1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
use crate::{eyre, Buffer, Parse};
#[derive(Debug, Copy, Clone, PartialEq)]
pub struct OneOf<const CHARS: &'static str>(char);
impl<const CHARS: &'static str> From<OneOf<CHARS>> for char {
fn from(v: OneOf<CHARS>) -> Self {
v.0
}
}
impl<const CHARS: &'static str> Parse<char> for OneOf<CHARS> {
fn parse(input: &mut impl Buffer<char>) -> eyre::Result<Self> {
match input.next() {
Some(c) => {
if CHARS.contains(c) {
Ok(Self(c))
} else {
Err(eyre::eyre!(
"error parsing one of {:?}, found {:?}",
CHARS,
c
))
}
}
None => Err(eyre::eyre!("error parsing one of {:?}, reached EOF", CHARS)),
}
}
fn peek(input: &mut impl Buffer<char>) -> bool {
match input.next() {
Some(c) => CHARS.contains(c),
None => false,
}
}
}