diff --git a/Writer/Validator.php b/Writer/Validator.php
new file mode 100644
index 0000000..6d99afe
--- /dev/null
+++ b/Writer/Validator.php
@@ -0,0 +1,225 @@
+<?php
+/*
+*  Module written by Herman Kuiper <herman@ozuzo.net>
+*
+*  License Information:
+*
+*    Spreadsheet_Excel_Writer:  A library for generating Excel Spreadsheets
+*    Copyright (c) 2002-2003 Xavier Noguer xnoguer@rezebra.com
+*
+*    This library is free software; you can redistribute it and/or
+*    modify it under the terms of the GNU Lesser General Public
+*    License as published by the Free Software Foundation; either
+*    version 2.1 of the License, or (at your option) any later version.
+*
+*    This library is distributed in the hope that it will be useful,
+*    but WITHOUT ANY WARRANTY; without even the implied warranty of
+*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+*    Lesser General Public License for more details.
+*
+*    You should have received a copy of the GNU Lesser General Public
+*    License along with this library; if not, write to the Free Software
+*    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+//require_once('PEAR.php');
+
+// Possible operator types
+
+/*
+FIXME: change prefixes
+*/
+define("OP_BETWEEN",    0x00);
+define("OP_NOTBETWEEN", 0x01);
+define("OP_EQUAL",      0x02);
+define("OP_NOTEQUAL",   0x03);
+define("OP_GT",         0x04);
+define("OP_LT",         0x05);
+define("OP_GTE",        0x06);
+define("OP_LTE",        0x07);
+
+/**
+* Baseclass for generating Excel DV records (validations)
+*
+* @author   Herman Kuiper
+* @category FileFormats
+* @package  Spreadsheet_Excel_Writer
+*/
+class Spreadsheet_Excel_Writer_Validator
+{
+   var $_type;
+   var $_style;
+   var $_fixedList;
+   var $_blank;
+   var $_incell;
+   var $_showprompt;
+   var $_showerror;
+   var $_title_prompt;
+   var $_descr_prompt;
+   var $_title_error;
+   var $_descr_error;
+   var $_operator;
+   var $_formula1;
+   var $_formula2;
+    /**
+    * The parser from the workbook. Used to parse validation formulas also
+    * @var Spreadsheet_Excel_Writer_Parser
+    */
+    var $_parser;
+
+    function Spreadsheet_Excel_Writer_Validator(&$parser)
+    {
+        $this->_parser       = $parser;
+        $this->_type         = 0x01; // FIXME: add method for setting datatype
+        $this->_style        = 0x00;
+        $this->_fixedList    = false;
+        $this->_blank        = false;
+        $this->_incell       = false;
+        $this->_showprompt   = false;
+        $this->_showerror    = true;
+        $this->_title_prompt = "\x00";
+        $this->_descr_prompt = "\x00";
+        $this->_title_error  = "\x00";
+        $this->_descr_error  = "\x00";
+        $this->_operator     = 0x00; // default is equal
+        $this->_formula1    = "";
+        $this->_formula2    = "";
+    }
+
+   function setPrompt($promptTitle = "\x00", $promptDescription = "\x00", $showPrompt = true)
+   {
+      $this->_showprompt = $showPrompt;
+      $this->_title_prompt = $promptTitle;
+      $this->_descr_prompt = $promptDescription;
+   }
+
+   function setError($errorTitle = "\x00", $errorDescription = "\x00", $showError = true)
+   {
+      $this->_showerror = $showError;
+      $this->_title_error = $errorTitle;
+      $this->_descr_error = $errorDescription;
+   }
+
+   function allowBlank()
+   {
+      $this->_blank = true;
+   }
+
+   function onInvalidStop()
+   {
+      $this->_style = 0x00;
+   }
+
+    function onInvalidWarn()
+    {
+        $this->_style = 0x01;
+    }
+
+    function onInvalidInfo()
+    {
+        $this->_style = 0x02;
+    }
+
+    function setFormula1($formula)
+    {
+        // Parse the formula using the parser in Parser.php
+        $error = $this->_parser->parse($formula);
+        if (PEAR::isError($error)) {
+            return $this->_formula1;
+        }
+
+        $this->_formula1 = $this->_parser->toReversePolish();
+        if (PEAR::isError($this->_formula1)) {
+            return $this->_formula1;
+        }
+        return true;
+    }
+
+    function setFormula2($formula)
+    {
+        // Parse the formula using the parser in Parser.php
+        $error = $this->_parser->parse($formula);
+        if (PEAR::isError($error)) {
+            return $this->_formula2;
+        }
+
+        $this->_formula2 = $this->_parser->toReversePolish();
+        if (PEAR::isError($this->_formula2)) {
+            return $this->_formula2;
+        }
+        return true;
+    }
+
+   function _getOptions()
+   {
+      $options = $this->_type;
+      $options |= $this->_style << 3;
+      if($this->_fixedList)
+         $options |= 0x80;
+      if($this->_blank)
+         $options |= 0x100;
+      if(!$this->_incell)
+         $options |= 0x200;
+      if($this->_showprompt)
+         $options |= 0x40000;
+      if($this->_showerror)
+         $options |= 0x80000;
+      $options |= $this->_operator << 20;
+      
+      return $options;
+   }
+
+   function _getData()
+   {
+      $title_prompt_len = strlen($this->_title_prompt);
+      $descr_prompt_len = strlen($this->_descr_prompt);
+      $title_error_len = strlen($this->_title_error);
+      $descr_error_len = strlen($this->_descr_error);
+      
+      $formula1_size = strlen($this->_formula1);
+      $formula2_size = strlen($this->_formula2);
+
+      $data  = pack("V", $this->_getOptions());
+      $data .= pack("vC", $title_prompt_len, 0x00) . $this->_title_prompt;
+      $data .= pack("vC", $title_error_len, 0x00) . $this->_title_error;
+      $data .= pack("vC", $descr_prompt_len, 0x00) . $this->_descr_prompt;
+      $data .= pack("vC", $descr_error_len, 0x00) . $this->_descr_error;
+
+      $data .= pack("vv", $formula1_size, 0x0000) . $this->_formula1;
+      $data .= pack("vv", $formula2_size, 0x0000) . $this->_formula2;
+
+      return $data;
+   }
+}
+
+/*class Spreadsheet_Excel_Writer_Validation_List extends Spreadsheet_Excel_Writer_Validation
+{
+   function Spreadsheet_Excel_Writer_Validation_list()
+   {
+      parent::Spreadsheet_Excel_Writer_Validation();
+      $this->_type = 0x03;
+   }
+
+   function setList($source, $incell = true)
+   {
+      $this->_incell = $incell;
+      $this->_fixedList = true;
+      
+      $source = implode("\x00", $source);
+      $this->_formula1 = pack("CCC", 0x17, strlen($source), 0x0c) . $source;
+   }
+
+   function setRow($row, $col1, $col2, $incell = true)
+   {
+      $this->_incell = $incell;
+      //$this->_formula1 = ...;
+   }
+
+   function setCol($col, $row1, $row2, $incell = true)
+   {
+      $this->_incell = $incell;
+      //$this->_formula1 = ...;
+   }
+}*/
+
+?>