Method try_find_regex

subprojects/llama.cpp/common/chat-parser.cpp:440–458

Tries to find the regex, consumes it (pos right after it) and gives the prelude (right before it) and the groups to the callback.

// Tries to find the regex, consumes it (pos right after it) and gives the prelude (right before it) and the groups to the callback.
std::optional<common_chat_msg_parser::find_regex_result> common_chat_msg_parser::try_find_regex(const common_regex & regex, size_t from, bool add_prelude_to_content) {
    auto m = regex.search(input_, from == std::string::npos ? pos_ : from);
    if (m.type == COMMON_REGEX_MATCH_TYPE_NONE) {
        return std::nullopt;
    }
    auto prelude = input_.substr(pos_, m.groups[0].begin - pos_);
    pos_ = m.groups[0].end;

    if (add_prelude_to_content) {
        add_content(prelude);
    }
    if (m.type == COMMON_REGEX_MATCH_TYPE_PARTIAL) {
        if (is_partial()) {
            throw common_chat_msg_partial_exception(regex.str());
        }
        return std::nullopt;
    }
    return find_regex_result{prelude, m.groups};
}

common_chat_msg_parser::find_regex_result common_chat_msg_parser::consume_regex(const common_regex & regex) {
    if (auto result = try_consume_regex(regex)) {