public static double Eval(string expression)
{
expression = Normalize(expression);
string rpn = GetRPN(expression);
Stack stVals = new Stack();
RPNEnumerator rpnEnum = new RPNEnumerator(rpn);
while (rpnEnum.MoveNext())
{
RPNValue rpnVal = (RPNValue)rpnEnum.Current;
if (rpnVal.type == RPNValueType.OPERAND)
{
stVals.Push(Double.Parse(rpnVal.val, new CultureInfo("en-US")));
}
else
{
double v2 = (double)stVals.Pop();
double v1 = (double)stVals.Pop();
if (rpnVal.val == "+")
{
stVals.Push(v1 + v2);
}
else if (rpnVal.val == "-")
{
stVals.Push(v1 - v2);
}
else if (rpnVal.val == "*")
{
stVals.Push(v1 * v2);
}
else if (rpnVal.val == "/")
{
stVals.Push(v1 / v2);
}
}
}
return (double)stVals.Pop();
}
public static IExpression GenerateExpressionFromString(string strExpr, IMetadataHost host, IMethodDefinition method)
{
strExpr = Normalize(strExpr);
string rpn = GetRPN(strExpr);
Stack<IExpression> stVals = new Stack<IExpression>();
RPNEnumerator rpnEnum = new RPNEnumerator(rpn);
var int32Type = host.PlatformType.SystemInt32;
var boolType = host.PlatformType.SystemBoolean;
while (rpnEnum.MoveNext())
{
RPNValue rpnVal = (RPNValue)rpnEnum.Current;
if (rpnVal.type == RPNValueType.OPERAND)
{
if (reNum.IsMatch(rpnVal.val))
{
stVals.Push(new CompileTimeConstant() { Type = int32Type, Value = int.Parse(rpnVal.val.Replace(':', '-')) });
}
else
{
IExpression expr = null;
var exprParts = rpnVal.val.Split('.');
if (exprParts[0] == "this")
{
expr = new ThisReference() { Type = method.ContainingType.ResolvedType };
}
else
{
foreach (var arg in method.Parameters)
{
if (arg.Name.Value == exprParts[0])
{
expr = new BoundExpression() { Type = arg.Type.ResolvedType, Definition = arg };
break;
}
}
}
if (expr != null && exprParts.Length > 1)
{
for (int i = 1; i < exprParts.Length; i++)
{
expr = GetExprWithAccesor(expr, exprParts[i], host);
}
}
if (expr == null || expr.Type.ResolvedType != int32Type.ResolvedType)
{
return null;
}
stVals.Push(expr);
}
}
else
{
var v1 = stVals.Pop();
var v2 = stVals.Pop();
if (rpnVal.val == "+") stVals.Push(new Addition() { Type = int32Type, LeftOperand = v2, RightOperand = v1 });
else if (rpnVal.val == "-") stVals.Push(new Subtraction() { Type = int32Type, LeftOperand = v2, RightOperand = v1 });
else if (rpnVal.val == "*") stVals.Push(new Multiplication() { Type = int32Type, LeftOperand = v2, RightOperand = v1 });
else if (rpnVal.val == "/") stVals.Push(new Division() { Type = int32Type, LeftOperand = v2, RightOperand = v1 });
else if (rpnVal.val == "=") stVals.Push(new Equality() { Type = int32Type, LeftOperand = v2, RightOperand = v1 });
else if (rpnVal.val == "&") stVals.Push(new Conditional() { Type = boolType, Condition = v2, ResultIfTrue = v1, ResultIfFalse = new CompileTimeConstant() { Type = int32Type, Value = 0 } });
else if (rpnVal.val == "|") stVals.Push(new Conditional() { Type = boolType, Condition = v2, ResultIfTrue = new CompileTimeConstant() { Type = int32Type, Value = 1 }, ResultIfFalse = v1 });
else if (rpnVal.val == ">") stVals.Push(new GreaterThan() { Type = boolType, LeftOperand = v2, RightOperand = v1 });
else if (rpnVal.val == "<") stVals.Push(new LessThan() { Type = boolType, LeftOperand = v2, RightOperand = v1 });
else if (rpnVal.val == "%") stVals.Push(new GreaterThanOrEqual() { Type = boolType, LeftOperand = v2, RightOperand = v1 });
else if (rpnVal.val == "#") stVals.Push(new LessThanOrEqual() { Type = boolType, LeftOperand = v2, RightOperand = v1 });
else return null;
}
}
if (stVals.Count > 0)
{
return stVals.Pop();
}
return null;
}