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example and docs for word1

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Trevor Settles 2024-03-12 20:11:17 -06:00
parent 47b537c278
commit 7884d92e29
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crates/compiler/parse/src/parser.rs
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@ -1889,6 +1889,31 @@ where
}
}
/// Creates a new parser that changes the `Err` type.
/// This can be used as `.map`, but for errors.
/// It has no effect, if the inner parser succeeds.
///
/// # Examples
/// ```
/// # use roc_parse::state::{State};
/// # use crate::roc_parse::parser::{Parser, Progress, word, specialize};
/// # use roc_region::all::{Loc, Position};
/// # use bumpalo::Bump;
/// # #[derive(Debug, PartialEq)]
/// # enum Problem {
/// # NotFound(Position),
/// # Other(Position),
/// # }
/// # let arena = Bump::new();
/// let parser = specialize(
/// |_prev_err, pos| Problem::Other(pos),
/// word("bye", Problem::NotFound)
/// );
///
/// let (progress, err) = parser.parse(&arena, State::new("hello, world".as_bytes()), 0).unwrap_err();
/// assert_eq!(progress, Progress::NoProgress);
/// assert_eq!(err, Problem::Other(Position::new(0)));
/// ```
pub fn specialize<'a, F, P, T, X, Y>(map_error: F, parser: P) -> impl Parser<'a, T, Y>
where
F: Fn(X, Position) -> Y,
@ -1904,6 +1929,32 @@ where
}
}
/// Creates a new parser that changes the `Err` type.
/// This can be used as `.map`, but for errors.
/// Similar to `specialize`, the error is allocated, and the mapping function receives a reference to the error.
/// It has no effect, if the inner parser succeeds.
///
/// # Examples
/// ```
/// # use roc_parse::state::{State};
/// # use crate::roc_parse::parser::{Parser, Progress, word, specialize_ref};
/// # use roc_region::all::{Loc, Position};
/// # use bumpalo::Bump;
/// # #[derive(Debug, PartialEq)]
/// # enum Problem {
/// # NotFound(Position),
/// # Other(Position),
/// # }
/// # let arena = Bump::new();
/// let parser = specialize_ref(
/// |_prev_err, pos| Problem::Other(pos),
/// word("bye", Problem::NotFound)
/// );
///
/// let (progress, err) = parser.parse(&arena, State::new("hello, world".as_bytes()), 0).unwrap_err();
/// assert_eq!(progress, Progress::NoProgress);
/// assert_eq!(err, Problem::Other(Position::new(0)));
/// ```
pub fn specialize_ref<'a, F, P, T, X, Y>(map_error: F, parser: P) -> impl Parser<'a, T, Y>
where
F: Fn(&'a X, Position) -> Y,
@ -1976,6 +2027,45 @@ where
}
}
/// Matches a single `u8` and moves the state's position forward if it succeeds
///
/// # Example
/// ## Success case
/// ```rust
/// # use roc_parse::state::{State};
/// # use crate::roc_parse::parser::{Parser, Progress, word1};
/// # use roc_region::all::Position;
/// # use bumpalo::Bump;
/// # #[derive(Debug, PartialEq)]
/// # enum Problem {
/// # NotFound(Position),
/// # }
/// # let arena = Bump::new();
/// let parser = word1(b'h', Problem::NotFound);
/// let (progress, output, state) = parser.parse(&arena, State::new("hello, world".as_bytes()), 0).unwrap();
/// assert_eq!(progress, Progress::MadeProgress);
/// assert_eq!(output, ());
/// assert_eq!(state.pos(), Position::new(1));
/// ```
///
/// ## Failure case
/// ```rust
/// # use roc_parse::state::{State};
/// # use crate::roc_parse::parser::{Parser, Progress, word1};
/// # use roc_region::all::Position;
/// # use bumpalo::Bump;
/// # #[derive(Debug, PartialEq)]
/// # enum Problem {
/// # NotFound(Position),
/// # }
/// # let arena = Bump::new();
/// let parser = word1(b'?', Problem::NotFound);
/// let actual = parser.parse(&arena, State::new("hello, world".as_bytes()), 0).unwrap_err();
/// assert_eq!(
/// actual,
/// (Progress::NoProgress, Problem::NotFound(Position::zero())),
/// );
/// ```
pub fn word1<'a, ToError, E>(word: u8, to_error: ToError) -> impl Parser<'a, (), E>
where
ToError: Fn(Position) -> E,