* ext/nkf/nkf.c ext/nkf/lib/kconv.rb: Add rdoc.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@9990 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 564 insertions, 121 deletions

diff --git a/ext/nkf/lib/kconv.rb b/ext/nkf/lib/kconv.rb
index 3512135ecc..0cf7da1200 100644
--- a/ext/nkf/lib/kconv.rb
+++ b/ext/nkf/lib/kconv.rb
@@ -1,82 +1,65 @@
+#
+# kconv.rb - Kanji Converter.
+#
+# $Id$
+#
+
 require 'nkf'
 
 module Kconv
+  #
+  # Public Constants
+  #
+  
   #Constant of Encoding
-  AUTO = ::NKF::AUTO
-  JIS = ::NKF::JIS
-  EUC = ::NKF::EUC
-  SJIS = ::NKF::SJIS
-  BINARY = ::NKF::BINARY
-  NOCONV = ::NKF::NOCONV
-  ASCII = ::NKF::ASCII
-  UTF8 = ::NKF::UTF8
-  UTF16 = ::NKF::UTF16
-  UTF32 = ::NKF::UTF32
-  UNKNOWN = ::NKF::UNKNOWN
+  
+  # Auto-Detect
+  AUTO = NKF::AUTO
+  # ISO-2022-JP
+  JIS = NKF::JIS
+  # EUC-JP
+  EUC = NKF::EUC
+  # Shift_JIS
+  SJIS = NKF::SJIS
+  # BINARY
+  BINARY = NKF::BINARY
+  # NOCONV
+  NOCONV = NKF::NOCONV
+  # ASCII
+  ASCII = NKF::ASCII
+  # UTF-8
+  UTF8 = NKF::UTF8
+  # UTF-16
+  UTF16 = NKF::UTF16
+  # UTF-32
+  UTF32 = NKF::UTF32
+  # UNKNOWN
+  UNKNOWN = NKF::UNKNOWN
+  
+  #
+  # Private Constants
+  #
+  
+  # Revision of kconv.rb
+  REVISION = %q$Revision$
   
   #Regexp of Encoding
-  Iconv_Shift_JIS = /\A(?:
-		  [\x00-\x7f\xa1-\xdf]                                             |
-		  \x81[\x40-\x7e\x80-\xac\xb8-\xbf\xc8-\xce\xda-\xe8\xf0-\xf7\xfc] |
-		  \x82[\x4f-\x58\x60-\x79\x81-\x9a\x9f-\xf1]                       |
-		  \x83[\x40-\x7e\x80-\x96\x9f-\xb6\xbf-\xd6\x40-\x60]              |
-		  \x84[\x40-\x60\x70-\x7e\x80-\x91\x9f-\xbe\x9f-\xfc]              |
-		  [\x89-\x8f\x90-\x97\x99-\x9f\xe0-\xea][\x40-\x7e]                |
-		  [\x89-\x97\x99-\x9f\xe0-\xe9][\x80-\xfc]                         |
-		  \x98[\x40-\x72\x9f-\xfc]                                         |
-		  \xea[\x80-\xa4]
-		 )*\z/nx
-  Iconv_EUC_JP = /\A(?:
-	       [\x00-\x7f]                                             |
-	       \x8e        [\xa1-\xdf]                                 |
-	       \x8f        [\xa1-\xdf] [\xa1-\xdf]                     |
-	       [\xa1\xb0-\xbce\xd0-\xf3][\xa1-\xfe]                    |
-	       \xa2[\xa1-\xae\xba-\xc1\xca-\xd0\xdc-\xea\xf2-\xf9\xfe] |
-	       \xa3[\xb0-\xb9\xc1-\xda\xe1-\xfa]                       |
-	       \xa4[\xa1-\xf3]                                         |
-	       \xa5[\xa1-\xf6]                                         |
-	       \xa6[\xa1-\xb8\xc1-\xd8]                                |
-	       \xa7[\xa1-\xc1\xd1-\xf1]                                |
-	       \xa8[\xa1-\xc0]                                         |
-	       \xcf[\xa1-\xd3]                                         |
-	       \xf4[\xa1-\xa6]
-	      )*\z/nx
-  Iconv_UTF8  = /\A(?:\xef\xbb\xbf)?(?:
-  [\x00-\x7f]                                                       |
-  \xc2[\x80-\x8d\x90-\x9f\xa1\xaa\xac\xae-\xb1\xb4\xb6\xb8\xba\xbf] |
-  \xc3[\x80-\xbf]                                                   |
-  \xc4[\x80-\x93\x96-\xa2\xa4-\xab\xae-\xbf]                        |
-  \xc5[\x80-\x8d\x90-\xbe]                                          |
-  \xc7[\x8d-\x9c\xb5]                                               |
-  \xcb[\x87\x98-\x9b\x9d]                                           |
-  \xce[\x84-\x86\x88-\x8a\x8c\x8e-\xa1\xa3-\xbf]                    |
-  \xcf[\x80-\x8e]                                                   |
-  \xd0[\x81-\x8c\x8e-\xbf]                                          |
-  \xd1[\x80-\x8f\x91-\x9f]                                          |
-  \xe2\x84[\x83\x96\xa2\xab]                                        |
-  \xe2\x86[\x83\x91-\x93\x96\xa2\xab]                               |
-  \xe2\x87[\x83\x91-\x94\x96\xa2\xab]                               |
-  \xe2\x88[\x82-\x83\x87-\x88\x8b\x91-\x94\x96\x9a\x9d-\x9e\xa0\xa2\xa7-\xac\xb4-\xb5\xbd]  |
-  \xe2\x89[\x82-\x83\x87-\x88\x8b\x91-\x94\x96\x9a\x9d-\x9e\xa0-\xa2\xa6-\xac\xb4-\xb5\xbd] |
-  \xe2[\x8a\x8c][\x82-\x83\x86-\x88\x8b\x91-\x94\x96\x9a\x9d-\x9e\xa0-\xa2\xa5-\xac\xb4-\xb5\xbd] |
-  \xe2[\x94-\x99][\x81-\x83\x86-\x88\x8b-\x8c\x8f-\x94\x96-\x98\x9a-\x9e\xa0-\xac\xaf-\xb0\xb3-\xb5\xb7-\xb8\xbb-\xbd\xbf] |
-  \xe3\x80[\x81-\x83\x85-\x98\x9a-\x9e\xa0-\xad\xaf-\xb0\xb2-\xb5\xb7-\xb8\xbb-\xbd\xbf] |
-  \xe3[\x81-\x83\xb8-\xbf][\x81-\xbf]          |
-  [\xe5-\xe7][\x80-\xbf][\x81-\xbf]            |
-  \xe8[\x80-\xae\xb0-\xbf][\x81-\xbf]          |
-  \xe9[\x80-\x92\x95-\xb1\xb3-\xbe][\x81-\xbf] |
-  \xef[\xbc-\xbe][\x81-\xbf]                   |
-  )*\z/nx
+  
+  # Regexp of Shift_JIS string (private constant)
   RegexpShiftjis = /\A(?:
 		       [\x00-\x7f\xa1-\xdf] |
 		       [\x81-\x9f\xe0-\xfc][\x40-\x7e\x80-\xfc] 
 		      )*\z/nx
+
+  # Regexp of EUC-JP string (private constant)
   RegexpEucjp = /\A(?:
 		    [\x00-\x7f]                         |
 		    \x8e        [\xa1-\xdf]             |
 		    \x8f        [\xa1-\xdf] [\xa1-\xfe] |
 		    [\xa1-\xdf] [\xa1-\xfe]
 		   )*\z/nx
+
+  # Regexp of UTF-8 string (private constant)
   RegexpUtf8  = /\A(?:
 		    [\x00-\x7f]                                     |
 		    [\xc2-\xdf] [\x80-\xbf]                         |
@@ -88,9 +71,19 @@ module Kconv
 		   )*\z/nx
 
   #
-  # kconv
+  # Public Methods
   #
   
+  # call-seq:
+  #    Kconv.kconv(str, out_code, in_code = Kconv::AUTO)
+  #
+  # Convert <code>str</code> to out_code.
+  # <code>out_code</code> and <code>in_code</code> are given as constants of Kconv.
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want to decode them, use NKF.nkf.
   def kconv(str, out_code, in_code = AUTO)
     opt = '-'
     case in_code
@@ -131,26 +124,71 @@ module Kconv
   # Encode to
   #
 
+  # call-seq:
+  #    Kconv.tojis(str)   -> string
+  #
+  # Convert <code>str</code> to ISO-2022-JP
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-jxm0', str).
   def tojis(str)
     ::NKF::nkf('-j', str)
   end
   module_function :tojis
 
+  # call-seq:
+  #    Kconv.toeuc(str)   -> string
+  #
+  # Convert <code>str</code> to EUC-JP
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-exm0', str).
   def toeuc(str)
     ::NKF::nkf('-e', str)
   end
   module_function :toeuc
 
+  # call-seq:
+  #    Kconv.tosjis(str)   -> string
+  #
+  # Convert <code>str</code> to Shift_JIS
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-sxm0', str).
   def tosjis(str)
     ::NKF::nkf('-s', str)
   end
   module_function :tosjis
 
+  # call-seq:
+  #    Kconv.toutf8(str)   -> string
+  #
+  # Convert <code>str</code> to UTF-8
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-wxm0', str).
   def toutf8(str)
     ::NKF::nkf('-w', str)
   end
   module_function :toutf8
 
+  # call-seq:
+  #    Kconv.toutf16(str)   -> string
+  #
+  # Convert <code>str</code> to UTF-16
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-w16xm0', str).
   def toutf16(str)
     ::NKF::nkf('-w16', str)
   end
@@ -160,11 +198,19 @@ module Kconv
   # guess
   #
 
+  # call-seq:
+  #    Kconv.guess(str)   -> integer
+  #
+  # Guess input encoding by NKF.guess2
   def guess(str)
     ::NKF::guess(str)
   end
   module_function :guess
 
+  # call-seq:
+  #    Kconv.guess_old(str)   -> integer
+  #
+  # Guess input encoding by NKF.guess1
   def guess_old(str)
     ::NKF::guess1(str)
   end
@@ -174,16 +220,34 @@ module Kconv
   # isEncoding
   #
 
+  # call-seq:
+  #    Kconv.iseuc(str)   -> obj or nil
+  #
+  # Returns whether input encoding is EUC-JP or not.
+  #
+  # *Note* don't expect this return value is MatchData.
   def iseuc(str)
     RegexpEucjp.match( str )
   end
   module_function :iseuc
 
+  # call-seq:
+  #    Kconv.issjis(str)   -> obj or nil
+  #
+  # Returns whether input encoding is Shift_JIS or not.
+  #
+  # *Note* don't expect this return value is MatchData.
   def issjis(str)
     RegexpShiftjis.match( str )
   end
   module_function :issjis
 
+  # call-seq:
+  #    Kconv.isutf8(str)   -> obj or nil
+  #
+  # Returns whether input encoding is UTF-8 or not.
+  #
+  # *Note* don't expect this return value is MatchData.
   def isutf8(str)
     RegexpUtf8.match( str )
   end
@@ -192,37 +256,104 @@ module Kconv
 end
 
 class String
+  # call-seq:
+  #    String#kconv(out_code, in_code = Kconv::AUTO)
+  #
+  # Convert <code>self</code> to out_code.
+  # <code>out_code</code> and <code>in_code</code> are given as constants of Kconv.
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want to decode them, use NKF.nkf.
   def kconv(out_code, in_code=Kconv::AUTO)
     Kconv::kconv(self, out_code, in_code)
   end
   
+  #
   # to Encoding
-  def tojis
-    ::NKF::nkf('-j', self)
-  end
-  def toeuc
-    ::NKF::nkf('-e', self)
-  end
-  def tosjis
-    ::NKF::nkf('-s', self)
-  end
-  def toutf8
-    ::NKF::nkf('-w', self)
-  end
-  def toutf16
-    ::NKF::nkf('-w16', self)
-  end
+  #
   
+  # call-seq:
+  #    String#tojis   -> string
+  #
+  # Convert <code>self</code> to ISO-2022-JP
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-jxm0', str).
+  def tojis; Kconv.tojis(self) end
+
+  # call-seq:
+  #    String#toeuc   -> string
+  #
+  # Convert <code>self</code> to EUC-JP
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-exm0', str).
+  def toeuc; Kconv.toeuc(self) end
+
+  # call-seq:
+  #    String#tosjis   -> string
+  #
+  # Convert <code>self</code> to Shift_JIS
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-sxm0', str).
+  def tosjis; Kconv.tosjis(self) end
+
+  # call-seq:
+  #    String#toutf8   -> string
+  #
+  # Convert <code>self</code> to UTF-8
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-wxm0', str).
+  def toutf8; Kconv.toutf8(self) end
+
+  # call-seq:
+  #    String#toutf16   -> string
+  #
+  # Convert <code>self</code> to UTF-16
+  #
+  # *Note*
+  # This method decode MIME encoded string and
+  # convert halfwidth katakana to fullwidth katakana.
+  # If you don't want it, use NKF.nkf('-w16xm0', str).
+  def toutf16; Kconv.toutf16(self) end
+
+  #
   # is Encoding
-  def iseuc
-    Kconv.iseuc( self )
-  end
+  #
 
-  def issjis
-    Kconv.issjis( self )
-  end
+  # call-seq:
+  #    String#iseuc   -> obj or nil
+  #
+  # Returns whether <code>self</code>'s encoding is EUC-JP or not.
+  #
+  # *Note* don't expect this return value is MatchData.
+  def iseuc;	Kconv.iseuc(self) end
 
-  def isutf8
-    Kconv.isutf8( self )
-  end
+  # call-seq:
+  #    String#issjis   -> obj or nil
+  #
+  # Returns whether <code>self</code>'s encoding is Shift_JIS or not.
+  #
+  # *Note* don't expect this return value is MatchData.
+  def issjis;	Kconv.issjis(self) end
+
+  # call-seq:
+  #    String#isutf8   -> obj or nil
+  #
+  # Returns whether <code>self</code>'s encoding is UTF-8 or not.
+  #
+  # *Note* don't expect this return value is MatchData.
+  def isutf8;	Kconv.isutf8(self) end
 end
diff --git a/ext/nkf/nkf.c b/ext/nkf/nkf.c
index 65442a130c..f03a858c64 100644
--- a/ext/nkf/nkf.c
+++ b/ext/nkf/nkf.c
@@ -1,9 +1,9 @@
 /*
- * NKF Module for Ruby base on nkf 2.x
+ *  NKF - Ruby extension for Network Kanji Filter
  *
- * original nkf2.x is maintained at http://sourceforge.jp/projects/nkf/
+ *  original nkf2.x is maintained at http://sourceforge.jp/projects/nkf/
  *
- * $Id$
+ *  $Id$
  *
  */
 
@@ -78,6 +78,21 @@ rb_nkf_putchar(c)
 #include "nkf-utf8/utf8tbl.c"
 #include "nkf-utf8/nkf.c"
 
+/*
+ *  call-seq:
+ *     NKF.nkf(opt, str)   -> string
+ *
+ *  Convert _str_ and return converted result.
+ *  Conversion details are specified by _opt_ as String.
+ *
+ *     require 'nkf'
+ *     output = NKF.nkf("-s", input)
+ *
+ *  *Note*
+ *  By default, nkf decodes MIME encoded string.
+ *  If you want not to decode input, use NKF.nkf with <b>-m0</b> flag.
+ */
+
 static VALUE
 rb_nkf_kconv(obj, opt, src)
   VALUE obj, opt, src;
@@ -118,11 +133,27 @@ rb_nkf_kconv(obj, opt, src)
 
 
 /*
- * NKF.guess1
+ *  call-seq:
+ *     NKF.guess1(str)  -> integer
+ *
+ *  Returns guessed encoding of _str_ as integer.
+ *
+ *  Algorithm described in:
+ *  Ken Lunde. `Understanding Japanese Information Processing'
+ *  Sebastopol, CA: O'Reilly & Associates.
  *
- * Character code detection - Algorithm described in:
- * Ken Lunde. `Understanding Japanese Information Processing'
- * Sebastopol, CA: O'Reilly & Associates.
+ *      case NKF.guess1(input)
+ *      when NKF::JIS
+ *        "ISO-2022-JP"
+ *      when NKF::SJIS
+ *        "Shift_JIS"
+ *      when NKF::EUC
+ *        "EUC-JP"
+ *      when NKF::UNKNOWN
+ *        "UNKNOWN(ASCII)"
+ *      when NKF::BINARY
+ *        "BINARY"
+ *      end
  */
 
 static VALUE
@@ -214,9 +245,29 @@ rb_nkf_guess1(obj, src)
 
 
 /*
- * NKF.guess2
+ *  call-seq:
+ *     NKF.guess2(str)  -> integer
  *
- * Guess Encoding By NKF2.0 Routine 
+ *  Returns guessed encoding of _str_ as integer by nkf routine.
+ *
+ *     case NKF.guess(input)
+ *     when NKF::ASCII
+ *       "ASCII"
+ *     when NKF::JIS
+ *       "ISO-2022-JP"
+ *     when NKF::SJIS
+ *       "Shift_JIS"
+ *     when NKF::EUC
+ *       "EUC-JP"
+ *     when NKF::UTF8
+ *       "UTF-8"
+ *     when NKF::UTF16
+ *       "UTF-16"
+ *     when NKF::UNKNOWN
+ *       "UNKNOWN"
+ *     when NKF::BINARY
+ *       "BINARY"
+ *     end
  */
 
 static VALUE
@@ -261,32 +312,293 @@ rb_nkf_guess2(obj, src)
 }
 
 
-/* Initialize NKF Module */
+/*
+ *  NKF - Ruby extension for Network Kanji Filter 
+ *
+ *  == Description
+ *
+ *  This is a Ruby Extension version of nkf (Netowrk Kanji Filter).
+ *  It converts the first argument and return converted result. Conversion
+ *  details are specified by flags as the first argument.
+ *
+ *  *Nkf* is a yet another kanji code converter among networks, hosts and terminals.
+ *  It converts input kanji code to designated kanji code
+ *  such as ISO-2022-JP, Shift_JIS, EUC-JP, UTF-8 or UTF-16.
+ *
+ *  One of the most unique faculty of *nkf* is the guess of the input kanji encodings.
+ *  It currently recognizes ISO-2022-JP, Shift_JIS, EUC-JP, UTF-8 and UTF-16.
+ *  So users needn't set the input kanji code explicitly.
+ *
+ *  By default, X0201 kana is converted into X0208 kana.
+ *  For X0201 kana, SO/SI, SSO and ESC-(-I methods are supported.
+ *  For automatic code detection, nkf assumes no X0201 kana in Shift_JIS.
+ *  To accept X0201 in Shift_JIS, use <b>-X</b>, <b>-x</b> or <b>-S</b>.
+ *
+ *  == Flags
+ *
+ *  === -b -u
+ *
+ *  Output is buffered (DEFAULT), Output is unbuffered.
+ *
+ *  === -j -s -e -w -w16
+ *
+ *  Output code is ISO-2022-JP (7bit JIS), Shift_JIS, EUC-JP,
+ *  UTF-8N, UTF-16BE.
+ *  Without this option and compile option, ISO-2022-JP is assumed.
+ *
+ *  === -J -S -E -W -W16
+ *
+ *  Input assumption is JIS 7 bit, Shift_JIS, EUC-JP,
+ *  UTF-8, UTF-16LE.
+ *
+ *  ==== -J
+ *
+ *  Assume  JIS input. It also accepts EUC-JP.
+ *  This is the default. This flag does not exclude Shift_JIS.
+ *
+ *  ==== -S
+ *
+ *  Assume Shift_JIS and X0201 kana input. It also accepts JIS.
+ *  EUC-JP is recognized as X0201 kana. Without <b>-x</b> flag,
+ *  X0201 kana (halfwidth kana) is converted into X0208.
+ *
+ *  ==== -E
+ *
+ *  Assume EUC-JP input. It also accepts JIS.
+ *  Same as -J.
+ *
+ *  === -t
+ *
+ *  No conversion.
+ *
+ *  === -i_
+ *
+ *  Output sequence to designate JIS-kanji. (DEFAULT B)
+ *
+ *  === -o_
+ *
+ *  Output sequence to designate ASCII. (DEFAULT B)
+ *
+ *  === -r
+ *
+ *  {de/en}crypt ROT13/47
+ *
+ *  === -h[123] --hiragana --katakana --katakana-hiragana
+ *
+ *  [-h1 --hiragana] Katakana to Hiragana conversion.
+ *
+ *  [-h2 --katakana] Hiragana to Katakana conversion.
+ *
+ *  [-h3 --katakana-hiragana] Katakana to Hiragana and Hiragana to Katakana conversion.
+ *
+ *  === -T
+ *
+ *  Text mode output (MS-DOS)
+ *
+ *  === -l
+ *
+ *  ISO8859-1 (Latin-1) support
+ *
+ *  === -f[<code>m</code> [- <code>n</code>]]
+ *
+ *  Folding on <code>m</code> length with <code>n</code> margin in a line.
+ *  Without this option, fold length is 60 and fold margin is 10.
+ *
+ *  === -F
+ *
+ *  New line preserving line folding.
+ *
+ *  === -Z[0-3]
+ *
+ *  Convert X0208 alphabet (Fullwidth Alphabets) to ASCII.
+ *
+ *  [-Z -Z0] Convert X0208 alphabet to ASCII.
+ *
+ *  [-Z1] Converts X0208 kankaku to single ASCII space.
+ *
+ *  [-Z2] Converts X0208 kankaku to double ASCII spaces.
+ *
+ *  [-Z3] Replacing Fullwidth >, <, ", & into '&gt;', '&lt;', '&quot;', '&amp;' as in HTML.
+ *
+ *  === -X -x
+ *
+ *  Assume X0201 kana in MS-Kanji.
+ *  With <b>-X</b> or without this option, X0201 is converted into X0208 Kana.
+ *  With <b>-x</b>, try to preserve X0208 kana and do not convert X0201 kana to X0208.
+ *  In JIS output, ESC-(-I is used. In EUC output, SSO is used.
+ *
+ *  === -B[0-2]
+ *
+ *  Assume broken JIS-Kanji input, which lost ESC.
+ *  Useful when your site is using old B-News Nihongo patch.
+ *
+ *  [-B1] allows any char after ESC-( or ESC-$.
+ *
+ *  [-B2] forces ASCII after NL.
+ *
+ *  === -I
+ *
+ *  Replacing non iso-2022-jp char into a geta character
+ *  (substitute character in Japanese).
+ *
+ *  === -d -c
+ *
+ *  Delete \r in line feed, Add \r in line feed.
+ *
+ *  === -m[BQN0]
+ *
+ *  MIME ISO-2022-JP/ISO8859-1 decode. (DEFAULT)
+ *  To see ISO8859-1 (Latin-1) -l is necessary.
+ *
+ *  [-mB] Decode MIME base64 encoded stream. Remove header or other part before
+ *  conversion. 
+ *
+ *  [-mQ] Decode MIME quoted stream. '_' in quoted stream is converted to space.
+ *
+ *  [-mN] Non-strict decoding.
+ *  It allows line break in the middle of the base64 encoding.
+ *
+ *  [-m0] No MIME decode.
+ *
+ *  === -M
+ *
+ *  MIME encode. Header style. All ASCII code and control characters are intact.
+ *  Kanji conversion is performed before encoding, so this cannot be used as a picture encoder.
+ *
+ *  [-MB] MIME encode Base64 stream.
+ *
+ *  [-MQ] Perfome quoted encoding.
+ *
+ *  === -l
+ *
+ *  Input and output code is ISO8859-1 (Latin-1) and ISO-2022-JP.
+ *  <b>-s</b>, <b>-e</b> and <b>-x</b> are not compatible with this option.
+ *
+ *  === -L[uwm]
+ *
+ *  new line mode
+ *  Without this option, nkf doesn't convert line breaks.
+ *
+ *  [-Lu] unix (LF)
+ *
+ *  [-Lw] windows (CRLF)
+ *
+ *  [-Lm] mac (CR)
+ *
+ *  === --fj --unix --mac --msdos --windows
+ *
+ *  convert for these system
+ *
+ *  === --jis --euc --sjis --mime --base64
+ *
+ *  convert for named code
+ *
+ *  === --jis-input --euc-input --sjis-input --mime-input --base64-input
+ *
+ *  assume input system
+ *
+ *  === --ic=<code>input codeset</code> --oc=<code>output codeset</code>
+ *
+ *  Set the input or output codeset.
+ *  NKF supports following codesets and those codeset name are case insensitive.
+ *
+ *  [ISO-2022-JP] a.k.a. RFC1468, 7bit JIS, JUNET
+ *
+ *  [EUC-JP (eucJP-nkf)] a.k.a. AT&T JIS, Japanese EUC, UJIS
+ *
+ *  [eucJP-ascii] a.k.a. x-eucjp-open-19970715-ascii
+ *
+ *  [eucJP-ms] a.k.a. x-eucjp-open-19970715-ms
+ *
+ *  [CP51932] Microsoft Version of EUC-JP.
+ *
+ *  [Shift_JIS] SJIS, MS-Kanji
+ *
+ *  [CP932] a.k.a. Windows-31J
+ *
+ *  [UTF-8] same as UTF-8N
+ *
+ *  [UTF-8N] UTF-8 without BOM
+ *
+ *  [UTF-8-BOM] UTF-8 with BOM
+ *
+ *  [UTF-16] same as UTF-16BE
+ *
+ *  [UTF-16BE] UTF-16 Big Endian without BOM
+ *
+ *  [UTF-16BE-BOM] UTF-16 Big Endian with BOM
+ *
+ *  [UTF-16LE] UTF-16 Little Endian without BOM
+ *
+ *  [UTF-16LE-BOM] UTF-16 Little Endian with BOM
+ *
+ *  [UTF8-MAC] NKDed UTF-8, a.k.a. UTF8-NFD (input only)
+ *
+ *  === --fb-{skip, html, xml, perl, java, subchar}
+ *
+ *  Specify the way that nkf handles unassigned characters.
+ *  Without this option, --fb-skip is assumed.
+ *
+ *  === --prefix= <code>escape character</code> <code>target character</code> ..
+ *
+ *  When nkf converts to Shift_JIS,
+ *  nkf adds a specified escape character to specified 2nd byte of Shift_JIS characters.
+ *  1st byte of argument is the escape character and following bytes are target characters.
+ *
+ *  === --disable-cp932ext
+ *
+ *  Handle the characters extended in CP932 as unassigned characters.
+ *
+ *  === --cap-input
+ *
+ *  Decode hex encoded characters.
+ *
+ *  === --url-input
+ *
+ *  Unescape percent escaped characters.
+ *
+ *  === --
+ *
+ *  Ignore rest of -option.
+ */
 
 void
 Init_nkf()
 {
-  VALUE mKconv = rb_define_module("NKF");
-
-  rb_define_module_function(mKconv, "nkf", rb_nkf_kconv, 2);
-  rb_define_module_function(mKconv, "guess", rb_nkf_guess2, 1);
-  rb_define_module_function(mKconv, "guess1", rb_nkf_guess1, 1);
-  rb_define_module_function(mKconv, "guess2", rb_nkf_guess2, 1);
-
-  rb_define_const(mKconv, "AUTO", INT2FIX(_AUTO));
-  rb_define_const(mKconv, "JIS", INT2FIX(_JIS));
-  rb_define_const(mKconv, "EUC", INT2FIX(_EUC));
-  rb_define_const(mKconv, "SJIS", INT2FIX(_SJIS));
-  rb_define_const(mKconv, "BINARY", INT2FIX(_BINARY));
-  rb_define_const(mKconv, "NOCONV", INT2FIX(_NOCONV));
-  rb_define_const(mKconv, "ASCII", INT2FIX(_ASCII));
-  rb_define_const(mKconv, "UTF8", INT2FIX(_UTF8));
-  rb_define_const(mKconv, "UTF16", INT2FIX(_UTF16));
-  rb_define_const(mKconv, "UTF32", INT2FIX(_UTF32));
-  rb_define_const(mKconv, "UNKNOWN", INT2FIX(_UNKNOWN));
-  rb_define_const(mKconv, "VERSION", rb_str_new2(RUBY_NKF_VERSION));
-  /* for debug */
-  rb_define_const(mKconv, "NKF_VERSION", rb_str_new2(NKF_VERSION));
-  rb_define_const(mKconv, "NKF_RELEASE_DATE", rb_str_new2(NKF_RELEASE_DATE));
-  rb_define_const(mKconv, "REVISION", rb_str_new2(RUBY_NKF_REVISION));
+    VALUE mKconv = rb_define_module("NKF");
+
+    rb_define_module_function(mKconv, "nkf", rb_nkf_kconv, 2);
+    rb_define_module_function(mKconv, "guess1", rb_nkf_guess1, 1);
+    rb_define_module_function(mKconv, "guess2", rb_nkf_guess2, 1);
+    rb_define_alias(mKconv, "guess", "guess2");
+    rb_define_alias(rb_singleton_class(mKconv), "guess", "guess2");
+
+    /* Auto-Detect */
+    rb_define_const(mKconv, "AUTO", INT2FIX(_AUTO));
+    /* ISO-2022-JP */
+    rb_define_const(mKconv, "JIS", INT2FIX(_JIS));
+    /* EUC-JP */
+    rb_define_const(mKconv, "EUC", INT2FIX(_EUC));
+    /* Shift_JIS */
+    rb_define_const(mKconv, "SJIS", INT2FIX(_SJIS));
+    /* BINARY */
+    rb_define_const(mKconv, "BINARY", INT2FIX(_BINARY));
+    /* No conversion */
+    rb_define_const(mKconv, "NOCONV", INT2FIX(_NOCONV));
+    /* ASCII */
+    rb_define_const(mKconv, "ASCII", INT2FIX(_ASCII));
+    /* UTF-8 */
+    rb_define_const(mKconv, "UTF8", INT2FIX(_UTF8));
+    /* UTF-16 */
+    rb_define_const(mKconv, "UTF16", INT2FIX(_UTF16));
+    /* UTF-32 */
+    rb_define_const(mKconv, "UTF32", INT2FIX(_UTF32));
+    /* UNKNOWN */
+    rb_define_const(mKconv, "UNKNOWN", INT2FIX(_UNKNOWN));
+    /* Full version string of nkf */
+    rb_define_const(mKconv, "VERSION", rb_str_new2(RUBY_NKF_VERSION));
+    /* Version of nkf */
+    rb_define_const(mKconv, "NKF_VERSION", rb_str_new2(NKF_VERSION));
+    /* Release date of nkf */
+    rb_define_const(mKconv, "NKF_RELEASE_DATE", rb_str_new2(NKF_RELEASE_DATE));
 }