/// <summary>
/// Recalculate a cell's value from it's formula
/// </summary>
private ResultSet RefreshCell(int x, int y, bool formulaChanged)
{
var gc = bigGrid1.Items[x, y] as GridCell ?? new GridCell();
var rs = new ResultSet {Result = gc.Value};
if (formulaChanged) {// Clear out old refs and add new ones:
rs = RecalculateFromCell(x, y);
var data = new SheetDataTableAdapters.DependsAdapter();
ulong key = bigGrid1.Items.GetUniqueKey(x, y);
data.ClearDependenciesForHash((long)key);
foreach (var refr in rs.References) {
data.AddDependency((long)key, (long)bigGrid1.Items.GetUniqueKey(refr.X, refr.Y));
}
UpdateCell(gc, x, y);
return rs;
}
Stack<string> rpn = null;
try {
rpn = calculator.InfixToPostfix(gc.Formula ?? "");
} catch (Exception ex) {
gc.Value = "Formula Error: " + ex.Message;
}
if (rpn != null && rpn.Count > 0) { // formula is non-empty
try {
rs = calculator.EvaluatePostfix(rpn, y, x);
gc.Value = rs.Result;
} catch (Exception ex) {
gc.Value = "Calculation Error: " + ex.Message;
}
}
UpdateCell(gc,x,y);
return rs;
}
/// <summary>
/// Evaluate the result of a postfix expression string.
/// Expected to be space-delimited
/// </summary>
public ResultSet EvaluatePostfix(Stack<string> postfix, int row, int column)
{
// very simple for the moment, doesn't handle variables or functions
var @out = new ResultSet();
var values = new Stack<CValue>();
values.Push(new CValue((decimal)0.0)); // quick hack to deal with leading uniary operators
foreach (string token in postfix/*.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)*/) {
if (String.IsNullOrEmpty(token)) continue;
decimal value;
if (decimal.TryParse(token, out value)) {
values.Push(new CValue(value));
continue;
}
CValue l, r;
switch (token.ToLowerInvariant()) {
case "+":
r = values.Pop(); l = values.Pop();
values.Push(l + r);
break;
case "-":
r = values.Pop(); l = values.Pop();
values.Push(l - r);
break;
case "*":
r = values.Pop(); l = values.Pop();
values.Push(l * r);
break;
case "/":
r = values.Pop(); l = values.Pop();
values.Push(l / r);
break;
case "^":
r = values.Pop(); l = values.Pop();
values.Push(CValue.Pow(l, r));
break;
case "%":
r = values.Pop(); l = values.Pop();
values.Push(l % r);
break;
case "!":
l = CValue.Floor(values.Pop());
decimal f = 1;
for (var c = (int)l.NumericValue; c > 0; c--) { f *= c; }
values.Push(new CValue(f));
break;
// not used in postfix notation:
case ",":
case "(":
case ")":
throw new Exception("Unexpected token in Postfix");
default:
if (token.StartsWith("['") && token.EndsWith("']")) {
// it's a string literal. Like this: ['String literal']
values.Push(new CValue(token.Substring(2, token.Length - 4)));
} else {
@out.References.AddRange(
funcs.HandleFunction(token, values, column, row)
);
}
break;
}
} // end foreach
@out.Result = values.Pop().ToString();
return @out;
}