diff --git a/ext/tk/lib/tkafter.rb b/ext/tk/lib/tkafter.rb
index be2e50ff3a..4876797c01 100644
--- a/ext/tk/lib/tkafter.rb
+++ b/ext/tk/lib/tkafter.rb
@@ -1,6 +1,6 @@
 #
 #   tkafter.rb : methods for Tcl/Tk after command
-#                     1998/07/02 by Hidetoshi Nagai <nagai@ai.kyutech.ac.jp>
+#                     2000/08/01 by Hidetoshi Nagai <nagai@ai.kyutech.ac.jp>
 #
 require 'tk'
 
@@ -37,7 +37,16 @@ class TkAfter
   ###############################
   def do_callback(*args)
     @in_callback = true
-    ret = @current_proc.call(*args)
+    begin
+      ret = @current_proc.call(*args)
+    rescue StandardError, NameError
+      if @cancel_on_exception
+	cancel
+	return nil
+      else
+	fail $!
+      end
+    end
     if @set_next
       set_next_callback(*args)
     else
@@ -118,6 +127,8 @@ class TkAfter
     @after_id = nil
     @after_script = nil
 
+    @cancel_on_exception = true
+
     set_procs(*args) if args != []
 
     @running = false
@@ -135,7 +146,16 @@ class TkAfter
   end
 
   def current_status
-    [@running, @current_sleep, @current_proc, @current_args, @do_loop]
+    [@running, @current_sleep, @current_proc, @current_args, 
+      @do_loop, @cancel_on_exception]
+  end
+
+  def cancel_on_exception?
+    @cancel_on_exception
+  end
+
+  def cancel_on_exception=(mode)
+    @cancel_on_exception = mode
   end
 
   def running?
diff --git a/ext/tk/lib/tktext.rb b/ext/tk/lib/tktext.rb
index 163583f139..f7b3f84ba7 100644
--- a/ext/tk/lib/tktext.rb
+++ b/ext/tk/lib/tktext.rb
@@ -460,7 +460,7 @@ class TkText<TkTextWin
 	  when 'anchor'
 	    result.push TkTextMarkAnchor.new(self)
 	  else
-	    result.push tk_tcl2rb(val)
+	    result.push tk_tcl2ruby(val)
 	  end
 	when 'tagon'
 	  if val == 'sel'
@@ -470,12 +470,12 @@ class TkText<TkTextWin
 	      result.push TkTextTagSel.new(self)
 	    end
 	  else
-	    result.push tk_tcl2rb val
+	    result.push tk_tcl2ruby(val)
 	  end
 	when 'tagoff'
-	    result.push tk_tcl2rb sel
+	    result.push tk_tcl2ruby(sel)
 	when 'window'
-	  result.push tk_tcl2rb val
+	  result.push tk_tcl2ruby(val)
 	end
 	i = idx + 1
       end
diff --git a/lib/shellwords.rb b/lib/shellwords.rb
index 7b16c6cb52..5c31f8ca78 100644
--- a/lib/shellwords.rb
+++ b/lib/shellwords.rb
@@ -16,27 +16,27 @@ module Shellwords
     unless line.kind_of?(String)
       raise ArgumentError, "Argument must be String class object."
     end
-    line.sub!(/^\s+/, '')
+    line.sub!(/\A\s+/, '')
     words = []
     while line != ''
       field = ''
       while true
-	if line.sub!(/^"(([^"\\]|\\.)*)"/, '') then #"
+	if line.sub!(/\A"(([^"\\]|\\.)*)"/, '') then #"
 	  snippet = $1
 	  snippet.gsub!(/\\(.)/, '\1')
-	elsif line =~ /^"/ then #"
+	elsif line =~ /\A"/ then #"
 	  raise ArgumentError, "Unmatched double quote: #{line}"
-        elsif line.sub!(/^'(([^'\\]|\\.)*)'/, '') then #'
+        elsif line.sub!(/\A'(([^'\\]|\\.)*)'/, '') then #'
 	  snippet = $1
 	  snippet.gsub!(/\\(.)/, '\1')
-	elsif line =~ /^'/ then #'
+	elsif line =~ /\A'/ then #'
 	  raise ArgumentError, "Unmatched single quote: #{line}"
-	elsif line.sub!(/^\\(.)/, '') then
+	elsif line.sub!(/\A\\(.)/, '') then
 	  snippet = $1
-	elsif line.sub!(/^([^\s\\'"]+)/, '') then #'
+	elsif line.sub!(/\A([^\s\\'"]+)/, '') then #'
 	  snippet = $1
 	else
-	  line.sub!(/^\s+/, '')
+	  line.sub!(/\A\s+/, '')
 	  break
 	end
 	field.concat(snippet)