/// <summary>
/// Evaluates the specified expression.
/// </summary>
/// <param name="expression">The expression.</param>
/// <returns>Result of the expression evaluated</returns>
public ExpressionResult Evaluate(Expression expression)
{
values.Clear();
result = new ExpressionResult();
// Small optim, if LiteralExpression, we perform a direct eval.
var literalExpression = expression as LiteralExpression;
if (literalExpression != null)
{
Visit(literalExpression);
}
else
{
VisitDynamic(expression);
}
if (values.Count == 1)
{
result.Value = values.Pop();
}
else
{
result.Error("Cannot evaluate expression {0}", expression.Span, expression);
}
return(result);
}
protected virtual void Visit(BinaryExpression binaryExpression)
{
Visit((Node)binaryExpression);
var rightValue = values.Pop();
var leftValue = values.Pop();
switch (binaryExpression.Operator)
{
case BinaryOperator.Plus:
values.Push(leftValue + rightValue);
break;
case BinaryOperator.Minus:
values.Push(leftValue - rightValue);
break;
case BinaryOperator.Multiply:
values.Push(leftValue * rightValue);
break;
case BinaryOperator.Divide:
values.Push(leftValue / rightValue);
break;
case BinaryOperator.Modulo:
values.Push(leftValue % rightValue);
break;
case BinaryOperator.LeftShift:
values.Push((int)leftValue << (int)rightValue);
break;
case BinaryOperator.RightShift:
values.Push((int)leftValue >> (int)rightValue);
break;
case BinaryOperator.BitwiseOr:
values.Push(((int)leftValue) | ((int)rightValue));
break;
case BinaryOperator.BitwiseAnd:
values.Push(((int)leftValue) & ((int)rightValue));
break;
case BinaryOperator.BitwiseXor:
values.Push(((int)leftValue) ^ ((int)rightValue));
break;
default:
result.Error("Binary operator [{0}] is not supported", binaryExpression.Span, binaryExpression);
values.Push(0);
break;
}
}
public override void DefaultVisit(Node node)
{
var expression = node as Expression;
if (expression != null)
{
if (!(expression is BinaryExpression || expression is MethodInvocationExpression || expression is VariableReferenceExpression || expression is LiteralExpression || expression is ParenthesizedExpression || expression is UnaryExpression))
{
result.Error("Expression evaluation [{0}] is not supported", expression.Span, expression);
}
}
}
/// <summary>
/// Evaluates the specified expression.
/// </summary>
/// <param name="expression">The expression.</param>
/// <returns>Result of the expression evaluated</returns>
public ExpressionResult Evaluate(Expression expression)
{
values.Clear();
result = new ExpressionResult();
// Small optim, if LiteralExpression, we perform a direct eval.
var literalExpression = expression as LiteralExpression;
if (literalExpression != null)
{
Visit(literalExpression);
}
else
{
VisitDynamic(expression);
}
if (values.Count == 1)
result.Value = values.Pop();
else
{
result.Error("Cannot evaluate expression {0}", expression.Span, expression);
}
return result;
}
protected virtual void Visit(Expression expression)
{
result.Error("Expression evaluation [{0}] is not supported", expression.Span, expression);
}
