Function extract

src/debug_utils/generic_function/parse.rs:25–35

Helper function to extract N sub-pairs when the layout of a rule is fixed.

(pair: Pair<'_, Rule>, expected_rules: [Rule; N])

/// Helper function to extract N sub-pairs when the layout of a rule is fixed.
fn extract<const N: usize>(pair: Pair<'_, Rule>, expected_rules: [Rule; N]) -> [Pair<'_, Rule>; N] {
    let mut out = [(); N].map(|()| pair.clone());
    let mut i = 0;
    for pair in pair.into_inner() {
        assert_eq!(pair.as_rule(), expected_rules[i]);
        out[i] = pair;
        i += 1;
    }
    assert_eq!(i, N);
    out
}

/// Helper function to emit a custom error at the given span.
fn custom_error(span: Span<'_>, msg: &str) -> Error<Rule> {