public static Object Eval(ExpressionNode node, IDataResolver dataResolver)
{
var operatorNode = (OperatorNode)node;
if (String.Equals(node.Action, "||"))
{
var leftFlag = Convert.ToBoolean(ExpressionEvaluator.Eval(operatorNode.Left, dataResolver));
if (leftFlag)
{
return(true);
}
return(Convert.ToBoolean(ExpressionEvaluator.Eval(operatorNode.Right, dataResolver)));
}
if (String.Equals(node.Action, "&&"))
{
var leftFlag = Convert.ToBoolean(ExpressionEvaluator.Eval(operatorNode.Left, dataResolver));
if (!leftFlag)
{
return(false);
}
return(Convert.ToBoolean(ExpressionEvaluator.Eval(operatorNode.Right, dataResolver)));
}
var leftNode = operatorNode.Left;
var rightNode = operatorNode.Right;
var leftValue = ExpressionEvaluator.Eval(leftNode, dataResolver);
var rightValue = ExpressionEvaluator.Eval(rightNode, dataResolver);
switch (node.Action.ToLower())
{
case "!":
return(!Convert.ToBoolean(rightValue));
case "+":
{
if (leftNode == null)
{
return(+ExpressionHelper.GetNumber(rightValue));
}
if (ExpressionHelper.IsDateTimeNode(leftNode, leftValue) || ExpressionHelper.IsDateTimeNode(rightNode, rightValue))
{
var leftDate = ExpressionHelper.GetDateTime(leftValue);
var rightDate = ExpressionHelper.GetDateTime(rightValue);
return(leftDate.AddTicks(rightDate.Ticks));
}
return(ExpressionHelper.GetNumber(leftValue) + ExpressionHelper.GetNumber(rightValue));
}
case "++":
return(ExpressionHelper.GetNumber(rightValue) + 1D);
case "-":
{
if (leftNode == null)
{
return(-ExpressionHelper.GetNumber(rightValue));
}
if (ExpressionHelper.IsDateTimeNode(leftNode, leftValue) || ExpressionHelper.IsDateTimeNode(rightNode, rightValue))
{
var leftDate = ExpressionHelper.GetDateTime(leftValue);
var rightDate = ExpressionHelper.GetDateTime(rightValue);
var ticksDiff = Math.Abs(leftDate.Ticks - rightDate.Ticks);
return(new DateTime(ticksDiff));
}
return(ExpressionHelper.GetNumber(leftValue) - ExpressionHelper.GetNumber(rightValue));
}
case "--":
return(ExpressionHelper.GetNumber(rightValue) - 1D);
case "=":
{
var name = leftNode.Action;
dataResolver.SetValue(name, rightValue);
return(rightValue);
}
case "==":
return(ExpressionHelper.Compare(leftNode, leftValue, rightNode, rightValue) == 0);
case "!=":
case "<>":
return(ExpressionHelper.Compare(leftNode, leftValue, rightNode, rightValue) != 0);
case "<=":
return(ExpressionHelper.Compare(leftNode, leftValue, rightNode, rightValue) <= 0);
case ">=":
return(ExpressionHelper.Compare(leftNode, leftValue, rightNode, rightValue) >= 0);
case "&&":
return(Convert.ToBoolean(leftValue) && Convert.ToBoolean(rightValue));
case "||":
return(Convert.ToBoolean(leftValue) || Convert.ToBoolean(rightValue));
case "^":
{
var a = ExpressionHelper.GetNumber(leftValue);
var b = ExpressionHelper.GetNumber(rightValue);
return(Math.Pow(a, b));
}
case "&":
return(String.Concat(leftValue, rightValue));
case "|":
return(ExpressionHelper.GetNumber(leftValue) % ExpressionHelper.GetNumber(rightValue));
case "%":
return(ExpressionHelper.GetNumber(leftValue) / 100D * ExpressionHelper.GetNumber(rightValue));
case "*":
return(ExpressionHelper.GetNumber(leftValue) * ExpressionHelper.GetNumber(rightValue));
case "/":
case "\\":
return(ExpressionHelper.GetNumber(leftValue) / ExpressionHelper.GetNumber(rightValue));
case "<":
return(ExpressionHelper.Compare(leftNode, leftValue, rightNode, rightValue) < 0);
case ">":
return(ExpressionHelper.Compare(leftNode, leftValue, rightNode, rightValue) > 0);
}
var message = $"Unknown operator '{node.Action}'";
throw new Exception(message);
}
