cypress 0.3.0

Build simple yet expressive parsers
Documentation 
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use crate::{error::Error, parser::*};

/// A parser combinator that parses a sequence of two parsers in order.
///
/// `PSeq` runs the first parser `p1` followed by the second parser `p2`,
/// returning a tuple of their parsed outputs.
///
/// # Type Parameters
///
/// * `P1` - The first parser type.
/// * `P2` - The second parser type.
#[derive(Clone)]
pub struct PSeq<P1, P2> {
    /// The first parser to run.
    p1: P1,
    /// The second parser to run after `p1`.
    p2: P2,
}

/// Creates a new `PSeq` parser combinator that parses two parsers in sequence.
///
/// # Arguments
///
/// * `p1` - The first parser to run.
/// * `p2` - The second parser to run after `p1`.
///
/// # Returns
///
/// A `PSeq` instance implementing `ParserCore` which returns a tuple of
/// `(output_of_p1, output_of_p2)`.
pub fn pseq<P1, P2>(p1: P1, p2: P2) -> PSeq<P1, P2> {
    PSeq { p1, p2 }
}

impl<'a, P1, P2, K, O1, O2> ParserCore<'a, K, (O1, O2)> for PSeq<P1, P2>
where
    K: PartialEq + Clone + 'a,
    O1: Clone + 'a,
    O2: Clone + 'a,
    P1: Parser<'a, K, O1>,
    P2: Parser<'a, K, O2>,
{
    /// Parses input sequentially with `p1` and then `p2`.
    ///
    /// First, attempts to parse input with `p1`.
    /// If successful, uses the remaining input to parse with `p2`.
    /// Returns a tuple of both parsed results.
    ///
    /// # Arguments
    ///
    /// * `i` - The parser input.
    ///
    /// # Returns
    ///
    /// * `Ok(PSuccess)` with a tuple `(O1, O2)` containing results of both parsers and the remaining input.
    /// * `Err(Error)` if either parser fails.
    fn parse(&self, i: PInput<'a, K>) -> Result<PSuccess<'a, K, (O1, O2)>, Error<'a, K>> {
        // Parse with the first parser
        let PSuccess { val: f_val, rest } = self.p1.parse(i)?;
        // Parse with the second parser from the remaining input
        let PSuccess { val: s_val, rest } = self.p2.parse(rest)?;

        Ok(PSuccess {
            val: (f_val, s_val),
            rest,
        })
    }
}

impl<'a, P1, P2, K, O1, O2> Parser<'a, K, (O1, O2)> for PSeq<P1, P2>
where
    K: PartialEq + Clone + 'a,
    O1: Clone + 'a,
    O2: Clone + 'a,
    P1: Parser<'a, K, O1>,
    P2: Parser<'a, K, O2>,
{
}