Function at

crates/sre_engine/src/engine.rs:1192–1208

(req: &Request<'_, S>, ctx: &MatchContext, at_code: SreAtCode)

}

fn at<S: StrDrive>(req: &Request<'_, S>, ctx: &MatchContext, at_code: SreAtCode) -> bool {
    match at_code {
        SreAtCode::BEGINNING | SreAtCode::BEGINNING_STRING => ctx.at_beginning(),
        SreAtCode::BEGINNING_LINE => ctx.at_beginning() || is_linebreak(ctx.back_peek_char::<S>()),
        SreAtCode::BOUNDARY => ctx.at_boundary(req, is_word),
        SreAtCode::NON_BOUNDARY => ctx.at_non_boundary(req, is_word),
        SreAtCode::END => {
            (ctx.remaining_chars(req) == 1 && ctx.at_linebreak(req)) || ctx.at_end(req)
        }
        SreAtCode::END_LINE => ctx.at_linebreak(req) || ctx.at_end(req),
        SreAtCode::END_STRING => ctx.at_end(req),
        SreAtCode::LOC_BOUNDARY => ctx.at_boundary(req, is_loc_word),
        SreAtCode::LOC_NON_BOUNDARY => ctx.at_non_boundary(req, is_loc_word),
        SreAtCode::UNI_BOUNDARY => ctx.at_boundary(req, is_uni_word),
        SreAtCode::UNI_NON_BOUNDARY => ctx.at_non_boundary(req, is_uni_word),
    }
}

fn char_loc_ignore(code: u32, c: u32) -> bool {
    code == c || code == lower_locate(c) || code == upper_locate(c)