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use wast::parser::{self, Parse, ParseBuffer, Parser, Result};
pub struct Comments<'a> {
comments: Vec<&'a str>,
}
impl<'a> Parse<'a> for Comments<'a> {
fn parse(parser: Parser<'a>) -> Result<Comments<'a>> {
let comments = parser.step(|mut cursor| {
let mut comments = Vec::new();
loop {
let (comment, c) = match cursor.comment()? {
Some(pair) => pair,
None => break,
};
cursor = c;
comments.push(if comment.starts_with(";;") {
&comment[2..]
} else {
&comment[2..comment.len() - 2]
});
}
Ok((comments, cursor))
})?;
Ok(Comments { comments })
}
}
pub struct Documented<'a, T> {
comments: Comments<'a>,
item: T,
}
impl<'a, T: Parse<'a>> Parse<'a> for Documented<'a, T> {
fn parse(parser: Parser<'a>) -> Result<Self> {
let comments = parser.parse()?;
let item = parser.parens(T::parse)?;
Ok(Documented { comments, item })
}
}
#[test]
fn parse_comments() -> anyhow::Result<()> {
let buf = ParseBuffer::new(
r#"
;; hello
(; again ;)
(module)
"#,
)?;
let d: Documented<wast::core::Module> = parser::parse(&buf)?;
assert_eq!(d.comments.comments, vec![" hello", " again "]);
drop(d.item);
let buf = ParseBuffer::new(
r#"
;; this
(; is
on
multiple;)
;; lines
(func)
"#,
)?;
let d: Documented<wast::core::Func> = parser::parse(&buf)?;
assert_eq!(
d.comments.comments,
vec![" this", " is\non\nmultiple", " lines"]
);
drop(d.item);
Ok(())
}