* lib/irb/init.rb (IRB.opt_parse): (M17N) adds -U and -E as command

  line options. [ruby-dev:37161]. Fixes #711.
  improved long optinos.

* lib/irb/init.rb (IRB.set_encoding): new subroutine for IRB.opt_parse

* lib/irb/input-method.rb (IRB::StdioInputMethod): (M17N) regards
  scripts that user types as encoded in the external_encoding.

* lib/irb/input-method.rb (IRB::ReadlineInputMethod): ditto.

* lib/irb/input-method.rb (IRB::FileInputMethod): (M17N) respects
  magic comment.

* lib/irb/help.rb (IRB.print_usage): (M17N) respects magic comment
  in the resource file.

* lib/irb/lc/help-message: adds -U and -E.

* lib/irb/lc/ja/help-message: ditto. re-encoded from ISO-2022-JP into UTF-8.

* lib/irb/lc/ja/encoding_aliases.rb: new file. provides Japanese specific
  character encoding name table for backward compatibility.

* lib/irb/lc/ja/error.rb: re-eoncoded from ISO-2022-JP into UTF-8.
  magic comment.

* lib/irb/locale.rb: integrated with Ruby 1.9's M17N support.

* lib/irb/magic-file.rb: new file. utility to handle files with magic
  comment and opens in the correct encoding.

* lib/irb/ruby-lex.rb (RubyLex#each_top_level_statement): recovers
  character encoding for a statement after it lexed so that irb can
  eval the statement in correct encoding.

* lib/irb/src_encoding.rb: new file. utility.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@20862 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

11 files changed, 232 insertions, 108 deletions

diff --git a/lib/irb/help.rb b/lib/irb/help.rb
index 01e5878d18..2b064d5d6d 100644
--- a/lib/irb/help.rb
+++ b/lib/irb/help.rb
@@ -9,24 +9,27 @@
 #   
 #
 
+require 'irb/magic-file'
+
 module IRB
   def IRB.print_usage
     lc = IRB.conf[:LC_MESSAGES]
     path = lc.find("irb/help-message")
     space_line = false
-    File.foreach(path) do
-      |l|
-      if /^\s*$/ =~ l
-	lc.puts l unless space_line
-	space_line = true
-	next
+    IRB::MagicFile.open(path){|f|
+      f.each_line do |l|
+	if /^\s*$/ =~ l
+	  lc.puts l unless space_line
+	  space_line = true
+	  next
+	end
+	space_line = false
+
+	l.sub!(/#.*$/, "")
+	  next if /^\s*$/ =~ l
+	lc.puts l
       end
-      space_line = false
-      
-      l.sub!(/#.*$/, "")
-      next if /^\s*$/ =~ l
-      lc.puts l
-    end
+    }
   end
 end
 
diff --git a/lib/irb/init.rb b/lib/irb/init.rb
index 576b99d1c8..62c862a1c3 100644
--- a/lib/irb/init.rb
+++ b/lib/irb/init.rb
@@ -139,6 +139,11 @@ module IRB
       when /^-I(.+)?/
         opt = $1 || ARGV.shift
 	load_path.concat(opt.split(File::PATH_SEPARATOR)) if opt
+      when '-U'
+	set_encoding("UTF-8", "UTF-8")
+      when /^-E(.+)?/, /^--encoding(?:=(.+))?/
+	opt = $1 || ARGV.shift
+	set_encoding(*opt.split(':', 2))
       when "--inspect"
 	@CONF[:INSPECT_MODE] = true
       when "--noinspect"
@@ -155,8 +160,9 @@ module IRB
 	@CONF[:VERBOSE] = true
       when "--noverbose"
 	@CONF[:VERBOSE] = false
-      when "--prompt-mode", "--prompt"
-	prompt_mode = ARGV.shift.upcase.tr("-", "_").intern
+      when /^--prompt-mode(?:=(.+))?/, /^--prompt(?:=(.+))?/
+	opt = $1 || ARGV.shift
+	prompt_mode = opt.upcase.tr("-", "_").intern
 	@CONF[:PROMPT_MODE] = prompt_mode
       when "--noprompt"
 	@CONF[:PROMPT_MODE] = :NULL
@@ -166,14 +172,14 @@ module IRB
 	@CONF[:PROMPT_MODE] = :SIMPLE
       when "--tracer"
 	@CONF[:USE_TRACER] = true
-      when "--back-trace-limit"
-	@CONF[:BACK_TRACE_LIMIT] = ARGV.shift.to_i
-      when "--context-mode"
-	@CONF[:CONTEXT_MODE] = ARGV.shift.to_i
+      when /^--back-trace-limit(?:=(.+))?/
+	@CONF[:BACK_TRACE_LIMIT] = ($1 || ARGV.shift).to_i
+      when /^--context-mode(?:=(.+))?/
+	@CONF[:CONTEXT_MODE] = ($1 || ARGV.shift).to_i
       when "--single-irb"
 	@CONF[:SINGLE_IRB] = true
-      when "--irb_debug"
-	@CONF[:DEBUG_LEVEL] = ARGV.shift.to_i
+      when /^--irb_debug=(?:=(.+))?/
+	@CONF[:DEBUG_LEVEL] = ($1 || ARGV.shift).to_i
       when "-v", "--version"
 	print IRB.version, "\n"
 	exit 0
@@ -181,6 +187,12 @@ module IRB
 	require "irb/help"
 	IRB.print_usage
 	exit 0
+      when "--"
+	if opt = ARGV.shfit
+	  @CONF[:SCRIPT] = opt
+	  $0 = opt
+	end
+        break
       when /^-/
 	IRB.fail UnrecognizedSwitch, opt
       else
@@ -195,6 +207,7 @@ module IRB
       end
     end
     $LOAD_PATH.unshift(*load_path)
+
   end
 
   # running config
@@ -253,4 +266,21 @@ module IRB
     end
   end
 
+
+  DefaultEncodings = Struct.new(:external, :internal)
+  class << IRB
+    private
+    def set_encoding(extern, intern = nil)
+      verbose, $VERBOSE = $VERBOSE, nil
+      Encoding.default_external = extern unless extern.nil? || extern.empty?
+      Encoding.default_internal = intern unless intern.nil? || intern.empty?
+      @CONF[:ENCODINGS] = IRB::DefaultEncodings.new(extern, intern)
+      [$stdin, $stdout, $stderr].each do |io|
+	io.set_encoding(extern, intern)
+      end
+      @CONF[:LC_MESSAGES].instance_variable_set(:@encoding, extern)
+    ensure
+      $VERBOSE = verbose
+    end
+  end
 end
diff --git a/lib/irb/input-method.rb b/lib/irb/input-method.rb
index fc8d476eae..c4142a924e 100644
--- a/lib/irb/input-method.rb
+++ b/lib/irb/input-method.rb
@@ -8,6 +8,9 @@
 #
 #   
 #
+require 'irb/src_encoding'
+require 'irb/magic-file'
+
 module IRB
   # 
   # InputMethod
@@ -41,15 +44,19 @@ module IRB
       super
       @line_no = 0
       @line = []
+      @stdin = IO.open(STDIN.to_i, :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
+      @stdout = IO.open(STDOUT.to_i, :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
     end
 
     def gets
       print @prompt
-      @line[@line_no += 1] = $stdin.gets
+      line = @stdin.gets
+      p line.encoding
+      @line[@line_no += 1] = line
     end
 
     def eof?
-      $stdin.eof?
+      @stdin.eof?
     end
 
     def readable_atfer_eof?
@@ -59,12 +66,16 @@ module IRB
     def line(line_no)
       @line[line_no]
     end
+
+    def encoding
+      @stdin.external_encoding
+    end
   end
   
   class FileInputMethod < InputMethod
     def initialize(file)
       super
-      @io = open(file)
+      @io = IRB::MagicFile.open(file)
     end
     attr_reader :file_name
 
@@ -78,6 +89,10 @@ module IRB
 #      print @prompt, l
       l
     end
+
+    def encoding
+      @io.external_encoding
+    end
   end
 
   begin
@@ -90,11 +105,14 @@ module IRB
 	@line_no = 0
 	@line = []
 	@eof = false
+
+	@stdin = IO.open(STDIN.to_i, :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
+	@stdout = IO.open(STDOUT.to_i, :external_encoding => IRB.conf[:LC_MESSAGES].encoding, :internal_encoding => "-")
       end
 
       def gets
-        Readline.input = STDIN
-        Readline.output = STDOUT
+        Readline.input = @stdin
+        Readline.output = @stdout
 	if l = readline(@prompt, false)
 	  HISTORY.push(l) if !l.empty?
 	  @line[@line_no += 1] = l + "\n"
@@ -115,6 +133,10 @@ module IRB
       def line(line_no)
 	@line[line_no]
       end
+
+      def encoding
+	@stdin.external_encoding
+      end
     end
   rescue LoadError
   end
diff --git a/lib/irb/lc/help-message b/lib/irb/lc/help-message
index d93951b33d..9c08a5c29d 100644
--- a/lib/irb/lc/help-message
+++ b/lib/irb/lc/help-message
@@ -1,3 +1,4 @@
+# -*- coding: US-ASCII -*-
 #
 #   irb/lc/help-message.rb - 
 #   	$Release Version: 0.9.5$
@@ -14,6 +15,8 @@ Usage:  irb.rb [options] [programfile] [arguments]
   -d                Set $DEBUG to true (same as `ruby -d')
   -r load-module    Same as `ruby -r'
   -I path           Specify $LOAD_PATH directory
+  -U                Same as `ruby -U`
+  -E enc            Same as `ruby -E`
   --inspect	    Use `inspect' for output (default except for bc mode)
   --noinspect	    Don't use inspect for output
   --readline	    Use Readline extension module
@@ -32,3 +35,4 @@ Usage:  irb.rb [options] [programfile] [arguments]
 		    value is 16. 
   --irb_debug n	    Set internal debug level to n (not for popular use)
   -v, --version	    Print the version of irb
+# vim:fileencoding=us-ascii
diff --git a/lib/irb/lc/ja/encoding_aliases.rb b/lib/irb/lc/ja/encoding_aliases.rb
new file mode 100644
index 0000000000..a713dff4be
--- /dev/null
+++ b/lib/irb/lc/ja/encoding_aliases.rb
@@ -0,0 +1,8 @@
+module IRB
+  class Locale
+    @@legacy_encoding_alias_map = {
+      'ujis' => Encoding::EUC_JP,
+      'euc' => Encoding::EUC_JP
+    }.freeze
+  end
+end
diff --git a/lib/irb/lc/ja/error.rb b/lib/irb/lc/ja/error.rb
index 13cf180142..dc0345e6df 100644
--- a/lib/irb/lc/ja/error.rb
+++ b/lib/irb/lc/ja/error.rb
@@ -1,4 +1,4 @@
-#
+# -*- coding: utf-8 -*-
 #   irb/lc/ja/error.rb - 
 #   	$Release Version: 0.9.5$
 #   	$Revision$
@@ -13,14 +13,15 @@ require "e2mmap"
 module IRB
   # exceptions
   extend Exception2MessageMapper
-  def_exception :UnrecognizedSwitch, '$B%9%$%C%A(B(%s)$B$,J,$j$^$;$s(B'
-  def_exception :NotImplementedError, '`%s\'$B$NDj5A$,I,MW$G$9(B'
-  def_exception :CantReturnToNormalMode, 'Normal$B%b!<%I$KLa$l$^$;$s(B.'
-  def_exception :IllegalParameter, '$B%Q%i%a!<%?(B(%s)$B$,4V0c$C$F$$$^$9(B.'
-  def_exception :IrbAlreadyDead, 'Irb$B$O4{$K;`$s$G$$$^$9(B.'
-  def_exception :IrbSwitchedToCurrentThread, '$B%+%l%s%H%9%l%C%I$K@Z$jBX$o$j$^$7$?(B.'
-  def_exception :NoSuchJob, '$B$=$N$h$&$J%8%g%V(B(%s)$B$O$"$j$^$;$s(B.'
-  def_exception :CantShiftToMultiIrbMode, 'multi-irb mode$B$K0\$l$^$;$s(B.'
-  def_exception :CantChangeBinding, '$B%P%$%s%G%#%s%0(B(%s)$B$KJQ99$G$-$^$;$s(B.'
-  def_exception :UndefinedPromptMode, '$B%W%m%s%W%H%b!<%I(B(%s)$B$ODj5A$5$l$F$$$^$;$s(B.'
+  def_exception :UnrecognizedSwitch, 'スイッチ(%s)が分りません'
+  def_exception :NotImplementedError, '`%s\'の定義が必要です'
+  def_exception :CantReturnToNormalMode, 'Normalモードに戻れません.'
+  def_exception :IllegalParameter, 'パラメータ(%s)が間違っています.'
+  def_exception :IrbAlreadyDead, 'Irbは既に死んでいます.'
+  def_exception :IrbSwitchedToCurrentThread, 'カレントスレッドに切り替わりました.'
+  def_exception :NoSuchJob, 'そのようなジョブ(%s)はありません.'
+  def_exception :CantShiftToMultiIrbMode, 'multi-irb modeに移れません.'
+  def_exception :CantChangeBinding, 'バインディング(%s)に変更できません.'
+  def_exception :UndefinedPromptMode, 'プロンプトモード(%s)は定義されていません.'
 end
+# vim:fileencoding=utf-8
diff --git a/lib/irb/lc/ja/help-message b/lib/irb/lc/ja/help-message
index ff09b073da..d156039c9b 100644
--- a/lib/irb/lc/ja/help-message
+++ b/lib/irb/lc/ja/help-message
@@ -1,4 +1,4 @@
-#
+# -*- coding: utf-8 -*-
 #   irb/lc/ja/help-message.rb - 
 #   	$Release Version: 0.9.5$
 #   	$Revision$
@@ -9,27 +9,31 @@
 #   
 #
 Usage:  irb.rb [options] [programfile] [arguments]
-  -f		    ~/.irbrc $B$rFI$_9~$^$J$$(B.
-  -m		    bc$B%b!<%I(B($BJ,?t(B, $B9TNs$N7W;;$,$G$-$k(B)
-  -d                $DEBUG $B$r(Btrue$B$K$9$k(B(ruby -d $B$HF1$8(B)
-  -r load-module    ruby -r $B$HF1$8(B.
-  -I path           $LOAD_PATH $B$K(B path $B$rDI2C$9$k(B.
-  --inspect	    $B7k2L=PNO$K(Binspect$B$rMQ$$$k(B(bc$B%b!<%I0J30$O%G%U%)%k%H(B). 
-  --noinspect	    $B7k2L=PNO$K(Binspect$B$rMQ$$$J$$(B.
-  --readline	    readline$B%i%$%V%i%j$rMxMQ$9$k(B.
-  --noreadline	    readline$B%i%$%V%i%j$rMxMQ$7$J$$(B. 
+  -f		    ~/.irbrc を読み込まない.
+  -m		    bcモード(分数, 行列の計算ができる)
+  -d                $DEBUG をtrueにする(ruby -d と同じ)
+  -r load-module    ruby -r と同じ.
+  -I path           $LOAD_PATH に path を追加する.
+  -U                ruby -U と同じ.
+  -E enc            ruby -E と同じ.
+  --inspect	    結果出力にinspectを用いる(bcモード以外はデフォルト). 
+  --noinspect	    結果出力にinspectを用いない.
+  --readline	    readlineライブラリを利用する.
+  --noreadline	    readlineライブラリを利用しない. 
   --prompt prompt-mode/--prompt-mode prompt-mode
-		    $B%W%m%s%W%H%b!<%I$r@ZBX$($^$9(B. $B8=:_Dj5A$5$l$F$$$k%W(B
-		    $B%m%s%W%H%b!<%I$O(B, default, simple, xmp, inf-ruby$B$,(B
-		    $BMQ0U$5$l$F$$$^$9(B. 
-  --inf-ruby-mode   emacs$B$N(Binf-ruby-mode$BMQ$N%W%m%s%W%HI=<($r9T$J$&(B. $BFC(B
-		    $B$K;XDj$,$J$$8B$j(B, readline$B%i%$%V%i%j$O;H$o$J$/$J$k(B.
-  --simple-prompt   $BHs>o$K%7%s%W%k$J%W%m%s%W%H$rMQ$$$k%b!<%I$G$9(B.
-  --noprompt	    $B%W%m%s%W%HI=<($r9T$J$o$J$$(B.
-  --tracer	    $B%3%^%s%I<B9T;~$K%H%l!<%9$r9T$J$&(B.
+		    プロンプトモードを切替えます. 現在定義されているプ
+		    ロンプトモードは, default, simple, xmp, inf-rubyが
+		    用意されています. 
+  --inf-ruby-mode   emacsのinf-ruby-mode用のプロンプト表示を行なう. 特
+		    に指定がない限り, readlineライブラリは使わなくなる.
+  --simple-prompt   非常にシンプルなプロンプトを用いるモードです.
+  --noprompt	    プロンプト表示を行なわない.
+  --tracer	    コマンド実行時にトレースを行なう.
   --back-trace-limit n
-		    $B%P%C%/%H%l!<%9I=<($r%P%C%/%H%l!<%9$NF,$+$i(B n, $B8e$m(B
-		    $B$+$i(Bn$B$@$19T$J$&(B. $B%G%U%)%k%H$O(B16 
-  --irb_debug n	    irb$B$N%G%P%C%0%G%P%C%0%l%Y%k$r(Bn$B$K@_Dj$9$k(B($BMxMQ$7$J(B
-		    $B$$J}$,L5Fq$G$7$g$&(B).
-  -v, --version	    irb$B$N%P!<%8%g%s$rI=<($9$k(B
+		    バックトレース表示をバックトレースの頭から n, 後ろ
+		    からnだけ行なう. デフォルトは16 
+  --irb_debug n	    irbのデバッグデバッグレベルをnに設定する(利用しな
+		    い方が無難でしょう).
+  -v, --version	    irbのバージョンを表示する
+
+# vim:fileencoding=utf-8
diff --git a/lib/irb/locale.rb b/lib/irb/locale.rb
index 855be31052..d36cc5a805 100644
--- a/lib/irb/locale.rb
+++ b/lib/irb/locale.rb
@@ -8,43 +8,51 @@
 #
 #   
 #
-
-autoload :Kconv, "kconv"
-
 module IRB
   class Locale
     @RCS_ID='-$Id$-'
 
-    JPDefaultLocale = "ja"
+    LOCALE_NAME_RE = %r[
+      (?<language>[[:alpha:]]{2})
+      (?:_
+       (?<territory>[[:alpha:]]{2,3})
+       (?:\.
+	(?<codeset>[^@]+)
+       )?
+      )?
+      (?:@
+       (?<modifier>.*)
+      )?
+    ]x
     LOCALE_DIR = "/lc/"
 
-    def initialize(locale = nil)
-      @lang = locale || ENV["IRB_LANG"] || ENV["LC_MESSAGES"] || ENV["LC_ALL"] || ENV["LANG"] || "C" 
-    end
-
-    attr_reader :lang
+    @@legacy_encoding_alias_map = {}.freeze
 
-    def lc2kconv(lang)
-      case lang
-      when "ja_JP.ujis", "ja_JP.euc", "ja_JP.eucJP", "ja_JP.EUC-JP"
-        Kconv::EUC
-      when "ja_JP.sjis", "ja_JP.SJIS"
-        Kconv::SJIS
-      when /ja_JP.utf-?8/i
-	Kconv::UTF8
+    def initialize(locale = nil)
+      @locale = locale || ENV["IRB_LANG"] || ENV["LC_MESSAGES"] || ENV["LC_ALL"] || ENV["LANG"] || "C" 
+      if m = LOCALE_NAME_RE.match(@locale)
+	@lang, @territory, @encoding_name, @modifier = m[:language], m[:territory], m[:codeset], m[:modifier]
+
+	if @encoding_name
+	  begin; load 'irb/encoding_aliases.rb' rescue LoadError; end
+	  if @encoding = @@legacy_encoding_alias_map[@encoding_name]
+	    warn "%s is obsolete. use %s" % ["#{@lang}_#{@territory}.#{@encoding_name}", "#{@lang}_#{@territory}.#{@encoding.name}"]
+	  end
+	  @encoding = Encoding.find(@encoding_name) rescue nil
+	end
       end
+      @encoding ||= (Encoding.find('locale') rescue Encoding::ASCII_8BIT)
     end
-    private :lc2kconv
+
+    attr_reader :lang, :territory, :encoding, :modifieer
 
     def String(mes)
       mes = super(mes)
-      case @lang
-      when /^ja/
-	mes = Kconv::kconv(mes, lc2kconv(@lang))
+      if @encoding
+	mes.encode(@encoding) 
       else
 	mes
       end
-      mes
     end
 
     def format(*opts)
@@ -106,27 +114,20 @@ module IRB
       dir = "" if dir == "."
       base = File.basename(file)
 
-      if /^ja(_JP)?$/ =~ @lang
- 	back, @lang = @lang, "C"
+      if dir[0] == ?/ #/
+	lc_path = search_file(dir, base)
+	return real_load(lc_path, priv) if lc_path
       end
-      begin
-	if dir[0] == ?/ #/
-	  lc_path = search_file(dir, base)
-	  return real_load(lc_path, priv) if lc_path
-	end
-	
-	for path in $:
-	  lc_path = search_file(path + "/" + dir, base)
-	  return real_load(lc_path, priv) if lc_path
-	end
-      ensure
-	@lang = back if back
+
+      for path in $:
+	lc_path = search_file(path + "/" + dir, base)
+	return real_load(lc_path, priv) if lc_path
       end
       raise LoadError, "No such file to load -- #{file}"
     end 
 
     def real_load(path, priv)
-      src = self.String(File.read(path))
+      src = MagicFile.open(path){|f| f.read}
       if priv
 	eval("self", TOPLEVEL_BINDING).extend(Module.new {eval(src, nil, path)})
       else
@@ -152,29 +153,39 @@ module IRB
     end
 
     def search_file(path, file)
-      if File.exist?(p1 = path + lc_path(file, "C"))
-	if File.exist?(p2 = path + lc_path(file))
-	  return p2
-	else
-	end
-	return p1
-      else
+      each_sublocale do |lc|
+	full_path = path + lc_path(file, lc)
+	return full_path if File.exist?(full_path)
       end
       nil
     end
     private :search_file
 
-    def lc_path(file = "", lc = @lang)
-      case lc
-      when "C"
+    def lc_path(file = "", lc = @locale)
+      if lc.nil?
 	LOCALE_DIR + file
-      when /^ja/
-	LOCALE_DIR + "ja/" + file
       else
 	LOCALE_DIR + @lang + "/" + file
       end
     end
     private :lc_path
+
+    def each_sublocale
+      if @lang
+	if @territory
+	  if @encoding_name
+	    yield "#{@lang}_#{@territory}.#{@encoding_name}@#{@modifier}" if @modifier
+	    yield "#{@lang}_#{@territory}.#{@encoding_name}"
+	  end
+	  yield "#{@lang}_#{@territory}@#{@modifier}" if @modifier
+	  yield "#{@lang}_#{@territory}"
+	end
+	yield "#{@lang}@#{@modifier}" if @modifier
+	yield "#{@lang}"
+      end
+      yield nil
+    end
+    private :each_sublocale
   end
 end
 
diff --git a/lib/irb/magic-file.rb b/lib/irb/magic-file.rb
new file mode 100644
index 0000000000..861262050e
--- /dev/null
+++ b/lib/irb/magic-file.rb
@@ -0,0 +1,36 @@
+module IRB
+  class << (MagicFile = Object.new)
+    # see parser_magic_comment in parse.y
+    ENCODING_SPEC_RE = %r"coding\s*[=:]\s*([[:alnum:]\-_]+)"
+
+    def open(path)
+      io = File.open(path, 'rb')
+      line = io.gets
+      line = io.gets if line[0,2] == "#!"
+      encoding = detect_encoding(line)
+      encoding ||= default_src_encoding
+      io.rewind
+      io.set_encoding(encoding, nil)
+
+      if block_given?
+        begin
+          return (yield io)
+        ensure
+          io.close
+        end
+      else
+        return io
+      end
+    end
+
+    private
+    def detect_encoding(line)
+      return unless line[0] == ?#
+      line = line[1..-1]
+      line = $1 if line[/-\*-\s*(.*?)\s*-*-$/]
+      return nil unless ENCODING_SPEC_RE =~ line
+      encoding = $1
+      return encoding.sub(/-(?:mac|dos|unix)/i, '')
+    end
+  end
+end
diff --git a/lib/irb/ruby-lex.rb b/lib/irb/ruby-lex.rb
index 2569fd93d5..b21f0d34f8 100644
--- a/lib/irb/ruby-lex.rb
+++ b/lib/irb/ruby-lex.rb
@@ -240,6 +240,7 @@ class RubyLex
 	    end
 	  end
 	  if @line != "\n"
+      @line.force_encoding(@io.encoding)
 	    yield @line, @exp_line_no
 	  end
 	  break unless l
diff --git a/lib/irb/src_encoding.rb b/lib/irb/src_encoding.rb
new file mode 100644
index 0000000000..958cef104c
--- /dev/null
+++ b/lib/irb/src_encoding.rb
@@ -0,0 +1,4 @@
+# DO NOT WRITE ANY MAGIC COMMENT HERE.
+def default_src_encoding
+  return __ENCODING__
+end