{
    my ($line, $char); BEGIN { ($line, $char) = (1, 0) }

    sub text_show {
        my ($text, $str) = @_;

        if (0 == index $str, "\r") {
            $str = substr $str, 1;
            $text->delete("$line.0", "$line.$char");
            $char = 0;
        }

        $text->insert("$line.$char" => $str);

        if (-1 < index $str, "\n") {
            $line += $str =~ y/\n//;
            $char = length(substr $str, rindex $str, "\n") - 1;
        }
        else {
            $char += length $str;
        }

        $text->see("$line.$char");
    }
}