メールアドレスの正規表現は？ 。。難しいとは聞いていたが、ここまでとは。 以下、fj.comp.lang.perlより。 Path: st.rim.or.jp!t3.rim.or.jp!rim.or.jp!Q.T.Honey!bay-noc-news!news.baku.or.jp!pooh.isoternet.org!satoru From: satoru@isoternet.org (Satoru Takabayashi) Newsgroups: fj.comp.lang.perl Subject: Re: perl でメールアドレスのチェックを行うには？ Date: 7 Oct 1998 18:10:16 GMT Organization: ISOTERNET ASSOCIATION JAPAN. Lines: 124 Message-ID: <6vgaq8$rk3$1@pooh.isoternet.org> References: <6vfifp$l2m$1@news2.dti.ne.jp> <361B5FCC.30FD2B28@safins.or.jp> NNTP-Posting-Host: pooh.isoternet.org X-Newsreader: mnews [version 1.21] 1997-12/23(Tue) Xref: st.rim.or.jp fj.comp.lang.perl:516 m-ono@safins.or.jp wrote: >comp.lang.perl.misc で以前活発に議論されているのを見たことがある >のですが、厳密には不可能だ、というのが識者の見解だったと思います。 >英文が難しくて、理由まで完全に理解できませんでした。どなたかこの >認識について理論的に説明していただけませんでしょうか。 Mastering Regular Expressions によると | Verifying correct syntax of an Internet email address is a common | need, but unfortunately, because of the standard's complexity, it | is quite difficult to do simply. In fact, it is impossible with a | regular expression because address comments may be nested. (Yes, | email addresses can have comments: comments are anything between | parentheses.) とのことです。著者はネストしたコメントはあきらめて下のような正規表 現を作成しました。 6,598 bytesに及ぶ芸術作品です。 [\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x 80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\ \x80-\xff\n\015()]*)*\)[\040\t]*)*(?:(?:[^(\040)<>@,;:".\\\[\]\000 -\037\x80-\xff]+(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff])|"[^\ \\x80-\xff\n\015"]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015"]*)*")[\04 0\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\ xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80 -\xff\n\015()]*)*\)[\040\t]*)*(?:\.[\040\t]*(?:\([^\\\x80-\xff\n\0 15()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\x ff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t] *)*(?:[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@,;:" .\\\[\]\000-\037\x80-\xff])|"[^\\\x80-\xff\n\015"]*(?:\\[^\x80-\xf f][^\\\x80-\xff\n\015"]*)*")[\040\t]*(?:\([^\\\x80-\xff\n\015()]*( ?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\ \x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*)*@[ \040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x8 0-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\ x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040)<>@,;:".\\\[\]\000-\03 7\x80-\xff]+(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff])|\[(?:[^\ \\x80-\xff\n\015\[\]]|\\[^\x80-\xff])*\])[\040\t]*(?:\([^\\\x80-\x ff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\ x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\ 040\t]*)*(?:\.[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80- \xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\01 5()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040)<>@,;:" .\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@,;:".\\\[\]\000-\037\x80- \xff])|\[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80-\xff])*\])[\040\t]*( ?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\ 015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\ n\015()]*)*\)[\040\t]*)*)*|(?:[^(\040)<>@,;:".\\\[\]\000-\037\x80- \xff]+(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff])|"[^\\\x80-\xff \n\015"]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015"]*)*")[^()<>@,;:".\\ \[\]\x80-\xff\000-\010\012-\037]*(?:(?:\([^\\\x80-\xff\n\015()]*(? :(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\ x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)|"[^\\\x80-\xff\ n\015"]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015"]*)*")[^()<>@,;:".\\\ [\]\x80-\xff\000-\010\012-\037]*)*<[\040\t]*(?:\([^\\\x80-\xff\n\0 15()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\x ff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t] *)*(?:@[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\ ([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)* \))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040)<>@,;:".\\\[\] \000-\037\x80-\xff]+(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff])| \[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80-\xff])*\])[\040\t]*(?:\([^\ \\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]* (?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015() ]*)*\)[\040\t]*)*(?:\.[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\ \[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\ xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040 )<>@,;:".\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@,;:".\\\[\]\000-\ 037\x80-\xff])|\[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80-\xff])*\])[\ 040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80 -\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x 80-\xff\n\015()]*)*\)[\040\t]*)*)*(?:,[\040\t]*(?:\([^\\\x80-\xff\ n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80 -\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040 \t]*)*@[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\ ([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)* \))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040)<>@,;:".\\\[\] \000-\037\x80-\xff]+(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff])| \[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80-\xff])*\])[\040\t]*(?:\([^\ \\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]* (?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015() ]*)*\)[\040\t]*)*(?:\.[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\ \[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\ xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040 )<>@,;:".\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@,;:".\\\[\]\000-\ 037\x80-\xff])|\[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80-\xff])*\])[\ 040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80 -\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x 80-\xff\n\015()]*)*\)[\040\t]*)*)*)*:[\040\t]*(?:\([^\\\x80-\xff\n \015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80- \xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\ t]*)*)?(?:[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@ ,;:".\\\[\]\000-\037\x80-\xff])|"[^\\\x80-\xff\n\015"]*(?:\\[^\x80 -\xff][^\\\x80-\xff\n\015"]*)*")[\040\t]*(?:\([^\\\x80-\xff\n\015( )]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff] [^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)* (?:\.[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([ ^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\) )[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:[^(\040)<>@,;:".\\\[\]\0 00-\037\x80-\xff]+(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff])|"[ ^\\\x80-\xff\n\015"]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015"]*)*")[\ 040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80 -\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x 80-\xff\n\015()]*)*\)[\040\t]*)*)*@[\040\t]*(?:\([^\\\x80-\xff\n\0 15()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\x ff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t] *)*(?:[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+(?![^(\040)<>@,;:" .\\\[\]\000-\037\x80-\xff])|\[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80 -\xff])*\])[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xf f]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015() ]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:\.[\040\t]*(?:\([^ \\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()] *(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015( )]*)*\)[\040\t]*)*(?:[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+(?! [^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff])|\[(?:[^\\\x80-\xff\n\01 5\[\]]|\\[^\x80-\xff])*\])[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?: (?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x 80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*)*>) # http://enterprise.ic.gc.ca/~jfriedl/regex/email-opt.pl に元の # コードがあります -- Satoru Takabayashi __EOF__ -------------------------------------------------------------------------- この正規表現を実際に使うには、Perl5で全ての行をつないでください。 -------------------------------------------------------------------------- http://enterprise.ic.gc.ca/~jfriedl/regex/email-opt.pl より。 # # Program to build a regex to match an internet email address, # from Chapter 7 of _Mastering Regular Expressions_ (Friedl / O'Reilly) # (http://www.ora.com/catalog/regexp/) # # Optimized version. # # Copyright 1997 O'Reilly & Associates, Inc. # # Some things for avoiding backslashitis later on. $esc = '\\\\'; $Period = '\.'; $space = '\040'; $tab = '\t'; $OpenBR = '\['; $CloseBR = '\]'; $OpenParen = '\('; $CloseParen = '\)'; $NonASCII = '\x80-\xff'; $ctrl = '\000-\037'; $CRlist = '\n\015'; # note: this should really be only \015. # Items 19, 20, 21 $qtext = qq/[^$esc$NonASCII$CRlist\"]/; # for within "..." $dtext = qq/[^$esc$NonASCII$CRlist$OpenBR$CloseBR]/; # for within [...] $quoted_pair = qq< $esc [^$NonASCII] >; # an escaped character ############################################################################## # Items 22 and 23, comment. # Impossible to do properly with a regex, I make do by allowing at most one level of nesting. $ctext = qq< [^$esc$NonASCII$CRlist()] >; # $Cnested matches one non-nested comment. # It is unrolled, with normal of $ctext, special of $quoted_pair. $Cnested = qq< $OpenParen # ( $ctext* # normal* (?: $quoted_pair $ctext* )* # (special normal*)* $CloseParen # ) >; # $comment allows one level of nested parentheses # It is unrolled, with normal of $ctext, special of ($quoted_pair|$Cnested) $comment = qq< $OpenParen # ( $ctext* # normal* (?: # ( (?: $quoted_pair | $Cnested ) # special $ctext* # normal* )* # )* $CloseParen # ) >; ############################################################################## # $X is optional whitespace/comments. $X = qq< [$space$tab]* # Nab whitespace. (?: $comment [$space$tab]* )* # If comment found, allow more spaces. >; # Item 10: atom $atom_char = qq/[^($space)<>\@,;:\".$esc$OpenBR$CloseBR$ctrl$NonASCII]/; $atom = qq< $atom_char+ # some number of atom characters... (?!$atom_char) # ..not followed by something that could be part of an atom >; # Item 11: doublequoted string, unrolled. $quoted_str = qq< \" # " $qtext * # normal (?: $quoted_pair $qtext * )* # ( special normal* )* \" # " >; # Item 7: word is an atom or quoted string $word = qq< (?: $atom # Atom | # or $quoted_str # Quoted string ) >; # Item 12: domain-ref is just an atom $domain_ref = $atom; # Item 13: domain-literal is like a quoted string, but [...] instead of "..." $domain_lit = qq< $OpenBR # [ (?: $dtext | $quoted_pair )* # stuff $CloseBR # ] >; # Item 9: sub-domain is a domain-ref or domain-literal $sub_domain = qq< (?: $domain_ref | $domain_lit ) $X # optional trailing comments >; # Item 6: domain is a list of subdomains separated by dots. $domain = qq< $sub_domain (?: $Period $X $sub_domain )* >; # Item 8: a route. A bunch of "@ $domain" separated by commas, followed by a colon. $route = qq< \@ $X $domain (?: , $X \@ $X $domain )* # additional domains : $X # optional trailing comments >; # Item 6: local-part is a bunch of $word separated by periods $local_part = qq< $word $X (?: $Period $X $word $X # additional words )* >; # Item 2: addr-spec is local@domain $addr_spec = qq< $local_part \@ $X $domain >; # Item 4: route-addr is $route_addr = qq[ < $X # < (?: $route )? # optional route $addr_spec # address spec > # > ]; # Item 3: phrase........ $phrase_ctrl = '\000-\010\012-\037'; # like ctrl, but without tab # Like atom-char, but without listing space, and uses phrase_ctrl. # Since the class is negated, this matches the same as atom-char plus space and tab $phrase_char = qq/[^()<>\@,;:\".$esc$OpenBR$CloseBR$NonASCII$phrase_ctrl]/; # We've worked it so that $word, $comment, and $quoted_str to not consume trailing $X # because we take care of it manually. $phrase = qq< $word # leading word $phrase_char * # "normal" atoms and/or spaces (?: (?: $comment | $quoted_str ) # "special" comment or quoted string $phrase_char * # more "normal" )* >; ## Item #1: mailbox is an addr_spec or a phrase/route_addr $mailbox = qq< $X # optional leading comment (?: $addr_spec # address | # or $phrase $route_addr # name and address ) >; ########################################################################### # Here's a little snippet to test it. # Addresses given on the commandline are described. # my $error = 0; my $valid; foreach $address (@ARGV) { $valid = $address =~ m/^$mailbox$/xo; printf "`$address' is syntactically %s.\n", $valid ? "valid" : "invalid"; $error = 1 if not $valid; } exit $error;