[perldocjp-cvs 369] CVS update: docs/perl/5.10.0

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argra****@users***** argra****@users*****
2009年 1月 1日 (木) 23:38:19 JST


Index: docs/perl/5.10.0/perlunifaq.pod
diff -u /dev/null docs/perl/5.10.0/perlunifaq.pod:1.1
--- /dev/null	Thu Jan  1 23:38:19 2009
+++ docs/perl/5.10.0/perlunifaq.pod	Thu Jan  1 23:38:18 2009
@@ -0,0 +1,853 @@
+
+=encoding euc-jp
+
+=head1 NAME
+
+=begin original
+
+perlunifaq - Perl Unicode FAQ
+
+=end original
+
+perlunifaq - Perl Unicode FAQ
+
+=head1 Q and A
+
+=begin original
+
+This is a list of questions and answers about Unicode in Perl, intended to be
+read after L<perlunitut>.
+
+=end original
+
+これは、L<perlunitut> の後で読むことを想定した、Perl での Unicode に関する
+質問と答えの一覧です。
+
+=head2 perlunitut isn't really a Unicode tutorial, is it?
+
+(perlunitut は実際には Unicode チュートリアルじゃないんじゃないの?)
+
+=begin original
+
+No, and this isn't really a Unicode FAQ.
+
+=end original
+
+はい、違います; そしてこれは実際には Unicode FAQ ではありません。
+
+=begin original
+
+Perl has an abstracted interface for all supported character encodings, so they
+is actually a generic C<Encode> tutorial and C<Encode> FAQ. But many people
+think that Unicode is special and magical, and I didn't want to disappoint
+them, so I decided to call the document a Unicode tutorial.
+
+=end original
+
+Perl は対応している全ての文字エンコーディングへの抽象インターフェースを
+持っているので、実際には汎用の C<Encode> チュートリアルと
+C<Encode> FAQ です。
+しかし、多くの人々が、Unicode は特別でマジカルなものだと考えていて、
+私は彼らを失望させたくなかったので、そのドキュメントを
+Unicode チュートリアルと呼ぶことに決めました。
+
+=head2 What character encodings does Perl support?
+
+(Perl が対応している文字エンコーディングは何?)
+
+=begin original
+
+To find out which character encodings your Perl supports, run:
+
+=end original
+
+Perl がどの文字エンコーディングに対応しているかを見つけるには、以下を
+実行してください:
+
+    perl -MEncode -le "print for Encode->encodings(':all')"
+
+=head2 Which version of perl should I use?
+
+(どのバージョンの perl を使うべき?)
+
+=begin original
+
+Well, if you can, upgrade to the most recent, but certainly C<5.8.1> or newer.
+The tutorial and FAQ are based on the status quo as of C<5.8.8>.
+
+=end original
+
+うーん、もし可能なら、最新にアップグレードしてください; 但し、確実に
+C<5.8.1> 以降にはしてください。
+チュートリアルと FAQ は C<5.8.8> の状態を基にしています。
+
+=begin original
+
+You should also check your modules, and upgrade them if necessary. For example,
+HTML::Entities requires version >= 1.32 to function correctly, even though the
+changelog is silent about this.
+
+=end original
+
+モジュールもチェックして、もし必要ならアップグレードするべきです。
+例えば HTML::Entities は、changelog は何も触れていませんが、正しく
+動作するためにはバージョン >= 1.32 が必要です。
+
+=head2 What about binary data, like images?
+
+(イメージのようなバイナリデータはどうするの?)
+
+=begin original
+
+Well, apart from a bare C<binmode $fh>, you shouldn't treat them specially.
+(The binmode is needed because otherwise Perl may convert line endings on Win32
+systems.)
+
+=end original
+
+うーん、生の C<binmode $fh> を別として、特別に扱う必要はないはずです。
+(Win32 システムで Perl が行端を変更しないようにするために、binmode が
+必要です。)
+
+=begin original
+
+Be careful, though, to never combine text strings with binary strings. If you
+need text in a binary stream, encode your text strings first using the
+appropriate encoding, then join them with binary strings. See also: "What if I
+don't encode?".
+
+=end original
+
+但し、決してテキスト文字列とバイナリ文字列を結合しないように
+注意してください。
+もしバイナリストリームにテキストが必要なら、まずテキスト文字列を適切な
+エンコーディングを使ってエンコードして、それをバイナリ文字列と
+結合してください。
+L<"What if I don't encode?"> も参照してください。
+
+=head2 When should I decode or encode?
+
+(デコードやエンコードはいつ行うべき?)
+
+=begin original
+
+Whenever you're communicating text with anything that is external to your perl
+process, like a database, a text file, a socket, or another program. Even if
+the thing you're communicating with is also written in Perl.
+
+=end original
+
+データベース、テキストファイル、ソケット、他のプログラムといった、自分の
+perl プロセスの外側にある何かとテキストを通信するときはいつでも、です。
+通信の相手が Perl で書かれている場合も同じです。
+
+=head2 What if I don't decode?
+
+(デコードしないとどうなるの?)
+
+=begin original
+
+Whenever your encoded, binary string is used together with a text string, Perl
+will assume that your binary string was encoded with ISO-8859-1, also known as
+latin-1. If it wasn't latin-1, then your data is unpleasantly converted. For
+example, if it was UTF-8, the individual bytes of multibyte characters are seen
+as separate characters, and then again converted to UTF-8. Such double encoding
+can be compared to double HTML encoding (C<&amp;gt;>), or double URI encoding
+(C<%253E>).
+
+=end original
+
+エンコードされたバイナリ文字列をテキスト文字列と一緒に使ったときはいつでも、
+Perl はバイナリ文字列が ISO-8859-1 またの名を latin-1 と仮定します。
+もしこれが latin-1 でなかった場合、データは不愉快な形に変換されます。
+例えば、もしデータが UTF-8 だった場合、マルチバイト文字のそれぞれのバイトが
+文字として扱われ、それから再び UTF-8 に変換されます。
+このような二重エンコードは二重 HTML エンコーディング (C<&amp;gt;>) や
+二重 URI エンコーディング (C<%253E>) と比較できます。
+
+=begin original
+
+This silent implicit decoding is known as "upgrading". That may sound
+positive, but it's best to avoid it.
+
+=end original
+
+この、暗黙のうちに行われるデコードは「昇格」("upgrading")と呼ばれます。
+これは前向きなことに聞こえるかもしれませんが、避けるのが最良です。
+
+=head2 What if I don't encode?
+
+(エンコードしないとどうなるの?)
+
+=begin original
+
+Your text string will be sent using the bytes in Perl's internal format. In
+some cases, Perl will warn you that you're doing something wrong, with a
+friendly warning:
+
+=end original
+
+テキスト文字列は Perl の内部形式のバイト列を使って送信されます。
+いくつかの場合では、Perl は何かが間違っていることを、親切なメッセージで
+警告します:
+
+    Wide character in print****@examp***** line 2.
+
+=begin original
+
+Because the internal format is often UTF-8, these bugs are hard to spot,
+because UTF-8 is usually the encoding you wanted! But don't be lazy, and don't
+use the fact that Perl's internal format is UTF-8 to your advantage. Encode
+explicitly to avoid weird bugs, and to show to maintenance programmers that you
+thought this through.
+
+=end original
+
+内部形式はしばしば UTF-8 なので、このバグは発見しにくいです; なぜなら
+あなたがほしいのは普通 UTF-8 だからです!
+しかし、手を抜かないでください; そして Perl の内部形式が UTF-8 であることを
+利用しようとしないでください。
+奇妙なバグを防ぐため、そして保守プログラマに対してあなたが何を考えたかを
+示すために、明示的にエンコードしてください。
+
+=head2 Is there a way to automatically decode or encode?
+
+(自動的にデコードやエンコードする方法はある?)
+
+=begin original
+
+If all data that comes from a certain handle is encoded in exactly the same
+way, you can tell the PerlIO system to automatically decode everything, with
+the C<encoding> layer. If you do this, you can't accidentally forget to decode
+or encode anymore, on things that use the layered handle.
+
+=end original
+
+もし、あるハンドルから来る全てのデータが正確に同じ方法で
+エンコードされているなら、C<encoding> 層を使って、 PerlIO システムに自動的に
+全てをデコードするように伝えることができます。
+これを行えば、この層のハンドルを使っている限り、うっかりデコードや
+エンコードを忘れることはありません。
+
+=begin original
+
+You can provide this layer when C<open>ing the file:
+
+=end original
+
+ファイルを C<open> するときにこの層を指定することができます:
+
+    open my $fh, '>:encoding(UTF-8)', $filename;  # auto encoding on write
+    open my $fh, '<:encoding(UTF-8)', $filename;  # auto decoding on read
+
+=begin original
+
+Or if you already have an open filehandle:
+
+=end original
+
+あるいは既にオープンしているファイルハンドルがあるなら:
+
+    binmode $fh, ':encoding(UTF-8)';
+
+=begin original
+
+Some database drivers for DBI can also automatically encode and decode, but
+that is sometimes limited to the UTF-8 encoding.
+
+=end original
+
+DBI のデータベースドライバのいくつかも、エンコードとデコードを自動的に
+行いますが、ときどきこれは UTF-8 エンコーディングに制限されています。
+
+=head2 What if I don't know which encoding was used?
+
+(どのエンコーディングが使われているかわからないときは?)
+
+=begin original
+
+Do whatever you can to find out, and if you have to: guess. (Don't forget to
+document your guess with a comment.)
+
+=end original
+
+なんとかして見つけるか、もし必要なら、推測してください。
+(どう推測したかをコメントとして文書化するのを忘れないでください。)
+
+=begin original
+
+You could open the document in a web browser, and change the character set or
+character encoding until you can visually confirm that all characters look the
+way they should.
+
+=end original
+
+ドキュメントを web ブラウザで開いて、全ての文字があるべき形であることを
+視覚的に確認できるまで文字集合や文字エンコーディングを変更する方法も
+あります。
+
+=begin original
+
+There is no way to reliably detect the encoding automatically, so if people
+keep sending you data without charset indication, you may have to educate them.
+
+=end original
+
+エンコーディングを自動的に検出するための信頼性のある方法はないので、
+もし人々があなたに文字集合の指示なしにデータを送り続けるなら、彼らを
+教育する必要があるかもしれません。
+
+=head2 Can I use Unicode in my Perl sources?
+
+(Perl のソースコードに Unicode は使える?)
+
+=begin original
+
+Yes, you can! If your sources are UTF-8 encoded, you can indicate that with the
+C<use utf8> pragma.
+
+=end original
+
+はい、できます!
+ソースコードが UTF-8 でエンコードされているなら、C<use utf8> プラグマを
+使ってそれを示すことができます。
+
+    use utf8;
+
+=begin original
+
+This doesn't do anything to your input, or to your output. It only influences
+the way your sources are read. You can use Unicode in string literals, in
+identifiers (but they still have to be "word characters" according to C<\w>),
+and even in custom delimiters.
+
+=end original
+
+This doesn't do anything to your input, or to your output. It only influences
+the way your sources are read. You can use Unicode in string literals, in
+identifiers (but they still have to be "word characters" according to C<\w>),
+and even in custom delimiters.
+(TBT)
+
+=head2 Data::Dumper doesn't restore the UTF8 flag; is it broken?
+
+(Data::Dumper は UTF8 フラグを復元しません; これは壊れてるの?)
+
+=begin original
+
+No, Data::Dumper's Unicode abilities are as they should be. There have been
+some complaints that it should restore the UTF8 flag when the data is read
+again with C<eval>. However, you should really not look at the flag, and
+nothing indicates that Data::Dumper should break this rule.
+
+=end original
+
+No, Data::Dumper's Unicode abilities are as they should be. There have been
+some complaints that it should restore the UTF8 flag when the data is read
+again with C<eval>. However, you should really not look at the flag, and
+nothing indicates that Data::Dumper should break this rule.
+(TBT)
+
+=begin original
+
+Here's what happens: when Perl reads in a string literal, it sticks to 8 bit
+encoding as long as it can. (But perhaps originally it was internally encoded
+as UTF-8, when you dumped it.) When it has to give that up because other
+characters are added to the text string, it silently upgrades the string to
+UTF-8. 
+
+=end original
+
+Here's what happens: when Perl reads in a string literal, it sticks to 8 bit
+encoding as long as it can. (But perhaps originally it was internally encoded
+as UTF-8, when you dumped it.) When it has to give that up because other
+characters are added to the text string, it silently upgrades the string to
+UTF-8. 
+(TBT)
+
+=begin original
+
+If you properly encode your strings for output, none of this is of your
+concern, and you can just C<eval> dumped data as always.
+
+=end original
+
+出力用の文字列を適切にエンコードしていれば、これについてあなたは何も
+心配することはなく、いつも通りにダンプしたデータを C<eval> できます。
+
+=head2 Why do regex character classes sometimes match only in the ASCII range?
+
+(なぜ正規表現文字クラスは時々 ASCII の範囲にしかマッチしないの?)
+
+=head2 Why do some characters not uppercase or lowercase correctly?
+
+(なぜいくつかの文字は正しく大文字や小文字にならないの?)
+
+=begin original
+
+It seemed like a good idea at the time, to keep the semantics the same for
+standard strings, when Perl got Unicode support. While it might be repaired
+in the future, we now have to deal with the fact that Perl treats equal
+strings differently, depending on the internal state.
+
+=end original
+
+It seemed like a good idea at the time, to keep the semantics the same for
+standard strings, when Perl got Unicode support. While it might be repaired
+in the future, we now have to deal with the fact that Perl treats equal
+strings differently, depending on the internal state.
+(TBT)
+
+=begin original
+
+Affected are C<uc>, C<lc>, C<ucfirst>, C<lcfirst>, C<\U>, C<\L>, C<\u>, C<\l>,
+C<\d>, C<\s>, C<\w>, C<\D>, C<\S>, C<\W>, C</.../i>, C<(?i:...)>,
+C</[[:posix:]]/>.
+
+=end original
+
+影響を受けるのは C<uc>, C<lc>, C<ucfirst>, C<lcfirst>, C<\U>, C<\L>, C<\u>, C<\l>,
+C<\d>, C<\s>, C<\w>, C<\D>, C<\S>, C<\W>, C</.../i>, C<(?i:...)>,
+C</[[:posix:]]/> です。
+
+=begin original
+
+To force Unicode semantics, you can upgrade the internal representation to
+by doing C<utf8::upgrade($string)>. This does not change strings that were
+already upgraded.
+
+=end original
+
+Unicode の意味論を強制するために、C<utf8::upgrade($string)> とすることで
+内部表現を昇格できます。
+これは既に昇格している文字列は変更しません。
+
+=begin original
+
+For a more detailed discussion, see L<Unicode::Semantics> on CPAN.
+
+=end original
+
+さらなる詳細な議論については、CPAN の L<Unicode::Semantics> を
+参照してください。
+
+=head2 How can I determine if a string is a text string or a binary string?
+
+(文字列がテキスト文字列かバイナリ文字列かを決定するには?)
+
+=begin original
+
+You can't. Some use the UTF8 flag for this, but that's misuse, and makes well
+behaved modules like Data::Dumper look bad. The flag is useless for this
+purpose, because it's off when an 8 bit encoding (by default ISO-8859-1) is
+used to store the string.
+
+=end original
+
+それはできません。
+このために UTF8 フラグを使う人もいますが、これは誤用で、Data::Dumper のように
+正しく振る舞うモジュールをおかしくします。
+このフラグはこの目的のためには使えません; なぜなら文字列の保管に 8 ビット
+エンコーディングが使われている場合 (デフォルトでは ISO-8859-1 です)、
+オフだからです。
+
+=begin original
+
+This is something you, the programmer, has to keep track of; sorry. You could
+consider adopting a kind of "Hungarian notation" to help with this.
+
+=end original
+
+把握しておく必要があるプログラマに言えることはこれです; ごめんなさい。
+これを助けるために、「ハンガリアン記法」のようなものの採用を
+検討することもできます。
+
+=head2 How do I convert from encoding FOO to encoding BAR?
+
+(エンコーディング FOO から エンコーディング BAR に変換するには?)
+
+=begin original
+
+By first converting the FOO-encoded byte string to a text string, and then the
+text string to a BAR-encoded byte string:
+
+=end original
+
+まず FOO でエンコードされたバイト文字列をテキスト文字列に変化し、
+それからテキスト文字列を BAR エンコードされたバイト文字列に変換します:
+
+    my $text_string = decode('FOO', $foo_string);
+    my $bar_string  = encode('BAR', $text_string);
+
+=begin original
+
+or by skipping the text string part, and going directly from one binary
+encoding to the other:
+
+=end original
+
+あるいは、テキスト文字列の部分を飛ばして、あるバイナリエンコーディングから
+他のものへ直接変換します:
+
+    use Encode qw(from_to);
+    from_to($string, 'FOO', 'BAR');  # changes contents of $string
+
+=begin original
+
+or by letting automatic decoding and encoding do all the work:
+
+=end original
+
+あるいは、自動でデコードとエンコードをさせることで全ての作業を行います:
+
+    open my $foofh, '<:encoding(FOO)', 'example.foo.txt';
+    open my $barfh, '>:encoding(BAR)', 'example.bar.txt';
+    print { $barfh } $_ while <$foofh>;
+
+=head2 What are C<decode_utf8> and C<encode_utf8>?
+
+(C<decode_utf8> と C<encode_utf8> って何?)
+
+=begin original
+
+These are alternate syntaxes for C<decode('utf8', ...)> and C<encode('utf8',
+...)>.
+
+=end original
+
+これらは C<decode('utf8', ...)> および C<encode('utf8', ...)> のもう一つの
+文法です。
+
+=head2 What is a "wide character"?
+
+(「ワイド文字」って何?)
+
+=begin original
+
+This is a term used both for characters with an ordinal value greater than 127,
+characters with an ordinal value greater than 255, or any character occupying
+than one byte, depending on the context.
+
+=end original
+
+This is a term used both for characters with an ordinal value greater than 127,
+characters with an ordinal value greater than 255, or any character occupying
+than one byte, depending on the context.
+(TBT)
+
+=begin original
+
+The Perl warning "Wide character in ..." is caused by a character with an
+ordinal value greater than 255. With no specified encoding layer, Perl tries to
+fit things in ISO-8859-1 for backward compatibility reasons. When it can't, it
+emits this warning (if warnings are enabled), and outputs UTF-8 encoded data
+instead.
+
+=end original
+
+The Perl warning "Wide character in ..." is caused by a character with an
+ordinal value greater than 255. With no specified encoding layer, Perl tries to
+fit things in ISO-8859-1 for backward compatibility reasons. When it can't, it
+emits this warning (if warnings are enabled), and outputs UTF-8 encoded data
+instead.
+(TBT)
+
+=begin original
+
+To avoid this warning and to avoid having different output encodings in a single
+stream, always specify an encoding explicitly, for example with a PerlIO layer:
+
+=end original
+
+To avoid this warning and to avoid having different output encodings in a single
+stream, always specify an encoding explicitly, for example with a PerlIO layer:
+(TBT)
+
+    binmode STDOUT, ":encoding(UTF-8)";
+
+=head1 INTERNALS
+
+(内部構造)
+
+=head2 What is "the UTF8 flag"?
+
+(「UTF8 フラグ」って何?)
+
+=begin original
+
+Please, unless you're hacking the internals, or debugging weirdness, don't
+think about the UTF8 flag at all. That means that you very probably shouldn't
+use C<is_utf8>, C<_utf8_on> or C<_utf8_off> at all.
+
+=end original
+
+Please, unless you're hacking the internals, or debugging weirdness, don't
+think about the UTF8 flag at all. That means that you very probably shouldn't
+use C<is_utf8>, C<_utf8_on> or C<_utf8_off> at all.
+(TBT)
+
+=begin original
+
+The UTF8 flag, also called SvUTF8, is an internal flag that indicates that the
+current internal representation is UTF-8. Without the flag, it is assumed to be
+ISO-8859-1. Perl converts between these automatically.
+
+=end original
+
+The UTF8 flag, also called SvUTF8, is an internal flag that indicates that the
+current internal representation is UTF-8. Without the flag, it is assumed to be
+ISO-8859-1. Perl converts between these automatically.
+(TBT)
+
+=begin original
+
+One of Perl's internal formats happens to be UTF-8. Unfortunately, Perl can't
+keep a secret, so everyone knows about this. That is the source of much
+confusion. It's better to pretend that the internal format is some unknown
+encoding, and that you always have to encode and decode explicitly.
+
+=end original
+
+One of Perl's internal formats happens to be UTF-8. Unfortunately, Perl can't
+keep a secret, so everyone knows about this. That is the source of much
+confusion. It's better to pretend that the internal format is some unknown
+encoding, and that you always have to encode and decode explicitly.
+(TBT)
+
+=head2 What about the C<use bytes> pragma?
+
+(C<use bytes> プラグマって何?)
+
+=begin original
+
+Don't use it. It makes no sense to deal with bytes in a text string, and it
+makes no sense to deal with characters in a byte string. Do the proper
+conversions (by decoding/encoding), and things will work out well: you get
+character counts for decoded data, and byte counts for encoded data.
+
+=end original
+
+これは使わないでください。
+It makes no sense to deal with bytes in a text string, and it
+makes no sense to deal with characters in a byte string. Do the proper
+conversions (by decoding/encoding), and things will work out well: you get
+character counts for decoded data, and byte counts for encoded data.
+(TBT)
+
+=begin original
+
+C<use bytes> is usually a failed attempt to do something useful. Just forget
+about it.
+
+=end original
+
+C<use bytes> is usually a failed attempt to do something useful. Just forget
+about it.
+(TBT)
+
+=head2 What about the C<use encoding> pragma?
+
+(C<use encoding> プラグマって何?)
+
+=begin original
+
+Don't use it. Unfortunately, it assumes that the programmer's environment and
+that of the user will use the same encoding. It will use the same encoding for
+the source code and for STDIN and STDOUT. When a program is copied to another
+machine, the source code does not change, but the STDIO environment might.
+
+=end original
+
+これは使わないでください。
+Unfortunately, it assumes that the programmer's environment and
+that of the user will use the same encoding. It will use the same encoding for
+the source code and for STDIN and STDOUT. When a program is copied to another
+machine, the source code does not change, but the STDIO environment might.
+(TBT)
+
+=begin original
+
+If you need non-ASCII characters in your source code, make it a UTF-8 encoded
+file and C<use utf8>.
+
+=end original
+
+もしソースコードに非 ASCII 文字が必要なら、ファイルを UTF-8 で
+エンコードして、C<use utf8> を使ってください。
+
+=begin original
+
+If you need to set the encoding for STDIN, STDOUT, and STDERR, for example
+based on the user's locale, C<use open>.
+
+=end original
+
+If you need to set the encoding for STDIN, STDOUT, and STDERR, for example
+based on the user's locale, C<use open>.
+(TBT)
+
+=head2 What is the difference between C<:encoding> and C<:utf8>?
+
+(C<:encoding> と C<:utf8> の違いは?)
+
+=begin original
+
+Because UTF-8 is one of Perl's internal formats, you can often just skip the
+encoding or decoding step, and manipulate the UTF8 flag directly.
+
+=end original
+
+UTF-8 は Perl の内部形式のひとつなので、しばしばエンコードやデコードの
+手順を省略して、UTF8 フラグを直接操作できます。
+
+=begin original
+
+Instead of C<:encoding(UTF-8)>, you can simply use C<:utf8>, which skips the
+encoding step if the data was already represented as UTF8 internally. This is
+widely accepted as good behavior when you're writing, but it can be dangerous
+when reading, because it causes internal inconsistency when you have invalid
+byte sequences. Using C<:utf8> for input can sometimes result in security
+breaches, so please use C<:encoding(UTF-8)> instead.
+
+=end original
+
+C<:encoding(UTF-8)> の代わりに単に C<:utf8> を使うことで、もしデータが
+内部で既に UTF8 で表現されていれば、エンコードの手順を省略します。
+This is
+widely accepted as good behavior when you're writing, but it can be dangerous
+when reading, because it causes internal inconsistency when you have invalid
+byte sequences. Using C<:utf8> for input can sometimes result in security
+breaches, so please use C<:encoding(UTF-8)> instead.
+(TBT)
+
+=begin original
+
+Instead of C<decode> and C<encode>, you could use C<_utf8_on> and C<_utf8_off>,
+but this is considered bad style. Especially C<_utf8_on> can be dangerous, for
+the same reason that C<:utf8> can.
+
+=end original
+
+C<decode> と C<encode> の代わりに、C<_utf8_on> と C<_utf8_off> を
+使えますが、これは悪いスタイルと考えられています。
+特に C<_utf8_on> は、C<:utf8> と同じ理由で危険です。
+
+=begin original
+
+There are some shortcuts for oneliners; see C<-C> in L<perlrun>.
+
+=end original
+
+一行野郎のための省略形があります; L<perlrun> の C<-C> を参照してください。
+
+=head2 What's the difference between C<UTF-8> and C<utf8>?
+
+(C<UTF-8> と C<utf8> の違いは?)
+
+=begin original
+
+C<UTF-8> is the official standard. C<utf8> is Perl's way of being liberal in
+what it accepts. If you have to communicate with things that aren't so liberal,
+you may want to consider using C<UTF-8>. If you have to communicate with things
+that are too liberal, you may have to use C<utf8>. The full explanation is in
+L<Encode>.
+
+=end original
+
+C<UTF-8> は公式な標準です。
+C<utf8> is Perl's way of being liberal in
+what it accepts.
+もしそれほど自由でないものと対話する必要があるなら、
+C<UTF-8> を使うことを考えたくなるかもしれません。
+自由すぎるものと対話する必要があるなら、C<utf8> を
+使わなければならないかもしれません。
+完全な説明は L<Encode> にあります。
+(TBT)
+
+=begin original
+
+C<UTF-8> is internally known as C<utf-8-strict>. The tutorial uses UTF-8
+consistently, even where utf8 is actually used internally, because the
+distinction can be hard to make, and is mostly irrelevant.
+
+=end original
+
+C<UTF-8> は内部では C<utf-8-strict> として知られます。
+チュートリアルでは、たとえ内部では実際には utf8 が使われる場合でも
+一貫して UTF-8 を使っています; なぜなら区別をつけるのは難しく、ほとんど
+無意味だからです。
+
+=begin original
+
+For example, utf8 can be used for code points that don't exist in Unicode, like
+9999999, but if you encode that to UTF-8, you get a substitution character (by
+default; see L<Encode/"Handling Malformed Data"> for more ways of dealing with
+this.)
+
+=end original
+
+例えば utf8 は、9999999 のような、Unicode に存在しない符号位置も使えますが、
+これを UTF-8 でエンコードすると、代替文字を得ることになります(これは
+デフォルトの場合です; これを扱う他の方法については
+L<Encode/"Handling Malformed Data"> を参照してください。)
+
+=begin original
+
+Okay, if you insist: the "internal format" is utf8, not UTF-8. (When it's not
+some other encoding.)
+
+=end original
+
+Okay, if you insist: the "internal format" is utf8, not UTF-8. (When it's not
+some other encoding.)
+(TBT)
+
+=head2 I lost track; what encoding is the internal format really?
+
+(迷子になりました; 実際のところ内部形式のエンコーディングは何?)
+
+=begin original
+
+It's good that you lost track, because you shouldn't depend on the internal
+format being any specific encoding. But since you asked: by default, the
+internal format is either ISO-8859-1 (latin-1), or utf8, depending on the
+history of the string. On EBCDIC platforms, this may be different even.
+
+=end original
+
+迷子になったのはよいことです; なぜなら内部形式が特定のエンコーディングで
+あることに依存するべきではないからです。
+しかし聞かれたので答えましょう: デフォルトでは、内部形式は
+ISO-8859-1 (latin-1) か utf8 で、どちらになるかは文字列の歴史に
+依存します。
+EBCDIC プラットフォームでは、これは異なっているかもしれません。
+
+=begin original
+
+Perl knows how it stored the string internally, and will use that knowledge
+when you C<encode>. In other words: don't try to find out what the internal
+encoding for a certain string is, but instead just encode it into the encoding
+that you want.
+
+=end original
+
+Perl は文字列が内部でどのように保管されているかを知っていて、この知識を
+C<エンコードする> ときに使います。
+言い換えると: 特定の文字列の内部エンコーディングが何かを
+調べようとしてはいけません; 代わりに、単に望みのエンコーディングに
+エンコードしてください。
+
+=head1 AUTHOR
+
+Juerd Waalboer <#####@juerd.nl>
+
+=head1 SEE ALSO
+
+L<perlunicode>, L<perluniintro>, L<Encode>
+
+=begin meta
+
+Created: Kentaro Shirakata <argra****@ub32*****> (5.10.0-)
+
+=end meta
+


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