diff --git a/ChangeLog b/ChangeLog
index 5f372f0686..0420ebd9e9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+Wed Dec  3 13:49:07 2003  Hidetoshi NAGAI  <nagai@ai.kyutech.ac.jp>
+
+	* ext/tk/lib/tk.rb: 'format'==>'Kernel.format' (avoid override trouble)
+
+	* ext/tk/lib/tkafter.rb: ditto.
+
+	* ext/tk/lib/tkcanvas.rb: ditto.
+
+	* ext/tk/lib/tkdialog.rb: ditto.
+
+	* ext/tk/lib/tktext.rb: ditto.
+
 Wed Dec  3 13:28:13 2003  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* Makefile.in (lex.c): try gperf first, and copy from the source
diff --git a/ext/tk/lib/tk.rb b/ext/tk/lib/tk.rb
index 5905746722..69c214175a 100644
--- a/ext/tk/lib/tk.rb
+++ b/ext/tk/lib/tk.rb
@@ -229,7 +229,8 @@ module TkComm
     when /^-?\d+\.?\d*(e[-+]?\d+)?$/
       val.to_f
     else
-      fail ArgumentError, format('invalid value for Number:"%s"', val.to_s)
+      fail(ArgumentError, 
+	   Kernel.format('invalid value for Number:"%s"', val.to_s))
     end
   end
   def string(val)
@@ -334,7 +335,7 @@ module TkComm
     @cmdtbl = [] unless defined? @cmdtbl
     @cmdtbl.taint unless @cmdtbl.tainted?
     @cmdtbl.push id
-    return format("rb_out %s", id);
+    return Kernel.format("rb_out %s", id);
   end
   def uninstall_cmd(id)
     id = $1 if /rb_out (c\d+)/ =~ id
@@ -354,9 +355,9 @@ module TkComm
     if name[0] == ?.
       @path = name.dup
     elsif !ppath or ppath == "."
-      @path = format(".%s", name);
+      @path = Kernel.format(".%s", name);
     else
-      @path = format("%s.%s", ppath, name)
+      @path = Kernel.format("%s.%s", ppath, name)
     end
     #Tk_WINDOWS[@path] = self
     TkCore::INTERP.tk_windows[@path] = self
@@ -1549,8 +1550,8 @@ module Tk
 
     def self.tk_escape(str)
       s = '"' + str.gsub(/[\[\]$"]/, '\\\\\&') + '"'
-      TkCore::INTERP.__eval(format('global %s; set %s %s', 
-				   @@enc_buf, @@enc_buf, s))
+      TkCore::INTERP.__eval(Kernel.format('global %s; set %s %s', 
+					  @@enc_buf, @@enc_buf, s))
     end
 
     def self.new(str, enc = Tk.encoding_system)
@@ -1782,7 +1783,7 @@ class TkBindTag
   end
 
   def inspect
-    format "#<TkBindTag: %s>", @id
+    Kernel.format "#<TkBindTag: %s>", @id
   end
 end
 
@@ -1808,7 +1809,7 @@ class TkDatabaseClass<TkBindTag
   end
 
   def inspect
-    format "#<TkDatabaseClass: %s>", @id
+    Kernel.format "#<TkDatabaseClass: %s>", @id
   end
 end
 
@@ -1871,10 +1872,10 @@ class TkVariable
     if  val.kind_of?(Hash)
       s = '"' + val.to_a.collect{|e| array2tk_list(e)}.join(" ")\
                    .gsub(/[\[\]$"]/, '\\\\\&') + '"'
-      INTERP._eval(format('global %s; array set %s %s', @id, @id, s))
+      INTERP._eval(Kernel.format('global %s; array set %s %s', @id, @id, s))
     else
       s = '"' + _get_eval_string(val).gsub(/[\[\]$"]/, '\\\\\&') + '"'
-      INTERP._eval(format('global %s; set %s %s', @id, @id, s))
+      INTERP._eval(Kernel.format('global %s; set %s %s', @id, @id, s))
     end
   end
 
@@ -1918,14 +1919,13 @@ class TkVariable
 
   def value
     begin
-      INTERP._eval(format('global %s; set %s', @id, @id))
+      INTERP._eval(Kernel.format('global %s; set %s', @id, @id))
     rescue
-      if INTERP._eval(format('global %s; array exists %s', @id, @id)) != "1"
+      if INTERP._eval(Kernel.format('global %s; array exists %s', 
+				    @id, @id)) != "1"
 	fail
       else
-	Hash[*tk_split_simplelist(INTERP.
-				  _eval(format('global %s; array get %s', 
-					       @id, @id)))]
+	Hash[*tk_split_simplelist(INTERP._eval(Kernel.format('global %s; array get %s', @id, @id)))]
       end
     end
   end
@@ -1933,25 +1933,25 @@ class TkVariable
   def value=(val)
     begin
       s = '"' + _get_eval_string(val).gsub(/[\[\]$"]/, '\\\\\&') + '"'
-      INTERP._eval(format('global %s; set %s %s', @id, @id, s))
+      INTERP._eval(Kernel.format('global %s; set %s %s', @id, @id, s))
     rescue
-      if INTERP._eval(format('global %s; array exists %s', @id, @id)) != "1"
+      if INTERP._eval(Kernel.format('global %s; array exists %s', 
+				    @id, @id)) != "1"
 	fail
       else
 	if val == []
-	  INTERP._eval(format('global %s; unset %s; set %s(0) 0; unset %s(0)', 
-			      @id, @id, @id, @id))
+	  INTERP._eval(Kernel.format('global %s; unset %s; set %s(0) 0; unset %s(0)', @id, @id, @id, @id))
 	elsif val.kind_of?(Array)
 	  a = []
 	  val.each_with_index{|e,i| a.push(i); a.push(array2tk_list(e))}
 	  s = '"' + a.join(" ").gsub(/[\[\]$"]/, '\\\\\&') + '"'
-	  INTERP._eval(format('global %s; unset %s; array set %s %s', 
-			      @id, @id, @id, s))
+	  INTERP._eval(Kernel.format('global %s; unset %s; array set %s %s', 
+				     @id, @id, @id, s))
 	elsif  val.kind_of?(Hash)
 	  s = '"' + val.to_a.collect{|e| array2tk_list(e)}.join(" ")\
 	                        .gsub(/[\[\]$"]/, '\\\\\&') + '"'
-	  INTERP._eval(format('global %s; unset %s; array set %s %s', 
-			      @id, @id, @id, s))
+	  INTERP._eval(Kernel.format('global %s; unset %s; array set %s %s', 
+				     @id, @id, @id, s))
 	else
 	  fail
 	end
@@ -1960,13 +1960,13 @@ class TkVariable
   end
 
   def [](index)
-    INTERP._eval(format('global %s; set %s(%s)', 
-			@id, @id, _get_eval_string(index)))
+    INTERP._eval(Kernel.format('global %s; set %s(%s)', 
+			       @id, @id, _get_eval_string(index)))
   end
 
   def []=(index,val)
-    INTERP._eval(format('global %s; set %s(%s) %s', @id, @id, 
-			_get_eval_string(index), _get_eval_string(val)))
+    INTERP._eval(Kernel.format('global %s; set %s(%s) %s', @id, @id, 
+			       _get_eval_string(index), _get_eval_string(val)))
   end
 
   def numeric
@@ -2016,7 +2016,7 @@ class TkVariable
   end
 
   def inspect
-    format "#<TkVariable: %s>", @id
+    Kernel.format "#<TkVariable: %s>", @id
   end
 
   def coerce(other)
@@ -2151,10 +2151,10 @@ class TkVariable
 
   def unset(elem=nil)
     if elem
-      INTERP._eval(format('global %s; unset %s(%s)', 
-			  @id, @id, tk_tcl2ruby(elem)))
+      INTERP._eval(Kernel.format('global %s; unset %s(%s)', 
+				 @id, @id, tk_tcl2ruby(elem)))
     else
-      INTERP._eval(format('global %s; unset %s', @id, @id))
+      INTERP._eval(Kernel.format('global %s; unset %s', @id, @id))
     end
   end
   alias remove unset
@@ -2302,7 +2302,7 @@ class TkVarAccess<TkVariable
     TkVar_ID_TBL[@id] = self
     if val
       s = '"' + _get_eval_string(val).gsub(/[\[\]$"]/, '\\\\\&') + '"' #"
-      INTERP._eval(format('global %s; set %s %s', @id, @id, s))
+      INTERP._eval(Kernel.format('global %s; set %s %s', @id, @id, s))
     end
   end
 end
@@ -3919,8 +3919,9 @@ class TkObject<TkKernel
 
   def tk_trace_variable(v)
     unless v.kind_of?(TkVariable)
-      fail ArgumentError, 
-	format("type error (%s); must be TkVariable object", v.class)
+      fail(ArgumentError, 
+	   Kernel.format("type error (%s); must be TkVariable object", 
+			 v.class))
     end
     v
   end
@@ -5547,7 +5548,7 @@ module TkSystemMenu
     unless parent.kind_of? TkMenu
       fail ArgumentError, "parent must be a TkMenu object"
     end
-    @path = format("%s.%s", parent.path, self.class::SYSMENU_NAME)
+    @path = Kernel.format("%s.%s", parent.path, self.class::SYSMENU_NAME)
     #TkComm::Tk_WINDOWS[@path] = self
     TkCore::INTERP.tk_windows[@path] = self
     if self.method(:create_self).arity == 0
diff --git a/ext/tk/lib/tkafter.rb b/ext/tk/lib/tkafter.rb
index 728f7f70d3..53e78b8808 100644
--- a/ext/tk/lib/tkafter.rb
+++ b/ext/tk/lib/tkafter.rb
@@ -193,7 +193,7 @@ class TkTimer
   def set_procs(interval, loop_exec, *procs)
     if !interval == 'idle' \
        && !interval.kind_of?(Integer) && !interval.kind_of?(Proc)
-      fail format("%s need to be Integer or Proc", interval.inspect)
+      fail Kernel.format("%s need to be Integer or Proc", interval.inspect)
     end
     @sleep_time = interval
 
@@ -216,7 +216,7 @@ class TkTimer
 	@loop_exec = 1
       else
 	if not loop_exec.kind_of?(Integer)
-	  fail format("%s need to be Integer", loop_exec.inspect)
+	  fail Kernel.format("%s need to be Integer", loop_exec.inspect)
 	end
 	@loop_exec = loop_exec
       end
@@ -263,7 +263,7 @@ class TkTimer
 
   def set_start_proc(sleep, init_proc, *init_args)
     if !sleep == 'idle' && !sleep.kind_of?(Integer)
-      fail format("%s need to be Integer", sleep.inspect)
+      fail Kernel.format("%s need to be Integer", sleep.inspect)
     end
     @init_sleep = sleep
     @init_proc = init_proc
@@ -282,7 +282,7 @@ class TkTimer
     if argc > 0
       sleep = init_args.shift
       if !sleep == 'idle' && !sleep.kind_of?(Integer)
-	fail format("%s need to be Integer", sleep.inspect)
+	fail Kernel.format("%s need to be Integer", sleep.inspect)
       end
       @init_sleep = sleep
     end
@@ -293,7 +293,7 @@ class TkTimer
     @running = true
     if @init_proc
       if not @init_proc.kind_of? Proc
-	fail format("%s need to be Proc", @init_proc.inspect)
+	fail Kernel.format("%s need to be Proc", @init_proc.inspect)
       end
       @current_proc = @init_proc
       set_callback(@init_sleep, @init_args)
@@ -346,7 +346,7 @@ class TkTimer
     fail RuntimeError, "no procedure to continue" unless cmd
     if wait
       if not wait.kind_of? Integer
-	fail RuntimeError, format("%s need to be Integer", wait.inspect)
+	fail RuntimeError, Kernel.format("%s need to be Integer", wait.inspect)
       end
       sleep = wait
     end
diff --git a/ext/tk/lib/tkcanvas.rb b/ext/tk/lib/tkcanvas.rb
index 687f521655..58177584af 100644
--- a/ext/tk/lib/tkcanvas.rb
+++ b/ext/tk/lib/tkcanvas.rb
@@ -569,7 +569,7 @@ class TkcTag<TkObject
 
   def initialize(parent, mode=nil, *args)
     if not parent.kind_of?(TkCanvas)
-      fail format("%s need to be TkCanvas", parent.inspect)
+      fail Kernel.format("%s need to be TkCanvas", parent.inspect)
     end
     @c = parent
     @cpath = parent.path
@@ -647,7 +647,7 @@ class TkcTagString<TkcTag
 
   def initialize(parent, name, mode=nil, *args)
     if not parent.kind_of?(TkCanvas)
-      fail format("%s need to be TkCanvas", parent.inspect)
+      fail Kernel.format("%s need to be TkCanvas", parent.inspect)
     end
     @c = parent
     @cpath = parent.path
@@ -664,7 +664,7 @@ TkcNamedTag = TkcTagString
 class TkcTagAll<TkcTag
   def initialize(parent)
     if not parent.kind_of?(TkCanvas)
-      fail format("%s need to be TkCanvas", parent.inspect)
+      fail Kernel.format("%s need to be TkCanvas", parent.inspect)
     end
     @c = parent
     @cpath = parent.path
@@ -677,7 +677,7 @@ end
 class TkcTagCurrent<TkcTag
   def initialize(parent)
     if not parent.kind_of?(TkCanvas)
-      fail format("%s need to be TkCanvas", parent.inspect)
+      fail Kernel.format("%s need to be TkCanvas", parent.inspect)
     end
     @c = parent
     @cpath = parent.path
@@ -691,7 +691,7 @@ class TkcGroup<TkcTag
   Tk_cGroup_ID = ['tkcg'.freeze, '00000'.taint].freeze
   def create_self(parent, *args)
     if not parent.kind_of?(TkCanvas)
-      fail format("%s need to be TkCanvas", parent.inspect)
+      fail Kernel.format("%s need to be TkCanvas", parent.inspect)
     end
     @c = parent
     @cpath = parent.path
@@ -737,7 +737,7 @@ class TkcItem<TkObject
 
   def initialize(parent, *args)
     if not parent.kind_of?(TkCanvas)
-      fail format("%s need to be TkCanvas", parent.inspect)
+      fail Kernel.format("%s need to be TkCanvas", parent.inspect)
     end
     @parent = @c = parent
     @path = parent.path
diff --git a/ext/tk/lib/tkdialog.rb b/ext/tk/lib/tkdialog.rb
index 8ac598c605..d5c13dca1a 100644
--- a/ext/tk/lib/tkdialog.rb
+++ b/ext/tk/lib/tkdialog.rb
@@ -18,8 +18,8 @@ class TkDialog2 < TkWindow
 		     "to the dialog button#{i}. It was removed.\n")
       end
       c.delete('command'); c.delete(:command)
-      @config << format("%s.button%s configure %s; ", 
-			@path, i, hash_kv(c).join(' '))
+      @config << Kernel.format("%s.button%s configure %s; ", 
+			       @path, i, hash_kv(c).join(' '))
     }
     case configs
     when Proc
@@ -114,23 +114,23 @@ class TkDialog2 < TkWindow
     }
 
     if @message_config.kind_of? Hash
-      @config << format("%s.msg configure %s;", 
-		       @path, hash_kv(@message_config).join(' '))
+      @config << Kernel.format("%s.msg configure %s;", 
+			       @path, hash_kv(@message_config).join(' '))
     end
 
     if @msgframe_config.kind_of? Hash
-      @config << format("%s.top configure %s;", 
-		       @path, hash_kv(@msgframe_config).join(' '))
+      @config << Kernel.format("%s.top configure %s;", 
+			       @path, hash_kv(@msgframe_config).join(' '))
     end
 
     if @btnframe_config.kind_of? Hash
-      @config << format("%s.bot configure %s;", 
-		       @path, hash_kv(@btnframe_config).join(' '))
+      @config << Kernel.format("%s.bot configure %s;", 
+			       @path, hash_kv(@btnframe_config).join(' '))
     end
 
     if @bitmap_config.kind_of? Hash
-      @config << format("%s.bitmap configure %s;", 
-		       @path, hash_kv(@bitmap_config).join(' '))
+      @config << Kernel.format("%s.bitmap configure %s;", 
+			       @path, hash_kv(@bitmap_config).join(' '))
     end
 
     _set_button_config(@button_configs) if @button_configs
diff --git a/ext/tk/lib/tktext.rb b/ext/tk/lib/tktext.rb
index 8ab57d8065..d7cb055a40 100644
--- a/ext/tk/lib/tktext.rb
+++ b/ext/tk/lib/tktext.rb
@@ -834,7 +834,7 @@ class TkTextTag<TkObject
 
   def initialize(parent, *args)
     if not parent.kind_of?(TkText)
-      fail format("%s need to be TkText", parent.inspect)
+      fail Kernel.format("%s need to be TkText", parent.inspect)
     end
     @parent = @t = parent
     @tpath = parent.path
@@ -1006,7 +1006,7 @@ class TkTextNamedTag<TkTextTag
 
   def initialize(parent, name, *args)
     if not parent.kind_of?(TkText)
-      fail format("%s need to be TkText", parent.inspect)
+      fail Kernel.format("%s need to be TkText", parent.inspect)
     end
     @parent = @t = parent
     @tpath = parent.path
@@ -1050,7 +1050,7 @@ class TkTextMark<TkObject
 
   def initialize(parent, index)
     if not parent.kind_of?(TkText)
-      fail format("%s need to be TkText", parent.inspect)
+      fail Kernel.format("%s need to be TkText", parent.inspect)
     end
     @parent = @t = parent
     @tpath = parent.path
@@ -1122,7 +1122,7 @@ class TkTextNamedMark<TkTextMark
 
   def initialize(parent, name, index=nil)
     if not parent.kind_of?(TkText)
-      fail format("%s need to be TkText", parent.inspect)
+      fail Kernel.format("%s need to be TkText", parent.inspect)
     end
     @parent = @t = parent
     @tpath = parent.path
@@ -1156,7 +1156,7 @@ end
 class TkTextWindow<TkObject
   def initialize(parent, index, keys)
     if not parent.kind_of?(TkText)
-      fail format("%s need to be TkText", parent.inspect)
+      fail Kernel.format("%s need to be TkText", parent.inspect)
     end
     @t = parent
     if index == 'end'
@@ -1245,7 +1245,7 @@ end
 class TkTextImage<TkObject
   def initialize(parent, index, keys)
     if not parent.kind_of?(TkText)
-      fail format("%s need to be TkText", parent.inspect)
+      fail Kernel.format("%s need to be TkText", parent.inspect)
     end
     @t = parent
     if index == 'end'