= command line options

: -W option

  new option to specify warning level. -W0 to shut up warnings, -W1 for normal level,
  -W2 for verbose level.  -w equals to -W2.

= language syntax

: arbitrary delimited string array

  %W(...) notation, word list literal like %w(...) with the
  exception that #{} interpolation is allowed.

: arbitrary delimited symbol literl

  :"foo", :"foo#{bar}", etc.

: expression interpolation in strings

  Now arbitrary statements are allowed inside #{} interpolation
  without escapes.  In other hand, they can no longer access to
  variables defined in eval.

: negative number literals

  Digits preceded minus sign is a literal integer.

: 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

: break and next

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

: direct assignment to Foo::Bar is allowed

  also, you can define "class Foo::Bar; end".

= language core

: $stdin, $stdout, $stderr

  can be assignable again.  the original stdio are preserved as STDIN,
  STDOUT, STDERR.

: $VERBOSE now has 3 levels

  nil - silence, false - medium (default), true - verbose

: allocation framework

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

: 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.

  calls const_missing method of the class/module, if constant is not
  found in the look up path.

: expression parenthesis in the first argument

  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

  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]

: multiple assignment behavior

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

= changes in core class library

: open

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

: sprintf

  new format specifier "%p" is available.

: lambda and proc

  Proc object returns from these methods has the following attributes:

  * strict argument number check
  * break and return terminates the proc execution.

: warn(message)

  a method to give warnings.

: abort()

  takes optional terminate message argument.

: Object#initialize_copy

  copy constructor for clone and dup.

: Object#instance_variable_set, Object#instance_variable_get

  added.

: Object#singleton_method_removed
: Object#singleton_method_undefined

  Added.

: Array#transpose

  added.

: Array#fetch(index [, default])

  Added.  If a default value isn't given, raises index error if index
  is out of range.

: 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]

: Array#filter

  Previously deprecated, now removed.  Use Array#collect!.

: 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#new

  Now takes block to fill initial values.  E.g.

	Array.new(10) { |i| i + 1 }
	=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

: Array#fill

  Takes block to get the values to fill.

: Array#fetch

  Takes block to get the default value.

: Array#zip

  added.

: Hash#update

  Takes block to resolve key conflict.

: Hash#merge and Hash#merge!

  update hash.  Hash#merge! is a synonym of Hash#update.

: String#split

  if "sep" argument is a string, regular expression meta characters
  are escaped internally.

: String#rstrip

  chop off NULs at the end of strings.

: String#to_i

  Now accepts optional base argument.

	"101".to_i(10) => 101
	"101".to_i(2)  => 5
	"101".to_i(8)  => 65
	"101".to_i(16) => 257

  A base argument of 0 guesses at the base.

	"101".to_i(0)   => 101
	"0b101".to_i(0) => 5
	"0101".to_i(0)  => 65
	"0x101".to_i(0) => 257

: String#[regexp, nth]

  Extended to accepts optional second argument.

  It 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]

: IO

  64bit off_t support by Janathan Baker.

: IO#read
: IO#sysread

  takes optinal second argument for read buffer.

: IO::sysopen

  New method to get a raw file descriptor.

: IO#sysseek

  Added.

: IO#fsync

  new method that copies all in-memory parts of a file to disk and
  waits until the device reports that all parts are on stable storage.
  Implemented with fsync(2) or equivalent.

: IO.open

  Made public.  Can only associate an IO object with a file number
  like IO.new and IO.for_fd, but can take a block.

: IO.for_fd

  Added as a synonym for IO.new.

: IO.read

  Added.  Like IO.readlines, except it returns the entire file as a
  string.  [ruby-talk:9460]

: 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.

: File.open, IO.open

  File mode can be specified by flags like open(2),
  e.g. File::open(path, File::CREAT|File::WRONLY).

: Regexp#options

  Added.

: Regexp.last_match(n)

  Extended to take an optional argument.

: MatchData#captures

  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
      }
    }

: Dir#pos=

  Returns the new position instead of self.

: Dir::glob

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

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

: Class#inherited

  Method is called when Class is inherited by another class.

	class A; end
	def A.inherited(by)
          puts "A inherited by #{by.inspect}"
        end
        class B < A; end

        Prints out "A inherited by B"

: 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.

: 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.

: Marshal to use marshal_dump and marshal_load

  if a dumping object responds to 'marshal_dump', Marshal.dump calls
  it, and dumps object returned.  Marshal.load allocates a new instance
  using "allocate", then calls its "marshal_load" with dumped data.
  Marshal format version is now 4.8 (was 4.6 in 1.6.8).

: Marshal

  Fixed not to dump anonymous classes/modules.

  Fixed with loading modules.

: Thread#group

  new method to get belonging  ThreadGroup.

: Thread#terminate

  synonym of Thread#exit

: Thread#join

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

: ThreagGroup#enclose

  prohibits thread movement from/to enclosed groups.

: Range#step([step=1])

  Added.

: SystemCallError

  SystemCallError's "===" match (used in rescue also) is now based on its errno.

: Interrupt

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

: NameError and NoMethodError

  Moved and now NoMethodError < NameError < StandardError.

: NoMethodError

  Added. [ruby-dev:12763]

: NotImplementError

  Finally obsoleted.  Use NotImplementedError.

: SystemCallError.===

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

: SystemExit#status

  Added.

: Proc#==

  Added.

: Method#==

  Added.

: UnboundMethod is no longer subclass of Method

  class hierarchy changed. 

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

  Added.

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

  Added.

: Process.abort
: Process.exit

  synonym of Kernel#abort, and Kernel#exit respectively.

: Process::detach(pid)

  new method to detach child process.  child process will be "wait"ed
  automagically.

: 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.

: Process::UID, Process::GID, Process::Sys,

  Added.

: Signal

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

= changes in bundled libraries

: lib/cgi.rb

  cgi[name] returns CGI::QueryExtension::Value that wraps string
  value, no longer array.

: lib/timeout

  timeout "function" wrapped in Timeout module.

: 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.).

  Date#mjd now returns the chronological modified Julian day number.

  All facilities about tjd have been removed.

: Curses

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

: Net::HTTP

  New version of Net::HTTP has introduced seriously incompatible
  changes. For details, see document embedded in net/http.rb itself.

: 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.

: 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.

= newly bundled library

: ext/bigdecimal

  variable precision decimal number 

: ext/dl

  an interface to the dynamic linker.

: ext/enumerator

  a helper module for the Enumerable interface.

: ext/io/wait

  IO wait methods.

: ext/iconv

  wrapper library of (({iconv})).

: ext/openssl

  OpenSSL for Ruby

: ext/racc/cparse

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

: ext/stringio

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

: ext/strscan

  Fast string scanner library.

: ext/syck

  fast YAML parser.

: lib/abbrev

  creates an abbreviation table from a list

: lib/benchmark

  Ruby scripts benchmarker

: lib/cgi/session/pstore

  cgi/session back-end using pstore 

: lib/csv

  reads/writes CSV files.

: lib/date/format

  strftime for Date class

: lib/drb

  dRuby or distributed Ruby

: lib/fileutils

  file utility library.

: lib/generator

  converts an internal iterator to an external iterator

: lib/gserver

  generic server used by xmlrpc

: lib/ipaddr

  manipulates IP address.

: lib/multi-tk

  to allow safe Tk, etc.

: lib/open-uri

  easy-to-use wrapper for net/http and net/ftp

: lib/optparse

  command line options utility library

: lib/pathname

  handles pathname in OO manner.

: lib/pp

  prettyprinter for Ruby objects

: lib/prettyprint

  implements prettyprint algorithm.

: lib/profiler

  library to implement -r "profile"

: lib/racc/parser

  RACC parser generator runtime in Ruby.

: lib/scanf

  scan string and retrieve object with format

: lib/set

  Set class

: lib/runit

  RubyUnit compatible layer for test/unit

: lib/test/unit

  unit testing framework for Ruby

: lib/tmpdir

  get temporary directory path.

: lib/tsort

  topological sorting library.

: lib/rexml

  REXML XML library

: lib/webrick

  generic internet server kit

: lib/xmlrpc

  simple RPC via XML

: lib/un

  used like 'ruby -run -e cp -- -p foo bar'.  neat, isn't it?

: lib/win32/registry

  win32/registry is registry accessor

: lib/yaml

  YAML Ain't Mark-up Language

= removed libraries

: lib/ftplib

  use net/ftp instead.

: lib/telnet

  use net/telnet instead.

= new port

: WindowsCE port
: Win32 BCC

= interpreter implementation

: garbage collector

  faster, but uses more memory for the worst case.

: string concatenation

  faster by avoiding too frequent realloc(3).