perl將ascii轉成utf-8的方法

似乎每隔一陣子就會遇到，參考 http://perldoc.perl.org/utf8.html



    use utf8;
    no utf8;
    # Convert the internal representation of a Perl scalar to/from UTF-8.
    $num_octets = utf8::upgrade($string);
    $success    = utf8::downgrade($string[, FAIL_OK]);
    # Change each character of a Perl scalar to/from a series of
    # characters that represent the UTF-8 bytes of each original character.
    utf8::encode($string);  # "\x{100}"  becomes "\xc4\x80"
    utf8::decode($string);  # "\xc4\x80" becomes "\x{100}"
    $flag = utf8::is_utf8(STRING); # since Perl 5.8.1
    $flag = utf8::valid(STRING);