| class methods | 
| compile | Regexp.compile( pattern
         [, options [lang]] )
         -> aRegexp | 
 | Synonym for Regexp.new. | | escape | Regexp.escape( aString )
        -> aNewString | 
 | Escapes any characters that would have special meaning in a
      regular expression. For any string, Regexp.escape(str)=~strwill be true.
  | Regexp.escape('\\*?{}.') | » | \\\\\*\?\{\}\. |  | | last_match | Regexp.last_match
        -> aMatchData | 
 | Returns the MatchDataobject generated by the last
      successful pattern match. Equivalent to reading the global
      variable$~.MatchDatais described
      on page 340. | | new | Regexp.new( pattern
                                    [, options [lang]] )
        -> aRegexp | 
 | Constructs a new regular expression from pattern, which can 
      be either a Stringor aRegexp(in which case that
      regexp's options are not propagated). If options is
      aFixnum, it should be one or more of the constantsRegexp::EXTENDED,Regexp::IGNORECASE, andRegexp::POSIXLINE, or-ed together.
      Otherwise, if options is notnil, the regexp will be case insensitive. The lang
      parameter enables multibyte support for the regexp: `n', `N' = none,
      `e', `E' =  EUC, `s', `S' = SJIS, `u',
      `U' = UTF-8.
  | r1 = Regexp.new('^a-z+:\\s+\w+') | » | /^a-z+:\s+\w+/ |  
  | r2 = Regexp.new(r1, true) | » | /^a-z+:\s+\w+/i |  
  | r3 = Regexp.new(r2, Regexp::EXTENDED) | » | /^a-z+:\s+\w+/x |  | | quote | Regexp.quote( aString )
        -> aNewString | 
 | Synonym for Regexp.escape. | 
| instance methods | 
| == | rxp == aRegexp
        -> trueorfalse | 
 | Equality---Two regexps are equal if their patterns are identical, they have 
      the same character set code, and their casefold?values are 
      the same.
  | /abc/  == /abc/x | » | true |  
  | /abc/  == /abc/i | » | false |  
  | /abc/u == /abc/n | » | false |  | | === | rxp === aString -> trueorfalse | 
 | Case Equality---Synonym for Regexp#=~used in case statements.produces:| 
a = "HELLO"
case a
when /^a-z*$/; print "Lower case\n"
when /^A-Z*$/; print "Upper case\n"
else;            print "Mixed case\n"
end
 | 
 | | =~ | rxp =~ aString
        -> anInteger or nil | 
 | Match---Matches rxp against aString, returning the offset 
      of the start of the match or nilif the match failed.
  | /SIT/  =~ "insensitive" | » | nil |  
  | /SIT/i =~ "insensitive" | » | 5 |  | | ~ | ~ rxp
        -> anInteger or nil | 
 | Match---Matches rxp against the contents of $_. Equivalent torxp =~ $_.
| $_ = "input data" |  
  | ~ /at/ | » | 7 |  | | casefold? | rxp.casefold? -> trueorfalse | 
 | Returns the value of the case-insensitive flag. | | kcode | rxp.kcode -> aString | 
 | Returns the  character set code for the regexp. | | match | rxp.match(aString)
        -> aMatchData or nil | 
 | Returns a MatchDataobject (see page 340)
        describing the match, ornilif there was no match. This
        is equivalent to retrieving the value of the special variable$~following a normal match.
  | /(.)(.)(.)/.match("abc")[2] | » | "b" |  | | source | rxp.source -> aString | 
 | Returns the original string of the pattern. |