27 lines
627 B
Rust
27 lines
627 B
Rust
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use crate::parser::Parser;
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pub fn choice<P1, P2, I, O, E>(parser1: P1, parser2: P2) -> impl Parser<I, O, E>
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where
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P1: Parser<I, O, E>,
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P2: Parser<I, O, E>,
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I: Copy,
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{
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move |input| match parser1.parse(input) {
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ok @ Ok(..) => ok,
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Err(_e) => parser2.parse(input),
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::combinators::one_or_more;
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use crate::primitives::literal;
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#[test]
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fn test_choice() {
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let p = choice(literal("gnostika").to(1), one_or_more(literal(" ")).to(2));
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assert_eq!(p.parse("gnostika twentynine"), Ok((1, " twentynine")));
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}
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}
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