Parser Extension
This commit is contained in:
parent
2ad7707349
commit
afae0d0840
44
src/lib.rs
44
src/lib.rs
@ -26,6 +26,35 @@ where
|
||||
}
|
||||
}
|
||||
|
||||
pub trait ParserExtension<I, O, E>: Parser<I, O, E> {
|
||||
fn map<F, O2>(self, map_fn: F) -> impl Parser<I, O2, E>
|
||||
where
|
||||
F: Fn(O) -> O2;
|
||||
|
||||
fn to<O2: Clone>(self, item: O2) -> impl Parser<I, O2, E>;
|
||||
fn then<O2, P: Parser<I, O2, E>>(self, next: P) -> impl Parser<I, (O, O2), E>;
|
||||
}
|
||||
|
||||
impl<T, I, O, E> ParserExtension<I, O, E> for T
|
||||
where
|
||||
T: Parser<I, O, E>,
|
||||
{
|
||||
fn map<F, O2>(self, map_fn: F) -> impl Parser<I, O2, E>
|
||||
where
|
||||
F: Fn(O) -> O2,
|
||||
{
|
||||
map(self, map_fn)
|
||||
}
|
||||
|
||||
fn to<O2: Clone>(self, item: O2) -> impl Parser<I, O2, E> {
|
||||
self.map(move |_| item.clone())
|
||||
}
|
||||
|
||||
fn then<O2, P: Parser<I, O2, E>>(self, next: P) -> impl Parser<I, (O, O2), E> {
|
||||
seq2(self, next)
|
||||
}
|
||||
}
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::*;
|
||||
@ -60,17 +89,20 @@ mod tests {
|
||||
|
||||
#[test]
|
||||
fn test_map() {
|
||||
let parser = map(
|
||||
seq2(literal("a"), literal("b")),
|
||||
|(_a, _b): (&str, &str)| 59,
|
||||
);
|
||||
let parser =
|
||||
seq2(literal("a"), literal("b")).map(|(a, _b): (&str, &str)| (a.to_uppercase(), 59));
|
||||
let output = parser.parse("abcd").unwrap();
|
||||
assert_eq!((59, "cd"), output);
|
||||
assert_eq!((("A".to_owned(), 59), "cd"), output);
|
||||
|
||||
let spaces = repeated(literal_char(' ')).at_least(1);
|
||||
let parser = seq2(literal("lute"), spaces).to(500);
|
||||
assert_eq!(parser.parse("lute "), Ok((500, "")));
|
||||
assert_eq!(parser.parse("lute"), Err(((), "")));
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_combinators() {
|
||||
let parser = seq2(map(repeated(literal_char('a')), |_| 10), literal_char('b'));
|
||||
let parser = repeated(literal_char('a')).to(10).then(literal_char('b'));
|
||||
let output = parser.parse("aaaaaaaabcd").unwrap();
|
||||
assert_eq! {((10, 'b'), "cd"), output};
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user