// Since the parser holds state, this output is showed up only once.
dbg!(&num);
let alpha = many1(&mut anchor, |b| b.is_ascii_alphabetic()).await?;
dbg!(&alpha);
// parsing is successful, so we can forget the anchor in other words, current index of the input is valid.
anchor.forget();
Ok::<_, ()>((num, alpha))
}
// This makes the future `Unpin`, currently this is required but any workaround is welcome.
.boxed_local()
});
// There is no input to parse, so parsing should fail.
assert!(!parsing.poll());
parsing.cursor_mut().buf.extend_from_slice(b"123a");
// The parser recognizing the input as a number followed by an alphabet. But because of there may be more alphabets, it should fail.
assert!(!parsing.poll());
parsing.cursor_mut().buf.extend_from_slice(b"bc;");
// the parser should ends.
assert!(parsing.poll());
dbg!(parsing.into_result());
}