handle NaN

src/com/bytezone/diskbrowser/visicalc/Cell.java

@@ -125,6 +125,8 @@ class Cell implements Comparable<Cell>, Value
           return justify (value.getText (), colWidth);
 
         Double thisValue = value.getValue ();
+        if (thisValue.isNaN ())
+          return justify ("NaN", colWidth);
 
         char format = cellFormat != ' ' ? cellFormat : defaultFormat;
         if (format == 'I')
@@ -213,7 +215,7 @@ class Cell implements Comparable<Cell>, Value
   {
     if (!isValue ())
     {
-      //      System.out.println ("Not a value");
+      //      System.out.println (value);
       return this;
     }
     assert isValue () : "Cell type: " + type + " @ " + address;

src/com/bytezone/diskbrowser/visicalc/Count.java

@@ -31,6 +31,7 @@ class Count extends Function
       if (cell.getValue () != 0.0)
         value++;
     }
+
     return this;
   }
 }

src/com/bytezone/diskbrowser/visicalc/Expression.java

@@ -272,6 +272,7 @@ class Expression implements Value
       else if (text.charAt (ptr) == '(')
         ++depth;
     }
+
     return text.substring (0, ptr + 1);   // include closing parenthesis
   }