Merged revisions 699178,699487,699489,699761 via svnmerge from

https://svn.apache.org/repos/asf/poi/trunk

........
  r699178 | josh | 2008-09-25 21:49:20 -0700 (Thu, 25 Sep 2008) | 1 line
  
  Changed HSSFEvaluationWorkbook to avoid re-parsing cell formulas during execution. (working towards fix for bug 45865)
........
  r699487 | josh | 2008-09-26 13:25:45 -0700 (Fri, 26 Sep 2008) | 1 line
  
  Fix formula parser to properly support the range operator. Small fixes to parsing of sheet names and full column references.
........
  r699489 | josh | 2008-09-26 13:32:06 -0700 (Fri, 26 Sep 2008) | 1 line
  
  Code cleanup in junit
........
  r699761 | josh | 2008-09-27 19:04:31 -0700 (Sat, 27 Sep 2008) | 1 line
  
  Bug 45865 - modified Formula Parser/Evaluator to handle cross-worksheet formulas
........


git-svn-id: https://svn.apache.org/repos/asf/poi/branches/ooxml@700234 13f79535-47bb-0310-9956-ffa450edef68

29 files changed, 1444 insertions, 738 deletions

diff --git a/src/java/org/apache/poi/hssf/model/LinkTable.java b/src/java/org/apache/poi/hssf/model/LinkTable.java
index 2caab0fb56..998712e5e8 100755
--- a/src/java/org/apache/poi/hssf/model/LinkTable.java
+++ b/src/java/org/apache/poi/hssf/model/LinkTable.java
@@ -29,6 +29,7 @@ import org.apache.poi.hssf.record.ExternalNameRecord;
 import org.apache.poi.hssf.record.NameRecord;
 import org.apache.poi.hssf.record.Record;
 import org.apache.poi.hssf.record.SupBookRecord;
+import org.apache.poi.hssf.record.UnicodeString;
 import org.apache.poi.hssf.record.formula.NameXPtg;
 
 /**
@@ -109,8 +110,8 @@ final class LinkTable {
 			temp.toArray(_crnBlocks);
 		}
 
-		public ExternalBookBlock(short numberOfSheets) {
-			_externalBookRecord = SupBookRecord.createInternalReferences(numberOfSheets);
+		public ExternalBookBlock(int numberOfSheets) {
+			_externalBookRecord = SupBookRecord.createInternalReferences((short)numberOfSheets);
 			_externalNameRecords = new ExternalNameRecord[0];
 			_crnBlocks = new CRNBlock[0];
 		}
@@ -197,7 +198,7 @@ final class LinkTable {
 		return ExternSheetRecord.combine(esrs);
 	}
 
-	public LinkTable(short numberOfSheets, WorkbookRecordList workbookRecordList) {
+	public LinkTable(int numberOfSheets, WorkbookRecordList workbookRecordList) {
 		_workbookRecordList = workbookRecordList;
 		_definedNames = new ArrayList();
 		_externalBookBlocks = new ExternalBookBlock[] {
@@ -303,8 +304,62 @@ final class LinkTable {
 		return lastName.getSheetNumber() == firstName.getSheetNumber();
 	}
 
-	
-	public int getIndexToSheet(int extRefIndex) {
+	public String[] getExternalBookAndSheetName(int extRefIndex) {
+		int ebIx = _externSheetRecord.getExtbookIndexFromRefIndex(extRefIndex);
+		SupBookRecord ebr = _externalBookBlocks[ebIx].getExternalBookRecord();
+		if (!ebr.isExternalReferences()) {
+			return null;
+		}
+		int shIx = _externSheetRecord.getFirstSheetIndexFromRefIndex(extRefIndex);
+		UnicodeString usSheetName = ebr.getSheetNames()[shIx];
+		return new String[] {
+				ebr.getURL(),
+				usSheetName.getString(),
+		};
+	}
+
+	public int getExternalSheetIndex(String workbookName, String sheetName) {
+		SupBookRecord ebrTarget = null;
+		int externalBookIndex = -1;
+		for (int i=0; i<_externalBookBlocks.length; i++) {
+			SupBookRecord ebr = _externalBookBlocks[i].getExternalBookRecord();
+			if (!ebr.isExternalReferences()) {
+				continue;
+			}
+			if (workbookName.equals(ebr.getURL())) { // not sure if 'equals()' works when url has a directory
+				ebrTarget = ebr;
+				externalBookIndex = i;
+				break;
+			}
+		}
+		if (ebrTarget == null) {
+			throw new RuntimeException("No external workbook with name '" + workbookName + "'");
+		}
+		int sheetIndex = getSheetIndex(ebrTarget.getSheetNames(), sheetName);
+		
+		int result = _externSheetRecord.getRefIxForSheet(externalBookIndex, sheetIndex);
+		if (result < 0) {
+			throw new RuntimeException("ExternSheetRecord does not contain combination (" 
+					+ externalBookIndex + ", " + sheetIndex + ")");
+		}
+		return result;
+	}
+
+	private static int getSheetIndex(UnicodeString[] sheetNames, String sheetName) {
+		for (int i = 0; i < sheetNames.length; i++) {
+			if (sheetNames[i].getString().equals(sheetName)) {
+				return i;
+			}
+			
+		}
+		throw new RuntimeException("External workbook does not contain sheet '" + sheetName + "'");
+	}
+
+	/**
+	 * @param extRefIndex as from a {@link Ref3DPtg} or {@link Area3DPtg}
+	 * @return -1 if the reference is to an external book
+	 */
+	public int getIndexToInternalSheet(int extRefIndex) {
 		return _externSheetRecord.getFirstSheetIndexFromRefIndex(extRefIndex);
 	}
 
@@ -315,20 +370,26 @@ final class LinkTable {
 		return _externSheetRecord.getFirstSheetIndexFromRefIndex(extRefIndex);
 	}
 
-	public int addSheetIndexToExternSheet(int sheetNumber) {
-		// TODO - what about the first parameter (extBookIndex)?
-		return _externSheetRecord.addRef(0, sheetNumber, sheetNumber);
-	}
-
-	public short checkExternSheet(int sheetIndex) {
+	public int checkExternSheet(int sheetIndex) {
+		int thisWbIndex = -1; // this is probably always zero
+		for (int i=0; i<_externalBookBlocks.length; i++) {
+			SupBookRecord ebr = _externalBookBlocks[i].getExternalBookRecord();
+			if (ebr.isInternalReferences()) {
+				thisWbIndex = i;
+				break;
+			}
+		}
+		if (thisWbIndex < 0) {
+			throw new RuntimeException("Could not find 'internal references' EXTERNALBOOK");
+		}
 
 		//Trying to find reference to this sheet
-		int i = _externSheetRecord.getRefIxForSheet(sheetIndex);
+		int i = _externSheetRecord.getRefIxForSheet(thisWbIndex, sheetIndex);
 		if (i>=0) {
-			return (short)i;
+			return i;
 		}
-		//We Haven't found reference to this sheet
-		return (short)addSheetIndexToExternSheet((short) sheetIndex);
+		//We haven't found reference to this sheet
+		return _externSheetRecord.addRef(thisWbIndex, sheetIndex, sheetIndex);
 	}
 
 
diff --git a/src/java/org/apache/poi/hssf/model/Workbook.java b/src/java/org/apache/poi/hssf/model/Workbook.java
index dbf7ecf7e1..0728d0e29f 100644
--- a/src/java/org/apache/poi/hssf/model/Workbook.java
+++ b/src/java/org/apache/poi/hssf/model/Workbook.java
@@ -26,6 +26,7 @@ import org.apache.poi.ddf.*;
 import org.apache.poi.hssf.record.*;
 import org.apache.poi.hssf.record.formula.NameXPtg;
 import org.apache.poi.hssf.util.HSSFColor;
+import org.apache.poi.ss.formula.EvaluationWorkbook.ExternalSheet;
 import org.apache.poi.util.POILogFactory;
 import org.apache.poi.util.POILogger;
 
@@ -328,9 +329,9 @@ public final class Workbook implements Model {
         for ( int k = 0; k < nBoundSheets; k++ ) {   
             BoundSheetRecord bsr = retval.createBoundSheet(k);
 
-			records.add(bsr);
-			retval.boundsheets.add(bsr);
-			retval.records.setBspos(records.size() - 1);
+            records.add(bsr);
+            retval.boundsheets.add(bsr);
+            retval.records.setBspos(records.size() - 1);
         }
         // retval.records.supbookpos = retval.records.bspos + 1;
         //        retval.records.namepos = retval.records.supbookpos + 2;
@@ -586,19 +587,19 @@ public final class Workbook implements Model {
      * @param hidden 0 for not hidden, 1 for hidden, 2 for very hidden
      */
     public void setSheetHidden(int sheetnum, int hidden) {
-    	BoundSheetRecord bsr = getBoundSheetRec(sheetnum);
-    	boolean h = false;
-    	boolean vh = false;
-    	if(hidden == 0) {
-    	} else if(hidden == 1) {
-    		h = true;
-    	} else if(hidden == 2) {
-    		vh = true;
-    	} else {
-    		throw new IllegalArgumentException("Invalid hidden flag " + hidden + " given, must be 0, 1 or 2");
-    	}
-    	bsr.setHidden(h);
-    	bsr.setVeryHidden(vh);
+        BoundSheetRecord bsr = getBoundSheetRec(sheetnum);
+        boolean h = false;
+        boolean vh = false;
+        if(hidden == 0) {
+        } else if(hidden == 1) {
+            h = true;
+        } else if(hidden == 2) {
+            vh = true;
+        } else {
+            throw new IllegalArgumentException("Invalid hidden flag " + hidden + " given, must be 0, 1 or 2");
+        }
+        bsr.setHidden(h);
+        bsr.setVeryHidden(vh);
     }
     
     
@@ -761,23 +762,23 @@ public final class Workbook implements Model {
      *  have a Style set.
      */
     public StyleRecord getStyleRecord(int xfIndex) {
-    	// Style records always follow after 
-    	//  the ExtendedFormat records
-    	boolean done = false;
-    	for(int i=records.getXfpos(); i<records.size() &&
-    			!done; i++) {
-    		Record r = records.get(i);
-    		if(r instanceof ExtendedFormatRecord) {
-    		} else if(r instanceof StyleRecord) {
-    			StyleRecord sr = (StyleRecord)r;
-    			if(sr.getIndex() == xfIndex) {
-    				return sr;
-    			}
-    		} else {
-    			done = true;
-    		}
-    	}
-    	return null;
+        // Style records always follow after 
+        //  the ExtendedFormat records
+        boolean done = false;
+        for(int i=records.getXfpos(); i<records.size() &&
+                !done; i++) {
+            Record r = records.get(i);
+            if(r instanceof ExtendedFormatRecord) {
+            } else if(r instanceof StyleRecord) {
+                StyleRecord sr = (StyleRecord)r;
+                if(sr.getIndex() == xfIndex) {
+                    return sr;
+                }
+            } else {
+                done = true;
+            }
+        }
+        return null;
     }
     /**
      * Creates a new StyleRecord, for the given Extended
@@ -785,29 +786,29 @@ public final class Workbook implements Model {
      *  records collection
      */
     public StyleRecord createStyleRecord(int xfIndex) {
-    	// Style records always follow after 
-    	//  the ExtendedFormat records
-    	StyleRecord newSR = new StyleRecord();
-    	newSR.setIndex((short)xfIndex);
-    	
-    	// Find the spot
-    	int addAt = -1;
-    	for(int i=records.getXfpos(); i<records.size() &&
-    			addAt == -1; i++) {
-    		Record r = records.get(i);
-    		if(r instanceof ExtendedFormatRecord ||
-    				r instanceof StyleRecord) {
-    			// Keep going
-    		} else {
-    			addAt = i;
-    		}
-    	}
-    	if(addAt == -1) {
-    		throw new IllegalStateException("No XF Records found!");
-    	}
-    	records.add(addAt, newSR);
-    	
-    	return newSR;
+        // Style records always follow after 
+        //  the ExtendedFormat records
+        StyleRecord newSR = new StyleRecord();
+        newSR.setIndex((short)xfIndex);
+        
+        // Find the spot
+        int addAt = -1;
+        for(int i=records.getXfpos(); i<records.size() &&
+                addAt == -1; i++) {
+            Record r = records.get(i);
+            if(r instanceof ExtendedFormatRecord ||
+                    r instanceof StyleRecord) {
+                // Keep going
+            } else {
+                addAt = i;
+            }
+        }
+        if(addAt == -1) {
+            throw new IllegalStateException("No XF Records found!");
+        }
+        records.add(addAt, newSR);
+        
+        return newSR;
     }
 
     /**
@@ -1914,8 +1915,7 @@ public final class Workbook implements Model {
      */
     public String findSheetNameFromExternSheet(int externSheetIndex){
 
-        int indexToSheet = linkTable.getIndexToSheet(externSheetIndex);
-        
+        int indexToSheet = linkTable.getIndexToInternalSheet(externSheetIndex);
         if (indexToSheet < 0) {
             // TODO - what does '-1' mean here?
             //error check, bail out gracefully!
@@ -1927,6 +1927,13 @@ public final class Workbook implements Model {
         }
         return getSheetName(indexToSheet);
     }
+    public ExternalSheet getExternalSheet(int externSheetIndex) {
+        String[] extNames = linkTable.getExternalBookAndSheetName(externSheetIndex);
+        if (extNames == null) {
+            return null;
+        }
+        return new ExternalSheet(extNames[0], extNames[1]);
+    }
 
     /**
      * Finds the sheet index for a particular external sheet number.
@@ -1944,9 +1951,14 @@ public final class Workbook implements Model {
      * @return index to extern sheet
      */
     public short checkExternSheet(int sheetNumber){
-        return getOrCreateLinkTable().checkExternSheet(sheetNumber);
+        return (short)getOrCreateLinkTable().checkExternSheet(sheetNumber);
     }
 
+	public int getExternalSheetIndex(String workbookName, String sheetName) {
+		return getOrCreateLinkTable().getExternalSheetIndex(workbookName, sheetName);
+	}
+    
+
     /** gets the total number of names
      * @return number of names
      */
diff --git a/src/java/org/apache/poi/hssf/record/ExternSheetRecord.java b/src/java/org/apache/poi/hssf/record/ExternSheetRecord.java
index c4f00581b2..64f86c3f12 100644
--- a/src/java/org/apache/poi/hssf/record/ExternSheetRecord.java
+++ b/src/java/org/apache/poi/hssf/record/ExternSheetRecord.java
@@ -250,10 +250,13 @@ public class ExternSheetRecord extends Record {
 		return _list.size() - 1;
 	}
 
-	public int getRefIxForSheet(int sheetIndex) {
+	public int getRefIxForSheet(int externalBookIndex, int sheetIndex) {
 		int nItems = _list.size();
 		for (int i = 0; i < nItems; i++) {
 			RefSubRecord ref = getRef(i);
+			if (ref.getExtBookIndex() != externalBookIndex) {
+				continue;
+			}
 			if (ref.getFirstSheetIndex() == sheetIndex && ref.getLastSheetIndex() == sheetIndex) {
 				return i;
 			}
diff --git a/src/java/org/apache/poi/hssf/record/SupBookRecord.java b/src/java/org/apache/poi/hssf/record/SupBookRecord.java
index c75e2db894..b4e46c6fdc 100644
--- a/src/java/org/apache/poi/hssf/record/SupBookRecord.java
+++ b/src/java/org/apache/poi/hssf/record/SupBookRecord.java
@@ -221,8 +221,33 @@ public final class SupBookRecord extends Record {
     {
         return sid;
     }
-    public UnicodeString getURL() {
-        return field_2_encoded_url;
+    public String getURL() {
+        String encodedUrl = field_2_encoded_url.getString();
+        switch(encodedUrl.charAt(0)) {
+            case 0: // Reference to an empty workbook name
+                return encodedUrl.substring(1); // will this just be empty string?
+            case 1: // encoded file name
+                return decodeFileName(encodedUrl);
+            case 2: // Self-referential external reference
+                return encodedUrl.substring(1);
+                
+        }
+        return encodedUrl;
+    }
+    private static String decodeFileName(String encodedUrl) {
+        return encodedUrl.substring(1);
+        // TODO the following special characters may appear in the rest of the string, and need to get interpreted
+        /* see "MICROSOFT OFFICE EXCEL 97-2007  BINARY FILE FORMAT SPECIFICATION"
+        chVolume  1 
+        chSameVolume  2 
+        chDownDir  3
+        chUpDir  4 
+        chLongVolume  5
+        chStartupDir  6
+        chAltStartupDir 7
+        chLibDir  8
+        
+        */
     }
     public UnicodeString[] getSheetNames() {
         return (UnicodeString[]) field_3_sheet_names.clone();
diff --git a/src/java/org/apache/poi/hssf/record/formula/Area3DPtg.java b/src/java/org/apache/poi/hssf/record/formula/Area3DPtg.java
index 9a538cf70d..58cdc5b275 100644
--- a/src/java/org/apache/poi/hssf/record/formula/Area3DPtg.java
+++ b/src/java/org/apache/poi/hssf/record/formula/Area3DPtg.java
@@ -18,8 +18,9 @@
 package org.apache.poi.hssf.record.formula;
 
 import org.apache.poi.hssf.record.RecordInputStream;
-import org.apache.poi.ss.formula.WorkbookDependentFormula;
+import org.apache.poi.ss.formula.ExternSheetReferenceToken;
 import org.apache.poi.ss.formula.FormulaRenderingWorkbook;
+import org.apache.poi.ss.formula.WorkbookDependentFormula;
 import org.apache.poi.util.LittleEndian;
 
 /**
@@ -31,7 +32,7 @@ import org.apache.poi.util.LittleEndian;
  * @author Jason Height (jheight at chariot dot net dot au)
  * @version 1.0-pre
  */
-public final class Area3DPtg extends AreaPtgBase implements WorkbookDependentFormula {
+public final class Area3DPtg extends AreaPtgBase implements WorkbookDependentFormula, ExternSheetReferenceToken {
 	public final static byte sid = 0x3b;
 	private final static int SIZE = 11; // 10 + 1 for Ptg
 	
@@ -76,8 +77,8 @@ public final class Area3DPtg extends AreaPtgBase implements WorkbookDependentFor
 		return SIZE;
 	}
 
-	public short getExternSheetIndex() {
-		return (short)field_1_index_extern_sheet;
+	public int getExternSheetIndex() {
+		return field_1_index_extern_sheet;
 	}
 
 	public void setExternSheetIndex(int index) {
diff --git a/src/java/org/apache/poi/hssf/record/formula/AreaI.java b/src/java/org/apache/poi/hssf/record/formula/AreaI.java
index 477d32f677..319a9819c9 100644
--- a/src/java/org/apache/poi/hssf/record/formula/AreaI.java
+++ b/src/java/org/apache/poi/hssf/record/formula/AreaI.java
@@ -50,10 +50,10 @@ public interface AreaI {
 
 		public OffsetArea(int baseRow, int baseColumn, int relFirstRowIx, int relLastRowIx,
 				int relFirstColIx, int relLastColIx) {
-			_firstRow = baseRow + relFirstRowIx;
-			_lastRow = baseRow + relLastRowIx;
-			_firstColumn = baseColumn + relFirstColIx;
-			_lastColumn = baseColumn + relLastColIx;
+			_firstRow = baseRow + Math.min(relFirstRowIx, relLastRowIx);
+			_lastRow = baseRow + Math.max(relFirstRowIx, relLastRowIx);
+			_firstColumn = baseColumn + Math.min(relFirstColIx, relLastColIx);
+			_lastColumn = baseColumn + Math.max(relFirstColIx, relLastColIx);
 		}
 
 		public int getFirstColumn() {
@@ -72,5 +72,4 @@ public interface AreaI {
 			return _lastRow;
 		}
 	}
-
 }
\ No newline at end of file
diff --git a/src/java/org/apache/poi/hssf/record/formula/AreaPtgBase.java b/src/java/org/apache/poi/hssf/record/formula/AreaPtgBase.java
index 7bfefc5526..a97ecd4f03 100644
--- a/src/java/org/apache/poi/hssf/record/formula/AreaPtgBase.java
+++ b/src/java/org/apache/poi/hssf/record/formula/AreaPtgBase.java
@@ -30,248 +30,264 @@ import org.apache.poi.util.LittleEndian;
  * @author Jason Height (jheight at chariot dot net dot au)
  */
 public abstract class AreaPtgBase extends OperandPtg implements AreaI {
-    /**
-     * TODO - (May-2008) fix subclasses of AreaPtg 'AreaN~' which are used in shared formulas.
-     * see similar comment in ReferencePtg
-     */
-    protected final RuntimeException notImplemented() {
-        return new RuntimeException("Coding Error: This method should never be called. This ptg should be converted");
-    }
+	/**
+	 * TODO - (May-2008) fix subclasses of AreaPtg 'AreaN~' which are used in shared formulas.
+	 * see similar comment in ReferencePtg
+	 */
+	protected final RuntimeException notImplemented() {
+		return new RuntimeException("Coding Error: This method should never be called. This ptg should be converted");
+	}
 
-    /** zero based, unsigned 16 bit */
-    private int             field_1_first_row;
-    /** zero based, unsigned 16 bit */
-    private int             field_2_last_row;
-    /** zero based, unsigned 8 bit */
-    private int             field_3_first_column;
-    /** zero based, unsigned 8 bit */
-    private int             field_4_last_column;
-    
-    private final static BitField   rowRelative = BitFieldFactory.getInstance(0x8000);
-    private final static BitField   colRelative = BitFieldFactory.getInstance(0x4000);
-    private final static BitField   columnMask      = BitFieldFactory.getInstance(0x3FFF);
+	/** zero based, unsigned 16 bit */
+	private int             field_1_first_row;
+	/** zero based, unsigned 16 bit */
+	private int             field_2_last_row;
+	/** zero based, unsigned 8 bit */
+	private int             field_3_first_column;
+	/** zero based, unsigned 8 bit */
+	private int             field_4_last_column;
+	
+	private final static BitField   rowRelative = BitFieldFactory.getInstance(0x8000);
+	private final static BitField   colRelative = BitFieldFactory.getInstance(0x4000);
+	private final static BitField   columnMask      = BitFieldFactory.getInstance(0x3FFF);
 
-    protected AreaPtgBase() {
-        // do nothing
-    }
-    
-    protected AreaPtgBase(String arearef) {
-        AreaReference ar = new AreaReference(arearef);
-        CellReference firstCell = ar.getFirstCell();
-        CellReference lastCell = ar.getLastCell();
-        setFirstRow(firstCell.getRow());
-        setFirstColumn(firstCell.getCol());
-        setLastRow(lastCell.getRow());
-        setLastColumn(lastCell.getCol());
-        setFirstColRelative(!firstCell.isColAbsolute());
-        setLastColRelative(!lastCell.isColAbsolute());
-        setFirstRowRelative(!firstCell.isRowAbsolute());
-        setLastRowRelative(!lastCell.isRowAbsolute());        
-    }
-    
-    protected AreaPtgBase(int firstRow, int lastRow, int firstColumn, int lastColumn,
-            boolean firstRowRelative, boolean lastRowRelative, boolean firstColRelative, boolean lastColRelative) {
-        
-        checkColumnBounds(firstColumn);
-        checkColumnBounds(lastColumn);
-        checkRowBounds(firstRow);
-        checkRowBounds(lastRow);
-      setFirstRow(firstRow);
-      setLastRow(lastRow);
-      setFirstColumn(firstColumn);
-      setLastColumn(lastColumn);
-      setFirstRowRelative(firstRowRelative);
-      setLastRowRelative(lastRowRelative);
-      setFirstColRelative(firstColRelative);
-      setLastColRelative(lastColRelative);
-    }    
+	protected AreaPtgBase() {
+		// do nothing
+	}
+	
+	protected AreaPtgBase(String arearef) {
+		AreaReference ar = new AreaReference(arearef);
+		CellReference firstCell = ar.getFirstCell();
+		CellReference lastCell = ar.getLastCell();
+		setFirstRow(firstCell.getRow());
+		setFirstColumn(firstCell.getCol());
+		setLastRow(lastCell.getRow());
+		setLastColumn(lastCell.getCol());
+		setFirstColRelative(!firstCell.isColAbsolute());
+		setLastColRelative(!lastCell.isColAbsolute());
+		setFirstRowRelative(!firstCell.isRowAbsolute());
+		setLastRowRelative(!lastCell.isRowAbsolute());        
+	}
+	
+	protected AreaPtgBase(int firstRow, int lastRow, int firstColumn, int lastColumn,
+			boolean firstRowRelative, boolean lastRowRelative, boolean firstColRelative, boolean lastColRelative) {
+		
+		checkColumnBounds(firstColumn);
+		checkColumnBounds(lastColumn);
+		checkRowBounds(firstRow);
+		checkRowBounds(lastRow);
+		
+		if (lastRow > firstRow) {
+			setFirstRow(firstRow);
+			setLastRow(lastRow);
+			setFirstRowRelative(firstRowRelative);
+			setLastRowRelative(lastRowRelative);
+		} else {
+			setFirstRow(lastRow);
+			setLastRow(firstRow);
+			setFirstRowRelative(lastRowRelative);
+			setLastRowRelative(firstRowRelative);
+		}
+			
+		if (lastColumn > firstColumn) {
+			setFirstColumn(firstColumn);
+			setLastColumn(lastColumn);
+			setFirstColRelative(firstColRelative);
+			setLastColRelative(lastColRelative);
+		} else {
+			setFirstColumn(lastColumn);
+			setLastColumn(firstColumn);
+			setFirstColRelative(lastColRelative);
+			setLastColRelative(firstColRelative);
+		}
+	}    
 
-    private static void checkColumnBounds(int colIx) {
-        if((colIx & 0x0FF) != colIx) {
-            throw new IllegalArgumentException("colIx (" + colIx + ") is out of range");
-        }
-    }
-    private static void checkRowBounds(int rowIx) {
-        if((rowIx & 0x0FFFF) != rowIx) {
-            throw new IllegalArgumentException("rowIx (" + rowIx + ") is out of range");
-        }
-    }
+	private static void checkColumnBounds(int colIx) {
+		if((colIx & 0x0FF) != colIx) {
+			throw new IllegalArgumentException("colIx (" + colIx + ") is out of range");
+		}
+	}
+	private static void checkRowBounds(int rowIx) {
+		if((rowIx & 0x0FFFF) != rowIx) {
+			throw new IllegalArgumentException("rowIx (" + rowIx + ") is out of range");
+		}
+	}
 
-    protected final void readCoordinates(RecordInputStream in) {
-        field_1_first_row = in.readUShort();
-        field_2_last_row = in.readUShort();
-        field_3_first_column = in.readUShort();
-        field_4_last_column = in.readUShort();
-    }
-    protected final void writeCoordinates(byte[] array, int offset) {
-        LittleEndian.putUShort(array, offset + 0, field_1_first_row);
-        LittleEndian.putUShort(array, offset + 2, field_2_last_row);
-        LittleEndian.putUShort(array, offset + 4, field_3_first_column);
-        LittleEndian.putUShort(array, offset + 6, field_4_last_column);        
-    }
+	protected final void readCoordinates(RecordInputStream in) {
+		field_1_first_row = in.readUShort();
+		field_2_last_row = in.readUShort();
+		field_3_first_column = in.readUShort();
+		field_4_last_column = in.readUShort();
+	}
+	protected final void writeCoordinates(byte[] array, int offset) {
+		LittleEndian.putUShort(array, offset + 0, field_1_first_row);
+		LittleEndian.putUShort(array, offset + 2, field_2_last_row);
+		LittleEndian.putUShort(array, offset + 4, field_3_first_column);
+		LittleEndian.putUShort(array, offset + 6, field_4_last_column);        
+	}
 
-    /**
-     * @return the first row in the area
-     */
-    public final int getFirstRow() {
-        return field_1_first_row;
-    }
+	/**
+	 * @return the first row in the area
+	 */
+	public final int getFirstRow() {
+		return field_1_first_row;
+	}
 
-    /**
-     * sets the first row
-     * @param rowIx number (0-based)
-     */
-    public final void setFirstRow(int rowIx) {
-        checkRowBounds(rowIx);
-        field_1_first_row = rowIx;
-    }
+	/**
+	 * sets the first row
+	 * @param rowIx number (0-based)
+	 */
+	public final void setFirstRow(int rowIx) {
+		checkRowBounds(rowIx);
+		field_1_first_row = rowIx;
+	}
 
-    /**
-     * @return last row in the range (x2 in x1,y1-x2,y2)
-     */
-    public final int getLastRow() {
-        return field_2_last_row;
-    }
+	/**
+	 * @return last row in the range (x2 in x1,y1-x2,y2)
+	 */
+	public final int getLastRow() {
+		return field_2_last_row;
+	}
 
-    /**
-     * @param rowIx last row number in the area 
-     */
-    public final void setLastRow(int rowIx) {
-        checkRowBounds(rowIx);
-        field_2_last_row = rowIx;
-    }
+	/**
+	 * @param rowIx last row number in the area 
+	 */
+	public final void setLastRow(int rowIx) {
+		checkRowBounds(rowIx);
+		field_2_last_row = rowIx;
+	}
 
-    /**
-     * @return the first column number in the area.
-     */
-    public final int getFirstColumn() {
-        return columnMask.getValue(field_3_first_column);
-    }
+	/**
+	 * @return the first column number in the area.
+	 */
+	public final int getFirstColumn() {
+		return columnMask.getValue(field_3_first_column);
+	}
 
-    /**
-     * @return the first column number + the options bit settings unstripped
-     */
-    public final short getFirstColumnRaw() {
-        return (short) field_3_first_column; // TODO
-    }
+	/**
+	 * @return the first column number + the options bit settings unstripped
+	 */
+	public final short getFirstColumnRaw() {
+		return (short) field_3_first_column; // TODO
+	}
 
-    /**
-     * @return whether or not the first row is a relative reference or not.
-     */
-    public final boolean isFirstRowRelative() {
-        return rowRelative.isSet(field_3_first_column);
-    }
-    
-    /**
-     * sets the first row to relative or not
-     * @param rel is relative or not.
-     */
-    public final void setFirstRowRelative(boolean rel) {
-        field_3_first_column=rowRelative.setBoolean(field_3_first_column,rel);
-    }
+	/**
+	 * @return whether or not the first row is a relative reference or not.
+	 */
+	public final boolean isFirstRowRelative() {
+		return rowRelative.isSet(field_3_first_column);
+	}
+	
+	/**
+	 * sets the first row to relative or not
+	 * @param rel is relative or not.
+	 */
+	public final void setFirstRowRelative(boolean rel) {
+		field_3_first_column=rowRelative.setBoolean(field_3_first_column,rel);
+	}
 
-    /**
-     * @return isrelative first column to relative or not
-     */
-    public final boolean isFirstColRelative() {
-        return colRelative.isSet(field_3_first_column);
-    }
-    
-    /**
-     * set whether the first column is relative 
-     */
-    public final void setFirstColRelative(boolean rel) {
-        field_3_first_column=colRelative.setBoolean(field_3_first_column,rel);
-    }
+	/**
+	 * @return isrelative first column to relative or not
+	 */
+	public final boolean isFirstColRelative() {
+		return colRelative.isSet(field_3_first_column);
+	}
+	
+	/**
+	 * set whether the first column is relative 
+	 */
+	public final void setFirstColRelative(boolean rel) {
+		field_3_first_column=colRelative.setBoolean(field_3_first_column,rel);
+	}
 
-    /**
-     * set the first column in the area
-     */
-    public final void setFirstColumn(int colIx) {
-        checkColumnBounds(colIx);
-        field_3_first_column=columnMask.setValue(field_3_first_column, colIx);
-    }
+	/**
+	 * set the first column in the area
+	 */
+	public final void setFirstColumn(int colIx) {
+		checkColumnBounds(colIx);
+		field_3_first_column=columnMask.setValue(field_3_first_column, colIx);
+	}
 
-    /**
-     * set the first column irrespective of the bitmasks
-     */
-    public final void setFirstColumnRaw(int column) {
-        field_3_first_column = column;
-    }
+	/**
+	 * set the first column irrespective of the bitmasks
+	 */
+	public final void setFirstColumnRaw(int column) {
+		field_3_first_column = column;
+	}
 
-    /**
-     * @return lastcolumn in the area
-     */
-    public final int getLastColumn() {
-        return columnMask.getValue(field_4_last_column);
-    }
+	/**
+	 * @return lastcolumn in the area
+	 */
+	public final int getLastColumn() {
+		return columnMask.getValue(field_4_last_column);
+	}
 
-    /**
-     * @return last column and bitmask (the raw field)
-     */
-    public final short getLastColumnRaw() {
-        return (short) field_4_last_column;
-    }
+	/**
+	 * @return last column and bitmask (the raw field)
+	 */
+	public final short getLastColumnRaw() {
+		return (short) field_4_last_column;
+	}
 
-    /**
-     * @return last row relative or not
-     */
-    public final boolean isLastRowRelative() {
-        return rowRelative.isSet(field_4_last_column);
-    }
-    
-    /**
-     * set whether the last row is relative or not
-     * @param rel <code>true</code> if the last row relative, else
-     * <code>false</code>
-     */
-    public final void setLastRowRelative(boolean rel) {
-        field_4_last_column=rowRelative.setBoolean(field_4_last_column,rel);
-    }
+	/**
+	 * @return last row relative or not
+	 */
+	public final boolean isLastRowRelative() {
+		return rowRelative.isSet(field_4_last_column);
+	}
+	
+	/**
+	 * set whether the last row is relative or not
+	 * @param rel <code>true</code> if the last row relative, else
+	 * <code>false</code>
+	 */
+	public final void setLastRowRelative(boolean rel) {
+		field_4_last_column=rowRelative.setBoolean(field_4_last_column,rel);
+	}
 
-    /**
-     * @return lastcol relative or not
-     */
-    public final boolean isLastColRelative() {
-        return colRelative.isSet(field_4_last_column);
-    }
-    
-    /**
-     * set whether the last column should be relative or not
-     */
-    public final void setLastColRelative(boolean rel) {
-        field_4_last_column=colRelative.setBoolean(field_4_last_column,rel);
-    }
-    
-    /**
-     * set the last column in the area
-     */
-    public final void setLastColumn(int colIx) {
-        checkColumnBounds(colIx);
-        field_4_last_column=columnMask.setValue(field_4_last_column, colIx);
-    }
+	/**
+	 * @return lastcol relative or not
+	 */
+	public final boolean isLastColRelative() {
+		return colRelative.isSet(field_4_last_column);
+	}
+	
+	/**
+	 * set whether the last column should be relative or not
+	 */
+	public final void setLastColRelative(boolean rel) {
+		field_4_last_column=colRelative.setBoolean(field_4_last_column,rel);
+	}
+	
+	/**
+	 * set the last column in the area
+	 */
+	public final void setLastColumn(int colIx) {
+		checkColumnBounds(colIx);
+		field_4_last_column=columnMask.setValue(field_4_last_column, colIx);
+	}
 
-    /**
-     * set the last column irrespective of the bitmasks
-     */
-    public final void setLastColumnRaw(short column) {
-        field_4_last_column = column;
-    }
-    protected final String formatReferenceAsString() {
-        CellReference topLeft = new CellReference(getFirstRow(),getFirstColumn(),!isFirstRowRelative(),!isFirstColRelative());
-        CellReference botRight = new CellReference(getLastRow(),getLastColumn(),!isLastRowRelative(),!isLastColRelative());
-        
-        if(AreaReference.isWholeColumnReference(topLeft, botRight)) {
-            return (new AreaReference(topLeft, botRight)).formatAsString();
-        }
-        return topLeft.formatAsString() + ":" + botRight.formatAsString(); 
-    }
-    
-    public String toFormulaString() {
-        return formatReferenceAsString();
-    }
+	/**
+	 * set the last column irrespective of the bitmasks
+	 */
+	public final void setLastColumnRaw(short column) {
+		field_4_last_column = column;
+	}
+	protected final String formatReferenceAsString() {
+		CellReference topLeft = new CellReference(getFirstRow(),getFirstColumn(),!isFirstRowRelative(),!isFirstColRelative());
+		CellReference botRight = new CellReference(getLastRow(),getLastColumn(),!isLastRowRelative(),!isLastColRelative());
+		
+		if(AreaReference.isWholeColumnReference(topLeft, botRight)) {
+			return (new AreaReference(topLeft, botRight)).formatAsString();
+		}
+		return topLeft.formatAsString() + ":" + botRight.formatAsString(); 
+	}
+	
+	public String toFormulaString() {
+		return formatReferenceAsString();
+	}
 
-    public byte getDefaultOperandClass() {
-        return Ptg.CLASS_REF;
-    }
+	public byte getDefaultOperandClass() {
+		return Ptg.CLASS_REF;
+	}
 }
diff --git a/src/java/org/apache/poi/hssf/record/formula/AttrPtg.java b/src/java/org/apache/poi/hssf/record/formula/AttrPtg.java
index 34558ebdf8..701a7aee74 100644
--- a/src/java/org/apache/poi/hssf/record/formula/AttrPtg.java
+++ b/src/java/org/apache/poi/hssf/record/formula/AttrPtg.java
@@ -34,13 +34,13 @@ public final class AttrPtg extends ControlPtg {
     private final static int  SIZE = 4;
     private byte              field_1_options;
     private short             field_2_data;
-    
+
     /** only used for tAttrChoose: table of offsets to starts of args */
     private final int[] _jumpTable;
     /** only used for tAttrChoose: offset to the tFuncVar for CHOOSE() */
     private final int   _chooseFuncOffset;
-    
-    // flags 'volatile' and 'space', can be combined.  
+
+    // flags 'volatile' and 'space', can be combined.
     // OOO spec says other combinations are theoretically possible but not likely to occur.
     private static final BitField semiVolatile = BitFieldFactory.getInstance(0x01);
     private static final BitField optiIf       = BitFieldFactory.getInstance(0x02);
@@ -49,12 +49,14 @@ public final class AttrPtg extends ControlPtg {
     private static final BitField sum          = BitFieldFactory.getInstance(0x10);
     private static final BitField baxcel       = BitFieldFactory.getInstance(0x20); // 'assignment-style formula in a macro sheet'
     private static final BitField space        = BitFieldFactory.getInstance(0x40);
-    
+
+    public static final AttrPtg SUM = new AttrPtg(0x0010, 0, null, -1);
+
     public static final class SpaceType {
         private SpaceType() {
             // no instances of this class
         }
-        
+
         /** 00H = Spaces before the next token (not allowed before tParen token) */
         public static final int SPACE_BEFORE = 0x00;
         /** 01H = Carriage returns before the next token (not allowed before tParen token) */
@@ -75,7 +77,7 @@ public final class AttrPtg extends ControlPtg {
         _jumpTable = null;
         _chooseFuncOffset = -1;
     }
-    
+
     public AttrPtg(RecordInputStream in)
     {
         field_1_options = in.readByte();
@@ -92,7 +94,7 @@ public final class AttrPtg extends ControlPtg {
             _jumpTable = null;
             _chooseFuncOffset = -1;
         }
-        
+
     }
     private AttrPtg(int options, int data, int[] jt, int chooseFuncOffset) {
         field_1_options = (byte) options;
@@ -100,7 +102,7 @@ public final class AttrPtg extends ControlPtg {
         _jumpTable = jt;
         _chooseFuncOffset = chooseFuncOffset;
     }
-    
+
     /**
      * @param type a constant from <tt>SpaceType</tt>
      * @param count the number of space characters
@@ -145,7 +147,7 @@ public final class AttrPtg extends ControlPtg {
     {
         return sum.isSet(getOptions());
     }
-    
+
     public void setSum(boolean bsum) {
         field_1_options=sum.setByteBoolean(field_1_options,bsum);
     }
@@ -155,13 +157,13 @@ public final class AttrPtg extends ControlPtg {
     }
 
     /**
-     * Flags this ptg as a goto/jump 
+     * Flags this ptg as a goto/jump
      * @param isGoto
      */
     public void setGoto(boolean isGoto) {
         field_1_options=optGoto.setByteBoolean(field_1_options, isGoto);
     }
-    
+
     // lets hope no one uses this anymore
     public boolean isBaxcel()
     {
@@ -201,7 +203,7 @@ public final class AttrPtg extends ControlPtg {
         } else if(isOptimizedChoose()) {
             sb.append("choose nCases=").append(getData());
         } else if(isGoto()) {
-            sb.append("skip dist=").append(getData()); 
+            sb.append("skip dist=").append(getData());
         } else if(isSum()) {
             sb.append("sum ");
         } else if(isBaxcel()) {
@@ -218,7 +220,7 @@ public final class AttrPtg extends ControlPtg {
         LittleEndian.putShort(array,offset+2, field_2_data);
         int[] jt = _jumpTable;
         if (jt != null) {
-            int joff = offset+4; 
+            int joff = offset+4;
             LittleEndian.putUShort(array, joff, _chooseFuncOffset);
             joff+=2;
             for (int i = 0; i < jt.length; i++) {
@@ -227,7 +229,7 @@ public final class AttrPtg extends ControlPtg {
             }
             LittleEndian.putUShort(array, joff, _chooseFuncOffset);
         }
-        
+
     }
 
     public int getSize()
@@ -249,7 +251,7 @@ public final class AttrPtg extends ControlPtg {
             return toFormulaString() + "(" + operands[ 0 ] + ")";
         }
     }
-  
+
 
     public int getNumberOfOperands()
     {
@@ -260,7 +262,7 @@ public final class AttrPtg extends ControlPtg {
     {
         return -1;
     }
-        
+
    public String toFormulaString() {
       if(semiVolatile.isSet(field_1_options)) {
         return "ATTR(semiVolatile)";
diff --git a/src/java/org/apache/poi/hssf/record/formula/ExternSheetNameResolver.java b/src/java/org/apache/poi/hssf/record/formula/ExternSheetNameResolver.java
index 412c110d3a..dadbcb8702 100644
--- a/src/java/org/apache/poi/hssf/record/formula/ExternSheetNameResolver.java
+++ b/src/java/org/apache/poi/hssf/record/formula/ExternSheetNameResolver.java
@@ -18,6 +18,7 @@
 package org.apache.poi.hssf.record.formula;
 
 import org.apache.poi.ss.formula.FormulaRenderingWorkbook;
+import org.apache.poi.ss.formula.EvaluationWorkbook.ExternalSheet;
 
 /**
  * @author Josh Micich
@@ -29,13 +30,22 @@ final class ExternSheetNameResolver {
 	}
 
 	public static String prependSheetName(FormulaRenderingWorkbook book, int field_1_index_extern_sheet, String cellRefText) {
-		String sheetName = book.getSheetNameByExternSheet(field_1_index_extern_sheet);
-		StringBuffer sb = new StringBuffer(sheetName.length() + cellRefText.length() + 4);
-		if (sheetName.length() < 1) {
-			// What excel does if sheet has been deleted
-			sb.append("#REF"); // note - '!' added just once below
+		ExternalSheet externalSheet = book.getExternalSheet(field_1_index_extern_sheet);
+		StringBuffer sb;
+		if (externalSheet != null) {
+			String wbName = externalSheet.getWorkbookName();
+			String sheetName = externalSheet.getSheetName();
+			sb = new StringBuffer(wbName.length() + sheetName.length() + cellRefText.length() + 4);
+			SheetNameFormatter.appendFormat(sb, wbName, sheetName);
 		} else {
-    		SheetNameFormatter.appendFormat(sb, sheetName);
+			String sheetName = book.getSheetNameByExternSheet(field_1_index_extern_sheet);
+			sb = new StringBuffer(sheetName.length() + cellRefText.length() + 4);
+			if (sheetName.length() < 1) {
+				// What excel does if sheet has been deleted
+				sb.append("#REF"); // note - '!' added just once below
+			} else {
+				SheetNameFormatter.appendFormat(sb, sheetName);
+			}
 		}
    		sb.append('!');
 		sb.append(cellRefText);
diff --git a/src/java/org/apache/poi/hssf/record/formula/Ref3DPtg.java b/src/java/org/apache/poi/hssf/record/formula/Ref3DPtg.java
index 261e98ce8b..053057925f 100644
--- a/src/java/org/apache/poi/hssf/record/formula/Ref3DPtg.java
+++ b/src/java/org/apache/poi/hssf/record/formula/Ref3DPtg.java
@@ -19,8 +19,9 @@ package org.apache.poi.hssf.record.formula;
 
 import org.apache.poi.hssf.record.RecordInputStream;
 import org.apache.poi.ss.util.CellReference;
-import org.apache.poi.ss.formula.WorkbookDependentFormula;
+import org.apache.poi.ss.formula.ExternSheetReferenceToken;
 import org.apache.poi.ss.formula.FormulaRenderingWorkbook;
+import org.apache.poi.ss.formula.WorkbookDependentFormula;
 import org.apache.poi.util.LittleEndian;
 
 /**
@@ -31,7 +32,7 @@ import org.apache.poi.util.LittleEndian;
  * @author Jason Height (jheight at chariot dot net dot au)
  * @version 1.0-pre
  */
-public final class Ref3DPtg extends RefPtgBase implements WorkbookDependentFormula {
+public final class Ref3DPtg extends RefPtgBase implements WorkbookDependentFormula, ExternSheetReferenceToken {
     public final static byte sid  = 0x3a;
 
     private final static int  SIZE = 7; // 6 + 1 for Ptg
@@ -75,11 +76,11 @@ public final class Ref3DPtg extends RefPtgBase implements WorkbookDependentFormu
         return SIZE;
     }
 
-    public int getExternSheetIndex(){
+    public int getExternSheetIndex() {
         return field_1_index_extern_sheet;
     }
 
-    public void setExternSheetIndex(int index){
+    public void setExternSheetIndex(int index) {
         field_1_index_extern_sheet = index;
     }
 
diff --git a/src/java/org/apache/poi/hssf/record/formula/SheetNameFormatter.java b/src/java/org/apache/poi/hssf/record/formula/SheetNameFormatter.java
index ace857da1e..fd822c3986 100755
--- a/src/java/org/apache/poi/hssf/record/formula/SheetNameFormatter.java
+++ b/src/java/org/apache/poi/hssf/record/formula/SheetNameFormatter.java
@@ -66,6 +66,22 @@ public final class SheetNameFormatter {
 			out.append(rawSheetName);
 		}
 	}
+	public static void appendFormat(StringBuffer out, String workbookName, String rawSheetName) {
+		boolean needsQuotes = needsDelimiting(workbookName) || needsDelimiting(rawSheetName);
+		if(needsQuotes) {
+			out.append(DELIMITER);
+			out.append('[');
+			appendAndEscape(out, workbookName.replace('[', '(').replace(']', ')'));
+			out.append(']');
+			appendAndEscape(out, rawSheetName);
+			out.append(DELIMITER);
+		} else {
+			out.append('[');
+			out.append(workbookName);
+			out.append(']');
+			out.append(rawSheetName);
+		}
+	}
 
 	private static void appendAndEscape(StringBuffer sb, String rawSheetName) {
 		int len = rawSheetName.length();
@@ -101,13 +117,27 @@ public final class SheetNameFormatter {
 				return true;
 			}
 		}
+		if (nameLooksLikeBooleanLiteral(rawSheetName)) {
+			return true;
+		}
+		// Error constant literals all contain '#' and other special characters
+		// so they don't get this far
 		return false;
 	}
 	
+	private static boolean nameLooksLikeBooleanLiteral(String rawSheetName) {
+		switch(rawSheetName.charAt(0)) {
+			case 'T': case 't':
+				return "TRUE".equalsIgnoreCase(rawSheetName);
+			case 'F': case 'f':
+				return "FALSE".equalsIgnoreCase(rawSheetName);
+		}
+		return false;
+	}
 	/**
 	 * @return <code>true</code> if the presence of the specified character in a sheet name would 
 	 * require the sheet name to be delimited in formulas.  This includes every non-alphanumeric 
-	 * character besides underscore '_'.
+	 * character besides underscore '_' and dot '.'.
 	 */
 	/* package */ static boolean isSpecialChar(char ch) {
 		// note - Character.isJavaIdentifierPart() would allow dollars '$'
@@ -115,7 +145,8 @@ public final class SheetNameFormatter {
 			return false;
 		}
 		switch(ch) {
-			case '_': // underscore is ok
+			case '.': // dot is OK
+			case '_': // underscore is OK
 				return false;
 			case '\n':
 			case '\r':
diff --git a/src/java/org/apache/poi/hssf/record/formula/eval/RangeEval.java b/src/java/org/apache/poi/hssf/record/formula/eval/RangeEval.java
new file mode 100644
index 0000000000..9398108fdc
--- /dev/null
+++ b/src/java/org/apache/poi/hssf/record/formula/eval/RangeEval.java
@@ -0,0 +1,71 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.hssf.record.formula.eval;
+
+
+/**
+ * 
+ * @author Josh Micich 
+ */
+public final class RangeEval implements OperationEval {
+
+	public static final OperationEval instance = new RangeEval();
+	
+	private RangeEval() {
+	}
+
+	public Eval evaluate(Eval[] args, int srcCellRow, short srcCellCol) {
+		if(args.length != 2) {
+			return ErrorEval.VALUE_INVALID;
+		}
+
+		try {
+			RefEval reA = evaluateRef(args[0]);
+			RefEval reB = evaluateRef(args[1]);
+			return resolveRange(reA, reB);
+		} catch (EvaluationException e) {
+			return e.getErrorEval();
+		}
+	}
+
+	private static AreaEval resolveRange(RefEval reA, RefEval reB) {
+		
+		int height = reB.getRow() - reA.getRow();
+		int width = reB.getColumn() - reA.getColumn();
+		
+		return reA.offset(0, height, 0, width);
+	}
+
+	private static RefEval evaluateRef(Eval arg) throws EvaluationException {
+		if (arg instanceof RefEval) {
+			return (RefEval) arg;
+		}
+		if (arg instanceof ErrorEval) {
+			throw new EvaluationException((ErrorEval)arg);
+		}
+		throw new IllegalArgumentException("Unexpected ref arg class (" + arg.getClass().getName() + ")");
+	}
+
+	public int getNumberOfOperands() {
+		return 2;
+	}
+
+	public int getType() {
+		throw new RuntimeException("obsolete code should not be called");
+	}
+}
diff --git a/src/java/org/apache/poi/hssf/usermodel/HSSFEvaluationWorkbook.java b/src/java/org/apache/poi/hssf/usermodel/HSSFEvaluationWorkbook.java
index d82a9d1144..0b6a954499 100644
--- a/src/java/org/apache/poi/hssf/usermodel/HSSFEvaluationWorkbook.java
+++ b/src/java/org/apache/poi/hssf/usermodel/HSSFEvaluationWorkbook.java
@@ -2,7 +2,9 @@ package org.apache.poi.hssf.usermodel;
 

 import org.apache.poi.hssf.model.HSSFFormulaParser;

 import org.apache.poi.hssf.model.Workbook;

+import org.apache.poi.hssf.record.FormulaRecord;

 import org.apache.poi.hssf.record.NameRecord;

+import org.apache.poi.hssf.record.aggregates.FormulaRecordAggregate;

 import org.apache.poi.hssf.record.formula.NamePtg;

 import org.apache.poi.hssf.record.formula.NameXPtg;

 import org.apache.poi.hssf.record.formula.Ptg;

@@ -39,6 +41,9 @@ public final class HSSFEvaluationWorkbook implements FormulaRenderingWorkbook, E
 		int sheetIndex = _uBook.getSheetIndex(sheetName);

 		return _iBook.checkExternSheet(sheetIndex);

 	}

+	public int getExternalSheetIndex(String workbookName, String sheetName) {

+		return _iBook.getExternalSheetIndex(workbookName, sheetName);

+	}

 

 	public EvaluationName getName(int index) {

 		return new Name(_iBook.getNameRecord(index), index);

@@ -57,6 +62,9 @@ public final class HSSFEvaluationWorkbook implements FormulaRenderingWorkbook, E
 	public int getSheetIndex(Sheet sheet) {

 		return _uBook.getSheetIndex(sheet);

 	}

+	public int getSheetIndex(String sheetName) {

+		return _uBook.getSheetIndex(sheetName);

+	}

 

 	public String getSheetName(int sheetIndex) {

 		return _uBook.getSheetName(sheetIndex);

@@ -75,8 +83,12 @@ public final class HSSFEvaluationWorkbook implements FormulaRenderingWorkbook, E
 	}

 	public int convertFromExternSheetIndex(int externSheetIndex) {

 		return _iBook.getSheetIndexFromExternSheetIndex(externSheetIndex);

-}

+	}

 

+	public ExternalSheet getExternalSheet(int externSheetIndex) {

+		return _iBook.getExternalSheet(externSheetIndex);

+	}

+	

 	public HSSFWorkbook getWorkbook() {

 		return _uBook;

 	}

@@ -96,7 +108,15 @@ public final class HSSFEvaluationWorkbook implements FormulaRenderingWorkbook, E
 		return new Name(_iBook.getNameRecord(ix), ix);

 	}

 	public Ptg[] getFormulaTokens(Cell cell) {

-		return HSSFFormulaParser.parse(cell.getCellFormula(), _uBook);

+		if (false) {

+			// re-parsing the formula text also works, but is a waste of time

+			// It is useful from time to time to run all unit tests with this code

+			// to make sure that all formulas POI can evaluate can also be parsed.

+			return HSSFFormulaParser.parse(cell.getCellFormula(), _uBook);

+		}

+		HSSFCell hCell = (HSSFCell) cell;

+		FormulaRecord fr = ((FormulaRecordAggregate) hCell.getCellValueRecord()).getFormulaRecord();

+		return fr.getParsedExpression();

 	}

 

 	private static final class Name implements EvaluationName {

diff --git a/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java b/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java
index d7a3207383..2f30d15c81 100644
--- a/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java
+++ b/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java
@@ -25,6 +25,7 @@ import org.apache.poi.hssf.record.formula.eval.ErrorEval;
 import org.apache.poi.hssf.record.formula.eval.NumberEval;

 import org.apache.poi.hssf.record.formula.eval.StringEval;

 import org.apache.poi.hssf.record.formula.eval.ValueEval;

+import org.apache.poi.ss.formula.CollaboratingWorkbooksEnvironment;

 import org.apache.poi.ss.formula.WorkbookEvaluator;

 import org.apache.poi.ss.usermodel.Cell;

 import org.apache.poi.ss.usermodel.CellValue;

@@ -56,6 +57,21 @@ public class HSSFFormulaEvaluator /* almost implements FormulaEvaluator */ {
 	public HSSFFormulaEvaluator(HSSFWorkbook workbook) {

 		_bookEvaluator = new WorkbookEvaluator(HSSFEvaluationWorkbook.create(workbook));

 	}

+	

+	/**

+	 * Coordinates several formula evaluators together so that formulas that involve external

+	 * references can be evaluated.

+	 * @param workbookNames the simple file names used to identify the workbooks in formulas

+	 * with external links (for example "MyData.xls" as used in a formula "[MyData.xls]Sheet1!A1")

+	 * @param evaluators all evaluators for the full set of workbooks required by the formulas. 

+	 */

+	public static void setupEnvironment(String[] workbookNames, HSSFFormulaEvaluator[] evaluators) {

+		WorkbookEvaluator[] wbEvals = new WorkbookEvaluator[evaluators.length];

+		for (int i = 0; i < wbEvals.length; i++) {

+			wbEvals[i] = evaluators[i]._bookEvaluator;

+		}

+		CollaboratingWorkbooksEnvironment.setup(workbookNames, wbEvals);

+	}

 

 	/**

 	 * Does nothing

diff --git a/src/java/org/apache/poi/hssf/util/AreaReference.java b/src/java/org/apache/poi/hssf/util/AreaReference.java
index d6575642ee..6a0b0e2d3a 100644
--- a/src/java/org/apache/poi/hssf/util/AreaReference.java
+++ b/src/java/org/apache/poi/hssf/util/AreaReference.java
@@ -30,6 +30,7 @@ public final class AreaReference extends org.apache.poi.ss.util.AreaReference {
     
     /**
      * Creates an area ref from a pair of Cell References.
+     * Also normalises such that the top-left
      */
     public AreaReference(CellReference topLeft, CellReference botRight) {
 		super(topLeft, botRight);
diff --git a/src/java/org/apache/poi/hssf/util/CellReference.java b/src/java/org/apache/poi/hssf/util/CellReference.java
index 0ddb0764ee..2e31b2a215 100644
--- a/src/java/org/apache/poi/hssf/util/CellReference.java
+++ b/src/java/org/apache/poi/hssf/util/CellReference.java
@@ -18,22 +18,13 @@
 package org.apache.poi.hssf.util;
 
 /**
- * Common convertion functions between Excel style A1, C27 style
+ * Common conversion functions between Excel style A1, C27 style
  *  cell references, and POI usermodel style row=0, column=0
  *  style references.
  * @author  Avik Sengupta
  * @author  Dennis Doubleday (patch to seperateRowColumns())
  */
 public final class CellReference extends org.apache.poi.ss.util.CellReference {
-	/**
-	 * Used to classify identifiers found in formulas as cell references or not.
-	 */
-	public static final class NameType {
-		public static final int CELL = 1;
-		public static final int NAMED_RANGE = 2;
-		public static final int BAD_CELL_OR_NAMED_RANGE = -1;
-	}
-
     /**
      * Create an cell ref from a string representation.  Sheet names containing special characters should be
      * delimited and escaped as per normal syntax rules for formulas.
@@ -45,9 +36,6 @@ public final class CellReference extends org.apache.poi.ss.util.CellReference {
     public CellReference(int pRow, int pCol) {
     	super(pRow, pCol, true, true);
     }
-    public CellReference(int pRow, short pCol) {
-    	super(pRow, (int)pCol, true, true);
-    }
     
     public CellReference(int pRow, int pCol, boolean pAbsRow, boolean pAbsCol) {
         super(null, pRow, pCol, pAbsRow, pAbsCol);
@@ -55,10 +43,6 @@ public final class CellReference extends org.apache.poi.ss.util.CellReference {
     public CellReference(String pSheetName, int pRow, int pCol, boolean pAbsRow, boolean pAbsCol) {
     	super(pSheetName, pRow, pCol, pAbsRow, pAbsCol);
     }
-    
-    protected void appendCellReference(StringBuffer sb) {
-    	super.appendCellReference(sb);
-    }
     protected static String convertNumToColString(int col) {
     	return org.apache.poi.ss.util.CellReference.convertNumToColString(col);
     }
diff --git a/src/java/org/apache/poi/ss/formula/CellLocation.java b/src/java/org/apache/poi/ss/formula/CellLocation.java
index d6bb9b7bfb..6857c4bc1b 100644
--- a/src/java/org/apache/poi/ss/formula/CellLocation.java
+++ b/src/java/org/apache/poi/ss/formula/CellLocation.java
@@ -17,25 +17,32 @@
 
 package org.apache.poi.ss.formula;
 
+import org.apache.poi.hssf.util.CellReference;
+
 /**
  * Stores the parameters that identify the evaluation of one cell.<br/>
  */
 final class CellLocation {
 	public static final CellLocation[] EMPTY_ARRAY = { };
 	
+	private final EvaluationWorkbook _book;
 	private final int _sheetIndex;
 	private final int _rowIndex;
 	private final int _columnIndex;
 	private final int _hashCode;
 
-	public CellLocation(int sheetIndex, int rowIndex, int columnIndex) {
+	public CellLocation(EvaluationWorkbook book, int sheetIndex, int rowIndex, int columnIndex) {
 		if (sheetIndex < 0) {
 			throw new IllegalArgumentException("sheetIndex must not be negative");
 		}
+		_book = book;
 		_sheetIndex = sheetIndex;
 		_rowIndex = rowIndex;
 		_columnIndex = columnIndex;
-		_hashCode = sheetIndex + 17 * (rowIndex + 17 * columnIndex);
+		_hashCode = System.identityHashCode(book) + sheetIndex + 17 * (rowIndex + 17 * columnIndex);
+	}
+	public Object getBook() {
+		return _book;
 	}
 	public int getSheetIndex() {
 		return _sheetIndex;
@@ -49,15 +56,18 @@ final class CellLocation {
 
 	public boolean equals(Object obj) {
 		CellLocation other = (CellLocation) obj;
-		if (getSheetIndex() != other.getSheetIndex()) {
-			return false;
-		}
 		if (getRowIndex() != other.getRowIndex()) {
 			return false;
 		}
 		if (getColumnIndex() != other.getColumnIndex()) {
 			return false;
 		}
+		if (getSheetIndex() != other.getSheetIndex()) {
+			return false;
+		}
+		if (getBook() != other.getBook()) {
+			return false;
+		}
 		return true;
 	}
 	public int hashCode() {
@@ -68,7 +78,8 @@ final class CellLocation {
 	 * @return human readable string for debug purposes
 	 */
 	public String formatAsString() {
-		return  "ShIx=" + getSheetIndex() + " R=" + getRowIndex() + " C=" + getColumnIndex();
+		CellReference cr = new CellReference(_rowIndex, _columnIndex, false, false);
+		return  "ShIx=" + getSheetIndex() + " " + cr.formatAsString();
 	}
 
 	public String toString() {
diff --git a/src/java/org/apache/poi/ss/formula/CollaboratingWorkbooksEnvironment.java b/src/java/org/apache/poi/ss/formula/CollaboratingWorkbooksEnvironment.java
new file mode 100644
index 0000000000..c62d2f182d
--- /dev/null
+++ b/src/java/org/apache/poi/ss/formula/CollaboratingWorkbooksEnvironment.java
@@ -0,0 +1,155 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+package org.apache.poi.ss.formula;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.IdentityHashMap;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Set;
+
+
+/**
+ * Manages a collection of {@link WorkbookEvaluator}s, in order to support evaluation of formulas
+ * across spreadsheets.<p/>
+ *
+ * For POI internal use only
+ *
+ * @author Josh Micich
+ */
+public final class CollaboratingWorkbooksEnvironment {
+	
+	public static final CollaboratingWorkbooksEnvironment EMPTY = new CollaboratingWorkbooksEnvironment();
+	
+	private final Map _evaluatorsByName;
+	private final WorkbookEvaluator[] _evaluators;
+
+	private boolean _unhooked;
+	private CollaboratingWorkbooksEnvironment() {
+		_evaluatorsByName = Collections.EMPTY_MAP;
+		_evaluators = new WorkbookEvaluator[0];
+	}
+	public static void setup(String[] workbookNames, WorkbookEvaluator[] evaluators) {
+		int nItems = workbookNames.length;
+		if (evaluators.length != nItems) {
+			throw new IllegalArgumentException("Number of workbook names is " + nItems 
+					+ " but number of evaluators is " + evaluators.length);
+		}
+		if (nItems < 1) {
+			throw new IllegalArgumentException("Must provide at least one collaborating worbook");
+		}
+		new CollaboratingWorkbooksEnvironment(workbookNames, evaluators, nItems);
+	}
+
+	private CollaboratingWorkbooksEnvironment(String[] workbookNames, WorkbookEvaluator[] evaluators, int nItems) {
+		Map m = new HashMap(nItems * 3 / 2);
+		IdentityHashMap uniqueEvals = new IdentityHashMap(nItems * 3 / 2);
+		for(int i=0; i<nItems; i++) {
+			String wbName = workbookNames[i];
+			WorkbookEvaluator wbEval = evaluators[i];
+			if (m.containsKey(wbName)) {
+				throw new IllegalArgumentException("Duplicate workbook name '" + wbName + "'");
+			}
+			if (uniqueEvals.containsKey(wbEval)) {
+				String msg = "Attempted to register same workbook under names '"
+					+ uniqueEvals.get(wbEval) + "' and '" + wbName + "'";
+				throw new IllegalArgumentException(msg);
+			}
+			uniqueEvals.put(wbEval, wbName);
+			m.put(wbName, wbEval);
+		}
+		unhookOldEnvironments(evaluators);
+		hookNewEnvironment(evaluators, this);
+		_unhooked = false;
+		_evaluators = evaluators;
+		_evaluatorsByName = m;
+	}
+
+	private static void hookNewEnvironment(WorkbookEvaluator[] evaluators, CollaboratingWorkbooksEnvironment env) {
+		
+		// All evaluators will need to share the same cache.
+		// but the cache takes an optional evaluation listener.
+		int nItems = evaluators.length;
+		IEvaluationListener evalListener = evaluators[0].getEvaluationListener();
+		// make sure that all evaluators have the same listener
+		for(int i=0; i<nItems; i++) {
+			if(evalListener != evaluators[i].getEvaluationListener()) {
+				// This would be very complex to support
+				throw new RuntimeException("Workbook evaluators must all have the same evaluation listener");
+			}
+		}
+		EvaluationCache cache = new EvaluationCache(evalListener);
+		
+		for(int i=0; i<nItems; i++) {
+			evaluators[i].attachToEnvironment(env, cache);
+		}
+		
+	}
+	private void unhookOldEnvironments(WorkbookEvaluator[] evaluators) {
+		Set oldEnvs = new HashSet();
+		for(int i=0; i<evaluators.length; i++) {
+			oldEnvs.add(evaluators[i].getEnvironment());
+		}
+		CollaboratingWorkbooksEnvironment[] oldCWEs = new CollaboratingWorkbooksEnvironment[oldEnvs.size()];
+		oldEnvs.toArray(oldCWEs);
+		for (int i = 0; i < oldCWEs.length; i++) {
+			oldCWEs[i].unhook();
+		}
+	}
+
+	/**
+	 * 
+	 */
+	private void unhook() {
+		if (_evaluators.length < 1) {
+			return;
+		}
+		for (int i = 0; i < _evaluators.length; i++) {
+			_evaluators[i].detachFromEnvironment();
+		}
+		_unhooked = true;
+	}
+
+	public WorkbookEvaluator getWorkbookEvaluator(String workbookName) {
+		if (_unhooked) {
+			throw new IllegalStateException("This environment has been unhooked");
+		}
+		WorkbookEvaluator result = (WorkbookEvaluator) _evaluatorsByName.get(workbookName);
+		if (result == null) {
+			StringBuffer sb = new StringBuffer(256);
+			sb.append("Could not resolve external workbook name '").append(workbookName).append("'.");
+			if (_evaluators.length < 1) {
+				sb.append(" Workbook environment has not been set up.");
+			} else {
+				sb.append(" The following workbook names are valid: (");
+				Iterator i = _evaluatorsByName.keySet().iterator();
+				int count=0;
+				while(i.hasNext()) {
+					if (count++>0) {
+						sb.append(", ");
+					}
+					sb.append("'").append(i.next()).append("'");
+				}
+				sb.append(")");
+			}
+			throw new RuntimeException(sb.toString());
+		}
+		return result;
+	}
+}
diff --git a/src/java/org/apache/poi/ss/formula/EvaluationCache.java b/src/java/org/apache/poi/ss/formula/EvaluationCache.java
index fdc933f6fa..b0c34fd78a 100644
--- a/src/java/org/apache/poi/ss/formula/EvaluationCache.java
+++ b/src/java/org/apache/poi/ss/formula/EvaluationCache.java
@@ -81,13 +81,7 @@ final class EvaluationCache {
 						+ cellLoc.formatAsString());
 			}
 		}
-		if (_evaluationListener == null) {
-			// optimisation - don't bother sorting if there is no listener.
-		} else {
-			// for testing
-			// make order of callbacks to listener more deterministic
-			Arrays.sort(usedCells, CellLocationComparator);
-		}
+		sortCellLocationsForLogging(usedCells);
 		CellCacheEntry entry = getEntry(cellLoc);
 		CellLocation[] consumingFormulaCells = entry.getConsumingCells();
 		CellLocation[] prevUsedCells = entry.getUsedCells();
@@ -110,6 +104,18 @@ final class EvaluationCache {
 		recurseClearCachedFormulaResults(consumingFormulaCells, 0);
 	}
 
+	/**
+	 * This method sorts the supplied cellLocs so that the order of call-backs to the evaluation 
+	 * listener is more deterministic
+	 */
+	private void sortCellLocationsForLogging(CellLocation[] cellLocs) {
+		if (_evaluationListener == null) {
+			// optimisation - don't bother sorting if there is no listener.
+		} else {
+			Arrays.sort(cellLocs, CellLocationComparator);
+		}
+	}
+
 	private void unlinkConsumingCells(CellLocation[] prevUsedCells, CellLocation[] usedCells,
 			CellLocation cellLoc) {
 		if (prevUsedCells == null) {
@@ -149,6 +155,7 @@ final class EvaluationCache {
 	 * @param formulaCells
 	 */
 	private void recurseClearCachedFormulaResults(CellLocation[] formulaCells, int depth) {
+		sortCellLocationsForLogging(formulaCells);
 		int nextDepth = depth+1;
 		for (int i = 0; i < formulaCells.length; i++) {
 			CellLocation fc = formulaCells[i];
@@ -196,6 +203,10 @@ final class EvaluationCache {
 			CellLocation clB = (CellLocation) b;
 			
 			int cmp;
+			cmp = System.identityHashCode(clA.getBook()) - System.identityHashCode(clB.getBook());
+			if (cmp != 0) {
+				return cmp;
+			}
 			cmp = clA.getSheetIndex() - clB.getSheetIndex();
 			if (cmp != 0) {
 				return cmp;
diff --git a/src/java/org/apache/poi/ss/formula/EvaluationWorkbook.java b/src/java/org/apache/poi/ss/formula/EvaluationWorkbook.java
index 02917d82a4..6cf938fe9f 100644
--- a/src/java/org/apache/poi/ss/formula/EvaluationWorkbook.java
+++ b/src/java/org/apache/poi/ss/formula/EvaluationWorkbook.java
@@ -31,12 +31,36 @@ import org.apache.poi.ss.usermodel.Sheet;
  */

 public interface EvaluationWorkbook {

 	String getSheetName(int sheetIndex);

+	/**

+	 * @return -1 if the specified sheet is from a different book

+	 */

 	int getSheetIndex(Sheet sheet);

+	int getSheetIndex(String sheetName);

 

 	Sheet getSheet(int sheetIndex);

 

+	/**

+	 * @return <code>null</code> if externSheetIndex refers to a sheet inside the current workbook

+	 */

+	ExternalSheet getExternalSheet(int externSheetIndex);

 	int convertFromExternSheetIndex(int externSheetIndex);

 	EvaluationName getName(NamePtg namePtg);

 	String resolveNameXText(NameXPtg ptg);

 	Ptg[] getFormulaTokens(Cell cell);

+	

+	class ExternalSheet {

+		private final String _workbookName;

+		private final String _sheetName;

+

+		public ExternalSheet(String workbookName, String sheetName) {

+			_workbookName = workbookName;

+			_sheetName = sheetName;

+		}

+		public String getWorkbookName() {

+			return _workbookName;

+		}

+		public String getSheetName() {

+			return _sheetName;

+		}

+	}

 }

diff --git a/src/java/org/apache/poi/ss/formula/ExternSheetReferenceToken.java b/src/java/org/apache/poi/ss/formula/ExternSheetReferenceToken.java
new file mode 100644
index 0000000000..09262a1320
--- /dev/null
+++ b/src/java/org/apache/poi/ss/formula/ExternSheetReferenceToken.java
@@ -0,0 +1,29 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+
+package org.apache.poi.ss.formula;
+
+/**
+ * Should be implemented by any {@link Ptg} subclass that needs has an extern sheet index <br/>
+ * 
+ * For POI internal use only
+ * 
+ * @author Josh Micich
+ */
+public interface ExternSheetReferenceToken {
+	int getExternSheetIndex();
+}
diff --git a/src/java/org/apache/poi/ss/formula/FormulaParser.java b/src/java/org/apache/poi/ss/formula/FormulaParser.java
index df2f8c282f..1398399ff4 100644
--- a/src/java/org/apache/poi/ss/formula/FormulaParser.java
+++ b/src/java/org/apache/poi/ss/formula/FormulaParser.java
@@ -49,6 +49,7 @@ import org.apache.poi.hssf.record.formula.ParenthesisPtg;
 import org.apache.poi.hssf.record.formula.PercentPtg;
 import org.apache.poi.hssf.record.formula.PowerPtg;
 import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.RangePtg;
 import org.apache.poi.hssf.record.formula.Ref3DPtg;
 import org.apache.poi.hssf.record.formula.RefPtg;
 import org.apache.poi.hssf.record.formula.StringPtg;
@@ -60,7 +61,7 @@ import org.apache.poi.hssf.record.formula.function.FunctionMetadataRegistry;
 import org.apache.poi.hssf.usermodel.HSSFErrorConstants;
 import org.apache.poi.hssf.util.AreaReference;
 import org.apache.poi.hssf.util.CellReference;
-import org.apache.poi.hssf.util.CellReference.NameType;
+import org.apache.poi.ss.util.CellReference.NameType;
 
 /**
  * This class parses a formula string into a List of tokens in RPN order.
@@ -81,6 +82,33 @@ import org.apache.poi.hssf.util.CellReference.NameType;
  *  @author Josh Micich
  */
 public final class FormulaParser {
+    private static final class Identifier {
+        private final String _name;
+        private final boolean _isQuoted;
+
+        public Identifier(String name, boolean isQuoted) {
+            _name = name;
+            _isQuoted = isQuoted;
+        }
+        public String getName() {
+            return _name;
+        }
+        public boolean isQuoted() {
+            return _isQuoted;
+        }
+        public String toString() {
+            StringBuffer sb = new StringBuffer(64);
+            sb.append(getClass().getName());
+            sb.append(" [");
+            if (_isQuoted) {
+                sb.append("'").append(_name).append("'");
+            } else {
+                sb.append(_name);
+            }
+            sb.append("]");
+            return sb.toString();
+        }
+    }
 
     /**
      * Specific exception thrown when a supplied formula does not parse properly.<br/>
@@ -176,23 +204,23 @@ public final class FormulaParser {
     }
 
     /** Recognize an Alpha Character */
-    private boolean IsAlpha(char c) {
+    private static boolean IsAlpha(char c) {
         return Character.isLetter(c) || c == '$' || c=='_';
     }
 
     /** Recognize a Decimal Digit */
-    private boolean IsDigit(char c) {
+    private static boolean IsDigit(char c) {
         return Character.isDigit(c);
     }
 
     /** Recognize an Alphanumeric */
-    private boolean  IsAlNum(char c) {
-        return  (IsAlpha(c) || IsDigit(c));
+    private static boolean IsAlNum(char c) {
+        return IsAlpha(c) || IsDigit(c);
     }
 
     /** Recognize White Space */
-    private boolean IsWhite( char c) {
-        return  (c ==' ' || c== TAB);
+    private static boolean IsWhite( char c) {
+        return  c ==' ' || c== TAB;
     }
 
     /** Skip Over Leading White Space */
@@ -213,7 +241,13 @@ public final class FormulaParser {
         }
         GetChar();
     }
-
+    private String parseUnquotedIdentifier() {
+        Identifier iden = parseIdentifier();
+        if (iden.isQuoted()) {
+            throw expected("unquoted identifier");
+        }
+        return iden.getName();
+    }
     /**
      * Parses a sheet name, named range name, or simple cell reference.<br/>
      * Note - identifiers in Excel can contain dots, so this method may return a String
@@ -221,18 +255,17 @@ public final class FormulaParser {
      * may return a value like "A1..B2", in which case the caller must convert it to
      * an area reference like "A1:B2"
      */
-    private String parseIdentifier() {
-        StringBuffer Token = new StringBuffer();
-        if (!IsAlpha(look) && look != '\'') {
+    private Identifier parseIdentifier() {
+        StringBuffer sb = new StringBuffer();
+        if (!IsAlpha(look) && look != '\'' && look != '[') {
             throw expected("Name");
         }
-        if(look == '\'')
-        {
+        boolean isQuoted = look == '\''; 
+        if(isQuoted) {
             Match('\'');
             boolean done = look == '\'';
-            while(!done)
-            {
-                Token.append(look);
+            while(!done) {
+                sb.append(look);
                 GetChar();
                 if(look == '\'')
                 {
@@ -240,17 +273,15 @@ public final class FormulaParser {
                     done = look != '\'';
                 }
             }
-        }
-        else
-        {
+        } else {
             // allow for any sequence of dots and identifier chars
             // special case of two consecutive dots is best treated in the calling code
-            while (IsAlNum(look) || look == '.') {
-                Token.append(look);
+            while (IsAlNum(look) || look == '.' || look == '[' || look == ']') {
+                sb.append(look);
                 GetChar();
             }
         }
-        return Token.toString();
+        return new Identifier(sb.toString(), isQuoted);
     }
 
     /** Get a Number */
@@ -265,72 +296,112 @@ public final class FormulaParser {
     }
 
     private ParseNode parseFunctionReferenceOrName() {
-        String name = parseIdentifier();
+        Identifier iden = parseIdentifier();
         if (look == '('){
             //This is a function
-            return function(name);
+            return function(iden.getName());
         }
-        return new ParseNode(parseNameOrReference(name));
-    }
-
-    private Ptg parseNameOrReference(String name) {
-
-        AreaReference areaRef = parseArea(name);
-        if (areaRef != null) {
-            // will happen if dots are used instead of colon
-            return new AreaPtg(areaRef.formatAsString());
+        if (!iden.isQuoted()) {
+            String name = iden.getName();
+            if (name.equalsIgnoreCase("TRUE") || name.equalsIgnoreCase("FALSE")) {
+                return  new ParseNode(new BoolPtg(name.toUpperCase()));
+            }
         }
+        return parseRangeExpression(iden);
+    }
 
-        if (look == ':' || look == '.') { // this is a AreaReference
+    private ParseNode parseRangeExpression(Identifier iden) {
+        Ptg ptgA = parseNameOrCellRef(iden);
+        if (look == ':') {
             GetChar();
-
-            while (look == '.') { // formulas can have . or .. or ... instead of :
-                GetChar();
+            Identifier iden2 = parseIdentifier();
+            Ptg ptgB = parseNameOrCellRef(iden2);
+            Ptg simplified = reduceRangeExpression(ptgA, ptgB);
+            
+            if (simplified == null) {
+                ParseNode[] children = {
+                    new ParseNode(ptgA),    
+                    new ParseNode(ptgB),
+                };
+                return new ParseNode(RangePtg.instance, children);
             }
+            return new ParseNode(simplified);
+        }
+        return new ParseNode(ptgA);
+    } 
+    
+    /**
+     * 
+     * "A1", "B3" -> "A1:B3"   
+     * "sheet1!A1", "B3" -> "sheet1!A1:B3"
+     * 
+     * @return <code>null</code> if the range expression cannot / shouldn't be reduced.
+     */
+    private static Ptg reduceRangeExpression(Ptg ptgA, Ptg ptgB) {
+        if (!(ptgB instanceof RefPtg)) {
+            // only when second ref is simple 2-D ref can the range 
+            // expression be converted to an area ref
+            return null;
+        }
+        RefPtg refB = (RefPtg) ptgB;
 
-            String first = name;
-            String second = parseIdentifier();
-            return new AreaPtg(first+":"+second);
+        if (ptgA instanceof RefPtg) {
+            RefPtg refA = (RefPtg) ptgA;
+            return new AreaPtg(refA.getRow(), refB.getRow(), refA.getColumn(), refB.getColumn(),
+                    refA.isRowRelative(), refB.isRowRelative(), refA.isColRelative(), refB.isColRelative());
+        }
+        if (ptgA instanceof Ref3DPtg) {
+            Ref3DPtg refA = (Ref3DPtg) ptgA;
+            return new Area3DPtg(refA.getRow(), refB.getRow(), refA.getColumn(), refB.getColumn(),
+                    refA.isRowRelative(), refB.isRowRelative(), refA.isColRelative(), refB.isColRelative(),
+                    refA.getExternSheetIndex());
         }
+        // Note - other operand types (like AreaPtg) which probably can't evaluate 
+        // do not cause validation errors at parse time
+        return null;
+    }
 
+    private Ptg parseNameOrCellRef(Identifier iden) {
+        
         if (look == '!') {
-            Match('!');
-            String sheetName = name;
-            String first = parseIdentifier();
-            int externIdx = book.getExternalSheetIndex(sheetName);
-            areaRef = parseArea(name);
-            if (areaRef != null) {
-                // will happen if dots are used instead of colon
-                return new Area3DPtg(areaRef.formatAsString(), externIdx);
-            }
-            if (look == ':') {
-                Match(':');
-                String second=parseIdentifier();
-                if (look == '!') {
-                    //The sheet name was included in both of the areas. Only really
-                    //need it once
-                    Match('!');
-                    String third=parseIdentifier();
-
-                    if (!sheetName.equals(second))
-                        throw new RuntimeException("Unhandled double sheet reference.");
-
-                    return new Area3DPtg(first+":"+third,externIdx);
-                }
-                return new Area3DPtg(first+":"+second,externIdx);
+            GetChar();
+            // 3-D ref
+            // this code assumes iden is a sheetName
+            // TODO - handle <book name> ! <named range name>
+            int externIdx = getExternalSheetIndex(iden.getName());
+            String secondIden = parseUnquotedIdentifier();
+            AreaReference areaRef = parseArea(secondIden);
+            if (areaRef == null) {
+                return new Ref3DPtg(secondIden, externIdx);
             }
-            return new Ref3DPtg(first, externIdx);
-        }
-        if (name.equalsIgnoreCase("TRUE") || name.equalsIgnoreCase("FALSE")) {
-            return new BoolPtg(name.toUpperCase());
+            // will happen if dots are used instead of colon
+            return new Area3DPtg(areaRef.formatAsString(), externIdx);
         }
 
+        String name = iden.getName();
+        AreaReference areaRef = parseArea(name);
+        if (areaRef != null) {
+            // will happen if dots are used instead of colon
+            return new AreaPtg(areaRef.formatAsString());
+        }
         // This can be either a cell ref or a named range
-        // Try to spot which it is
+
+
         int nameType = CellReference.classifyCellReference(name);
         if (nameType == NameType.CELL) {
             return new RefPtg(name);
         }
+        if (look == ':') {
+            if (nameType == NameType.COLUMN) {
+                GetChar();
+                String secondIden = parseUnquotedIdentifier();
+                if (CellReference.classifyCellReference(secondIden) != NameType.COLUMN) {
+                    throw new FormulaParseException("Expected full column after '" + name 
+                            + ":' but got '" + secondIden + "'");
+                }
+                return new AreaPtg(name + ":" + secondIden);
+            }
+        }
         if (nameType != NameType.NAMED_RANGE) {
             new FormulaParseException("Name '" + name
                 + "' does not look like a cell reference or named range");
@@ -347,6 +418,17 @@ public final class FormulaParser {
                     + name + "' is not a range as expected");
     }
 
+    private int getExternalSheetIndex(String name) {
+        if (name.charAt(0) == '[') {
+            // we have a sheet name qualified with workbook name e.g. '[MyData.xls]Sheet1'
+            int pos = name.lastIndexOf(']'); // safe because sheet names never have ']'
+            String wbName = name.substring(1, pos);
+            String sheetName = name.substring(pos+1);
+            return book.getExternalSheetIndex(wbName, sheetName);
+        }
+        return book.getExternalSheetIndex(name);
+    }
+
     /**
      * @param name an 'identifier' like string (i.e. contains alphanums, and dots)
      * @return <code>null</code> if name cannot be split at a dot
@@ -585,7 +667,7 @@ public final class FormulaParser {
                 Match('}');
                 return arrayNode;
         }
-        if (IsAlpha(look) || look == '\''){
+        if (IsAlpha(look) || look == '\'' || look == '['){
             return parseFunctionReferenceOrName();
         }
         // else - assume number
@@ -662,7 +744,7 @@ public final class FormulaParser {
     }
 
     private Boolean parseBooleanLiteral() {
-        String iden = parseIdentifier();
+        String iden = parseUnquotedIdentifier();
         if ("TRUE".equalsIgnoreCase(iden)) {
             return Boolean.TRUE;
         }
@@ -720,7 +802,7 @@ public final class FormulaParser {
 
     private int parseErrorLiteral() {
         Match('#');
-        String part1 = parseIdentifier().toUpperCase();
+        String part1 = parseUnquotedIdentifier().toUpperCase();
 
         switch(part1.charAt(0)) {
             case 'V':
diff --git a/src/java/org/apache/poi/ss/formula/FormulaParsingWorkbook.java b/src/java/org/apache/poi/ss/formula/FormulaParsingWorkbook.java
index 69431c2c22..e9be7d1d39 100644
--- a/src/java/org/apache/poi/ss/formula/FormulaParsingWorkbook.java
+++ b/src/java/org/apache/poi/ss/formula/FormulaParsingWorkbook.java
@@ -32,6 +32,16 @@ public interface FormulaParsingWorkbook {
 	 */

 	EvaluationName getName(String name);

 

-	int getExternalSheetIndex(String sheetName);

 	NameXPtg getNameXPtg(String name);

+

+	/**

+	 * gets the externSheet index for a sheet from this workbook

+	 */

+	int getExternalSheetIndex(String sheetName);

+	/**

+	 * gets the externSheet index for a sheet from an external workbook

+	 * @param workbookName e.g. "Budget.xls"

+	 * @param sheetName a name of a sheet in that workbook

+	 */

+	int getExternalSheetIndex(String workbookName, String sheetName);

 }

diff --git a/src/java/org/apache/poi/ss/formula/FormulaRenderingWorkbook.java b/src/java/org/apache/poi/ss/formula/FormulaRenderingWorkbook.java
index ac95f4da0f..c9b95f6b1c 100644
--- a/src/java/org/apache/poi/ss/formula/FormulaRenderingWorkbook.java
+++ b/src/java/org/apache/poi/ss/formula/FormulaRenderingWorkbook.java
@@ -19,6 +19,7 @@ package org.apache.poi.ss.formula;
 

 import org.apache.poi.hssf.record.formula.NamePtg;

 import org.apache.poi.hssf.record.formula.NameXPtg;

+import org.apache.poi.ss.formula.EvaluationWorkbook.ExternalSheet;

 

 /**

  * Abstracts a workbook for the purpose of converting formula to text.<br/>

@@ -29,6 +30,10 @@ import org.apache.poi.hssf.record.formula.NameXPtg;
  */

 public interface FormulaRenderingWorkbook {

 

+	/**

+	 * @return <code>null</code> if externSheetIndex refers to a sheet inside the current workbook

+	 */

+	ExternalSheet getExternalSheet(int externSheetIndex);

 	String getSheetNameByExternSheet(int externSheetIndex);

 	String resolveNameXText(NameXPtg nameXPtg);

 	String getNameText(NamePtg namePtg);

diff --git a/src/java/org/apache/poi/ss/formula/OperandClassTransformer.java b/src/java/org/apache/poi/ss/formula/OperandClassTransformer.java
index 79087e4d6d..91226bd53b 100644
--- a/src/java/org/apache/poi/ss/formula/OperandClassTransformer.java
+++ b/src/java/org/apache/poi/ss/formula/OperandClassTransformer.java
@@ -19,6 +19,7 @@ package org.apache.poi.ss.formula;
 
 import org.apache.poi.hssf.record.formula.AbstractFunctionPtg;
 import org.apache.poi.hssf.record.formula.ControlPtg;
+import org.apache.poi.hssf.record.formula.RangePtg;
 import org.apache.poi.hssf.record.formula.ValueOperatorPtg;
 import org.apache.poi.hssf.record.formula.Ptg;
 
@@ -115,6 +116,10 @@ final class OperandClassTransformer {
 			return;
 		}
 		if (children.length > 0) {
+			if (token == RangePtg.instance) {
+				// TODO is any token transformation required under the various ref operators?
+				return;
+			}
 			throw new IllegalStateException("Node should not have any children");
 		}
 
diff --git a/src/java/org/apache/poi/ss/formula/OperationEvaluatorFactory.java b/src/java/org/apache/poi/ss/formula/OperationEvaluatorFactory.java
index eaa57c114f..09c93723f9 100755
--- a/src/java/org/apache/poi/ss/formula/OperationEvaluatorFactory.java
+++ b/src/java/org/apache/poi/ss/formula/OperationEvaluatorFactory.java
@@ -40,6 +40,7 @@ import org.apache.poi.hssf.record.formula.OperationPtg;
 import org.apache.poi.hssf.record.formula.PercentPtg;
 import org.apache.poi.hssf.record.formula.PowerPtg;
 import org.apache.poi.hssf.record.formula.Ptg;
+import org.apache.poi.hssf.record.formula.RangePtg;
 import org.apache.poi.hssf.record.formula.SubtractPtg;
 import org.apache.poi.hssf.record.formula.UnaryMinusPtg;
 import org.apache.poi.hssf.record.formula.UnaryPlusPtg;
@@ -57,6 +58,7 @@ import org.apache.poi.hssf.record.formula.eval.NotEqualEval;
 import org.apache.poi.hssf.record.formula.eval.OperationEval;
 import org.apache.poi.hssf.record.formula.eval.PercentEval;
 import org.apache.poi.hssf.record.formula.eval.PowerEval;
+import org.apache.poi.hssf.record.formula.eval.RangeEval;
 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;
@@ -101,6 +103,7 @@ final class OperationEvaluatorFactory {
 		add(m, SubtractPtg.class, SubtractEval.instance);
 		add(m, UnaryMinusPtg.class, UnaryMinusEval.instance);
 		add(m, UnaryPlusPtg.class, UnaryPlusEval.instance);
+		add(m, RangePtg.class, RangeEval.instance);
 		return m;
 	}
 
diff --git a/src/java/org/apache/poi/ss/formula/WorkbookEvaluator.java b/src/java/org/apache/poi/ss/formula/WorkbookEvaluator.java
index b41e2c2c3f..9c02ca9f9e 100644
--- a/src/java/org/apache/poi/ss/formula/WorkbookEvaluator.java
+++ b/src/java/org/apache/poi/ss/formula/WorkbookEvaluator.java
@@ -22,12 +22,18 @@ import java.util.Map;
 import java.util.Stack;
 
 import org.apache.poi.hssf.record.formula.Area3DPtg;
+import org.apache.poi.hssf.record.formula.AreaErrPtg;
 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.ControlPtg;
+import org.apache.poi.hssf.record.formula.DeletedArea3DPtg;
+import org.apache.poi.hssf.record.formula.DeletedRef3DPtg;
 import org.apache.poi.hssf.record.formula.ErrPtg;
+import org.apache.poi.hssf.record.formula.FuncVarPtg;
 import org.apache.poi.hssf.record.formula.IntPtg;
 import org.apache.poi.hssf.record.formula.MemErrPtg;
+import org.apache.poi.hssf.record.formula.MemFuncPtg;
 import org.apache.poi.hssf.record.formula.MissingArgPtg;
 import org.apache.poi.hssf.record.formula.NamePtg;
 import org.apache.poi.hssf.record.formula.NameXPtg;
@@ -35,6 +41,7 @@ import org.apache.poi.hssf.record.formula.NumberPtg;
 import org.apache.poi.hssf.record.formula.OperationPtg;
 import org.apache.poi.hssf.record.formula.Ptg;
 import org.apache.poi.hssf.record.formula.Ref3DPtg;
+import org.apache.poi.hssf.record.formula.RefErrorPtg;
 import org.apache.poi.hssf.record.formula.RefPtg;
 import org.apache.poi.hssf.record.formula.StringPtg;
 import org.apache.poi.hssf.record.formula.UnionPtg;
@@ -53,6 +60,7 @@ 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;
 import org.apache.poi.hssf.util.CellReference;
+import org.apache.poi.ss.formula.EvaluationWorkbook.ExternalSheet;
 import org.apache.poi.ss.usermodel.Cell;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
@@ -68,13 +76,14 @@ import org.apache.poi.ss.usermodel.Sheet;
  *
  * @author Josh Micich
  */
-public class WorkbookEvaluator {
+public final class WorkbookEvaluator {
 
 	private final EvaluationWorkbook _workbook;
-	private final EvaluationCache _cache;
+	private EvaluationCache _cache;
 
 	private final IEvaluationListener _evaluationListener;
 	private final Map _sheetIndexesBySheet;
+	private CollaboratingWorkbooksEnvironment _collaboratingWorkbookEnvironment;
 
 	public WorkbookEvaluator(EvaluationWorkbook workbook) {
 		this (workbook, null);
@@ -84,6 +93,7 @@ public class WorkbookEvaluator {
 		_evaluationListener = evaluationListener;
 		_cache = new EvaluationCache(evaluationListener);
 		_sheetIndexesBySheet = new IdentityHashMap();
+		_collaboratingWorkbookEnvironment = CollaboratingWorkbooksEnvironment.EMPTY;
 	}
 
 	/**
@@ -101,7 +111,22 @@ public class WorkbookEvaluator {
 			System.out.println(s);
 		}
 	}
+	/* package */ void attachToEnvironment(CollaboratingWorkbooksEnvironment collaboratingWorkbooksEnvironment, EvaluationCache cache) {
+		_collaboratingWorkbookEnvironment = collaboratingWorkbooksEnvironment;
+		_cache = cache;
+	}
+	/* package */ CollaboratingWorkbooksEnvironment getEnvironment() {
+		return _collaboratingWorkbookEnvironment;
+	}
 
+	/* package */ void detachFromEnvironment() {
+		_collaboratingWorkbookEnvironment = CollaboratingWorkbooksEnvironment.EMPTY;
+		_cache = new EvaluationCache(_evaluationListener);
+	}
+	/* package */ IEvaluationListener getEvaluationListener() {
+		return _evaluationListener;
+	}
+	 
 	/**
 	 * Should be called whenever there are changes to input cells in the evaluated workbook.
 	 * Failure to call this method after changing cell values will cause incorrect behaviour
@@ -123,7 +148,7 @@ public class WorkbookEvaluator {
 			throw new IllegalArgumentException("value must not be null");
 		}
 		int sheetIndex = getSheetIndex(sheet);
-		_cache.setValue(new CellLocation(sheetIndex, rowIndex, columnIndex), true, CellLocation.EMPTY_ARRAY, value);
+		_cache.setValue(new CellLocation(_workbook, sheetIndex, rowIndex, columnIndex), true, CellLocation.EMPTY_ARRAY, value);
 
 	}
 	/**
@@ -132,13 +157,17 @@ public class WorkbookEvaluator {
 	 */
 	public void notifySetFormula(Sheet sheet, int rowIndex, int columnIndex) {
 		int sheetIndex = getSheetIndex(sheet);
-		_cache.setValue(new CellLocation(sheetIndex, rowIndex, columnIndex), false, CellLocation.EMPTY_ARRAY, null);
+		_cache.setValue(new CellLocation(_workbook, sheetIndex, rowIndex, columnIndex), false, CellLocation.EMPTY_ARRAY, null);
 
 	}
 	private int getSheetIndex(Sheet sheet) {
 		Integer result = (Integer) _sheetIndexesBySheet.get(sheet);
 		if (result == null) {
-			result = new Integer(_workbook.getSheetIndex(sheet));
+			int sheetIndex = _workbook.getSheetIndex(sheet);
+			if (sheetIndex < 0) {
+				throw new RuntimeException("Specified sheet from a different book");
+			}
+			result = new Integer(sheetIndex);
 			_sheetIndexesBySheet.put(sheet, result);
 		}
 		return result.intValue();
@@ -146,7 +175,7 @@ public class WorkbookEvaluator {
 
 	public ValueEval evaluate(Cell srcCell) {
 		int sheetIndex = getSheetIndex(srcCell.getSheet());
-		CellLocation cellLoc = new CellLocation(sheetIndex, srcCell.getRowIndex(), srcCell.getCellNum());
+		CellLocation cellLoc = new CellLocation(_workbook, sheetIndex, srcCell.getRowIndex(), srcCell.getCellNum());
 		return internalEvaluate(srcCell, cellLoc, new EvaluationTracker(_cache));
 	}
 
@@ -181,10 +210,10 @@ public class WorkbookEvaluator {
 				isPlainFormulaCell = false;
 				Ptg[] ptgs = _workbook.getFormulaTokens(srcCell);
 				if(evalListener == null) {
-					result = evaluateCell(sheetIndex, rowIndex, (short)columnIndex, ptgs, tracker);
+					result = evaluateFormula(sheetIndex, rowIndex, (short)columnIndex, ptgs, tracker);
 				} else {
 					evalListener.onStartEvaluate(sheetIndex, rowIndex, columnIndex, ptgs);
-					result = evaluateCell(sheetIndex, rowIndex, (short)columnIndex, ptgs, tracker);
+					result = evaluateFormula(sheetIndex, rowIndex, (short)columnIndex, ptgs, tracker);
 					evalListener.onEndEvaluate(sheetIndex, rowIndex, columnIndex, result);
 				}
 			}
@@ -225,17 +254,31 @@ public class WorkbookEvaluator {
 		}
 		throw new RuntimeException("Unexpected cell type (" + cellType + ")");
 	}
-	private ValueEval evaluateCell(int sheetIndex, int srcRowNum, short srcColNum, Ptg[] ptgs, EvaluationTracker tracker) {
+	// visibility raised for testing
+	/* package */ ValueEval evaluateFormula(int sheetIndex, int srcRowNum, int srcColNum, Ptg[] ptgs, EvaluationTracker tracker) {
 
 		Stack stack = new Stack();
 		for (int i = 0, iSize = ptgs.length; i < iSize; i++) {
 
 			// since we don't know how to handle these yet :(
 			Ptg ptg = ptgs[i];
+			if (ptg instanceof AttrPtg) {
+				AttrPtg attrPtg = (AttrPtg) ptg;
+				if (attrPtg.isSum()) {
+					// Excel prefers to encode 'SUM()' as a tAttr token, but this evaluator
+					// expects the equivalent function token
+					byte nArgs = 1;  // tAttrSum always has 1 parameter
+					ptg = new FuncVarPtg("SUM", nArgs); 
+				}
+			}
 			if (ptg instanceof ControlPtg) {
 				// skip Parentheses, Attr, etc
 				continue;
 			}
+			if (ptg instanceof MemFuncPtg) {
+				// can ignore, rest of tokens for this expression are in OK RPN order
+				continue;
+			}
 			if (ptg instanceof MemErrPtg) { continue; }
 			if (ptg instanceof MissingArgPtg) {
 				// TODO - might need to push BlankEval or MissingArgEval
@@ -289,7 +332,7 @@ public class WorkbookEvaluator {
 	 * @return a <tt>NumberEval</tt>, <tt>StringEval</tt>, <tt>BoolEval</tt>,
 	 *  <tt>BlankEval</tt> or <tt>ErrorEval</tt>. Never <code>null</code>.
 	 */
-	private static ValueEval dereferenceValue(ValueEval evaluationResult, int srcRowNum, short srcColNum) {
+	private static ValueEval dereferenceValue(ValueEval evaluationResult, int srcRowNum, int srcColNum) {
 		if (evaluationResult instanceof RefEval) {
 			RefEval rv = (RefEval) evaluationResult;
 			return rv.getInnerValueEval();
@@ -321,6 +364,20 @@ public class WorkbookEvaluator {
 		}
 		return operation.evaluate(ops, srcRowNum, (short)srcColNum);
 	}
+	private SheetRefEvaluator createExternSheetRefEvaluator(EvaluationTracker tracker,
+			ExternSheetReferenceToken ptg) {
+		int externSheetIndex = ptg.getExternSheetIndex();
+		ExternalSheet externalSheet = _workbook.getExternalSheet(externSheetIndex);
+		if (externalSheet != null) {
+			WorkbookEvaluator otherEvaluator = _collaboratingWorkbookEnvironment.getWorkbookEvaluator(externalSheet.getWorkbookName());
+			EvaluationWorkbook otherBook = otherEvaluator._workbook;
+			int otherSheetIndex = otherBook.getSheetIndex(externalSheet.getSheetName());
+			return new SheetRefEvaluator(otherEvaluator, tracker, otherBook, otherSheetIndex);
+		}
+		int otherSheetIndex = _workbook.convertFromExternSheetIndex(externSheetIndex);
+		return new SheetRefEvaluator(this, tracker, _workbook, otherSheetIndex);
+		
+	}
 
 	/**
 	 * returns an appropriate Eval impl instance for the Ptg. The Ptg must be
@@ -329,6 +386,8 @@ public class WorkbookEvaluator {
 	 * passed here!
 	 */
 	private Eval getEvalForPtg(Ptg ptg, int sheetIndex, EvaluationTracker tracker) {
+		//  consider converting all these (ptg instanceof XxxPtg) expressions to (ptg.getClass() == XxxPtg.class)
+
 		if (ptg instanceof NamePtg) {
 			// named ranges, macro functions
 			NamePtg namePtg = (NamePtg) ptg;
@@ -361,16 +420,18 @@ public class WorkbookEvaluator {
 		if (ptg instanceof ErrPtg) {
 			return ErrorEval.valueOf(((ErrPtg) ptg).getErrorCode());
 		}
+		if (ptg instanceof AreaErrPtg ||ptg instanceof RefErrorPtg 
+				|| ptg instanceof DeletedArea3DPtg || ptg instanceof DeletedRef3DPtg) {
+				return ErrorEval.REF_INVALID;
+		}
 		if (ptg instanceof Ref3DPtg) {
 			Ref3DPtg refPtg = (Ref3DPtg) ptg;
-			int otherSheetIndex = _workbook.convertFromExternSheetIndex(refPtg.getExternSheetIndex());
-			SheetRefEvaluator sre = new SheetRefEvaluator(this, tracker, _workbook, otherSheetIndex);
+			SheetRefEvaluator sre = createExternSheetRefEvaluator(tracker, refPtg);
 			return new LazyRefEval(refPtg, sre);
 		}
 		if (ptg instanceof Area3DPtg) {
 			Area3DPtg aptg = (Area3DPtg) ptg;
-			int otherSheetIndex = _workbook.convertFromExternSheetIndex(aptg.getExternSheetIndex());
-			SheetRefEvaluator sre = new SheetRefEvaluator(this, tracker, _workbook, otherSheetIndex);
+			SheetRefEvaluator sre = createExternSheetRefEvaluator(tracker, aptg);
 			return new LazyAreaEval(aptg, sre);
 		}
 		SheetRefEvaluator sre = new SheetRefEvaluator(this, tracker, _workbook, sheetIndex);
@@ -410,7 +471,7 @@ public class WorkbookEvaluator {
 		} else {
 			cell = row.getCell(columnIndex);
  		}
-		CellLocation cellLoc = new CellLocation(sheetIndex, rowIndex, columnIndex);
+		CellLocation cellLoc = new CellLocation(_workbook, sheetIndex, rowIndex, columnIndex);
 		tracker.acceptDependency(cellLoc);
 		return internalEvaluate(cell, cellLoc, tracker);
 	}
diff --git a/src/java/org/apache/poi/ss/util/AreaReference.java b/src/java/org/apache/poi/ss/util/AreaReference.java
index ae2c9192f0..30d92ebcf4 100644
--- a/src/java/org/apache/poi/ss/util/AreaReference.java
+++ b/src/java/org/apache/poi/ss/util/AreaReference.java
@@ -90,7 +90,7 @@ public class AreaReference {
         for(int i=refPart.length()-1; i>=0; i--) {
             int ch = refPart.charAt(i);
             if (ch == '$' && i==0) {
-            	continue;
+                continue;
             }
             if (ch < 'A' || ch > 'Z') {
                 return false;
@@ -103,8 +103,45 @@ public class AreaReference {
      * Creates an area ref from a pair of Cell References.
      */
     public AreaReference(CellReference topLeft, CellReference botRight) {
-        _firstCell = topLeft;
-        _lastCell = botRight;
+        boolean swapRows = topLeft.getRow() > botRight.getRow();
+        boolean swapCols = topLeft.getCol() > botRight.getCol();
+        if (swapRows || swapCols) {
+            int firstRow; 
+            int lastRow; 
+            int firstColumn; 
+            int lastColumn;
+            boolean firstRowAbs; 
+            boolean lastRowAbs; 
+            boolean firstColAbs;
+            boolean lastColAbs;   
+            if (swapRows) {
+                firstRow = botRight.getRow();
+                firstRowAbs = botRight.isRowAbsolute();
+                lastRow = topLeft.getRow();
+                lastRowAbs = topLeft.isRowAbsolute();
+            } else {
+                firstRow = topLeft.getRow();
+                firstRowAbs = topLeft.isRowAbsolute();
+                lastRow = botRight.getRow();
+                lastRowAbs = botRight.isRowAbsolute();
+            }
+            if (swapCols) {
+                firstColumn = botRight.getCol();
+                firstColAbs = botRight.isColAbsolute();
+                lastColumn = topLeft.getCol();
+                lastColAbs = topLeft.isColAbsolute();
+            } else {
+                firstColumn = topLeft.getCol();
+                firstColAbs = topLeft.isColAbsolute();
+                lastColumn = botRight.getCol();
+                lastColAbs = botRight.isColAbsolute();
+            }
+            _firstCell = new CellReference(firstRow, firstColumn, firstRowAbs, firstColAbs);
+            _lastCell = new CellReference(lastRow, lastColumn, lastRowAbs, lastColAbs);
+        } else {
+            _firstCell = topLeft;
+            _lastCell = botRight;
+        }
         _isSingleCell = false;
     }
 
diff --git a/src/java/org/apache/poi/ss/util/CellReference.java b/src/java/org/apache/poi/ss/util/CellReference.java
index e5005db5d4..23b4c806e8 100644
--- a/src/java/org/apache/poi/ss/util/CellReference.java
+++ b/src/java/org/apache/poi/ss/util/CellReference.java
@@ -34,22 +34,29 @@ public class CellReference {
 	public static final class NameType {
 		public static final int CELL = 1;
 		public static final int NAMED_RANGE = 2;
+		public static final int COLUMN = 3;
 		public static final int BAD_CELL_OR_NAMED_RANGE = -1;
 	}
 
-    /** The character ($) that signifies a row or column value is absolute instead of relative */ 
-    private static final char ABSOLUTE_REFERENCE_MARKER = '$';
-    /** The character (!) that separates sheet names from cell references */ 
-    private static final char SHEET_NAME_DELIMITER = '!';
-    /** The character (') used to quote sheet names when they contain special characters */
-    private static final char SPECIAL_NAME_DELIMITER = '\'';
-    
-    /**
-     * Matches a run of letters followed by a run of digits.  The run of letters is group 1 and the
-     * run of digits is group 2.  Each group may optionally be prefixed with a single '$'.
-     */
+	/** The character ($) that signifies a row or column value is absolute instead of relative */ 
+	private static final char ABSOLUTE_REFERENCE_MARKER = '$';
+	/** The character (!) that separates sheet names from cell references */ 
+	private static final char SHEET_NAME_DELIMITER = '!';
+	/** The character (') used to quote sheet names when they contain special characters */
+	private static final char SPECIAL_NAME_DELIMITER = '\'';
+	
+	/**
+	 * Matches a run of one or more letters followed by a run of one or more digits.
+	 * The run of letters is group 1 and the run of digits is group 2.  
+	 * Each group may optionally be prefixed with a single '$'.
+	 */
 	private static final Pattern CELL_REF_PATTERN = Pattern.compile("\\$?([A-Za-z]+)\\$?([0-9]+)");
 	/**
+	 * Matches a run of one or more letters.  The run of letters is group 1.  
+	 * The text may optionally be prefixed with a single '$'.
+	 */
+	private static final Pattern COLUMN_REF_PATTERN = Pattern.compile("\\$?([A-Za-z]+)");
+	/**
 	 * Named range names must start with a letter or underscore.  Subsequent characters may include
 	 * digits or dot.  (They can even end in dot).
 	 */
@@ -65,96 +72,96 @@ public class CellReference {
     private final boolean _isRowAbs;
     private final boolean _isColAbs;
 
-    /**
-     * Create an cell ref from a string representation.  Sheet names containing special characters should be
-     * delimited and escaped as per normal syntax rules for formulas.
-     */
-    public CellReference(String cellRef) {
-        String[] parts = separateRefParts(cellRef);
-        _sheetName = parts[0];
-        String colRef = parts[1]; 
-        if (colRef.length() < 1) {
-            throw new IllegalArgumentException("Invalid Formula cell reference: '"+cellRef+"'");
-        }
-        _isColAbs = colRef.charAt(0) == '$';
-        if (_isColAbs) {
-            colRef=colRef.substring(1);
-        }
-        _colIndex = convertColStringToIndex(colRef);
-        
-        String rowRef=parts[2];
-        if (rowRef.length() < 1) {
-            throw new IllegalArgumentException("Invalid Formula cell reference: '"+cellRef+"'");
-        }
-        _isRowAbs = rowRef.charAt(0) == '$';
-        if (_isRowAbs) {
-            rowRef=rowRef.substring(1);
-        }
-        _rowIndex = Integer.parseInt(rowRef)-1; // -1 to convert 1-based to zero-based
-    }
-
-    public CellReference(int pRow, int pCol) {
-    	this(pRow, pCol & 0xFFFF, false, false);
-    }
-    public CellReference(int pRow, short pCol) {
-    	this(pRow, (int)pCol, false, false);
-    }
+	/**
+	 * Create an cell ref from a string representation.  Sheet names containing special characters should be
+	 * delimited and escaped as per normal syntax rules for formulas.
+	 */
+	public CellReference(String cellRef) {
+		String[] parts = separateRefParts(cellRef);
+		_sheetName = parts[0];
+		String colRef = parts[1]; 
+		if (colRef.length() < 1) {
+			throw new IllegalArgumentException("Invalid Formula cell reference: '"+cellRef+"'");
+		}
+		_isColAbs = colRef.charAt(0) == '$';
+		if (_isColAbs) {
+			colRef=colRef.substring(1);
+		}
+		_colIndex = convertColStringToIndex(colRef);
+		
+		String rowRef=parts[2];
+		if (rowRef.length() < 1) {
+			throw new IllegalArgumentException("Invalid Formula cell reference: '"+cellRef+"'");
+		}
+		_isRowAbs = rowRef.charAt(0) == '$';
+		if (_isRowAbs) {
+			rowRef=rowRef.substring(1);
+		}
+		_rowIndex = Integer.parseInt(rowRef)-1; // -1 to convert 1-based to zero-based
+	}
 
-    public CellReference(int pRow, int pCol, boolean pAbsRow, boolean pAbsCol) {
-        this(null, pRow, pCol, pAbsRow, pAbsCol);
-    }
-    public CellReference(String pSheetName, int pRow, int pCol, boolean pAbsRow, boolean pAbsCol) {
-        // TODO - "-1" is a special value being temporarily used for whole row and whole column area references.
-        // so these checks are currently N.Q.R.
-        if(pRow < -1) {
-            throw new IllegalArgumentException("row index may not be negative");
-        }
-        if(pCol < -1) {
-            throw new IllegalArgumentException("column index may not be negative");
-        }
-        _sheetName = pSheetName;
-        _rowIndex=pRow;
-        _colIndex=pCol;
-        _isRowAbs = pAbsRow;
-        _isColAbs=pAbsCol;
-    }
+	public CellReference(int pRow, int pCol) {
+		this(pRow, pCol, false, false);
+	}
+	public CellReference(int pRow, short pCol) {
+		this(pRow, pCol & 0xFFFF, false, false);
+	}
 
-    public int getRow(){return _rowIndex;}
-    public short getCol(){return (short) _colIndex;}
-    public boolean isRowAbsolute(){return _isRowAbs;}
-    public boolean isColAbsolute(){return _isColAbs;}
-    /**
-      * @return possibly <code>null</code> if this is a 2D reference.  Special characters are not
-      * escaped or delimited
-      */
-    public String getSheetName(){
-        return _sheetName;
-    }
- 
-    public static boolean isPartAbsolute(String part) {
-        return part.charAt(0) == ABSOLUTE_REFERENCE_MARKER;
-    }
+	public CellReference(int pRow, int pCol, boolean pAbsRow, boolean pAbsCol) {
+		this(null, pRow, pCol, pAbsRow, pAbsCol);
+	}
+	public CellReference(String pSheetName, int pRow, int pCol, boolean pAbsRow, boolean pAbsCol) {
+		// TODO - "-1" is a special value being temporarily used for whole row and whole column area references.
+		// so these checks are currently N.Q.R.
+		if(pRow < -1) {
+			throw new IllegalArgumentException("row index may not be negative");
+		}
+		if(pCol < -1) {
+			throw new IllegalArgumentException("column index may not be negative");
+		}
+		_sheetName = pSheetName;
+		_rowIndex=pRow;
+		_colIndex=pCol;
+		_isRowAbs = pAbsRow;
+		_isColAbs=pAbsCol;
+	}
 
-    /**
-     * takes in a column reference portion of a CellRef and converts it from
-     * ALPHA-26 number format to 0-based base 10.
-     * 'A' -> 0
-     * 'Z' -> 25
-     * 'AA' -> 26
-     * 'IV' -> 255
-     * @return zero based column index
-     */
-    protected static int convertColStringToIndex(String ref) {
-        int pos = 0;
-        int retval=0;
+	public int getRow(){return _rowIndex;}
+	public short getCol(){return (short) _colIndex;}
+	public boolean isRowAbsolute(){return _isRowAbs;}
+	public boolean isColAbsolute(){return _isColAbs;}
+	/**
+	  * @return possibly <code>null</code> if this is a 2D reference.  Special characters are not
+	  * escaped or delimited
+	  */
+	public String getSheetName(){
+		return _sheetName;
+	}
+	
+	public static boolean isPartAbsolute(String part) {
+		return part.charAt(0) == ABSOLUTE_REFERENCE_MARKER;
+	}
+	/**
+	 * takes in a column reference portion of a CellRef and converts it from
+	 * ALPHA-26 number format to 0-based base 10.
+	 * 'A' -> 0
+	 * 'Z' -> 25
+	 * 'AA' -> 26
+	 * 'IV' -> 255
+	 * @return zero based column index
+	 */
+	public static int convertColStringToIndex(String ref) {
+	
+		int pos = 0;
+		int retval=0;
 		for (int k = ref.length()-1; k >= 0; k--) {
 			char thechar = ref.charAt(k);
-            if (thechar == ABSOLUTE_REFERENCE_MARKER) {
-               if (k != 0) {
-                  throw new IllegalArgumentException("Bad col ref format '" + ref + "'");
-               }
-               break;
-            }
+			if (thechar == ABSOLUTE_REFERENCE_MARKER) {
+				if (k != 0) {
+					throw new IllegalArgumentException("Bad col ref format '" + ref + "'");
+				}
+				break;
+			}
 			// Character.getNumericValue() returns the values
 			//  10-35 for the letter A-Z
 			int shift = (int)Math.pow(26, pos);
@@ -162,64 +169,70 @@ public class CellReference {
 			pos++;
 		}
 		return retval-1;
-    }
+	}
 
-    /**
-     * Classifies an identifier as either a simple (2D) cell reference or a named range name
-     * @return one of the values from <tt>NameType</tt> 
-     */
-    public static int classifyCellReference(String str) {
-    	int len = str.length();
-    	if (len < 1) {
-    		throw new IllegalArgumentException("Empty string not allowed");
-    	}
-    	char firstChar = str.charAt(0);
-    	switch (firstChar) {
-        	case ABSOLUTE_REFERENCE_MARKER:
-        	case '.':
-        	case '_':
-        		break;
-        	default:
-        		if (!Character.isLetter(firstChar)) {
-            		throw new IllegalArgumentException("Invalid first char (" + firstChar 
-            				+ ") of cell reference or named range.  Letter expected");
-            	}
-    	}
-    	if (!Character.isDigit(str.charAt(len-1))) {
-    		// no digits at end of str
-    		return validateNamedRangeName(str);
-    	}
-    	Matcher cellRefPatternMatcher = CELL_REF_PATTERN.matcher(str);
-    	if (!cellRefPatternMatcher.matches()) {
-    		return validateNamedRangeName(str);
-    	}
-    	String lettersGroup = cellRefPatternMatcher.group(1);
-    	String digitsGroup = cellRefPatternMatcher.group(2);
-    	if (cellReferenceIsWithinRange(lettersGroup, digitsGroup)) {
-    		// valid cell reference
-    		return NameType.CELL;
-    	}
-    	// If str looks like a cell reference, but is out of (row/col) range, it is a valid
-    	// named range name
-    	// This behaviour is a little weird.  For example, "IW123" is a valid named range name
-    	// because the column "IW" is beyond the maximum "IV".  Note - this behaviour is version
-    	// dependent.  In Excel 2007, "IW123" is not a valid named range name.
-    	if (str.indexOf(ABSOLUTE_REFERENCE_MARKER) >= 0) {
-    		// Of course, named range names cannot have '$'
-    		return NameType.BAD_CELL_OR_NAMED_RANGE;
-    	}
-    	return NameType.NAMED_RANGE;
-    }
+	/**
+	 * Classifies an identifier as either a simple (2D) cell reference or a named range name
+	 * @return one of the values from <tt>NameType</tt> 
+	 */
+	public static int classifyCellReference(String str) {
+		int len = str.length();
+		if (len < 1) {
+			throw new IllegalArgumentException("Empty string not allowed");
+		}
+		char firstChar = str.charAt(0);
+		switch (firstChar) {
+			case ABSOLUTE_REFERENCE_MARKER:
+			case '.':
+			case '_':
+				break;
+			default:
+				if (!Character.isLetter(firstChar)) {
+					throw new IllegalArgumentException("Invalid first char (" + firstChar 
+							+ ") of cell reference or named range.  Letter expected");
+				}
+		}
+		if (!Character.isDigit(str.charAt(len-1))) {
+			// no digits at end of str
+			return validateNamedRangeName(str);
+		}
+		Matcher cellRefPatternMatcher = CELL_REF_PATTERN.matcher(str);
+		if (!cellRefPatternMatcher.matches()) {
+			return validateNamedRangeName(str);
+		}
+		String lettersGroup = cellRefPatternMatcher.group(1);
+		String digitsGroup = cellRefPatternMatcher.group(2);
+		if (cellReferenceIsWithinRange(lettersGroup, digitsGroup)) {
+			// valid cell reference
+			return NameType.CELL;
+		}
+		// If str looks like a cell reference, but is out of (row/col) range, it is a valid
+		// named range name
+		// This behaviour is a little weird.  For example, "IW123" is a valid named range name
+		// because the column "IW" is beyond the maximum "IV".  Note - this behaviour is version
+		// dependent.  In BIFF12, "IW123" is not a valid named range name, but in BIFF8 it is.
+		if (str.indexOf(ABSOLUTE_REFERENCE_MARKER) >= 0) {
+			// Of course, named range names cannot have '$'
+			return NameType.BAD_CELL_OR_NAMED_RANGE;
+		}
+		return NameType.NAMED_RANGE;
+	}
 
-    private static int validateNamedRangeName(String str) {
+	private static int validateNamedRangeName(String str) {
+		Matcher colMatcher = COLUMN_REF_PATTERN.matcher(str);
+		if (colMatcher.matches()) {
+			String colStr = colMatcher.group(1);
+			if (isColumnWithnRange(colStr)) {
+				return NameType.COLUMN;
+			}
+		}
 		if (!NAMED_RANGE_NAME_PATTERN.matcher(str).matches()) {
 			return NameType.BAD_CELL_OR_NAMED_RANGE;
 		}
 		return NameType.NAMED_RANGE;
-		
 	}
-    
-    
+	
+	
 	/**
 	 * Used to decide whether a name of the form "[A-Z]*[0-9]*" that appears in a formula can be 
 	 * interpreted as a cell reference.  Names of that form can be also used for sheets and/or
@@ -240,7 +253,7 @@ public class CellReference {
 	 * <blockquote><table border="0" cellpadding="1" cellspacing="0" 
 	 *                 summary="Notable cases.">
 	 *   <tr><th>Input&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</th>
-	 *   	<th>Result&nbsp;</th></tr>
+	 *       <th>Result&nbsp;</th></tr>
 	 *   <tr><td>"A", "1"</td><td>true</td></tr>
 	 *   <tr><td>"a", "111"</td><td>true</td></tr>
 	 *   <tr><td>"A", "65536"</td><td>true</td></tr>
@@ -257,23 +270,13 @@ public class CellReference {
 	 * @return <code>true</code> if the row and col parameters are within range of a BIFF8 spreadsheet.
 	 */
 	public static boolean cellReferenceIsWithinRange(String colStr, String rowStr) {
-		int numberOfLetters = colStr.length();
-		if(numberOfLetters > BIFF8_LAST_COLUMN_TEXT_LEN) {
-			// "Sheet1" case etc
-			return false; // that was easy
+		if (!isColumnWithnRange(colStr)) {
+			return false;
 		}
 		int nDigits = rowStr.length();
 		if(nDigits > BIFF8_LAST_ROW_TEXT_LEN) {
 			return false; 
 		}
-		if(numberOfLetters == BIFF8_LAST_COLUMN_TEXT_LEN) {
-			if(colStr.toUpperCase().compareTo(BIFF8_LAST_COLUMN) > 0) {
-				return false;
-			}
-		} else {
-			// apparent column name has less chars than max
-			// no need to check range
-		}
 		
 		if(nDigits == BIFF8_LAST_ROW_TEXT_LEN) {
 			// ASCII comparison is valid if digit count is same
@@ -288,87 +291,104 @@ public class CellReference {
 		return true;
 	}
 
+	private static boolean isColumnWithnRange(String colStr) {
+		int numberOfLetters = colStr.length();
+		if(numberOfLetters > BIFF8_LAST_COLUMN_TEXT_LEN) {
+			// "Sheet1" case etc
+			return false; // that was easy
+		}
+		if(numberOfLetters == BIFF8_LAST_COLUMN_TEXT_LEN) {
+			if(colStr.toUpperCase().compareTo(BIFF8_LAST_COLUMN) > 0) {
+				return false;
+			}
+		} else {
+			// apparent column name has less chars than max
+			// no need to check range
+		}
+		return true;
+	}
+
 	/**
-     * Separates the row from the columns and returns an array of three Strings.  The first element
-     * is the sheet name. Only the first element may be null.  The second element in is the column 
-     * name still in ALPHA-26 number format.  The third element is the row.
-     */
-    private static String[] separateRefParts(String reference) {
-        
-        int plingPos = reference.lastIndexOf(SHEET_NAME_DELIMITER);
-        String sheetName = parseSheetName(reference, plingPos);
-        int start = plingPos+1;
+	 * Separates the row from the columns and returns an array of three Strings.  The first element
+	 * is the sheet name. Only the first element may be null.  The second element in is the column 
+	 * name still in ALPHA-26 number format.  The third element is the row.
+	 */
+	private static String[] separateRefParts(String reference) {
+		
+		int plingPos = reference.lastIndexOf(SHEET_NAME_DELIMITER);
+		String sheetName = parseSheetName(reference, plingPos);
+		int start = plingPos+1;
 
-        int length = reference.length();
+		int length = reference.length();
 
 
-        int loc = start;
-        // skip initial dollars 
-        if (reference.charAt(loc)==ABSOLUTE_REFERENCE_MARKER) {
-            loc++;
-        }
-        // step over column name chars until first digit (or dollars) for row number.
-        for (; loc < length; loc++) {
-            char ch = reference.charAt(loc);
-            if (Character.isDigit(ch) || ch == ABSOLUTE_REFERENCE_MARKER) {
-                break;
-            }
-        }
-        return new String[] {
-           sheetName,
-           reference.substring(start,loc),
-           reference.substring(loc),
-        };
-    }
+		int loc = start;
+		// skip initial dollars 
+		if (reference.charAt(loc)==ABSOLUTE_REFERENCE_MARKER) {
+			loc++;
+		}
+		// step over column name chars until first digit (or dollars) for row number.
+		for (; loc < length; loc++) {
+			char ch = reference.charAt(loc);
+			if (Character.isDigit(ch) || ch == ABSOLUTE_REFERENCE_MARKER) {
+				break;
+			}
+		}
+		return new String[] {
+		   sheetName,
+		   reference.substring(start,loc),
+		   reference.substring(loc),
+		};
+	}
 
-    private static String parseSheetName(String reference, int indexOfSheetNameDelimiter) {
-        if(indexOfSheetNameDelimiter < 0) {
-            return null;
-        }
-        
-        boolean isQuoted = reference.charAt(0) == SPECIAL_NAME_DELIMITER;
-        if(!isQuoted) {
-            return reference.substring(0, indexOfSheetNameDelimiter);
-        }
-        int lastQuotePos = indexOfSheetNameDelimiter-1;
-        if(reference.charAt(lastQuotePos) != SPECIAL_NAME_DELIMITER) {
-            throw new RuntimeException("Mismatched quotes: (" + reference + ")");
-        }
+	private static String parseSheetName(String reference, int indexOfSheetNameDelimiter) {
+		if(indexOfSheetNameDelimiter < 0) {
+			return null;
+		}
+		
+		boolean isQuoted = reference.charAt(0) == SPECIAL_NAME_DELIMITER;
+		if(!isQuoted) {
+			return reference.substring(0, indexOfSheetNameDelimiter);
+		}
+		int lastQuotePos = indexOfSheetNameDelimiter-1;
+		if(reference.charAt(lastQuotePos) != SPECIAL_NAME_DELIMITER) {
+			throw new RuntimeException("Mismatched quotes: (" + reference + ")");
+		}
 
-        // TODO - refactor cell reference parsing logic to one place.
-        // Current known incarnations: 
-        //   FormulaParser.GetName()
-        //   CellReference.parseSheetName() (here)
-        //   AreaReference.separateAreaRefs() 
-        //   SheetNameFormatter.format() (inverse)
-        
-        StringBuffer sb = new StringBuffer(indexOfSheetNameDelimiter);
-        
-        for(int i=1; i<lastQuotePos; i++) { // Note boundaries - skip outer quotes
-            char ch = reference.charAt(i);
-            if(ch != SPECIAL_NAME_DELIMITER) {
-                sb.append(ch);
-                continue;
-            }
-            if(i < lastQuotePos) {
-                if(reference.charAt(i+1) == SPECIAL_NAME_DELIMITER) {
-                    // two consecutive quotes is the escape sequence for a single one
-                    i++; // skip this and keep parsing the special name
-                    sb.append(ch);
-                    continue;
-                }
-            }
-            throw new RuntimeException("Bad sheet name quote escaping: (" + reference + ")");
-        }
-        return sb.toString();
-    }
+		// TODO - refactor cell reference parsing logic to one place.
+		// Current known incarnations: 
+		//   FormulaParser.GetName()
+		//   CellReference.parseSheetName() (here)
+		//   AreaReference.separateAreaRefs() 
+		//   SheetNameFormatter.format() (inverse)
+		
+		StringBuffer sb = new StringBuffer(indexOfSheetNameDelimiter);
+		
+		for(int i=1; i<lastQuotePos; i++) { // Note boundaries - skip outer quotes
+			char ch = reference.charAt(i);
+			if(ch != SPECIAL_NAME_DELIMITER) {
+				sb.append(ch);
+				continue;
+			}
+			if(i < lastQuotePos) {
+				if(reference.charAt(i+1) == SPECIAL_NAME_DELIMITER) {
+					// two consecutive quotes is the escape sequence for a single one
+					i++; // skip this and keep parsing the special name
+					sb.append(ch);
+					continue;
+				}
+			}
+			throw new RuntimeException("Bad sheet name quote escaping: (" + reference + ")");
+		}
+		return sb.toString();
+	}
 
-    /**
-     * Takes in a 0-based base-10 column and returns a ALPHA-26
-     *  representation.
-     * eg column #3 -> D
-     */
-    protected static String convertNumToColString(int col) {
+	/**
+	 * Takes in a 0-based base-10 column and returns a ALPHA-26
+	 *  representation.
+	 * eg column #3 -> D
+	 */
+	protected static String convertNumToColString(int col) {
 		// Excel counts column A as the 1st column, we
 		//  treat it as the 0th one
 		int excelColNum = col + 1;
@@ -387,36 +407,36 @@ public class CellReference {
 		}
 		
 		return colRef;
-    }
+	}
+
+	/**
+	 *  Example return values:
+	 *	<table border="0" cellpadding="1" cellspacing="0" summary="Example return values">
+	 *	  <tr><th align='left'>Result</th><th align='left'>Comment</th></tr>
+	 *	  <tr><td>A1</td><td>Cell reference without sheet</td></tr>
+	 *	  <tr><td>Sheet1!A1</td><td>Standard sheet name</td></tr>
+	 *	  <tr><td>'O''Brien''s Sales'!A1'&nbsp;</td><td>Sheet name with special characters</td></tr>
+	 *	</table>
+	 * @return the text representation of this cell reference as it would appear in a formula.
+	 */
+	public String formatAsString() {
+		StringBuffer sb = new StringBuffer(32);
+		if(_sheetName != null) {
+			SheetNameFormatter.appendFormat(sb, _sheetName);
+			sb.append(SHEET_NAME_DELIMITER);
+		}
+		appendCellReference(sb);
+		return sb.toString();
+	}
+	
+	public String toString() {
+		StringBuffer sb = new StringBuffer(64);
+		sb.append(getClass().getName()).append(" [");
+		sb.append(formatAsString());
+		sb.append("]");
+		return sb.toString();
+	}
 
-    /**
-     *  Example return values:
-     *    <table border="0" cellpadding="1" cellspacing="0" summary="Example return values">
-     *      <tr><th align='left'>Result</th><th align='left'>Comment</th></tr>
-     *      <tr><td>A1</td><td>Cell reference without sheet</td></tr>
-     *      <tr><td>Sheet1!A1</td><td>Standard sheet name</td></tr>
-     *      <tr><td>'O''Brien''s Sales'!A1'&nbsp;</td><td>Sheet name with special characters</td></tr>
-     *    </table>
-     * @return the text representation of this cell reference as it would appear in a formula.
-     */
-    public String formatAsString() {
-        StringBuffer sb = new StringBuffer(32);
-        if(_sheetName != null) {
-            SheetNameFormatter.appendFormat(sb, _sheetName);
-            sb.append(SHEET_NAME_DELIMITER);
-        }
-        appendCellReference(sb);
-        return sb.toString();
-    }
-    
-    public String toString() {
-        StringBuffer sb = new StringBuffer(64);
-        sb.append(getClass().getName()).append(" [");
-        sb.append(formatAsString());
-        sb.append("]");
-        return sb.toString();
-    }
-    
 	/**
 	 * Returns the three parts of the cell reference, the
 	 *  Sheet name (or null if none supplied), the 1 based
@@ -433,18 +453,18 @@ public class CellReference {
 		};
 	}
 
-    /**
-     * Appends cell reference with '$' markers for absolute values as required.
-     * Sheet name is not included.
-     */
-    protected void appendCellReference(StringBuffer sb) {
-        if(_isColAbs) {
-            sb.append(ABSOLUTE_REFERENCE_MARKER);
-        }
-        sb.append( convertNumToColString(_colIndex));
-        if(_isRowAbs) {
-            sb.append(ABSOLUTE_REFERENCE_MARKER);
-        }
-        sb.append(_rowIndex+1);
-    }
+	/**
+	 * Appends cell reference with '$' markers for absolute values as required.
+	 * Sheet name is not included.
+	 */
+	/* package */ void appendCellReference(StringBuffer sb) {
+		if(_isColAbs) {
+			sb.append(ABSOLUTE_REFERENCE_MARKER);
+		}
+		sb.append( convertNumToColString(_colIndex));
+		if(_isRowAbs) {
+			sb.append(ABSOLUTE_REFERENCE_MARKER);
+		}
+		sb.append(_rowIndex+1);
+	}
 }