diff --git a/ChangeLog b/ChangeLog
index f62cb069b0..384ffd3c36 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+Fri Oct 17 19:46:20 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* common.mk (ID_H_TARGET): phony target to update id.h.
+
+	* tool/ifchange, win32/ifchange.bat: --timestamp option added.
+
+	* tool/generic_erb.rb: --timestamp, --output and --if-change options
+	  added.
+
+	* template/id.h.tmpl: moved from id.h.
+
 Fri Oct 17 18:33:12 2008  Yuki Sonoda (Yugui)  <yugui@yugui.jp>
 
 	* array.c (ary_resize_capa): renamed RESIZE_CAPA.
diff --git a/common.mk b/common.mk
index 8556b23c33..fa9d62b0bb 100644
--- a/common.mk
+++ b/common.mk
@@ -17,6 +17,7 @@ EXTCONF       = extconf.rb
 RBCONFIG      = ./.rbconfig.time
 LIBRUBY_EXTS  = ./.libruby-with-ext.time
 RDOCOUT       = $(EXTOUT)/rdoc
+ID_H_TARGET   = -id.h-
 
 DMYEXT	      = dmyext.$(OBJEXT)
 NORMALMAINOBJ = main.$(OBJEXT)
@@ -441,7 +442,7 @@ win32.$(OBJEXT): {$(VPATH)}win32.c
 RUBY_H_INCLUDES    = {$(VPATH)}ruby.h {$(VPATH)}config.h {$(VPATH)}defines.h \
 		     {$(VPATH)}intern.h {$(VPATH)}missing.h {$(VPATH)}st.h
 ENCODING_H_INCLUDES= {$(VPATH)}encoding.h {$(VPATH)}oniguruma.h
-ID_H_INCLUDES      = {$(VPATH)}id.h {$(VPATH)}parse.h
+ID_H_INCLUDES      = {$(VPATH)}id.h
 VM_CORE_H_INCLUDES = {$(VPATH)}vm_core.h {$(VPATH)}vm_opts.h \
 	             {$(VPATH)}vm.h {$(VPATH)}thread_$(THREAD_MODEL).h \
 		     {$(VPATH)}node.h $(ID_H_INCLUDES)
@@ -465,20 +466,20 @@ enum.$(OBJEXT): {$(VPATH)}enum.c $(RUBY_H_INCLUDES) {$(VPATH)}node.h \
   {$(VPATH)}util.h
 enumerator.$(OBJEXT): {$(VPATH)}enumerator.c $(RUBY_H_INCLUDES)
 error.$(OBJEXT): {$(VPATH)}error.c {$(VPATH)}known_errors.inc $(RUBY_H_INCLUDES) \
-  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h {$(VPATH)}parse.y
+  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h
 eval.$(OBJEXT): {$(VPATH)}eval.c {$(VPATH)}eval_intern.h \
   $(RUBY_H_INCLUDES) $(VM_CORE_H_INCLUDES) {$(VPATH)}eval_error.c \
-  {$(VPATH)}eval_jump.c {$(VPATH)}debug.h {$(VPATH)}parse.y \
+  {$(VPATH)}eval_jump.c {$(VPATH)}debug.h \
   {$(VPATH)}iseq.h
 load.$(OBJEXT): {$(VPATH)}load.c {$(VPATH)}eval_intern.h \
   {$(VPATH)}util.h $(RUBY_H_INCLUDES) $(VM_CORE_H_INCLUDES) \
-  {$(VPATH)}dln.h {$(VPATH)}debug.h {$(VPATH)}parse.y
+  {$(VPATH)}dln.h {$(VPATH)}debug.h
 file.$(OBJEXT): {$(VPATH)}file.c $(RUBY_H_INCLUDES) {$(VPATH)}io.h \
   $(ENCODING_H_INCLUDES) {$(VPATH)}util.h {$(VPATH)}dln.h
 gc.$(OBJEXT): {$(VPATH)}gc.c $(RUBY_H_INCLUDES) {$(VPATH)}re.h \
   {$(VPATH)}regex.h $(ENCODING_H_INCLUDES) $(VM_CORE_H_INCLUDES) \
   {$(VPATH)}gc.h {$(VPATH)}io.h {$(VPATH)}eval_intern.h {$(VPATH)}util.h \
-  {$(VPATH)}debug.h {$(VPATH)}parse.y
+  {$(VPATH)}debug.h
 hash.$(OBJEXT): {$(VPATH)}hash.c $(RUBY_H_INCLUDES) {$(VPATH)}util.h
 inits.$(OBJEXT): {$(VPATH)}inits.c $(RUBY_H_INCLUDES)
 io.$(OBJEXT): {$(VPATH)}io.c $(RUBY_H_INCLUDES) {$(VPATH)}io.h \
@@ -492,16 +493,16 @@ numeric.$(OBJEXT): {$(VPATH)}numeric.c $(RUBY_H_INCLUDES) \
   $(ENCODING_H_INCLUDES)
 object.$(OBJEXT): {$(VPATH)}object.c $(RUBY_H_INCLUDES) {$(VPATH)}util.h
 pack.$(OBJEXT): {$(VPATH)}pack.c $(RUBY_H_INCLUDES)
-parse.$(OBJEXT): {$(VPATH)}parse.c {$(VPATH)}parse.y $(RUBY_H_INCLUDES) \
+parse.$(OBJEXT): {$(VPATH)}parse.c $(RUBY_H_INCLUDES) \
   {$(VPATH)}node.h $(ENCODING_H_INCLUDES) $(ID_H_INCLUDES) \
   {$(VPATH)}regenc.h {$(VPATH)}regex.h {$(VPATH)}util.h {$(VPATH)}lex.c \
   {$(VPATH)}keywords {$(VPATH)}id.c
 proc.$(OBJEXT): {$(VPATH)}proc.c {$(VPATH)}eval_intern.h \
   $(RUBY_H_INCLUDES) {$(VPATH)}gc.h $(VM_CORE_H_INCLUDES) \
-  {$(VPATH)}debug.h {$(VPATH)}parse.y
+  {$(VPATH)}debug.h
 process.$(OBJEXT): {$(VPATH)}process.c $(RUBY_H_INCLUDES) \
   {$(VPATH)}util.h {$(VPATH)}io.h $(ENCODING_H_INCLUDES) {$(VPATH)}dln.h \
-  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h {$(VPATH)}parse.y
+  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h
 random.$(OBJEXT): {$(VPATH)}random.c $(RUBY_H_INCLUDES)
 range.$(OBJEXT): {$(VPATH)}range.c $(RUBY_H_INCLUDES) \
   $(ENCODING_H_INCLUDES)
@@ -525,11 +526,11 @@ regsyntax.$(OBJEXT): {$(VPATH)}regsyntax.c {$(VPATH)}regint.h \
   {$(VPATH)}regenc.h {$(VPATH)}oniguruma.h $(RUBY_H_INCLUDES)
 ruby.$(OBJEXT): {$(VPATH)}ruby.c $(RUBY_H_INCLUDES) {$(VPATH)}util.h \
   $(ENCODING_H_INCLUDES) {$(VPATH)}eval_intern.h $(VM_CORE_H_INCLUDES) \
-  {$(VPATH)}dln.h {$(VPATH)}debug.h {$(VPATH)}parse.y
+  {$(VPATH)}dln.h {$(VPATH)}debug.h
 safe.$(OBJEXT): {$(VPATH)}safe.c $(RUBY_H_INCLUDES) \
-  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h {$(VPATH)}parse.y
+  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h
 signal.$(OBJEXT): {$(VPATH)}signal.c $(RUBY_H_INCLUDES) \
-  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h {$(VPATH)}parse.y
+  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h
 sprintf.$(OBJEXT): {$(VPATH)}sprintf.c $(RUBY_H_INCLUDES) {$(VPATH)}re.h \
   {$(VPATH)}regex.h {$(VPATH)}vsnprintf.c $(ENCODING_H_INCLUDES)
 st.$(OBJEXT): {$(VPATH)}st.c {$(VPATH)}config.h {$(VPATH)}defines.h \
@@ -542,12 +543,12 @@ string.$(OBJEXT): {$(VPATH)}string.c $(RUBY_H_INCLUDES) {$(VPATH)}re.h \
 struct.$(OBJEXT): {$(VPATH)}struct.c $(RUBY_H_INCLUDES)
 thread.$(OBJEXT): {$(VPATH)}thread.c {$(VPATH)}eval_intern.h \
   $(RUBY_H_INCLUDES) {$(VPATH)}gc.h $(VM_CORE_H_INCLUDES) \
-  {$(VPATH)}debug.h {$(VPATH)}parse.y {$(VPATH)}thread_$(THREAD_MODEL).c
+  {$(VPATH)}debug.h {$(VPATH)}thread_$(THREAD_MODEL).c
 transcode.$(OBJEXT): {$(VPATH)}transcode.c $(RUBY_H_INCLUDES) \
   $(ENCODING_H_INCLUDES) {$(VPATH)}transcode_data.h
 cont.$(OBJEXT): {$(VPATH)}cont.c $(RUBY_H_INCLUDES) \
   $(VM_CORE_H_INCLUDES) {$(VPATH)}gc.h {$(VPATH)}eval_intern.h \
-  {$(VPATH)}debug.h {$(VPATH)}parse.y
+  {$(VPATH)}debug.h
 time.$(OBJEXT): {$(VPATH)}time.c $(RUBY_H_INCLUDES) \
   $(ENCODING_H_INCLUDES)
 util.$(OBJEXT): {$(VPATH)}util.c $(RUBY_H_INCLUDES) {$(VPATH)}util.h
@@ -558,30 +559,28 @@ version.$(OBJEXT): {$(VPATH)}version.c $(RUBY_H_INCLUDES) \
 
 compile.$(OBJEXT): {$(VPATH)}compile.c {$(VPATH)}iseq.h \
   $(RUBY_H_INCLUDES) $(VM_CORE_H_INCLUDES) {$(VPATH)}insns.inc \
-  {$(VPATH)}insns_info.inc {$(VPATH)}optinsn.inc {$(VPATH)}debug.h \
-  {$(VPATH)}parse.y
+  {$(VPATH)}insns_info.inc {$(VPATH)}optinsn.inc {$(VPATH)}debug.h
 iseq.$(OBJEXT): {$(VPATH)}iseq.c {$(VPATH)}gc.h {$(VPATH)}iseq.h \
   $(RUBY_H_INCLUDES) $(VM_CORE_H_INCLUDES) {$(VPATH)}insns.inc \
-  {$(VPATH)}insns_info.inc {$(VPATH)}node_name.inc {$(VPATH)}debug.h \
-  {$(VPATH)}parse.y
+  {$(VPATH)}insns_info.inc {$(VPATH)}node_name.inc {$(VPATH)}debug.h
 vm.$(OBJEXT): {$(VPATH)}vm.c {$(VPATH)}gc.h {$(VPATH)}iseq.h \
   {$(VPATH)}eval_intern.h $(RUBY_H_INCLUDES) $(ENCODING_H_INCLUDES) \
   $(VM_CORE_H_INCLUDES) {$(VPATH)}vm_method.c {$(VPATH)}vm_eval.c \
   {$(VPATH)}vm_insnhelper.c {$(VPATH)}vm_insnhelper.h {$(VPATH)}vm_exec.c \
   {$(VPATH)}vm_exec.h {$(VPATH)}insns.def {$(VPATH)}vmtc.inc \
-  {$(VPATH)}vm.inc {$(VPATH)}insns.inc {$(VPATH)}debug.h {$(VPATH)}parse.y
+  {$(VPATH)}vm.inc {$(VPATH)}insns.inc {$(VPATH)}debug.h
 vm_dump.$(OBJEXT): {$(VPATH)}vm_dump.c $(RUBY_H_INCLUDES) \
-  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h {$(VPATH)}parse.y
+  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h
 debug.$(OBJEXT): {$(VPATH)}debug.c $(RUBY_H_INCLUDES) \
   $(ENCODING_H_INCLUDES) $(VM_CORE_H_INCLUDES) {$(VPATH)}eval_intern.h \
-  {$(VPATH)}util.h {$(VPATH)}debug.h {$(VPATH)}parse.y
+  {$(VPATH)}util.h {$(VPATH)}debug.h
 id.$(OBJEXT): {$(VPATH)}id.c $(RUBY_H_INCLUDES) $(ID_H_INCLUDES)
 miniprelude.$(OBJEXT): {$(VPATH)}miniprelude.c $(RUBY_H_INCLUDES) \
-  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h {$(VPATH)}parse.y
+  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h
 prelude.$(OBJEXT): {$(VPATH)}prelude.c $(RUBY_H_INCLUDES) \
-  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h {$(VPATH)}parse.y
+  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h
 golf_prelude.$(OBJEXT): {$(VPATH)}golf_prelude.c $(RUBY_H_INCLUDES) \
-  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h {$(VPATH)}parse.y
+  $(VM_CORE_H_INCLUDES) {$(VPATH)}debug.h
 goruby.$(OBJEXT): {$(VPATH)}goruby.c {$(VPATH)}main.c $(RUBY_H_INCLUDES) \
   {$(VPATH)}debug.h {$(VPATH)}node.h
 
@@ -626,7 +625,7 @@ vmtc.inc: $(srcdir)/template/vmtc.inc.tmpl
 
 vm.inc: $(srcdir)/template/vm.inc.tmpl
 
-srcs: {$(VPATH)}parse.c {$(VPATH)}lex.c {$(VPATH)}newline.c $(srcdir)/ext/ripper/ripper.c srcs-enc
+srcs: {$(VPATH)}parse.c $(ID_H_TARGET) {$(VPATH)}lex.c {$(VPATH)}newline.c $(srcdir)/ext/ripper/ripper.c srcs-enc
 
 srcs-enc: $(ENC_MK)
 	$(MAKE) -f $(ENC_MK) RUBY="$(MINIRUBY)" MINIRUBY="$(MINIRUBY)" $(MFLAGS) srcs
@@ -646,6 +645,12 @@ transdb.h: $(PREP) srcs-enc
 	$(MINIRUBY) $(srcdir)/enc/trans/make_transdb.rb $@.new $(srcdir)/enc/trans enc/trans
 	$(IFCHANGE) "$@" "$@.new"
 
+{$(VPATH)}id.h:
+	$(CPP) $(CPPFLAGS) -DUSE_PARSE_H $@
+
+$(ID_H_TARGET): {$(VPATH)}parse.c $(srcdir)/tool/generic_erb.rb $(srcdir)/template/id.h.tmpl
+	$(BASERUBY) $(srcdir)/tool/generic_erb.rb --if-change --output=$(srcdir)/id.h $(srcdir)/template/id.h.tmpl --vpath=$(VPATH) parse.c
+
 known_errors.inc: $(srcdir)/template/known_errors.inc.tmpl $(srcdir)/defs/known_errors.def
 	$(BASERUBY) $(srcdir)/tool/generic_erb.rb $(srcdir)/template/known_errors.inc.tmpl $(srcdir)/defs/known_errors.def > $@
 
diff --git a/cygwin/GNUmakefile.in b/cygwin/GNUmakefile.in
index 1e98a115a7..081c927575 100644
--- a/cygwin/GNUmakefile.in
+++ b/cygwin/GNUmakefile.in
@@ -9,7 +9,7 @@ ifeq (@target_os@,cygwin)
 else
   DLL_BASE_NAME := $(RUBY_SO_NAME)
   DLLWRAP += -mno-cygwin
-  VPATH += $(srcdir)/win32
+  VPATH := $(VPATH):$(srcdir)/win32
 endif
 
 ifneq ($(ENABLE_SHARED),yes)
diff --git a/parse.y b/parse.y
index b5743e4472..58283dceb2 100644
--- a/parse.y
+++ b/parse.y
@@ -19,6 +19,7 @@
 #include "ruby/st.h"
 #include "ruby/encoding.h"
 #include "node.h"
+#include "parse.h"
 #include "id.h"
 #include "regenc.h"
 #include <stdio.h>
diff --git a/id.h b/template/id.h.tmpl
similarity index 51%
rename from id.h
rename to template/id.h.tmpl
index 04cf72e976..597f2702d3 100644
--- a/id.h
+++ b/template/id.h.tmpl
@@ -1,3 +1,5 @@
+%#  -*- c -*-
+/* DO NOT EDIT THIS FILE DIRECTLY */
 /**********************************************************************
 
   id.h - 
@@ -8,7 +10,28 @@
   Copyright (C) 2007 Koichi Sasada
 
 **********************************************************************/
+<%
+require 'optparse'
+vpath = ["."]
+input = nil
+opt = OptionParser.new do |o|
+  o.on('-v', '--vpath=DIR') {|dirs| vpath.concat dirs.split(File::PATH_SEPARATOR)}
+  input, = o.order!(ARGV)
+end or abort opt.opt_s
 
+tokens = nil
+vpath.find do |dir|
+  begin
+    if line = File.read(File.join(dir, input))[/^\s*enum\s+yytokentype\s*\{([^{}]*)\s*\};/m, 1]
+      tokens = line.scan(/\b(t(?:LAST_TOKEN|U(?:PLUS|MINUS)|POW|CMP|EQQ?|[NGL]EQ|(?:AND|OR)OP|N?MATCH|DOT\d|AREF|ASET|[LR]SHFT|LAMBDA)|id\w+)\s*=\s*(\d+),?/m)
+    end
+  rescue Errno::ENOENT
+    nil
+  else
+    true
+  end
+end
+%>
 #ifndef RUBY_ID_H
 #define RUBY_ID_H
 
@@ -23,12 +46,21 @@
 #define ID_JUNK       0x07
 #define ID_INTERNAL   ID_JUNK
 
+#ifdef USE_PARSE_H
 #include "parse.h"
+#endif
 
 #define symIFUNC ID2SYM(idIFUNC)
 #define symCFUNC ID2SYM(idCFUNC)
 
 enum ruby_method_ids {
+#ifndef tLAST_TOKEN
+% tokens.each do |token, value|
+    <%=token%> = <%=value%>,
+% end
+#elif <%= tokens.map {|token, value|"#{token} != #{value}"}.join(" || \\\n    ") %>
+#error id.h is out of date.
+#endif
     idPLUS = '+',
     idMINUS = '-',
     idMULT = '*',
@@ -62,22 +94,22 @@ enum ruby_method_ids {
     tBitblt,
     tAnswer,
 #endif
-    tLAST_ID
+    tLAST_ID,
+#define TOKEN2ID(n) id##n = ((t##n<<ID_SCOPE_SHIFT)|ID_LOCAL)
+    TOKEN2ID(Intern),
+    TOKEN2ID(MethodMissing),
+    TOKEN2ID(Length),
+    TOKEN2ID(Gets),
+    TOKEN2ID(Succ),
+    TOKEN2ID(Each),
+    TOKEN2ID(Lambda),
+    TOKEN2ID(Send),
+    TOKEN2ID(__send__),
+    TOKEN2ID(Initialize),
+#if SUPPORT_JOKE
+    TOKEN2ID(Bitblt),
+    TOKEN2ID(Answer),
+#endif
 };
 
-#define idIntern ((tIntern<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idMethodMissing ((tMethodMissing<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idLength ((tLength<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idGets ((tGets<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idSucc ((tSucc<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idEach ((tEach<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idLambda ((tLambda<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idSend ((tSend<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define id__send__ ((t__send__<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idInitialize ((tInitialize<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#if SUPPORT_JOKE
-#define idBitblt ((tBitblt<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#define idAnswer ((tAnswer<<ID_SCOPE_SHIFT)|ID_LOCAL)
-#endif
-
 #endif /* RUBY_ID_H */
diff --git a/tool/generic_erb.rb b/tool/generic_erb.rb
index 7ea33fbc5f..c234f3a52f 100644
--- a/tool/generic_erb.rb
+++ b/tool/generic_erb.rb
@@ -1,4 +1,34 @@
 require 'erb'
+require 'optparse'
+require 'fileutils'
 
+timestamp = nil
+output = nil
+ifchange = nil
+opt = OptionParser.new do |o|
+  o.on('-t', '--timestamp[=PATH]') {|v| timestamp = v || true}
+  o.on('-o', '--output=PATH') {|v| output = v}
+  o.on('-c', '--[no-]if-change') {|v| ifchange = v}
+  o.order!(ARGV)
+end or abort opt.opt_s
 template = ARGV.shift
-ERB.new(File.read(template), nil, '%').run
+erb = ERB.new(File.read(template), nil, '%')
+erb.filename = template
+result = erb.result
+if output
+  if ifchange
+    if (IO.read(output) rescue nil) == result
+      puts "#{output} unchanged"
+    else
+      open(output, "wb") {|f| f.print result}
+      puts "#{output} updated"
+    end
+  end
+  if timestamp
+    if timestamp == true
+      dir, base = File.split(output)
+      timestamp = File.join(dir, ".time." + base)
+    end
+    FileUtils.touch(timestamp)
+  end
+end
diff --git a/tool/ifchange b/tool/ifchange
index 544513ad15..8bfca26703 100755
--- a/tool/ifchange
+++ b/tool/ifchange
@@ -1,6 +1,11 @@
 #!/bin/sh
 # usage: ifchange target temporary
 
+unset timestamp
+if [ "$1" = --timestamp ]; then
+    timestamp=yes
+    shift
+fi
 target="$1"
 temp="$2"
 if [ "$temp" = - ]; then
@@ -15,3 +20,6 @@ else
     echo "$target updated"
     mv -f "$temp" "$target"
 fi
+if [ $timestamp ]; then
+    touch `dirname "$target"`/.time.`basename "$target"`
+fi
diff --git a/win32/ifchange.bat b/win32/ifchange.bat
index 8411099020..9f6092747b 100755
--- a/win32/ifchange.bat
+++ b/win32/ifchange.bat
@@ -3,6 +3,11 @@
 
 if "%1" == "" goto :end
 
+set timestamp=
+if "%1" == "--timestamp" (
+    set timestamp=yes
+    shift
+)
 set dest=%1
 set src=%2
 set dest=%dest:/=\%
@@ -47,13 +52,18 @@ goto :end
 if not exist %src% goto :end
 if exist %dest% (
     fc.exe %dest% %src% > nul && (
-	echo %dest% unchanged.
+	echo %1 unchanged.
 	del %src%
-	goto :end
+	goto :nt_end
     )
 )
-echo %dest% updated.
+echo %1 updated.
 copy %src% %dest% > nul
 del %src%
 
+:nt_end
+if "%timestamp%" == "" goto :end
+    for %%I in ("%dest%") do set timestamp=%%~dpI\.time.%%~nxI
+    if not exist "%timestamp%" copy nul "%timestamp%" > nul
+    goto :end >> "%timestamp%"
 :end