Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/AddEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/AddEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/AddEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,70 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import java.lang.reflect.Constructor;
+
+import org.apache.poi.hssf.record.formula.AddPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh < amolweb at ya hoo dot com >
+ *
+ */
+public class AddEval implements OperationEval {
+
+    private AddPtg delegate;
+    
+    public AddEval(Ptg ptg) {
+        delegate = (AddPtg) ptg;
+    }
+    
+
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        double d = 0;
+        Eval retval = null;
+    	for (int i=0, iSize=getNumberOfOperands(); i<iSize; i++) {
+        	if (operands[i] instanceof NumericValueEval) {
+        		d += ((NumericValueEval) operands[i]).getNumberValue();
+        	}
+        	else if (operands[i] instanceof RefEval) {
+        	    RefEval re = (RefEval) operands[i];
+        	    ValueEval ve = (ValueEval) re.getInnerValueEval();
+            	if (ve instanceof NumericValueEval) {
+            		d += ((NumericValueEval) ve).getNumberValue();
+            	}
+            	else {
+            	    retval = ErrorEval.ERROR_502;
+            	    break;
+            	}
+        	}
+        	else {
+        	    retval = ErrorEval.ERROR_502;
+        	    break;
+        	}
+    	}
+    	if (retval == null) 
+    	    retval = new NumberEval(d);
+    	return retval;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Area2DEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Area2DEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Area2DEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,58 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.AreaPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Area2DEval implements AreaEval {
+
+    private AreaPtg delegate;
+    private ValueEval[] values;
+    
+    public Area2DEval(Ptg ptg, ValueEval[] values) {
+        this.delegate = (AreaPtg) ptg;
+        this.values = values;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getFirstCol()
+     */
+    public short getFirstColumn() {
+        return delegate.getFirstColumn();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getFirstRow()
+     */
+    public short getFirstRow() {
+        return delegate.getFirstRow();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getLastCol()
+     */
+    public short getLastColumn() {
+        return delegate.getLastColumn();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getLastRow()
+     */
+    public short getLastRow() {
+        return delegate.getLastRow();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getValues()
+     */
+    public ValueEval[] getValues() {
+        return values;
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Area3DEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Area3DEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Area3DEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,73 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import java.lang.reflect.Constructor;
+
+import org.apache.poi.hssf.record.formula.Area3DPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Area3DEval implements AreaEval {
+
+    private Area3DPtg delegate;
+    
+    private ValueEval[] values;
+    
+    public Area3DEval(Ptg ptg, ValueEval[] values) {
+        this.values = values;
+        this.delegate = (Area3DPtg) ptg;
+    }
+    
+    
+    public static void main(String[] args) throws Exception {
+        Class clazz = Area3DEval.class;
+        Constructor[] carr = clazz.getDeclaredConstructors();
+        for (int i=0, iSize=carr.length; i<iSize; i++) {
+            Object[] o = carr[i].getParameterTypes();
+            for (int j=0, jSize=o.length; j<jSize; j++) {
+                System.out.println(o[j]);
+            }
+        }
+    }
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getFirstCol()
+     */
+    public short getFirstColumn() {
+        return delegate.getFirstColumn();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getFirstRow()
+     */
+    public short getFirstRow() {
+        return delegate.getFirstRow();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getLastCol()
+     */
+    public short getLastColumn() {
+        return delegate.getLastColumn();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getLastRow()
+     */
+    public short getLastRow() {
+        return delegate.getLastRow();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.AreaEval#getValues()
+     */
+    public ValueEval[] getValues() {
+        return values;
+    }
+    
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/AreaEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/AreaEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/AreaEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,18 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public interface AreaEval extends Eval {
+
+    public short getFirstRow();
+    public short getLastRow();
+    public short getFirstColumn();
+    public short getLastColumn();
+    public ValueEval[] getValues();
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/BoolEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/BoolEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/BoolEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,37 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.BoolPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class BoolEval implements NumericValueEval, StringValueEval {
+
+    private boolean value;
+    
+    public BoolEval(Ptg ptg) {
+        this.value = ((BoolPtg) ptg).getValue();
+    }
+    
+    public BoolEval(boolean value) {
+        this.value = value;
+    }
+    
+    public boolean getBooleanValue() {
+        return value;
+    }
+    
+    public double getNumberValue() {
+        return value ? (short) 1 : (short) 0;
+    }
+    
+    public String getStringValue() {
+        return value ? "1" : "0";
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ConcatEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ConcatEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ConcatEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,54 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.ConcatPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class ConcatEval implements OperationEval {
+
+    private ConcatPtg delegate;
+    
+    public ConcatEval(Ptg ptg) {
+        this.delegate = (ConcatPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        Eval retval = null;
+        if (operands.length == getNumberOfOperands()) {
+            StringBuffer sb = new StringBuffer();
+            for (int i=0, iSize=operands.length; i<iSize; i++) {
+                if (operands[i] instanceof StringValueEval) {
+                    sb.append(operands[i]);
+                }
+            }
+        }
+        else {
+            retval = ErrorEval.ERROR_UNKNOWN;
+        }
+        return retval;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/DivideEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/DivideEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/DivideEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,82 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.DividePtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class DivideEval implements OperationEval {
+
+    private DividePtg delegate;
+    
+    public DivideEval(Ptg ptg) {
+        this.delegate = (DividePtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        double d0 = 0;
+        double d1 = 0;
+		ValueEval retval = null;
+		if (operands.length == 2) {
+		    if (operands[0] != null) {
+				if (operands[0] instanceof NumericValueEval) {
+				    d0 = ((NumericValueEval) operands[0]).getNumberValue();
+				}
+				else if (operands[0] instanceof StringValueEval) {
+				    retval = ErrorEval.ERROR_502;
+				}
+				else if (operands[0] instanceof ErrorEval) {
+				    retval = (ErrorEval) operands[0];
+				}
+				else {
+				    retval = ErrorEval.INVALID_VALUE;
+				}
+		    }
+		    if (retval == null && operands[1] != null) {
+				if (operands[1] instanceof NumericValueEval) {
+				    d1 = ((NumericValueEval) operands[1]).getNumberValue();
+				}
+				else if (operands[1] instanceof StringValueEval) {
+				    retval = ErrorEval.ERROR_502;
+				}
+				else if (operands[0] instanceof ErrorEval) {
+				    ErrorEval e = (ErrorEval) operands[0];
+				    retval = e;
+				}
+				else {
+				    retval = ErrorEval.INVALID_VALUE;
+				}
+		    }
+			if (retval != null)
+			    retval = new NumberEval(d0/d1);
+		}
+		else {
+		    retval = ErrorEval.ERROR_UNKNOWN;
+		}
+		return retval;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/EqualEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/EqualEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/EqualEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,43 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.EqualPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class EqualEval implements OperationEval {
+
+    private EqualPtg delegate;
+    
+    public EqualEval(Ptg ptg) {
+        this.delegate = (EqualPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ErrorEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ErrorEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ErrorEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,64 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class ErrorEval implements ValueEval {
+
+    private int errorCode;
+    
+    // Oo std error codes
+    public static final ErrorEval ERROR_501 = new ErrorEval(501);
+    public static final ErrorEval ERROR_502 = new ErrorEval(502);
+    public static final ErrorEval ERROR_503 = new ErrorEval(503);
+    public static final ErrorEval ERROR_504 = new ErrorEval(504);
+    public static final ErrorEval ERROR_505 = new ErrorEval(505);
+    public static final ErrorEval ERROR_506 = new ErrorEval(506);
+    public static final ErrorEval ERROR_507 = new ErrorEval(507);
+    public static final ErrorEval ERROR_508 = new ErrorEval(508);
+    public static final ErrorEval ERROR_509 = new ErrorEval(509);
+    public static final ErrorEval ERROR_510 = new ErrorEval(510);
+    public static final ErrorEval ERROR_511 = new ErrorEval(511);
+    public static final ErrorEval ERROR_512 = new ErrorEval(512);
+    public static final ErrorEval ERROR_513 = new ErrorEval(513);
+    public static final ErrorEval ERROR_514 = new ErrorEval(514);
+    public static final ErrorEval ERROR_515 = new ErrorEval(515);
+    public static final ErrorEval ERROR_516 = new ErrorEval(516);
+    public static final ErrorEval ERROR_517 = new ErrorEval(517);
+    public static final ErrorEval ERROR_518 = new ErrorEval(518);
+    public static final ErrorEval ERROR_519 = new ErrorEval(519);
+    public static final ErrorEval ERROR_520 = new ErrorEval(520);
+    public static final ErrorEval ERROR_521 = new ErrorEval(521);
+    public static final ErrorEval ERROR_522 = new ErrorEval(522);
+    public static final ErrorEval ERROR_523 = new ErrorEval(523);
+    public static final ErrorEval ERROR_524 = new ErrorEval(524);
+    public static final ErrorEval ERROR_525 = new ErrorEval(525);
+    public static final ErrorEval ERROR_526 = new ErrorEval(526);
+    public static final ErrorEval ERROR_527 = new ErrorEval(527);
+    public static final ErrorEval INVALID_NAME = ERROR_525;
+    public static final ErrorEval INVALID_VALUE = ERROR_519;
+
+    
+    // Non std error codes
+    public static final ErrorEval ERROR_UNKNOWN = new ErrorEval(-20);
+    public static final ErrorEval FUNCTION_NOT_IMPLEMENTED = new ErrorEval(-30);
+    
+    
+    private ErrorEval(int errorCode) {
+        this.errorCode = errorCode;
+    }
+    
+    public int getErrorCode() {
+        return errorCode;
+    }
+    
+    public String getStringValue() {
+        return "Err:"+Integer.toString(errorCode);
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Eval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Eval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Eval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,14 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public interface Eval {
+
+    
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/FuncVarEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/FuncVarEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/FuncVarEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,56 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.AbstractFunctionPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.functions.Function;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class FuncVarEval extends FunctionEval {
+
+    private AbstractFunctionPtg delegate;
+    
+    public FuncVarEval(Ptg funcPtg) {
+        delegate = (AbstractFunctionPtg) funcPtg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        Eval retval = null;
+		Function f = getFunction();
+		if (f!=null)
+		    retval = f.evaluate(operands);
+		else 
+		    retval = ErrorEval.FUNCTION_NOT_IMPLEMENTED;
+		return retval;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.FunctionEval#getFunctionIndex()
+     */
+    public short getFunctionIndex() {
+        return delegate.getFunctionIndex();
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/FunctionEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/FunctionEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/FunctionEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,377 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.functions.*;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public abstract class FunctionEval implements OperationEval {
+    protected static Function[] functions = produceFunctions();
+    public Function getFunction() {
+    	short fidx = getFunctionIndex();
+    	return functions[fidx];
+    }
+    public abstract short getFunctionIndex();
+
+    private static Function[] produceFunctions() {
+        Function[] retval = new Function[368];
+    	retval[0]  = new Count();	//	COUNT
+    	retval[1]  = null;	//	specialflag
+    	retval[2]  = new IsNa();	//	ISNA
+    	retval[3]  = new IsError();	//	ISERROR
+    	retval[4]  = new Sum();	//	SUM
+    	retval[5]  = new Average();	//	AVERAGE
+    	retval[6]  = new Min();	//	MIN
+    	retval[7]  = new Max();	//	MAX
+    	retval[8]  = new Row();	//	ROW
+    	retval[9]  = new Column();	//	COLUMN
+    	retval[10] = new Na();	//	NA
+    	retval[11] = new Npv();	//	NPV
+    	retval[12] = new Stdev();	//	STDEV
+    	retval[13] = new Dollar();	//	DOLLAR
+    	retval[14] = new Fixed();	//	FIXED
+    	retval[15] = new Sin();	//	SIN
+    	retval[16] = new Cos();	//	COS
+    	retval[17] = new Tan();	//	TAN
+    	retval[18] = new Atan();	//	ATAN
+    	retval[19] = new Pi();	//	PI
+    	retval[20] = new Sqrt();	//	SQRT
+    	retval[21] = new Exp();	//	EXP
+    	retval[22] = new Ln();	//	LN
+    	retval[23] = new Log10();	//	LOG10
+    	retval[24] = new Abs();	//	ABS
+    	retval[25] = new Int();	//	INT
+    	retval[26] = new Sign();	//	SIGN
+    	retval[27] = new Round();	//	ROUND
+    	retval[28] = null;	//	LOOKUP
+    	retval[29] = null;	//	INDEX
+    	retval[30] = null;	//	REPT
+    	retval[31] = null;	//	MID
+    	retval[32] = null;	//	LEN
+    	retval[33] = null;	//	VALUE
+    	retval[34] = null;	//	TRUE
+    	retval[35] = null;	//	FALSE
+    	retval[36] = null;	//	AND
+    	retval[37] = null;	//	OR
+    	retval[38] = null;	//	NOT
+    	retval[39] = null;	//	MOD
+    	retval[40] = null;	//	DCOUNT
+    	retval[41] = null;	//	DSUM
+    	retval[42] = null;	//	DAVERAGE
+    	retval[43] = null;	//	DMIN
+    	retval[44] = null;	//	DMAX
+    	retval[45] = null;	//	DSTDEV
+    	retval[46] = null;	//	VAR
+    	retval[47] = null;	//	DVAR
+    	retval[48] = null;	//	TEXT
+    	retval[49] = null;	//	LINEST
+    	retval[50] = null;	//	TREND
+    	retval[51] = null;	//	LOGEST
+    	retval[52] = null;	//	GROWTH
+    	retval[53] = null;	//	GOTO
+    	retval[54] = null;	//	HALT
+    	retval[55] = null;	//	PV
+    	retval[56] = null;	//	FV
+    	retval[57] = null;	//	NPER
+    	retval[58] = null;	//	PMT
+    	retval[59] = null;	//	RATE
+    	retval[60] = null;	//	MIRR
+    	retval[61] = null;	//	IRR
+    	retval[62] = null;	//	RAND
+    	retval[63] = null;	//	MATCH
+    	retval[64] = null;	//	DATE
+    	retval[65] = null;	//	TIME
+    	retval[66] = null;	//	DAY
+    	retval[67] = null;	//	MONTH
+    	retval[68] = null;	//	YEAR
+    	retval[69] = null;	//	WEEKDAY
+    	retval[70] = null;	//	HOUR
+    	retval[71] = null;	//	MINUTE
+    	retval[72] = null;	//	SECOND
+    	retval[73] = null;	//	NOW
+    	retval[74] = null;	//	AREAS
+    	retval[75] = null;	//	ROWS
+    	retval[76] = null;	//	COLUMNS
+    	retval[77] = null;	//	OFFSET
+    	retval[78] = null;	//	ABSREF
+    	retval[79] = null;	//	RELREF
+    	retval[80] = null;	//	ARGUMENT
+    	retval[81] = null;	//	SEARCH
+    	retval[82] = null;	//	TRANSPOSE
+    	retval[83] = null;	//	ERROR
+    	retval[84] = null;	//	STEP
+    	retval[85] = null;	//	TYPE
+    	retval[86] = null;	//	ECHO
+    	retval[87] = null;	//	SETNAME
+    	retval[88] = null;	//	CALLER
+    	retval[89] = null;	//	DEREF
+    	retval[90] = null;	//	WINDOWS
+    	retval[91] = null;	//	SERIES
+    	retval[92] = null;	//	DOCUMENTS
+    	retval[93] = null;	//	ACTIVECELL
+    	retval[94] = null;	//	SELECTION
+    	retval[95] = null;	//	RESULT
+    	retval[96] = null;	//	ATAN2
+    	retval[97] = null;	//	ASIN
+    	retval[98] = null;	//	ACOS
+    	retval[99] = null;	//	CHOOSE
+    	retval[100] = null;	//	HLOOKUP
+    	retval[101] = null;	//	VLOOKUP
+    	retval[102] = null;	//	LINKS
+    	retval[103] = null;	//	INPUT
+    	retval[104] = null;	//	ISREF
+    	retval[105] = null;	//	GETFORMULA
+    	retval[106] = null;	//	GETNAME
+    	retval[107] = null;	//	SETVALUE
+    	retval[108] = null;	//	LOG
+    	retval[109] = null;	//	EXEC
+    	retval[110] = null;	//	CHAR
+    	retval[111] = null;	//	LOWER
+    	retval[112] = null;	//	UPPER
+    	retval[113] = null;	//	PROPER
+    	retval[114] = null;	//	LEFT
+    	retval[115] = null;	//	RIGHT
+    	retval[116] = null;	//	EXACT
+    	retval[117] = null;	//	TRIM
+    	retval[118] = null;	//	REPLACE
+    	retval[119] = null;	//	SUBSTITUTE
+    	retval[120] = null;	//	CODE
+    	retval[121] = null;	//	NAMES
+    	retval[122] = null;	//	DIRECTORY
+    	retval[123] = null;	//	FIND
+    	retval[124] = null;	//	CELL
+    	retval[125] = null;	//	ISERR
+    	retval[126] = null;	//	ISTEXT
+    	retval[127] = null;	//	ISNUMBER
+    	retval[128] = null;	//	ISBLANK
+    	retval[129] = null;	//	T
+    	retval[130] = null;	//	N
+    	retval[131] = null;	//	FOPEN
+    	retval[132] = null;	//	FCLOSE
+    	retval[133] = null;	//	FSIZE
+    	retval[134] = null;	//	FREADLN
+    	retval[135] = null;	//	FREAD
+    	retval[136] = null;	//	FWRITELN
+    	retval[137] = null;	//	FWRITE
+    	retval[138] = null;	//	FPOS
+    	retval[139] = null;	//	DATEVALUE
+    	retval[140] = null;	//	TIMEVALUE
+    	retval[141] = null;	//	SLN
+    	retval[142] = null;	//	SYD
+    	retval[143] = null;	//	DDB
+    	retval[144] = null;	//	GETDEF
+    	retval[145] = null;	//	REFTEXT
+    	retval[146] = null;	//	TEXTREF
+    	retval[147] = null;	//	INDIRECT
+    	retval[148] = null;	//	REGISTER
+    	retval[149] = null;	//	CALL
+    	retval[150] = null;	//	ADDBAR
+    	retval[151] = null;	//	ADDMENU
+    	retval[152] = null;	//	ADDCOMMAND
+    	retval[153] = null;	//	ENABLECOMMAND
+    	retval[154] = null;	//	CHECKCOMMAND
+    	retval[155] = null;	//	RENAMECOMMAND
+    	retval[156] = null;	//	SHOWBAR
+    	retval[157] = null;	//	DELETEMENU
+    	retval[158] = null;	//	DELETECOMMAND
+    	retval[159] = null;	//	GETCHARTITEM
+    	retval[160] = null;	//	DIALOGBOX
+    	retval[161] = null;	//	CLEAN
+    	retval[162] = null;	//	MDETERM
+    	retval[163] = null;	//	MINVERSE
+    	retval[164] = null;	//	MMULT
+    	retval[165] = null;	//	FILES
+    	retval[166] = null;	//	IPMT
+    	retval[167] = null;	//	PPMT
+    	retval[168] = null;	//	COUNTA
+    	retval[169] = null;	//	CANCELKEY
+    	retval[170] = null;	//	INITIATE
+    	retval[171] = null;	//	REQUEST
+    	retval[172] = null;	//	POKE
+    	retval[173] = null;	//	EXECUTE
+    	retval[174] = null;	//	TERMINATE
+    	retval[175] = null;	//	RESTART
+    	retval[176] = null;	//	HELP
+    	retval[177] = null;	//	GETBAR
+    	retval[178] = null;	//	PRODUCT
+    	retval[179] = null;	//	FACT
+    	retval[180] = null;	//	GETCELL
+    	retval[181] = null;	//	GETWORKSPACE
+    	retval[182] = null;	//	GETWINDOW
+    	retval[183] = null;	//	GETDOCUMENT
+    	retval[184] = null;	//	DPRODUCT
+    	retval[185] = null;	//	ISNONTEXT
+    	retval[186] = null;	//	GETNOTE
+    	retval[187] = null;	//	NOTE
+    	retval[188] = null;	//	STDEVP
+    	retval[189] = null;	//	VARP
+    	retval[190] = null;	//	DSTDEVP
+    	retval[191] = null;	//	DVARP
+    	retval[192] = null;	//	TRUNC
+    	retval[193] = null;	//	ISLOGICAL
+    	retval[194] = null;	//	DCOUNTA
+    	retval[195] = null;	//	DELETEBAR
+    	retval[196] = null;	//	UNREGISTER
+    	retval[197] = null;	//	USDOLLAR
+    	retval[198] = null;	//	FINDB
+    	retval[199] = null;	//	SEARCHB
+    	retval[200] = null;	//	REPLACEB
+    	retval[201] = null;	//	LEFTB
+    	retval[202] = null;	//	RIGHTB
+    	retval[203] = null;	//	MIDB
+    	retval[204] = null;	//	LENB
+    	retval[205] = null;	//	ROUNDUP
+    	retval[206] = null;	//	ROUNDDOWN
+    	retval[207] = null;	//	ASC
+    	retval[208] = null;	//	DBCS
+    	retval[209] = null;	//	RANK
+    	retval[210] = null;	//	ADDRESS
+    	retval[211] = null;	//	DAYS360
+    	retval[212] = null;	//	TODAY
+    	retval[213] = null;	//	VDB
+    	retval[214] = null;	//	MEDIAN
+    	retval[215] = null;	//	SUMPRODUCT
+    	retval[216] = null;	//	SINH
+    	retval[217] = null;	//	COSH
+    	retval[218] = null;	//	TANH
+    	retval[219] = null;	//	ASINH
+    	retval[220] = null;	//	ACOSH
+    	retval[221] = null;	//	ATANH
+    	retval[222] = null;	//	DGET
+    	retval[223] = null;	//	CREATEOBJECT
+    	retval[224] = null;	//	VOLATILE
+    	retval[225] = null;	//	LASTERROR
+    	retval[226] = null;	//	CUSTOMUNDO
+    	retval[227] = null;	//	CUSTOMREPEAT
+    	retval[228] = null;	//	FORMULACONVERT
+    	retval[229] = null;	//	GETLINKINFO
+    	retval[230] = null;	//	TEXTBOX
+    	retval[231] = null;	//	INFO
+    	retval[232] = null;	//	GROUP
+    	retval[233] = null;	//	GETOBJECT
+    	retval[234] = null;	//	DB
+    	retval[235] = null;	//	PAUSE
+    	retval[236] = null;	//	RESUME
+    	retval[237] = null;	//	FREQUENCY
+    	retval[238] = null;	//	ADDTOOLBAR
+    	retval[239] = null;	//	DELETETOOLBAR
+    	retval[240] = null;	//	externalflag
+    	retval[241] = null;	//	RESETTOOLBAR
+    	retval[242] = null;	//	EVALUATE
+    	retval[243] = null;	//	GETTOOLBAR
+    	retval[244] = null;	//	GETTOOL
+    	retval[245] = null;	//	SPELLINGCHECK
+    	retval[246] = null;	//	ERRORTYPE
+    	retval[247] = null;	//	APPTITLE
+    	retval[248] = null;	//	WINDOWTITLE
+    	retval[249] = null;	//	SAVETOOLBAR
+    	retval[250] = null;	//	ENABLETOOL
+    	retval[251] = null;	//	PRESSTOOL
+    	retval[252] = null;	//	REGISTERID
+    	retval[253] = null;	//	GETWORKBOOK
+    	retval[254] = null;	//	AVEDEV
+    	retval[255] = null;	//	BETADIST
+    	retval[256] = null;	//	GAMMALN
+    	retval[257] = null;	//	BETAINV
+    	retval[258] = null;	//	BINOMDIST
+    	retval[259] = null;	//	CHIDIST
+    	retval[260] = null;	//	CHIINV
+    	retval[261] = null;	//	COMBIN
+    	retval[262] = null;	//	CONFIDENCE
+    	retval[263] = null;	//	CRITBINOM
+    	retval[264] = null;	//	EVEN
+    	retval[265] = null;	//	EXPONDIST
+    	retval[266] = null;	//	FDIST
+    	retval[267] = null;	//	FINV
+    	retval[268] = null;	//	FISHER
+    	retval[269] = null;	//	FISHERINV
+    	retval[270] = null;	//	FLOOR
+    	retval[271] = null;	//	GAMMADIST
+    	retval[272] = null;	//	GAMMAINV
+    	retval[273] = null;	//	CEILING
+    	retval[274] = null;	//	HYPGEOMDIST
+    	retval[275] = null;	//	LOGNORMDIST
+    	retval[276] = null;	//	LOGINV
+    	retval[277] = null;	//	NEGBINOMDIST
+    	retval[278] = null;	//	NORMDIST
+    	retval[279] = null;	//	NORMSDIST
+    	retval[280] = null;	//	NORMINV
+    	retval[281] = null;	//	NORMSINV
+    	retval[282] = null;	//	STANDARDIZE
+    	retval[283] = null;	//	ODD
+    	retval[284] = null;	//	PERMUT
+    	retval[285] = null;	//	POISSON
+    	retval[286] = null;	//	TDIST
+    	retval[287] = null;	//	WEIBULL
+    	retval[288] = null;	//	SUMXMY2
+    	retval[289] = null;	//	SUMX2MY2
+    	retval[290] = null;	//	SUMX2PY2
+    	retval[291] = null;	//	CHITEST
+    	retval[292] = null;	//	CORREL
+    	retval[293] = null;	//	COVAR
+    	retval[294] = null;	//	FORECAST
+    	retval[295] = null;	//	FTEST
+    	retval[296] = null;	//	INTERCEPT
+    	retval[297] = null;	//	PEARSON
+    	retval[298] = null;	//	RSQ
+    	retval[299] = null;	//	STEYX
+    	retval[300] = null;	//	SLOPE
+    	retval[301] = null;	//	TTEST
+    	retval[302] = null;	//	PROB
+    	retval[303] = null;	//	DEVSQ
+    	retval[304] = null;	//	GEOMEAN
+    	retval[305] = null;	//	HARMEAN
+    	retval[306] = null;	//	SUMSQ
+    	retval[307] = null;	//	KURT
+    	retval[308] = null;	//	SKEW
+    	retval[309] = null;	//	ZTEST
+    	retval[310] = null;	//	LARGE
+    	retval[311] = null;	//	SMALL
+    	retval[312] = null;	//	QUARTILE
+    	retval[313] = null;	//	PERCENTILE
+    	retval[314] = null;	//	PERCENTRANK
+    	retval[315] = null;	//	MODE
+    	retval[316] = null;	//	TRIMMEAN
+    	retval[317] = null;	//	TINV
+    	retval[318] = null;	//	MOVIECOMMAND
+    	retval[319] = null;	//	GETMOVIE
+    	retval[320] = null;	//	CONCATENATE
+    	retval[321] = null;	//	POWER
+    	retval[322] = null;	//	PIVOTADDDATA
+    	retval[323] = null;	//	GETPIVOTTABLE
+    	retval[324] = null;	//	GETPIVOTFIELD
+    	retval[325] = null;	//	GETPIVOTITEM
+    	retval[326] = null;	//	RADIANS
+    	retval[327] = null;	//	DEGREES
+    	retval[328] = null;	//	SUBTOTAL
+    	retval[329] = null;	//	SUMIF
+    	retval[330] = null;	//	COUNTIF
+    	retval[331] = null;	//	COUNTBLANK
+    	retval[332] = null;	//	SCENARIOGET
+    	retval[333] = null;	//	OPTIONSLISTSGET
+    	retval[334] = null;	//	ISPMT
+    	retval[335] = null;	//	DATEDIF
+    	retval[336] = null;	//	DATESTRING
+    	retval[337] = null;	//	NUMBERSTRING
+    	retval[338] = null;	//	ROMAN
+    	retval[339] = null;	//	OPENDIALOG
+    	retval[340] = null;	//	SAVEDIALOG
+    	retval[341] = null;	//	VIEWGET
+    	retval[342] = null;	//	GETPIVOTDATA
+    	retval[343] = null;	//	HYPERLINK
+    	retval[344] = null;	//	PHONETIC
+    	retval[345] = null;	//	AVERAGEA
+    	retval[346] = null;	//	MAXA
+    	retval[347] = null;	//	MINA
+    	retval[348] = null;	//	STDEVPA
+    	retval[349] = null;	//	VARPA
+    	retval[350] = null;	//	STDEVA
+    	retval[351] = null;	//	VARA
+    	return retval;
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/GreaterEqualEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/GreaterEqualEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/GreaterEqualEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,50 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.GreaterEqualPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class GreaterEqualEval implements OperationEval {
+
+    private GreaterEqualPtg delegate;
+    
+    public GreaterEqualEval(Ptg ptg) {
+        this.delegate = (GreaterEqualPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        boolean b = false;
+        double d0 = 0;
+        double d1 = 0;
+        if (operands[0] instanceof NumericValueEval) {
+            
+        }
+        
+        return new BoolEval(b);
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/GreaterThanEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/GreaterThanEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/GreaterThanEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.GreaterThanPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class GreaterThanEval implements OperationEval {
+
+    private GreaterThanPtg delegate;
+    
+    public GreaterThanEval(Ptg ptg) {
+        this.delegate = (GreaterThanPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/LessEqualEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/LessEqualEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/LessEqualEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.LessEqualPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class LessEqualEval implements OperationEval {
+
+    private LessEqualPtg delegate;
+    
+    public LessEqualEval(Ptg ptg) {
+        this.delegate = (LessEqualPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/LessThanEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/LessThanEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/LessThanEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.LessThanPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class LessThanEval implements OperationEval {
+
+    private LessThanPtg delegate;
+    
+    public LessThanEval(Ptg ptg) {
+        this.delegate = (LessThanPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/MultiplyEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/MultiplyEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/MultiplyEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,67 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.MultiplyPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class MultiplyEval implements OperationEval {
+
+    private MultiplyPtg delegate;
+    
+    public MultiplyEval(Ptg ptg) {
+        this.delegate = (MultiplyPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        double d = 0;
+        Eval retval = null;
+    	for (int i=0, iSize=getNumberOfOperands(); i<iSize; i++) {
+        	if (operands[i] instanceof NumericValueEval) {
+        		d *= ((NumericValueEval) operands[i]).getNumberValue();
+        	}
+        	else if (operands[i] instanceof RefEval) {
+        	    RefEval re = (RefEval) operands[i];
+        	    ValueEval ve = (ValueEval) re.getInnerValueEval();
+            	if (ve instanceof NumericValueEval) {
+            		d *= ((NumericValueEval) ve).getNumberValue();
+            	}
+            	else {
+            	    retval = ErrorEval.ERROR_502;
+            	    break;
+            	}
+        	}
+        	else {
+        	    retval = ErrorEval.ERROR_502;
+        	    break;
+        	}
+    	}
+    	if (retval == null) 
+    	    retval = new NumberEval(d);
+    	return retval;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NotEqualEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NotEqualEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NotEqualEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.NotEqualPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class NotEqualEval implements OperationEval {
+
+    private NotEqualPtg delegate;
+    
+    public NotEqualEval(Ptg ptg) {
+        this.delegate = (NotEqualPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NumberEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NumberEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NumberEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.IntPtg;
+import org.apache.poi.hssf.record.formula.NumberPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class NumberEval implements NumericValueEval, StringValueEval {
+
+    private double value;
+    
+    
+    public NumberEval(Ptg ptg) {
+        if (ptg instanceof IntPtg) {
+            this.value = ((IntPtg) ptg).getValue();
+        }
+        else if (ptg instanceof NumberPtg) {
+            this.value = ((NumberPtg) ptg).getValue();
+        }
+    }
+    
+    public NumberEval(double value) {
+        this.value = value;
+    }
+    
+    public double getNumberValue() {
+        return value;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.StringValueEval#getStringValue()
+     */
+    public String getStringValue() {
+        return String.valueOf(value);
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NumericValueEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NumericValueEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/NumericValueEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,14 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public interface NumericValueEval extends ValueEval {
+
+    public abstract double getNumberValue();
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/OperationEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/OperationEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/OperationEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,18 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public interface OperationEval extends Eval {
+
+    public abstract Eval evaluate(Eval[] evals);
+    
+    public abstract int getNumberOfOperands();
+    
+    public abstract int getType();
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/PowerEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/PowerEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/PowerEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.PowerPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class PowerEval implements OperationEval {
+
+    private PowerPtg delegate;
+    
+    public PowerEval(Ptg ptg) {
+        this.delegate = (PowerPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        // TODO Auto-generated method stub
+        return null;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Ref2DEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Ref2DEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Ref2DEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 9, 2005
+ *
+ * TODO To change the template for this generated file go to
+ * Window - Preferences - Java - Code Style - Code Templates
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.ReferencePtg;
+
+/**
+ * @author adeshmukh
+ *
+ * TODO To change the template for this generated type comment go to
+ * Window - Preferences - Java - Code Style - Code Templates
+ */
+public class Ref2DEval implements RefEval {
+
+	private ValueEval value;
+	
+	private ReferencePtg delegate;
+	
+	public Ref2DEval(Ptg ptg, ValueEval value) {
+		this.value = value;
+		this.delegate = (ReferencePtg) ptg;
+	}
+	
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.eval.RefEval#getInnerValueEval()
+	 */
+	public ValueEval getInnerValueEval() {
+		return value;
+	}
+	
+	public short getRow() {
+		return delegate.getRow();
+	}
+	
+	public short getColumn() {
+		return delegate.getColumn();
+	}
+	
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Ref3DEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Ref3DEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/Ref3DEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 9, 2005
+ *
+ * TODO To change the template for this generated file go to
+ * Window - Preferences - Java - Code Style - Code Templates
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.Ref3DPtg;
+
+/**
+ * @author adeshmukh
+ *
+ * TODO To change the template for this generated type comment go to
+ * Window - Preferences - Java - Code Style - Code Templates
+ */
+public class Ref3DEval implements RefEval {
+
+	private ValueEval value;
+	
+	private Ref3DPtg delegate;
+	
+	public Ref3DEval(Ptg ptg, ValueEval value) {
+		this.value = value;
+		this.delegate = (Ref3DPtg) ptg;
+	}
+	
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.eval.RefEval#getInnerValueEval()
+	 */
+	public ValueEval getInnerValueEval() {
+		return value;
+	}
+	
+	public short getRow() {
+		return delegate.getRow();
+	}
+	
+	public short getColumn() {
+		return delegate.getColumn();
+	}
+	
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/RefEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/RefEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/RefEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,29 @@ 
+/*
+ * Created on May 9, 2005
+ *
+ * 
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+
+/**
+ * @author Amol S Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ * RefEval is the super interface for Ref2D and Ref3DEval.
+ * Basically a RefEval impl should contain reference to
+ * the original ReferencePtg or Ref3DPtg as well as the
+ * final "value" resulting from the evaluation of the cell 
+ * reference. Thus if the HSSFCell has type CELL_TYPE_NUMERIC,
+ * the contained value object should be of type NumberEval;
+ * if cell type is CELL_TYPE_STRING, contained value object
+ * should be of type StringEval 
+ */
+public interface RefEval extends ValueEval {
+
+	public ValueEval getInnerValueEval();
+	
+	public short getColumn();
+	
+	public short getRow();
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/StringEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/StringEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/StringEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,29 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.StringPtg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class StringEval implements StringValueEval {
+
+    private String value;
+    
+    public StringEval(Ptg ptg) {
+        this.value = ((StringPtg) ptg).getValue();
+    }
+    
+    public StringEval(String value) {
+        this.value = value;
+    }
+    
+    public String getStringValue() {
+        return value;
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/StringValueEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/StringValueEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/StringValueEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,15 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public interface StringValueEval extends ValueEval {
+
+    public String getStringValue();
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/SubtractEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/SubtractEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/SubtractEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,82 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.SubtractPtg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class SubtractEval implements OperationEval {
+
+    private SubtractPtg delegate;
+    
+    public SubtractEval(Ptg ptg) {
+        delegate = (SubtractPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        double d0 = 0;
+        double d1 = 0;
+        Eval retval = null;
+    	
+        if (operands[0] instanceof NumericValueEval) {
+    		d0 = ((NumberEval) operands[0]).getNumberValue();
+    	}
+    	else if (operands[0] instanceof RefEval) {
+    	    RefEval re = (RefEval) operands[0];
+    	    ValueEval ve = (ValueEval) re.getInnerValueEval();
+        	if (ve instanceof NumericValueEval) {
+        		d0 = ((NumberEval) ve).getNumberValue();
+        	}
+        	else {
+        	    retval = ErrorEval.ERROR_502;
+        	}
+    	}
+    	else {
+    	    retval = ErrorEval.ERROR_502;
+    	}
+    	
+        if (operands[1] instanceof NumericValueEval) {
+    		d1 = ((NumberEval) operands[1]).getNumberValue();
+    	}
+    	else if (operands[1] instanceof RefEval) {
+    	    RefEval re = (RefEval) operands[1];
+    	    ValueEval ve = (ValueEval) re.getInnerValueEval();
+        	if (ve instanceof NumericValueEval) {
+        		d1 = ((NumberEval) ve).getNumberValue();
+        	}
+        	else {
+        	    retval = ErrorEval.ERROR_502;
+        	}
+    	}
+    	else {
+    	    retval = ErrorEval.ERROR_502;
+    	}
+    	
+    	if (retval == null) 
+    	    retval = new NumberEval(d0-d1);
+    	return retval;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/UnaryMinusEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/UnaryMinusEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/UnaryMinusEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,65 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.UnaryMinusPtg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class UnaryMinusEval implements OperationEval {
+
+    private UnaryMinusPtg delegate;
+    
+    public UnaryMinusEval(Ptg ptg) {
+        this.delegate = (UnaryMinusPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        ValueEval retval = null;
+        double d = 0;
+        if (operands[0] instanceof NumericValueEval) {
+            NumericValueEval nve = (NumericValueEval) operands[0];
+            d = nve.getNumberValue();
+        }
+        else if (operands[0] instanceof RefEval) {
+            RefEval re = (RefEval) operands[0];
+            ValueEval ve = re.getInnerValueEval();
+            if (ve instanceof NumericValueEval) {
+                NumericValueEval nve = (NumericValueEval) ve;
+                d = nve.getNumberValue();
+            }
+        }
+        else {
+            retval = ErrorEval.INVALID_VALUE;
+        }
+        
+        if (retval == null) {
+            retval = new NumberEval(-d);
+        }
+        
+        return retval;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/UnaryPlusEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/UnaryPlusEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/UnaryPlusEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,43 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.UnaryPlusPtg;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class UnaryPlusEval implements OperationEval {
+
+    private UnaryPlusPtg delegate;
+    
+    public UnaryPlusEval(Ptg ptg) {
+        this.delegate = (UnaryPlusPtg) ptg;
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        return operands[0];
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getNumberOfOperands()
+     */
+    public int getNumberOfOperands() {
+        return delegate.getNumberOfOperands();
+    }
+    
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.eval.OperationEval#getType()
+     */
+    public int getType() {
+        return delegate.getType();
+    }
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ValueEval.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ValueEval.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/eval/ValueEval.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,13 @@ 
+/*
+ * Created on May 8, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.eval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public interface ValueEval extends Eval {
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Abs.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Abs.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Abs.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,56 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Abs extends DefaultFunctionImpl {
+
+    
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		ValueEval retval = null;
+		if (operands.length == 1) {
+			if (operands[0] !=null && operands[0] instanceof NumericValueEval) {
+			    d = Math.abs(((NumericValueEval) operands[0]).getNumberValue());
+			}
+			else if (operands[0] instanceof AreaEval) {
+			    AreaEval ae = (AreaEval) operands[0];
+			    ValueEval v = ae.getValues()[0];
+			    if (v != null && v instanceof NumericValueEval) {
+			        d = Math.abs(((NumericValueEval) v).getNumberValue());
+			    }
+			}
+			else if (operands[0] instanceof ErrorEval) {
+			    ErrorEval e = (ErrorEval) operands[0];
+			    retval = e;
+			}
+			if (retval != null)
+			    retval = new NumberEval(d);
+		}
+		else {
+		    retval = ErrorEval.ERROR_508;
+		}
+		if (retval != null) {
+		    retval = (Double.isNaN(d)) 
+		    		? (ValueEval) ErrorEval.ERROR_502 
+		            : new NumberEval(d);
+		}
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Atan.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Atan.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Atan.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,22 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Atan extends DefaultFunctionImpl {
+
+    /* (non-Javadoc)
+     * @see org.apache.poi.hssf.record.formula.functions.DefaultFunctionImplEval#evaluate(org.apache.poi.hssf.record.formula.eval.Eval[])
+     */
+    public Eval evaluate(Eval[] operands) {
+        return super.evaluate(operands);
+    }
+    
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Average.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Average.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Average.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,75 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Average extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		int count = 0;
+		ValueEval retval = null;
+		for (int i=0, iSize=operands.length; i<iSize; i++) {
+		    if (operands[i] == null)
+		         continue;
+			if (operands[i] instanceof AreaEval) {
+				AreaEval ap = (AreaEval) operands[i];
+				Object[] values = ap.getValues();
+				for (int j=0, jSize=values.length; j<jSize; j++) {
+				    if (values[j]==null) 
+				        continue;
+					if (values[j] instanceof NumericValueEval) { 
+						d += ((NumericValueEval) values[j]).getNumberValue();
+						count++;
+					}
+					else if (values[j] instanceof RefEval) {
+					    RefEval re = (RefEval) values[j];
+					    ValueEval ve = re.getInnerValueEval();
+						if (ve!=null && ve instanceof NumericValueEval) { 
+							d += ((NumericValueEval) ve).getNumberValue();
+							count++;
+						}
+					}
+				}
+			}
+			else if (operands[i] instanceof NumericValueEval) {
+				NumericValueEval np = (NumericValueEval) operands[i];
+				d += np.getNumberValue();
+				count++;
+			}
+			else if (operands[i] instanceof RefEval) {
+			    RefEval re = (RefEval) operands[i];
+			    ValueEval ve = re.getInnerValueEval();
+			    if (ve instanceof NumericValueEval) {
+			        NumericValueEval ne = (NumericValueEval) ve;
+			        d += ne.getNumberValue();
+			        count++;
+			    }
+			}
+		}
+
+		if (retval == null) {
+		    retval = (Double.isNaN(d)) 
+		    		? (ValueEval) ErrorEval.ERROR_502 
+		            : new NumberEval(d/count);
+		}
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Column.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Column.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Column.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,33 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Column extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		Eval retval = null;
+		if (operands[0] instanceof RefEval) {
+			RefEval rp = (RefEval) operands[0];
+			retval = new NumberEval(rp.getColumn()+1);
+		}
+		else {
+			retval = ErrorEval.ERROR_504;
+		}
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Cos.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Cos.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Cos.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,55 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Cos extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		ValueEval retval = null;
+		double d = 0;
+		if (operands.length == 1) {
+			if (operands[0] instanceof NumericValueEval) {
+			    NumericValueEval np = (NumericValueEval) operands[0];
+				d = Math.cos(np.getNumberValue());
+			}
+			else if (operands[0] instanceof RefEval) {
+			    RefEval re = (RefEval) operands[0];
+			    ValueEval ve = re.getInnerValueEval();
+			    if (ve!=null && ve instanceof NumericValueEval) {
+			        NumericValueEval np = (NumericValueEval) ve;
+					d = Math.cos(np.getNumberValue());
+			    }
+			}
+			else if (operands[0] instanceof AreaEval) {
+				retval = ErrorEval.INVALID_VALUE;
+			}
+			else {
+				retval = ErrorEval.ERROR_502; 
+			}
+		}
+		else {
+			retval = ErrorEval.ERROR_508;
+		}
+		if (retval == null)
+		    retval = new NumberEval(d);
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Count.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Count.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Count.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,63 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Count extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		int count = 0;
+		for (int i=0, iSize=operands.length; i<iSize; i++) {
+			if (operands[i] instanceof AreaEval) {
+				AreaEval ap = (AreaEval) operands[i];
+				ValueEval[] values = ap.getValues();
+				for (int j=0, jSize=values.length; j<jSize; j++) {
+				    if (values[j]==null)
+				        continue;
+					if ((values[j] instanceof NumericValueEval)) {
+					    count++;
+					}
+					else if (values[j] instanceof RefEval){
+					    RefEval re = (RefEval) values[j];
+					    ValueEval ve = re.getInnerValueEval();
+						if ((values[j] instanceof NumericValueEval)) {
+						    count++;
+						}
+					}
+				}
+			}
+			else if (operands[i] instanceof NumericValueEval) {
+			    count++;
+			}
+			else if (operands[i] instanceof RefEval){
+			    RefEval re = (RefEval) operands[i];
+			    ValueEval ve = re.getInnerValueEval();
+				if ((operands[i] instanceof NumericValueEval)) {
+				    count++;
+				}
+			}
+		}
+
+		// TODO: --Note-- 
+		// Count behaves (slightly) differently in Oo and Excel.
+		// Oo counts boolean values (whether true or false), Excel
+		// ignores booleans. Strings are ignored by both Oo and Excel.
+		return new NumberEval(count);
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/DefaultFunctionImpl.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/DefaultFunctionImpl.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/DefaultFunctionImpl.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,21 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+
+/**
+ * 
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ */
+public abstract class DefaultFunctionImpl implements Function {
+
+	public Eval evaluate(Eval[] operands) {
+		return ErrorEval.FUNCTION_NOT_IMPLEMENTED;
+	}
+	
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Dollar.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Dollar.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Dollar.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,77 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.StringEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ * 
+ */
+public class Dollar extends DefaultFunctionImpl {
+    //private static final DecimalFormat DOLLAR_FORMAT = new DecimalFormat("$#,##0.0#");
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		ValueEval retval = null;
+		if (operands[0] != null) {
+			if (operands[0] instanceof NumericValueEval) {
+				NumericValueEval np = (NumericValueEval) operands[0];
+				d = np.getNumberValue();
+			}
+			else if (operands[0] instanceof RefEval) {
+				RefEval re = (RefEval) operands[0];
+				ValueEval ve = re.getInnerValueEval();
+				if (ve!=null && ve instanceof NumericValueEval) {
+					NumericValueEval np = (NumericValueEval) ve;
+					d = np.getNumberValue();
+				}
+			}
+			else if (operands[0] instanceof AreaEval) {
+				 retval = ErrorEval.INVALID_VALUE;
+			}
+			else if (operands[0] instanceof StringEval) {
+				StringEval se = (StringEval) operands[0];
+				String s = se.getStringValue();
+				try {
+					d = Double.parseDouble(s);
+				} catch (NumberFormatException nfe) {
+					retval = ErrorEval.INVALID_VALUE;
+				}
+			}
+			else {
+				d=Math.tan(0); 
+			}
+		}
+		if (retval == null) {
+		    retval = new NumberEval(d);
+		}
+		
+		// TODO: this is a little tricky function to implement:
+		// because while display value is a dollar format string, 
+		// the type is treated as numeric when used in formulas.
+		// For now, the returned type is kept "NumberEval"
+		// since it will cause it to work better with other
+		// formulas.
+		// MoreImportantly, OpenOffice and Excel differ in their
+		// implementation of DOLLAR, Oo treats DOLLAr eval as 
+		// String, Excel treats it as Number - This class
+		// treats it as a number but/hence does not do the
+		// formatting that DOLLAR should: In programs, this
+		//  impl should be more useful.
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Exp.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Exp.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Exp.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,36 @@ 
+/*
+ * Created on May 6, 2005
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Exp extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		ValueEval retval = null;
+		if (operands!=null) {
+			if (operands[0] instanceof NumericValueEval) {
+			    NumericValueEval np = (NumericValueEval) operands[0];
+				d = Math.pow(Math.E, np.getNumberValue());
+			}
+			else {
+				retval = ErrorEval.INVALID_VALUE;
+			}
+		}
+		if (retval == null) 
+		    retval = new NumberEval(d);
+		return retval;
+	}
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Fixed.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Fixed.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Fixed.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,127 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ * <pre>
+ * Function spec:
+ * 1. numargs= 1-3
+ * 2. args= 1: number; 2: decimal places; 3: show thousands separator?
+ * </pre>
+ */
+public class Fixed extends DefaultFunctionImpl {
+    
+    private static final boolean DEFAULT_SHOW_THOUSANDS_SEP = true;
+    private static final int DEFAULT_NUM_DIGITS_AFTER_DECIMALS = 2;
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d;
+		boolean showThousandsSep = DEFAULT_SHOW_THOUSANDS_SEP;
+		int numdecimals=DEFAULT_NUM_DIGITS_AFTER_DECIMALS;
+		
+		switch (operands.length) {
+		case 3:
+		    if (operands[2] instanceof NumericValueEval) {
+		        NumericValueEval np = (NumericValueEval) operands[2];
+		        showThousandsSep = np.getNumberValue() != 0;
+		    }
+		    else {
+		        showThousandsSep = false;
+		    }
+		case 2:
+		    if (operands[1] instanceof NumericValueEval) {
+		        NumericValueEval np = (NumericValueEval) operands[1];
+		        numdecimals = (int) np.getNumberValue();
+		    }
+		    else {
+		        numdecimals = 0;
+		    }
+		default: // 1 operand
+		    if (operands[0] instanceof NumericValueEval) {
+		        NumericValueEval np = (NumericValueEval) operands[0];
+		        d = np.getNumberValue();
+		    }
+		    else {
+		        d = 0;
+		    }
+		}
+		
+		// String str = formatDecimal(d, numdecimals, showThousandsSep);
+		// return new StringPtg(str);
+		// TODO: this is a little tricky function to implement:
+		// because while display value is a fixed format string, 
+		// the type is treated as numeric when used in formulas.
+		// For now, the returned type is kept "NumberEval"
+		// since it will cause it to work better with other
+		// formulas.
+		// MoreImportantly, OpenOffice and Excel differ in their
+		// implementation of FIXED, Oo treats FIXED eval as 
+		// String, Excel treats it as Number - This class
+		// treats it as a number but/hence does not do the
+		// formatting that FIXED should: In programs, this
+		//  impl should be more useful. 
+		// To switch to strictly Oo implementation, uncomment the 
+		// 2 lines above this_TODO and remove the lines below 
+		// this_TODO.
+		
+		return new NumberEval(d);
+	}
+	
+	/**
+	 * return string representation of double with specified formatting options
+	 * @param d
+	 * @param numdecimals
+	 * @param showT
+	 * @return
+	 */
+	static final String formatDecimal(double d, int numdecimals, boolean showT) {
+	    StringBuffer sb = new StringBuffer(50); // 50 => optimze for speed for common values
+	    long integral = (long) d;
+	    double fraction = d-integral;
+
+	    if (showT) {
+	        String sintegral = String.valueOf(integral);
+	        for (int i=sintegral.length()-1, j=1; i>=0; i--, j++) {
+	            char c = sintegral.charAt(i);
+	            sb.append(c);
+	            if (j%3==0 && i!=0) sb.append(',');
+	        }
+	        sb.reverse();
+	    }
+	    else {
+	        sb.append(integral);
+	    }
+	    sb.append(ensureLength(fraction, numdecimals));
+	    return sb.toString();
+	}
+	
+	// TODO: optimize this function
+	/**
+	 * returns a truncated or padded String representation of
+	 * double fraction. double fraction MUST be >0 && <1.
+	 */
+	static final String ensureLength(double fraction, int numdecimals) {
+	    StringBuffer sb = new StringBuffer();
+	    if (numdecimals != 0) {
+		    int ifraction = (int) (fraction * Math.pow(10, numdecimals));
+		    String sfraction = String.valueOf(ifraction);
+		    
+		    sb.append('.').append(ifraction);
+		    for (int i=numdecimals-sfraction.length(); i>0; i--) {
+		        sb.append('0');
+		    }
+	    }
+	    return sb.toString();
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Function.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Function.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Function.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,18 @@ 
+/*
+ * Created on May 9, 2005
+ *
+ * TODO To change the template for this generated file go to
+ * Window - Preferences - Java - Code Style - Code Templates
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public interface Function {
+
+    public Eval evaluate(Eval[] operands);
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Int.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Int.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Int.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,52 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.StringEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Int extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		ValueEval retval = null;
+		if (operands.length == 1) {
+			if (operands[0] instanceof NumericValueEval) {
+				NumericValueEval ne = (NumericValueEval) operands[0];
+				d = ne.getNumberValue();
+			}
+			else if (operands[0] instanceof RefEval) {
+			    
+			}
+			else if (operands[0] instanceof StringEval) {
+				retval = ErrorEval.ERROR_502;
+			}
+		}
+		else if (operands.length > 1) {
+		    retval = ErrorEval.ERROR_508;
+		}
+		else {
+		    retval = ErrorEval.ERROR_511;
+		}
+		if (retval == null) {
+		    retval = new NumberEval(d);
+		}
+		
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/IsError.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/IsError.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/IsError.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,26 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.BoolEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class IsError extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+	    boolean b = (operands[0] instanceof ErrorEval) || (operands[0] instanceof AreaEval);
+		return new BoolEval(b);
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/IsNa.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/IsNa.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/IsNa.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,25 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ * TODO To change the template for this generated file go to
+ * Window - Preferences - Java - Code Style - Code Templates
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ * Window - Preferences - Java - Code Style - Code Templates
+ */
+public class IsNa extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		return super.evaluate(operands);
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Ln.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Ln.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Ln.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,61 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Ln extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		ValueEval retval = null;
+		switch (operands.length) {
+		case 1:
+			if (operands[0] instanceof NumericValueEval) {
+			    NumericValueEval ne = (NumericValueEval) operands[0];
+				d = Math.log(ne.getNumberValue());
+			}
+			else if (operands[0] instanceof RefEval) {
+			    RefEval re = (RefEval) operands[0];
+			    ValueEval ve = re.getInnerValueEval();
+			    if (ve instanceof NumericValueEval) {
+				    NumericValueEval ne = (NumericValueEval) ve;
+					d = Math.log(ne.getNumberValue());
+			    }
+			}
+			else if (operands[0] instanceof AreaEval) {
+				 retval = ErrorEval.INVALID_VALUE;
+			}
+			else {
+			    retval = ErrorEval.ERROR_502; 
+			}
+		    break;
+		case 0:
+		    retval = ErrorEval.ERROR_502;
+		    break;
+		default:
+		    retval = ErrorEval.ERROR_508;
+		}
+		if (retval == null) {
+		    retval = (Double.isNaN(d)) ? (ValueEval) ErrorEval.ERROR_503 : new NumberEval(d);
+		}
+		
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Log10.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Log10.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Log10.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,63 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Log10 extends DefaultFunctionImpl {
+	private static final double LOG_10_TO_BASE_e = Math.log(10);
+	
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		ValueEval retval = null;
+		switch (operands.length) {
+		case 1:
+			if (operands[0] instanceof NumericValueEval) {
+			    NumericValueEval ne = (NumericValueEval) operands[0];
+				d = Math.log(ne.getNumberValue());
+			}
+			else if (operands[0] instanceof RefEval) {
+			    RefEval re = (RefEval) operands[0];
+			    ValueEval ve = re.getInnerValueEval();
+			    if (ve instanceof NumericValueEval) {
+				    NumericValueEval ne = (NumericValueEval) operands[0];
+					d = Math.log(ne.getNumberValue());
+			    }
+			}
+			else if (operands[0] instanceof AreaEval) {
+				 retval = ErrorEval.INVALID_VALUE;
+			}
+			else {
+			    retval = ErrorEval.ERROR_502; 
+			}
+		    break;
+		case 0:
+		    retval = ErrorEval.ERROR_502;
+		    break;
+		default:
+		    retval = ErrorEval.ERROR_508;
+		}
+		if (retval != null) {
+		    retval = (Double.isNaN(d)) ? (ValueEval) ErrorEval.ERROR_503 : new NumberEval(d/LOG_10_TO_BASE_e);
+		}
+		
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Max.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Max.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Max.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,54 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Max extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		for (int i=0, iSize=operands.length; i<iSize; i++) {
+			if (operands[i] instanceof AreaEval) {
+			    AreaEval ap = (AreaEval) operands[i];
+				ValueEval[] values = ap.getValues();
+				for (int j=0, jSize=values.length; j<jSize; j++) {
+				    if (values[j]!=null) {
+						if (values[j] instanceof NumericValueEval) {
+							d = Math.max(((NumericValueEval) values[j]).getNumberValue(), d);
+						}
+						else if (values[j] instanceof RefEval)	{
+						    ValueEval ve = ((RefEval) values[j]).getInnerValueEval();
+						    if (ve!=null)
+						        d = Math.max(((NumericValueEval) ve).getNumberValue(), d);
+						}
+				    }
+				}
+			}
+			else if (operands[i] instanceof NumericValueEval) {
+				d = Math.max(((NumericValueEval) operands[i]).getNumberValue(), d);
+			}
+			else if (operands[i] instanceof RefEval)	{
+			    ValueEval ve = ((RefEval) operands[i]).getInnerValueEval();
+			    if (ve!=null)
+			        d = Math.max(((NumericValueEval) ve).getNumberValue(), d);
+			}
+		}
+		
+		return new NumberEval(d);
+	}
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Min.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Min.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Min.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,54 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Min extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		for (int i=0, iSize=operands.length; i<iSize; i++) {
+			if (operands[i] instanceof AreaEval) {
+			    AreaEval ap = (AreaEval) operands[i];
+				ValueEval[] values = ap.getValues();
+				for (int j=0, jSize=values.length; j<jSize; j++) {
+				    if (values[j]!=null) {
+						if (values[j] instanceof NumericValueEval) {
+							d = Math.min(((NumericValueEval) values[j]).getNumberValue(), d);
+						}
+						else if (values[j] instanceof RefEval)	{
+						    ValueEval ve = ((RefEval) values[j]).getInnerValueEval();
+						    if (ve!=null)
+						        d = Math.min(((NumericValueEval) ve).getNumberValue(), d);
+						}
+				    }
+				}
+			}
+			else if (operands[i] instanceof NumericValueEval) {
+				d = Math.min(((NumericValueEval) operands[i]).getNumberValue(), d);
+			}
+			else if (operands[i] instanceof RefEval)	{
+			    ValueEval ve = ((RefEval) operands[i]).getInnerValueEval();
+			    if (ve!=null)
+			        d = Math.min(((NumericValueEval) ve).getNumberValue(), d);
+			}
+		}
+		
+		return new NumberEval(d);
+	}
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Na.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Na.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Na.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,24 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+
+public class Na extends DefaultFunctionImpl {
+
+    
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+	    return super.evaluate(operands);
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Npv.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Npv.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Npv.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,91 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author Amol S. Deshmukh &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+
+public class Npv extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Eval[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		double rate = 0;
+		ValueEval retval = null;
+		
+		if (operands[0] instanceof NumericValueEval) {
+		    NumericValueEval np = (NumericValueEval) operands[0];
+		    rate = np.getNumberValue();
+		}
+		else if (operands[0] instanceof RefEval) {
+		    RefEval re = (RefEval) operands[0];
+		    ValueEval ve = re.getInnerValueEval();
+		    if (ve instanceof NumericValueEval) {
+			    NumericValueEval np = (NumericValueEval) ve;
+			    rate = np.getNumberValue();
+			}				
+		}
+		else {
+		    retval = ErrorEval.ERROR_503;
+		}
+		double denomVal = rate+1;
+		
+		if (retval == null) {
+			for (int i=1, k=1, iSize=operands.length; i<iSize; i++) {
+				if (operands[i] instanceof AreaEval) {
+					AreaEval ap = (AreaEval) operands[i];
+					Object[] values = ap.getValues();
+					for (int j=0, jSize=values.length; j<jSize; j++) {
+						if (values[j]==null || !(values[j] instanceof Number)) 
+							continue;
+						double value = ((Number) values[j]).doubleValue();
+						d += value / denomVal;
+						denomVal = (rate+1) * denomVal;
+					}
+				}
+				else if (operands[i] instanceof NumericValueEval) {
+					NumberEval np = (NumberEval) operands[i];
+					double value = np.getNumberValue();
+					d += value / denomVal;
+					denomVal = (rate+1) * denomVal;
+				}
+				else if (operands[i] instanceof RefEval) {
+				    RefEval re = (RefEval) operands[i];
+				    ValueEval ve = re.getInnerValueEval();
+				    if (ve instanceof NumericValueEval) {
+						NumberEval np = (NumberEval) ve;
+						double value = np.getNumberValue();
+						d += value / denomVal;
+						denomVal = (rate+1) * denomVal;
+					}				
+				}
+				else {
+				    retval = ErrorEval.ERROR_503;
+				}
+			}
+		}
+		else {
+		    retval = ErrorEval.ERROR_503;
+		}
+		
+		if (retval == null)
+		    retval = new NumberEval(d);
+		
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Pi.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Pi.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Pi.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,25 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Pi extends DefaultFunctionImpl {
+
+    private static final NumberEval PI_EVAL = new NumberEval(Math.PI);
+    
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		return PI_EVAL;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Round.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Round.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Round.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,74 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Round extends DefaultFunctionImpl {
+
+    private static final short DEFAULT_ACCURACY = 0;
+    
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		short accuracy = DEFAULT_ACCURACY;
+		double d = 0;
+		ValueEval retval = null;
+		if (operands[0] instanceof NumericValueEval) {
+		    NumericValueEval bp = (NumericValueEval) operands[0];
+		    d = bp.getNumberValue();
+		}
+		else if (operands[0] instanceof RefEval) {
+		    RefEval re = (RefEval) operands[0];
+		    ValueEval ve = re.getInnerValueEval();
+			if (ve instanceof NumericValueEval) {
+			    NumericValueEval n = (NumericValueEval) ve;
+			    d = n.getNumberValue();
+			}
+		}
+		else {
+		    retval = ErrorEval.ERROR_502;
+		}
+		
+		if (operands.length == 2) {
+			if (operands[1] instanceof NumericValueEval) {
+			    NumericValueEval bp = (NumericValueEval) operands[0];
+			    accuracy = (short) bp.getNumberValue();
+			}
+			else if (operands[1] instanceof RefEval) {
+			    RefEval re = (RefEval) operands[1];
+			    ValueEval ve = re.getInnerValueEval();
+				if (ve instanceof NumericValueEval) {
+				    NumericValueEval n = (NumericValueEval) ve;
+				    accuracy = (short) n.getNumberValue();
+				}
+			}
+			else {
+			    retval = ErrorEval.ERROR_502;
+			}
+		}
+		else if (operands.length > 2) {
+		    retval = ErrorEval.ERROR_504;
+		}
+		if (retval == null) {
+			double power = Math.pow(10, accuracy);
+			d *= power;
+			d = Math.round(d);
+			retval = new NumberEval(d/power);
+		}
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Row.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Row.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Row.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,33 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Row extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		Eval retval = null;
+		if (operands[0] instanceof RefEval) {
+			RefEval rp = (RefEval) operands[0];
+			retval = new NumberEval(rp.getRow()+1);
+		}
+		else {
+			retval = ErrorEval.ERROR_504;
+		}
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sign.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sign.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sign.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,44 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Sign extends DefaultFunctionImpl {
+
+    private static final NumberEval NEG_SIGN_EVAL = new NumberEval(-1);
+    private static final NumberEval POS_SIGN_EVAL = new NumberEval(1);
+    private static final NumberEval ZERO_SIGN_EVAL = new NumberEval(0);
+    
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+	    double d = 0;
+	    ValueEval retval = null;
+	    if (operands[0] instanceof NumericValueEval) {
+	        NumericValueEval nve = (NumericValueEval) operands[0];
+	        d = nve.getNumberValue();
+	    }
+	    if (d == 0) {
+	        retval = ZERO_SIGN_EVAL;
+	    }
+	    else if (d < 0) {
+	        retval = NEG_SIGN_EVAL;
+	    }
+	    else if (d > 0) {
+	        retval = POS_SIGN_EVAL;
+	    }
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sin.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sin.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sin.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,55 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Sin extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		ValueEval retval = null;
+		double d = 0;
+		if (operands.length == 1) {
+			if (operands[0] instanceof NumericValueEval) {
+			    NumericValueEval np = (NumericValueEval) operands[0];
+				d = Math.sin(np.getNumberValue());
+			}
+			else if (operands[0] instanceof RefEval) {
+			    RefEval re = (RefEval) operands[0];
+			    ValueEval ve = re.getInnerValueEval();
+			    if (ve!=null && ve instanceof NumericValueEval) {
+			        NumericValueEval np = (NumericValueEval) ve;
+					d = Math.sin(np.getNumberValue());
+			    }
+			}
+			else if (operands[0] instanceof AreaEval) {
+				retval = ErrorEval.INVALID_VALUE;
+			}
+			else {
+				retval = ErrorEval.ERROR_502; 
+			}
+		}
+		else {
+			retval = ErrorEval.ERROR_508;
+		}
+		if (retval == null)
+		    retval = new NumberEval(d);
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sqrt.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sqrt.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sqrt.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,56 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Sqrt extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		ValueEval retval = null;
+		double d = 0;
+		if (operands.length == 1) {
+			if (operands[0] instanceof NumericValueEval) {
+			    NumericValueEval np = (NumericValueEval) operands[0];
+				d = Math.sqrt(np.getNumberValue());
+			}
+			else if (operands[0] instanceof RefEval) {
+			    RefEval re = (RefEval) operands[0];
+			    ValueEval ve = re.getInnerValueEval();
+			    if (ve!=null && ve instanceof NumericValueEval) {
+			        NumericValueEval np = (NumericValueEval) ve;
+					d = Math.sqrt(np.getNumberValue());
+			    }
+			}
+			else if (operands[0] instanceof AreaEval) {
+				retval = ErrorEval.INVALID_VALUE;
+			}
+			else {
+				retval = ErrorEval.ERROR_502; 
+			}
+		}
+		else {
+			retval = ErrorEval.ERROR_508;
+		}
+		if (retval != null) {
+		    retval = (Double.isNaN(d)) ? (ValueEval) ErrorEval.ERROR_502 : new NumberEval(d);
+		}
+		return retval;
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Stdev.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Stdev.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Stdev.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,79 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Stdev extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+	    return super.evaluate(operands);
+//		double mean = 0;
+//		int count = 0;
+//		double numerator = 0;
+//		
+//		for (int i=0, iSize=operands.length; i<iSize; i++) {
+//			if (operands[i] instanceof AreaPtg) {
+//				AreaPtg ap = (AreaPtg) operands[i];
+//				Object[] values = ap.getValues();
+//				for (int j=0, jSize=values.length; j<jSize; j++) {
+//					if (values[j]!=null && !(values[j] instanceof Number)) { 
+//						mean += ((Number) values[j]).doubleValue();
+//						count++;
+//					}
+//					else if (values[j] instanceof Boolean) {
+//					    mean += ((Boolean) values[j]).booleanValue() ? 1 : 0;
+//					    count++;
+//					}
+//				}
+//			}
+//			else if (operands[i] instanceof IntPtg) {
+//				IntPtg ip = (IntPtg) operands[i];
+//				mean += ip.getValue();
+//				count++;
+//			}
+//			else if (operands[i] instanceof NumberPtg) {
+//				NumberPtg np = (NumberPtg) operands[i];
+//				mean += np.getValue();
+//				count++;
+//			}
+//		}
+//		mean /= count;
+//
+//		for (int i=0, iSize=operands.length; i<iSize; i++) {
+//			if (operands[i] instanceof AreaPtg) {
+//				AreaPtg ap = (AreaPtg) operands[i];
+//				Object[] values = ap.getValues();
+//				for (int j=0, jSize=values.length; j<jSize; j++) {
+//					if (values[j]==null || !(values[j] instanceof Number)) 
+//						continue;
+//					double d = (((Number) values[j]).doubleValue() - mean);
+//					numerator += d*d;
+//				}
+//			}
+//			else if (operands[i] instanceof IntPtg) {
+//				IntPtg ip = (IntPtg) operands[i];
+//				double d = (ip.getValue() - mean);
+//				numerator += d*d;
+//			}
+//			else if (operands[i] instanceof NumberPtg) {
+//				NumberPtg np = (NumberPtg) operands[i];
+//				double d = (np.getValue() - mean);
+//				numerator += d*d;
+//			}
+//		}
+//		
+//		
+//		return new NumberPtg(Math.sqrt(mean/(count-1)));
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sum.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sum.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Sum.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,68 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Sum extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+		double d = 0;
+		ValueEval retval = null;
+		for (int i=0, iSize=operands.length; i<iSize; i++) {
+		    if (operands[i] == null)
+		         continue;
+			if (operands[i] instanceof AreaEval) {
+				AreaEval ap = (AreaEval) operands[i];
+				Object[] values = ap.getValues();
+				for (int j=0, jSize=values.length; j<jSize; j++) {
+				    if (values[j]==null) 
+				        continue;
+					if (values[j] instanceof NumericValueEval) { 
+						d += ((NumericValueEval) values[j]).getNumberValue();
+					}
+					else if (values[j] instanceof RefEval) {
+					    RefEval re = (RefEval) values[j];
+					    ValueEval ve = re.getInnerValueEval();
+						if (ve!=null && ve instanceof NumericValueEval) { 
+							d += ((NumericValueEval) ve).getNumberValue();
+						}
+					}
+				}
+			}
+			else if (operands[i] instanceof NumericValueEval) {
+				NumericValueEval np = (NumericValueEval) operands[i];
+				d += np.getNumberValue();
+			}
+			else if (operands[i] instanceof RefEval) {
+			    RefEval re = (RefEval) operands[i];
+			    ValueEval ve = re.getInnerValueEval();
+			    if (ve instanceof NumericValueEval) {
+			        NumericValueEval ne = (NumericValueEval) ve;
+			        d += ne.getNumberValue();
+			    }
+			}
+		}
+
+		if (retval == null) {
+		    retval = (Double.isNaN(d)) 
+		    		? (ValueEval) ErrorEval.ERROR_502 
+		            : new NumberEval(d);
+		}
+		return retval;	}
+}
Index: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Tan.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Tan.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Tan.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,45 @@ 
+/*
+ * Created on May 6, 2005
+ *
+ */
+package org.apache.poi.hssf.record.formula.functions;
+
+import org.apache.poi.hssf.record.formula.eval.Eval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ */
+public class Tan extends DefaultFunctionImpl {
+
+	/* (non-Javadoc)
+	 * @see org.apache.poi.hssf.record.formula.functions.Function#evaluate(org.apache.poi.hssf.record.formula.Ptg[])
+	 */
+	public Eval evaluate(Eval[] operands) {
+	    return super.evaluate(operands);
+//		double d;
+//		if (operands[0] instanceof IntPtg) {
+//		    IntPtg np = (IntPtg) operands[0];
+//			d = Math.tan(np.getValue());
+//		}
+//		else if (operands[0] instanceof NumberPtg) {
+//			NumberPtg np = (NumberPtg) operands[0];
+//			d = Math.tan(np.getValue());
+//		}
+//		else if (operands[0] instanceof AreaPtg) {
+//			d=Double.NaN; // TODO: Fix this: check with excel, Oo does weird things with Area refs 
+//		}
+//		else if (operands[0] instanceof BoolPtg) {
+//			BoolPtg bp = (BoolPtg) operands[0];
+//			d=bp.getValue() ? Math.tan(1) : Math.tan(0);  
+//		}
+//		else if (operands[0] instanceof StringPtg) {
+//			d=Math.tan(0);  
+//		}
+//		else {
+//			d=Math.tan(0); 
+//		}
+//		return new NumberPtg(d);
+	}
+
+}
Index: src/scratchpad/src/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java
===================================================================
RCS file: src/scratchpad/src/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/scratchpad/src/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java	1 Jan 1970 00:00:00 -0000
@@ -0,0 +1,480 @@ 
+/*
+ * Created on May 5, 2005
+ *
+ */
+package org.apache.poi.hssf.usermodel;
+import java.io.FileInputStream;
+import java.lang.reflect.Constructor;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Stack;
+
+import org.apache.poi.hssf.model.FormulaParser;
+import org.apache.poi.hssf.record.formula.AddPtg;
+import org.apache.poi.hssf.record.formula.Area3DPtg;
+import org.apache.poi.hssf.record.formula.AreaPtg;
+import org.apache.poi.hssf.record.formula.AttrPtg;
+import org.apache.poi.hssf.record.formula.BoolPtg;
+import org.apache.poi.hssf.record.formula.ConcatPtg;
+import org.apache.poi.hssf.record.formula.ControlPtg;
+import org.apache.poi.hssf.record.formula.DividePtg;
+import org.apache.poi.hssf.record.formula.EqualPtg;
+import org.apache.poi.hssf.record.formula.FuncPtg;
+import org.apache.poi.hssf.record.formula.FuncVarPtg;
+import org.apache.poi.hssf.record.formula.GreaterEqualPtg;
+import org.apache.poi.hssf.record.formula.GreaterThanPtg;
+import org.apache.poi.hssf.record.formula.IntPtg;
+import org.apache.poi.hssf.record.formula.LessEqualPtg;
+import org.apache.poi.hssf.record.formula.LessThanPtg;
+import org.apache.poi.hssf.record.formula.MemErrPtg;
+import org.apache.poi.hssf.record.formula.MissingArgPtg;
+import org.apache.poi.hssf.record.formula.MultiplyPtg;
+import org.apache.poi.hssf.record.formula.NamePtg;
+import org.apache.poi.hssf.record.formula.NameXPtg;
+import org.apache.poi.hssf.record.formula.NotEqualPtg;
+import org.apache.poi.hssf.record.formula.NumberPtg;
+import org.apache.poi.hssf.record.formula.OperationPtg;
+import org.apache.poi.hssf.record.formula.ParenthesisPtg;
+import org.apache.poi.hssf.record.formula.PowerPtg;
+import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.Ref3DPtg;
+import org.apache.poi.hssf.record.formula.ReferencePtg;
+import org.apache.poi.hssf.record.formula.StringPtg;
+import org.apache.poi.hssf.record.formula.SubtractPtg;
+import org.apache.poi.hssf.record.formula.UnaryMinusPtg;
+import org.apache.poi.hssf.record.formula.UnaryPlusPtg;
+import org.apache.poi.hssf.record.formula.UnionPtg;
+import org.apache.poi.hssf.record.formula.UnknownPtg;
+import org.apache.poi.hssf.record.formula.eval.AddEval;
+import org.apache.poi.hssf.record.formula.eval.Area2DEval;
+import org.apache.poi.hssf.record.formula.eval.Area3DEval;
+import org.apache.poi.hssf.record.formula.eval.AreaEval;
+import org.apache.poi.hssf.record.formula.eval.BoolEval;
+import org.apache.poi.hssf.record.formula.eval.ConcatEval;
+import org.apache.poi.hssf.record.formula.eval.DivideEval;
+import org.apache.poi.hssf.record.formula.eval.EqualEval;
+import org.apache.poi.hssf.record.formula.eval.ErrorEval;
+import org.apache.poi.hssf.record.formula.eval.Eval;
+import org.apache.poi.hssf.record.formula.eval.FuncVarEval;
+import org.apache.poi.hssf.record.formula.eval.GreaterEqualEval;
+import org.apache.poi.hssf.record.formula.eval.GreaterThanEval;
+import org.apache.poi.hssf.record.formula.eval.LessEqualEval;
+import org.apache.poi.hssf.record.formula.eval.LessThanEval;
+import org.apache.poi.hssf.record.formula.eval.MultiplyEval;
+import org.apache.poi.hssf.record.formula.eval.NotEqualEval;
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
+import org.apache.poi.hssf.record.formula.eval.OperationEval;
+import org.apache.poi.hssf.record.formula.eval.PowerEval;
+import org.apache.poi.hssf.record.formula.eval.Ref2DEval;
+import org.apache.poi.hssf.record.formula.eval.Ref3DEval;
+import org.apache.poi.hssf.record.formula.eval.RefEval;
+import org.apache.poi.hssf.record.formula.eval.StringEval;
+import org.apache.poi.hssf.record.formula.eval.StringValueEval;
+import org.apache.poi.hssf.record.formula.eval.SubtractEval;
+import org.apache.poi.hssf.record.formula.eval.UnaryMinusEval;
+import org.apache.poi.hssf.record.formula.eval.UnaryPlusEval;
+import org.apache.poi.hssf.record.formula.eval.ValueEval;
+
+/**
+ * @author amolweb &lt; amolweb at ya hoo dot com &gt;
+ *
+ * Limitations:
+ * Unfortunately, cyclic references will cause stackoverflow exception
+ */
+public class HSSFFormulaEvaluator {
+    
+    // params to lookup the right constructor using reflection
+    private static final Class[] OPERATION_CONTRUCTOR_CLASS_ARRAY = new Class[]{Ptg.class};
+    private static final Class[] VALUE_CONTRUCTOR_CLASS_ARRAY = new Class[]{Ptg.class};
+    private static final Class[] AREA_CONSTRUCTOR_CLASS_ARRAY = new Class[]{Ptg.class, ValueEval[].class};
+    private static final Class[] AREA3D_CONSTRUCTOR_CLASS_ARRAY = new Class[]{Ptg.class, ValueEval[].class};
+    private static final Class[] REFERENCE_CONSTRUCTOR_CLASS_ARRAY = new Class[]{Ptg.class, ValueEval.class};
+    private static final Class[] REF3D_CONSTRUCTOR_CLASS_ARRAY = new Class[]{Ptg.class, ValueEval.class};
+    
+    // Maps for mapping *Eval to *Ptg
+    private static final Map VALUE_EVALS_MAP = new HashMap();
+    private static final Map OPERATION_EVALS_MAP = new HashMap();    
+    
+    
+    /*
+     * If you dont like this map, join the club :)
+     * I did this becoz it was desired to keep the FormulaEvaluator
+     * separate from FormulaParser and related classes in the CVS-HEAD.
+     * So now we need some mapping between the Ptg tokens that
+     * the FormulaParser returns and the *Eval classes taht
+     * are used by the FormulaEvaluator - hence the following :)
+     */
+static {
+    VALUE_EVALS_MAP.put(BoolPtg.class, BoolEval.class);
+    VALUE_EVALS_MAP.put(IntPtg.class, NumberEval.class);
+    VALUE_EVALS_MAP.put(NumberPtg.class, NumberEval.class);
+    VALUE_EVALS_MAP.put(StringPtg.class, StringEval.class);
+    
+    OPERATION_EVALS_MAP.put(AddPtg.class, AddEval.class);
+    OPERATION_EVALS_MAP.put(ConcatPtg.class, ConcatEval.class);
+    OPERATION_EVALS_MAP.put(DividePtg.class, DivideEval.class);
+    OPERATION_EVALS_MAP.put(EqualPtg.class, EqualEval.class);
+    //OPERATION_EVALS_MAP.put(ExpPtg.class, ExpEval.class); // TODO: check this
+    OPERATION_EVALS_MAP.put(FuncPtg.class, FuncVarEval.class); // TODO: check this
+    OPERATION_EVALS_MAP.put(FuncVarPtg.class, FuncVarEval.class);
+    OPERATION_EVALS_MAP.put(GreaterEqualPtg.class, GreaterEqualEval.class);
+    OPERATION_EVALS_MAP.put(GreaterThanPtg.class, GreaterThanEval.class);
+    OPERATION_EVALS_MAP.put(LessEqualPtg.class, LessEqualEval.class);
+    OPERATION_EVALS_MAP.put(LessThanPtg.class, LessThanEval.class);
+    OPERATION_EVALS_MAP.put(MultiplyPtg.class, MultiplyEval.class);
+    OPERATION_EVALS_MAP.put(NotEqualPtg.class, NotEqualEval.class);
+    OPERATION_EVALS_MAP.put(PowerPtg.class, PowerEval.class);
+    OPERATION_EVALS_MAP.put(SubtractPtg.class, SubtractEval.class);
+    OPERATION_EVALS_MAP.put(UnaryMinusPtg.class, UnaryMinusEval.class);
+    OPERATION_EVALS_MAP.put(UnaryPlusPtg.class, UnaryPlusEval.class);
+
+
+}
+    
+	
+    /**
+     * debug method
+     * @param formula
+     * @param sheet
+     * @param workbook
+     */
+	static void inspectPtgs(String formula, HSSFSheet sheet, HSSFWorkbook workbook) {
+		FormulaParser fp = new FormulaParser(formula, workbook.getWorkbook());
+		fp.parse();
+		Ptg[] ptgs = fp.getRPNPtg();
+    	System.out.println("<ptg-group>");
+    	for (int i=0, iSize=ptgs.length; i<iSize; i++) {
+    		System.out.println("<ptg>");
+    		System.out.println(ptgs[i]);
+    		if (ptgs[i] instanceof OperationPtg) {
+    			System.out.println("numoperands: " + ((OperationPtg) ptgs[i]).getNumberOfOperands());
+    		}
+    		System.out.println("</ptg>");
+		}
+	}
+	
+	/**
+	 * returns the string value resulting from teh evaluation of the formula
+	 * @param formula
+	 * @param sheet
+	 * @param workbook
+	 * @return
+	 */
+	public static String evaluateToString(String formula, HSSFSheet sheet, HSSFWorkbook workbook) {
+    	String retval = null;
+    	Eval value = evaluate(formula, sheet, workbook);
+    	if (value instanceof NumericValueEval) {
+    	    NumericValueEval ne = (NumericValueEval) value;
+    		retval = String.valueOf(ne.getNumberValue());
+    	}
+    	else if (value instanceof StringValueEval) {
+    	    StringValueEval se = (StringValueEval) value;
+    		retval = se.getStringValue();
+    	}
+    	else {
+    		retval = value.getClass().getName();
+    	}
+    	return retval;
+	}
+
+	/**
+	 * evaluates a formula!!! :)
+	 * @param formula
+	 * @param sheet
+	 * @param workbook
+	 * @return
+	 */
+	private static Eval evaluate(String formula, HSSFSheet sheet, HSSFWorkbook workbook) {
+		FormulaParser parser = new FormulaParser(formula, workbook.getWorkbook());
+		parser.parse();
+		Ptg[] ptgs = parser.getRPNPtg();
+		// -- parsing over --
+		
+    	Stack stack = new Stack();
+    	for (int i=0, iSize=ptgs.length; i<iSize; i++) {
+			if (ptgs[i] instanceof ControlPtg) {continue;}
+			if (ptgs[i] instanceof MemErrPtg) {continue;}
+			if (ptgs[i] instanceof MissingArgPtg) {continue;}
+			if (ptgs[i] instanceof NamePtg) {continue;}
+			if (ptgs[i] instanceof NameXPtg) {continue;}
+			if (ptgs[i] instanceof UnknownPtg) {continue;}
+
+			
+    		if (ptgs[i] instanceof OperationPtg) {
+    			OperationPtg optg = (OperationPtg) ptgs[i];
+
+    			if (optg instanceof ParenthesisPtg) {continue;}
+    			if (optg instanceof AttrPtg) {continue;}
+    			if (optg instanceof UnionPtg) {continue;}
+    			
+    			OperationEval operation = (OperationEval) getOperationEvalForPtg(optg);
+    			
+    			int numops = operation.getNumberOfOperands();
+    			Eval[] ops = new Eval[numops];
+    			for (int j=numops-1; j>=0; j--) { // storing the ops in reverse order since they are popping ;)
+    				Eval p = (Eval) stack.pop();
+    				ops[j] = p;
+    			}
+    			Eval opresult = operation.evaluate(ops);
+    			stack.push(opresult);
+    		}
+    		else if (ptgs[i] instanceof ReferencePtg) {
+    			ReferencePtg ptg = (ReferencePtg) ptgs[i];
+    			short colnum = ptg.getColumn();
+    			short rownum = ptg.getRow();
+    			HSSFRow row = sheet.getRow(rownum);
+    			HSSFCell cell = (row!=null) ? row.getCell(colnum) : null;
+    			pushRef2DEval(ptg, stack, cell, sheet, workbook);
+    		}
+    		else if (ptgs[i] instanceof Ref3DPtg) {
+    		    Ref3DPtg ptg = (Ref3DPtg) ptgs[i];
+    			short colnum = ptg.getColumn();
+    			short rownum = ptg.getRow();
+    			HSSFSheet xsheet = workbook.getSheetAt(ptg.getExternSheetIndex());
+    			HSSFRow row = sheet.getRow(rownum);
+    			HSSFCell cell = (row!=null) ? row.getCell(colnum) : null;
+    			pushRef3DEval(ptg, stack, cell, sheet, workbook);
+    		}
+    		else if (ptgs[i] instanceof AreaPtg) {
+				AreaPtg ap = (AreaPtg) ptgs[i];
+				short row0 = ap.getFirstRow();
+				short col0 = ap.getFirstColumn();
+				short row1 = ap.getLastRow();
+				short col1 = ap.getLastColumn();
+				ValueEval[] values = new ValueEval[(row1-row0+1)*(col1-col0+1)];
+				for (short x=row0; sheet!=null && x<row1+1; x++) {
+					HSSFRow row = sheet.getRow(x);
+					for (short y=col0; row!=null && y<col1+1; y++) {
+						values[(x-row0)*(col1-col0+1)+(y-col0)] = getEvalForCell(row.getCell(y), sheet, workbook);
+					}
+				}
+				AreaEval ae = new Area2DEval(ap, values);
+				stack.push(ae);
+    		}
+    		else if (ptgs[i] instanceof Area3DPtg) {
+				Area3DPtg a3dp = (Area3DPtg) ptgs[i];
+				short row0 = a3dp.getFirstRow();
+				short col0 = a3dp.getFirstColumn();
+				short row1 = a3dp.getLastRow();
+				short col1 = a3dp.getLastColumn();
+				HSSFSheet xsheet = workbook.getSheetAt(a3dp.getExternSheetIndex());
+				ValueEval[] values = new ValueEval[(row1-row0+1)*(col1-col0+1)];
+				for (short x=row0; sheet!=null && x<row1+1; x++) {
+					HSSFRow row = sheet.getRow(x);
+					for (short y=col0; row!=null && y<col1+1; y++) {
+						values[(x-row0)*(col1-col0+1)+(y-col0)] = getEvalForCell(row.getCell(y), sheet, workbook);
+					}
+				}
+				AreaEval ae = new Area3DEval(a3dp, values);
+				stack.push(ae);
+    		}
+    		else {
+    		    Eval ptgEval = getEvalForPtg(ptgs[i]);
+    			stack.push(ptgEval);
+    		}
+    	}
+    	Eval value = ((Eval) stack.pop());
+    	if (value instanceof RefEval) {
+    	    RefEval rv = (RefEval) value;
+    	    value = rv.getInnerValueEval();
+    	}
+    	return value;
+	}
+	
+	protected static Eval getOperationEvalForPtg(OperationPtg ptg) {
+	    Eval retval = null;
+	    
+	    Class clazz = (Class) OPERATION_EVALS_MAP.get(ptg.getClass());
+	    try {
+		    Constructor constructor = clazz.getConstructor(OPERATION_CONTRUCTOR_CLASS_ARRAY);
+		    retval = (OperationEval) constructor.newInstance(new Ptg[]{ptg});
+	    }
+	    catch (Exception e) {throw new RuntimeException("Fatal Error: ", e);}
+	    return retval;
+	}
+	
+	
+	/**
+	 * returns an appropriate Eval impl instance for the Ptg.
+	 * The Ptg must be one of: 
+	 * Area3DPtg, AreaPtg, ReferencePtg, Ref3DPtg, IntPtg, 
+	 * NumberPtg, StringPtg, BoolPtg
+	 * <br/>
+	 * special Note: OperationPtg subtypes cannot be passed here!
+	 * @param ptg
+	 * @return
+	 */
+	protected static Eval getEvalForPtg(Ptg ptg) {
+	    Eval retval = null;
+	    
+	    Class clazz = (Class) VALUE_EVALS_MAP.get(ptg.getClass());
+        try {
+            if (ptg instanceof Area3DPtg) {
+                Constructor constructor = clazz.getConstructor(AREA3D_CONSTRUCTOR_CLASS_ARRAY);
+                retval = (OperationEval) constructor.newInstance(new Ptg[]{ptg});
+            }
+            else if (ptg instanceof AreaPtg) {
+                Constructor constructor = clazz.getConstructor(AREA3D_CONSTRUCTOR_CLASS_ARRAY);
+                retval = (OperationEval) constructor.newInstance(new Ptg[]{ptg});
+            }
+            else if (ptg instanceof ReferencePtg) {
+                Constructor constructor = clazz.getConstructor(REFERENCE_CONSTRUCTOR_CLASS_ARRAY);
+                retval = (OperationEval) constructor.newInstance(new Ptg[]{ptg});
+            }
+            else if (ptg instanceof Ref3DPtg) {
+                Constructor constructor = clazz.getConstructor(REF3D_CONSTRUCTOR_CLASS_ARRAY);
+                retval = (OperationEval) constructor.newInstance(new Ptg[]{ptg});
+            }
+            else {
+                if (ptg instanceof IntPtg
+                 || ptg instanceof NumberPtg
+                 || ptg instanceof StringPtg
+                 || ptg instanceof BoolPtg
+                 ) {
+                    Constructor constructor = clazz.getConstructor(VALUE_CONTRUCTOR_CLASS_ARRAY);
+            	    retval = (ValueEval) constructor.newInstance(new Ptg[]{ptg});
+                }
+            }
+        } catch (Exception e) {
+            throw new RuntimeException("Fatal Error: ", e);
+        }
+        return retval;
+
+	}
+	
+	/**
+	 * Given a cell, find its type and from that create an appropriate ValueEval impl instance
+	 * and return that. Since the cell could be an external reference, we need the sheet that
+	 * this belongs to.
+	 * @param cell
+	 * @param sheet
+	 * @param workbook
+	 * @return
+	 */
+	protected static ValueEval getEvalForCell(HSSFCell cell, HSSFSheet sheet, HSSFWorkbook workbook) {
+		ValueEval retval = null;
+		if (cell != null) {
+			switch (cell.getCellType()) {
+			case HSSFCell.CELL_TYPE_NUMERIC:
+				retval = new NumberEval(cell.getNumericCellValue());
+				break;
+			case HSSFCell.CELL_TYPE_STRING:
+				retval = new StringEval(cell.getStringCellValue());
+                break;
+			case HSSFCell.CELL_TYPE_FORMULA:
+				retval = (ValueEval) evaluate(cell.getCellFormula(), sheet, workbook);
+				break;
+			case HSSFCell.CELL_TYPE_BOOLEAN:
+				retval = new BoolEval(cell.getBooleanCellValue());
+				break;
+			case HSSFCell.CELL_TYPE_BLANK:
+			    retval = new StringEval("");
+				break;
+			case HSSFCell.CELL_TYPE_ERROR:
+				retval = ErrorEval.ERROR_UNKNOWN; // TODO: think about this...
+				break;
+			}
+		}
+		return retval;
+	}
+	
+	/**
+	 * create a Ref2DEval for ReferencePtg and push it on the stack.
+	 * @param ptg
+	 * @param stack
+	 * @param cell
+	 * @param sheet
+	 * @param workbook
+	 */
+	protected static void pushRef2DEval(ReferencePtg ptg, Stack stack, HSSFCell cell, HSSFSheet sheet, HSSFWorkbook workbook) {
+	    if (cell!=null)
+	    switch (cell.getCellType()) {
+		case HSSFCell.CELL_TYPE_NUMERIC:
+			stack.push(new Ref2DEval(ptg, new NumberEval(cell.getNumericCellValue())));
+			break;
+		case HSSFCell.CELL_TYPE_STRING:
+			stack.push(new Ref2DEval(ptg, new StringEval(cell.getStringCellValue())));
+			break;
+		case HSSFCell.CELL_TYPE_FORMULA:
+			stack.push(evaluate(cell.getCellFormula(), sheet, workbook));
+			break;
+		case HSSFCell.CELL_TYPE_BOOLEAN:
+			stack.push(new Ref2DEval(ptg, new BoolEval(cell.getBooleanCellValue())));
+			break;
+		case HSSFCell.CELL_TYPE_BLANK:
+			stack.push(new Ref2DEval(ptg, new StringEval("")));
+			break;
+		case HSSFCell.CELL_TYPE_ERROR:
+			stack.push(new Ref2DEval(ptg, ErrorEval.ERROR_UNKNOWN)); // TODO: think about this...
+			break;
+		}
+	    else {
+	        stack.push(new Ref2DEval(ptg, new StringEval("")));
+	    }
+	}
+
+	/**
+	 * create a Ref3DEval for Ref3DPtg and push it on the stack.
+	 * @param ptg
+	 * @param stack
+	 * @param cell
+	 * @param sheet
+	 * @param workbook
+	 */
+	protected static void pushRef3DEval(Ref3DPtg ptg, Stack stack, HSSFCell cell, HSSFSheet sheet, HSSFWorkbook workbook) {
+		if (cell!=null)
+	    switch (cell.getCellType()) {
+		case HSSFCell.CELL_TYPE_NUMERIC:
+			stack.push(new Ref3DEval(ptg, new NumberEval(cell.getNumericCellValue())));
+			break;
+		case HSSFCell.CELL_TYPE_STRING:
+			stack.push(new Ref3DEval(ptg, new StringEval(cell.getStringCellValue())));
+			break;
+		case HSSFCell.CELL_TYPE_FORMULA:
+			stack.push(evaluate(cell.getCellFormula(), sheet, workbook));
+			break;
+		case HSSFCell.CELL_TYPE_BOOLEAN:
+			stack.push(new Ref3DEval(ptg, new BoolEval(cell.getBooleanCellValue())));
+			break;
+		case HSSFCell.CELL_TYPE_BLANK:
+			stack.push(new Ref3DEval(ptg, new StringEval("")));
+			break;
+		case HSSFCell.CELL_TYPE_ERROR:
+			stack.push(new Ref3DEval(ptg, ErrorEval.ERROR_UNKNOWN)); // TODO: think about this...
+			break;
+		}
+		else {
+		    stack.push(new Ref3DEval(ptg, new StringEval("")));
+		}
+	}
+
+	
+	
+	/**
+	 * Manual testing... needs a c:/temp/test1.xls file to be present.
+	 * @param args
+	 * @throws Exception
+	 */
+    public static void main(String[] args) throws Exception {
+    	String FILE_NAME = "c:/temp/test1.xls";
+    	
+    	FileInputStream fis = new FileInputStream(FILE_NAME);
+    	HSSFWorkbook wb = new HSSFWorkbook(fis);
+    	fis.close();
+    	HSSFSheet sheet = wb.getSheetAt(0);
+    	
+    	for (int rn=1, rnSize=4; rn<=rnSize; rn++) {
+        	HSSFRow row = sheet.getRow(rn);
+    	    for (int cn=5, cnSize=7; cn<=cnSize; cn++) {
+    	    	HSSFCell     	cell = row.getCell((short) cn);
+    	    	String formula = cell.getCellFormula();
+    	    	System.out.println("-----------------------------------------------------");
+    	    	//inspectPtgs(formula, sheet, wb);
+    	    	System.out.println("["+rn+","+cn+"]: "+evaluateToString(formula, sheet, wb));
+    	    	System.out.println("-----------------------------------------------------");
+    	    }
+    	}
+    }
+    
+}