Function readline_advanced

smallthinker/common/console.cpp:355–456

    }

    static bool readline_advanced(std::string & line, bool multiline_input) {
        if (out != stdout) {
            fflush(stdout);
        }

        line.clear();
        std::vector<int> widths;
        bool is_special_char = false;
        bool end_of_stream = false;

        char32_t input_char;
        while (true) {
            fflush(out); // Ensure all output is displayed before waiting for input
            input_char = getchar32();

            if (input_char == '\r' || input_char == '\n') {
                break;
            }

            if (input_char == (char32_t) WEOF || input_char == 0x04 /* Ctrl+D*/) {
                end_of_stream = true;
                break;
            }

            if (is_special_char) {
                set_display(user_input);
                replace_last(line.back());
                is_special_char = false;
            }

            if (input_char == '\033') { // Escape sequence
                char32_t code = getchar32();
                if (code == '[' || code == 0x1B) {
                    // Discard the rest of the escape sequence
                    while ((code = getchar32()) != (char32_t) WEOF) {
                        if ((code >= 'A' && code <= 'Z') || (code >= 'a' && code <= 'z') || code == '~') {
                            break;
                        }
                    }
                }
            } else if (input_char == 0x08 || input_char == 0x7F) { // Backspace
                if (!widths.empty()) {
                    int count;
                    do {
                        count = widths.back();
                        widths.pop_back();
                        // Move cursor back, print space, and move cursor back again
                        for (int i = 0; i < count; i++) {
                            replace_last(' ');
                            pop_cursor();
                        }
                        pop_back_utf8_char(line);
                    } while (count == 0 && !widths.empty());
                }
            } else {
                int offset = line.length();
                append_utf8(input_char, line);
                int width = put_codepoint(line.c_str() + offset, line.length() - offset, estimateWidth(input_char));