: IO::sysopen

  a new method to get a raw file descriptor.

: TCPServer#accept, UNIXServer#accept, Socket#accept

  new methods to return an accepted socket fd.

: Date and DateTime

  lib/date.rb now provides both Date and DateTime.

  Some methods have been renamed.  But the old names are still alive.

  Some new methods have been added (Date::parse, Date#strftime, etc.).

: Thread#join

  Optional argument limits maximum time to wait the thread in second.
  And returns nil if timed out.

: dl module

  Imported. An interface to the dynamic linker.

: IO#sysseek

  Added.

: IO

  64bit off_t support by Janathan Baker.

: abort()

  optional terminate message argument.

: iconv module

  Imported.  Wrapper library of (({iconv})).

: Dir::glob

  Now accepts optional FNM_* flags via the second argument, whereas
  Dir::[] doesn't.

    Dir.glob("makefile", File::FNM_CASEFOLD) #=> ['Makefile', 'makefile']

: fileutils module

  Imported.  File utility library.

: racc runtime module

  Imported.  Racc runtime library. (Racc is a parser generator for ruby)

: tsort module

  Imported.  Topological sorting library.

: stringio module

  Imported.  Pseudo (({IO})) class from/to (({String})).

: strscan module

  Imported.  Fast string scanner library.

: Array#pack, String#unpack

  allows comment in template strings.

: Array#pack, String#unpack

  new templates 'q' and 'Q' for 64bit integer (signed and unsigned respectively).

: Array#fill

  takes block to get the values to fill.

: Array#new

  takes block to get the values to fill.

: Array#fetch

  takes block to get the default value.

: Hash#update

  takes block to resolve key conflict.

: IO#fsync

  Added.

: Array expansion

  Fixed with the following behavior:

    a = *[1]
    p a #=> [1]

  Now 1-element array in rhs is expanded properly.

    a = *[1]
    p a #=> 1

: allocation framework

  any instance of class can be allocated by class.allocate,
  (except a few classes).

: break and next

  Extended to take an optional expression, which is used as a value
  for termination. [experimental]

: comparison of exception classes in a rescue clause

  Changed to use Module#=== for comparing $! with the exception
  class specified in each rescue clause.

  As the previous behavior was to use kind_of?, the effect is limited
  to the SystemCallError case.  SystemCallError.=== has been newly
  defined to return true when the two have the same errno.  With this
  change, SystemCallError's with the same errno, such as Errno::EAGAIN
  and Errno::EWOULDBLOCK, can both be rescued by listing just one of
  them.

: constants lookup

  Improved at the performance of searching by using an internal hash
  table.

: expression parenthesis in the first argument

  Experimentally altered to get the following code (note the space
  after p):

    p ("xx"*2).to_i

  Interpreted as:

    p (("xx"*2).to_i)

  Instead of:

    (p("xx"*2)).to_i

: implicit comparison in conditional expressions

  is obsoleted except when it is used in -e.

  : between Range and $.
      Use explicit comparison instead.

  : between Regexp and $_
      Use the unary method ~/re/ instead.

: to_str

  Added to get objects which define to_str() treated as String's.

  Now almost all the built-in methods try each argument with to_str()
  when they expect it to be a String.

    foo = Object.new
    class <<foo
      def to_str
        "foo"
      end
    end
    p File.open(foo)
    => -:7:in `open': wrong argument type Object (expected String) (TypeError)
       ruby 1.6.4 (2001-04-19) [i586-linux]
    => -:7:in `open': No such file or directory - "foo" (Errno::ENOENT)
       ruby 1.7.0 (2001-05-02) [i586-linux]

: pp module

  Imported. Prity Printing library.

: open

  Extended so that when the third argument is permission flags it
  calls open(2) instead of fopen(3).

: Array#fetch

  Added.

: Array#insert(n, other, ...)

  Added. [ruby-talk:14289]

  This is much the same as (({ary[n,0] = [other,...]})) except
  returing self.

    ary = [0,1,2,3]
    ary[2, 0] = [4, 5, 6]
    p ary

    ary = [0,1,2,3]
    ary.insert(2, 4, 5, 6)
    p ary

: Array#sort!

  Changed to always return self without checking whether the sequence
  of the elements was modified or not.

  Beware that this behavior is not guaranteed to continue in the
  future.  Do not rely on its return value. [ruby-dev:12506]

: Curses

  Updated.  New methods and constants for using the mouse, character
  attributes, colors and key codes have been added.

: Dir#path

  Added.

: Dir.chdir

  Extended to take a block.

: Dir.glob

  Made to support meta-character escaping by a backslash.  Wildcards
  and spaces may now be escaped using a backslash.

: Dir.open

  Changed to return what the block returns when a block is given, just
  as File.open does. (It always returned (({nil})) in 1.6 and
  prior)

: Dir.chdir

  Changed to warn only when invoked from multiple threads or no block
  is given. [ruby-dev:13823]

    Dir.chdir('foo') {
      Dir.chdir('bar') {   # previously warned
        puts Dir.pwd
      }
    }

: Enumerable#all?
: Enumerable#any?
: Enumerable#inject
: Enumerable#sort_by

  Added.

: File#fnmatch, File::Constants::FNM_*

  Added.  Refer to the fnmatch(3) manpage for details.

  Localism is FNM_DOTMATCH which has the opposite meaning of the
  commonly known FNM_PERIOD, which does not exist in Ruby.

  e.g.

    # exclude files matching "*.bak" case-insensitively.
    files.reject! {|fn| File.fnmatch?("*.bak", fn, File::FNM_CASEFOLD) }

: File.lchmod
: File.lchown

  Added.

: IO#puts

  do not treat Array specially.

: IO.for_fd

  Added.

: IO.read

  Added. [ruby-talk:9460]

: Interrupt

  Made a subclass of SignalException. (It was a subclass of
  Exception in 1.6 and prior)

: Marshal

  Fixed not to dump anonymous classes/modules.

  Fixed with loading modules.

: MatchData#to_ary

  Added for convenience of Regexp#match. [ruby-dev:12766]

  Previously we had to do:

    foo, bar, baz = /(\w+?)\s+(\w+?)\s+(\w+)/.match("foo bar baz").to_a[1..-1]
    p [foo, bar, baz]

  But now can do:

    _, foo, bar, baz = /(\w+?)\s+(\w+?)\s+(\w+)/.match("foo bar baz")
    p [foo, bar, baz]

: Math.acos(x)
: Math.asin(x)
: Math.atan(x)
: Math.cosh(x)
: Math.hypot(x,y)
: Math.sinh(x)
: Math.tanh(x)

  Added.

: Method#==

  Added.

: Module#include?

  Added. [ruby-dev:13941] 

: Module#included

  Added.  This is a hook called after Module#append_feature.

: Module#method_removed
: Module#method_undefined

  Added.

: Module.new, Class.new

  Extended to take block.

: Multiple assignment behavior

  Fixed so that "*a = nil" results in "a == []".

: NameError and NoMethodError

  Moved and now NoMethodError < NameError < StandardError.

: NoMethodError

  Added. [ruby-dev:12763]

: NotImplementError

  Finally obsoleted.  Use NotImplementedError.

: Object#singleton_method_removed
: Object#singleton_method_undefined

  Added.

: Proc#==

  Added.

: Proc#yield

  Added.  This is equivalent to Proc#call except it does not check the
  number of given arguments, which are thus passed to the proc as-is.

: Process.times

  Moved from Time.times. (Time.times still remains but emits a
  warning)

: Process.waitall

  Added.

: Process::Status

  Added.  (({$?})) is now an instance of this class.

: Range#step([step=1])

  Added.

: Range#to_ary

  Added.  You can now do something like this:

    a, b, c = 1..3

: Regexp#options

  Added.

: Regexp.last_match(n)

  Extended to take an optional argument.

: Signal

  Added. This module has module functions Signal.trap and Signal.list.

: Socket.pack_sockaddr_in, Socket.unpack_sockaddr_in

  Added.  Utility for direct Socket access.

: Socket.pack_sockaddr_un, Socket.unpack_sockaddr_un

  Added.  Utility for direct Socket access.

: String#[regexp, nth]

  Extended to accepts optional second argument.

  tries match between self and REGEXP, then returns the
  content of the NTH regexp register.

: String#casecmp

  Added.  This is a case insensitive version of String#<=>.

: String#chomp

  if $/ == '\n', chops off last newlines (any of \n, \r, \r\n).

: String#eql?

  Changed to be always case sensitive.

: String#insert(n, other)

  Added.

  This is much the same as (({str[n, 0] = other})) except returing
  self.

: String#lstrip, rstrip, lstrip!, rstrip!

  Added.  These strip only left or right part of a string.

: String#match

  Added.

: String/Array methods

  returns an instance of receivers class.

: String.new

  The first argument becomes optional.

: Symbol#intern

  Added.

: Symbol.all_symbols

  Added. [ruby-dev:12921]

: SystemCallError.===

  Added. (See the "Comparison of exception classes in a rescue clause"
  paragraph above) [ruby-dev:12670]

: SystemExit#status

  Added.

: TCPServer#listen, UNIXServer#listen

  Added.

: TCPSocket.new
: TCPSocket.open

  Extended to take an address and a port number for the local side in
  optional 3rd and 4th arguments.

: Time

  Extended to accept a negative time_t. (Only when the platform
  supports it)

    p Time.at(-1)
    => Thu Jan 01 08:59:59 JST 1970

: Time#to_a
: Time#zone

  Made to return "UTC" under gmtime.  It used to return a platform
  dependent value, typically "GMT", in 1.6 and prior.

To be investigated:

 Sat Feb 24 03:15:49 2001  Yukihiro Matsumoto  <matz@ruby-lang.org>

        * io.c (set_stdin): preserve original stdin.

        * io.c (set_outfile): preserve original stdout/stderr.