rebuilding expressions

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

@@ -98,7 +98,12 @@ class Cell implements Comparable<Cell>
       char operator = m.group (1).isEmpty () ? '+' : m.group (1).charAt (0);
 
       if (m.group (3) != null)                                    // address
-        interim = parent.getValue (m.group (3));
+      {
+        Address address = new Address (m.group (3));
+        Cell cell = parent.getCell (address);
+        if (cell != null)
+          interim = cell.getValue ();
+      }
       else if (m.group (4) != null)                               // constant
         try
         {

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

@@ -1,6 +1,6 @@
 package com.bytezone.diskbrowser.visicalc;
 
-public class Count
+public class Count extends Function
 {
   Range range;
   Sheet parent;
@@ -11,6 +11,7 @@ public class Count
     range = parent.getRange (text);
   }
 
+  @Override
   public double getValue ()
   {
     double result = 0;

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

@@ -0,0 +1,192 @@
+package com.bytezone.diskbrowser.visicalc;
+
+import java.util.regex.Pattern;
+
+public class Expression
+{
+  // Expressions:
+  //  - number
+  //  - cell address
+  //  - function
+  //  - expression [+-*/^] expression
+  //  - [+-=] expression
+  //  - ( expression )
+
+  private static final Pattern pattern = Pattern.compile ("");
+
+  private boolean isUnavailable;
+  private boolean isError;
+
+  private boolean hasValue;
+  private double value;
+  private Function function;
+  private Address address;
+
+  private Expression expression1;
+  private char operator;
+  private Expression expression2;
+
+  private final Sheet parent;
+
+  public Expression (Sheet parent, String input)
+  {
+    this.parent = parent;
+    String text = input.trim ();
+
+    char firstChar = text.charAt (0);
+    if (firstChar == '-')
+    {
+      operator = '-';
+      expression1 = new Expression (parent, text.substring (1));
+    }
+    else if (firstChar == '=' || firstChar == '+')
+    {
+      expression1 = new Expression (parent, text.substring (1));
+    }
+    else if (firstChar == '@')
+    {
+      String functionText = getFunctionText (text);
+      char op = getOperator (functionText, text);
+      if (op == ' ')
+        function = Function.getInstance (parent, functionText);
+      else if (op != '!')
+        setExpressions (functionText, op, text);
+    }
+    else if (firstChar == '(')
+    {
+      String bracketText = getFunctionText (text);
+      char op = getOperator (bracketText, text);
+      if (op == ' ')
+        expression1 =
+            new Expression (parent, bracketText.substring (1, bracketText.length () - 2));
+      else if (op != '!')
+        setExpressions (bracketText, op, text);
+    }
+    else if ((firstChar >= '0' && firstChar <= '9') || firstChar == '.')
+    {
+      String numberText = getNumberText (text);
+      char op = getOperator (numberText, text);
+      if (op == ' ')
+      {
+        value = Double.parseDouble (numberText);
+        hasValue = true;
+      }
+      else if (op != '!')
+        setExpressions (numberText, op, text);
+    }
+    else if (firstChar >= 'A' && firstChar <= 'Z')
+    {
+      String addressText = getAddressText (text);
+      char op = getOperator (addressText, text);
+      if (op == ' ')
+        address = new Address (addressText);
+      else if (op != '!')
+        setExpressions (addressText, op, text);
+    }
+    else
+      System.out.printf ("Error processing [%s]%n", text);
+  }
+
+  private void setExpressions (String text1, char op, String text2)
+  {
+    expression1 = new Expression (parent, text1);
+    operator = op;
+    expression2 = new Expression (parent, text2.substring (text1.length () + 2));
+  }
+
+  double getValue ()
+  {
+    if (hasValue)
+      return value;
+
+    if (function != null)
+      return function.getValue ();
+
+    if (address != null)
+      return parent.getCell (address).getValue ();
+
+    if (expression2 == null)
+    {
+      if (operator == '-')
+        return expression1.getValue () * -1;
+      return expression1.getValue ();
+    }
+
+    switch (operator)
+    {
+      case ' ':
+        return expression1.getValue ();
+      case '+':
+        return expression1.getValue () + expression2.getValue ();
+      case '-':
+        return expression1.getValue () - expression2.getValue ();
+      case '*':
+        return expression1.getValue () * expression2.getValue ();
+      case '/':
+        return expression1.getValue () / expression2.getValue ();
+      case '^':
+        return Math.pow (expression1.getValue (), expression2.getValue ());
+    }
+
+    System.out.println ("Unresolved value");
+    return 0;
+  }
+
+  private String getFunctionText (String text)
+  {
+    int ptr = text.indexOf ('(');         // find first left parenthesis
+    int depth = 1;
+    while (++ptr < text.length ())        // find matching right parenthesis
+    {
+      if (text.charAt (ptr) == ')')
+      {
+        --depth;
+        if (depth == 0)
+          break;
+      }
+      else if (text.charAt (ptr) == '(')
+        ++depth;
+    }
+    return text.substring (0, ptr);
+  }
+
+  private String getNumberText (String text)
+  {
+    int ptr = 0;
+    while (++ptr < text.length ())
+    {
+      char c = text.charAt (ptr);
+      if (c != '.' && (c < '0' || c > '9'))
+        break;
+    }
+    return text.substring (0, ptr);
+  }
+
+  private String getAddressText (String text)
+  {
+    int ptr = 0;
+    while (++ptr < text.length ())
+    {
+      char c = text.charAt (ptr);
+      if ((c < '0' || c > '9') && (c < 'A' || c > 'Z'))
+        break;
+    }
+    return text.substring (0, ptr);
+  }
+
+  private char getOperator (String text1, String text2)
+  {
+    if (text1.length () == text2.length ())
+      return ' ';
+
+    char c = text2.charAt (text1.length ());
+    if (c == '+' || c == '-' || c == '*' || c == '/' || c == '^')
+    {
+      setExpressions (text1, c, text2);
+      return c;
+    }
+
+    // error
+    return '!';
+  }
+}

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

@@ -0,0 +1,26 @@
+package com.bytezone.diskbrowser.visicalc;
+
+public abstract class Function
+{
+  static Function getInstance (Sheet parent, String text)
+  {
+    if (text.startsWith ("@LOOKUP("))
+      return new Lookup (parent, text);
+
+    if (text.startsWith ("@COUNT("))
+      return new Count (parent, text);
+
+    if (text.startsWith ("@MIN("))
+      return new Min (parent, text);
+
+    if (text.startsWith ("@MAX("))
+      return new Max (parent, text);
+
+    if (text.startsWith ("@SUM("))
+      return new Sum (parent, text);
+
+    return null;
+  }
+
+  abstract double getValue ();
+}

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

@@ -1,22 +1,21 @@
 package com.bytezone.diskbrowser.visicalc;
 
-public class Lookup
+public class Lookup extends Function
 {
   Range range;
   Cell source;
   Sheet parent;
   boolean hasValue;
+  String sourceText;
+  String rangeText;
 
   public Lookup (Sheet parent, String text)
   {
     this.parent = parent;
 
     int pos = text.indexOf (',');
-    String sourceText = text.substring (8, pos);
-    String rangeText = text.substring (pos + 1, text.length () - 1);
-
-    source = parent.getCell (new Address (sourceText));
-    range = parent.getRange (rangeText);
+    sourceText = text.substring (8, pos);
+    rangeText = text.substring (pos + 1, text.length () - 1);
   }
 
   // need a mechanism to return NA and ERROR
@@ -25,18 +24,28 @@ public class Lookup
     return hasValue;
   }
 
+  @Override
   public double getValue ()
   {
+    // source could be a formula - @LOOKUP(.2*K8+K7,H3...H16)
+    source = parent.getCell (new Address (sourceText));
+    range = parent.getRange (rangeText);
+
     Address target = null;
     for (Address address : range)
     {
-      if (parent.getCell (address).getValue () > source.getValue ())
+      System.out.printf ("%s : %s%n", source, address);
+      Cell cell = parent.getCell (address);
+      if (cell != null && cell.getValue () > source.getValue ())
         break;
       target = address;
     }
 
     if (target != null)
+      if (range.isVertical ())
         return parent.getCell (target.nextColumn ()).getValue ();
+      else
+        return parent.getCell (target.nextRow ()).getValue ();
 
     return 0;
   }

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

@@ -1,6 +1,6 @@
 package com.bytezone.diskbrowser.visicalc;
 
-public class Max
+public class Max extends Function
 {
   Range range;
   Sheet parent;
@@ -11,6 +11,7 @@ public class Max
     range = parent.getRange (text);
   }
 
+  @Override
   public double getValue ()
   {
     double max = Double.MIN_VALUE;

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

@@ -1,6 +1,6 @@
 package com.bytezone.diskbrowser.visicalc;
 
-public class Min
+public class Min extends Function
 {
   Range range;
   Sheet parent;
@@ -11,6 +11,7 @@ public class Min
     range = parent.getRange (text);
   }
 
+  @Override
   public double getValue ()
   {
     double min = Double.MAX_VALUE;

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

@@ -39,6 +39,20 @@ class Range implements Iterable<Address>
       range.add (new Address (s));
   }
 
+  boolean isHorizontal ()
+  {
+    Address first = range.get (0);
+    Address last = range.get (range.size () - 1);
+    return first.row == last.row;
+  }
+
+  boolean isVertical ()
+  {
+    Address first = range.get (0);
+    Address last = range.get (range.size () - 1);
+    return first.column == last.column;
+  }
+
   @Override
   public String toString ()
   {

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

@@ -251,7 +251,7 @@ public class Sheet implements Iterable<Cell>
           currentCell.doCommand (command);
       }
     }
-    else if (command.startsWith ("@"))
+    else if (command.startsWith ("@"))              // function
     {
       currentCell.doCommand (command);
     }
@@ -414,19 +414,19 @@ public class Sheet implements Iterable<Cell>
     return range;
   }
 
-  public double getValue (Address address)
+  private double getValue (Address address)
   {
     Cell cell = sheet.get (address.sortValue);
     return cell == null ? 0.0 : cell.getValue ();
   }
 
-  public double getValue (String cellName)
+  private double getValue (String cellName)
   {
     Address address = new Address (cellName);
     return getValue (address);
   }
 
-  public Cell getCell (Address address)
+  Cell getCell (Address address)
   {
     return sheet.get (address.sortValue);
   }

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

@@ -1,6 +1,6 @@
 package com.bytezone.diskbrowser.visicalc;
 
-public class Sum
+public class Sum extends Function
 {
   Range range;
   Sheet parent;
@@ -11,6 +11,7 @@ public class Sum
     range = parent.getRange (text);
   }
 
+  @Override
   public double getValue ()
   {
     double result = 0;