public async override Task VisitAsync(BinaryExpression expression)
{
// simulate Lazy<Func<>> behavior for late evaluation
object leftValue = null;
Func <Task <object> > left = async() =>
{
if (leftValue == null)
{
await expression.LeftExpression.AcceptAsync(this);
leftValue = Result;
}
return(leftValue);
};
// simulate Lazy<Func<>> behavior for late evaluation
object rightValue = null;
Func <Task <object> > right = async() =>
{
if (rightValue == null)
{
await expression.RightExpression.AcceptAsync(this);
rightValue = Result;
}
return(rightValue);
};
switch (expression.Type)
{
case BinaryExpressionType.And:
Result = Convert.ToBoolean(await left()) && Convert.ToBoolean(await right());
break;
case BinaryExpressionType.Or:
Result = Convert.ToBoolean(await left()) || Convert.ToBoolean(await right());
break;
case BinaryExpressionType.Div:
//Actually doesn't need checked here, since if one is real,
// checked does nothing, and if they are int the result will only be same or smaller
// (since anything between 1 and 0 is not int and 0 is an exception anyway
Result = IsReal(await left()) || IsReal(await right())
? Numbers.Divide(await left(), await right(), _options)
: Numbers.Divide(Convert.ToDouble(await left()), await right(), _options);
break;
case BinaryExpressionType.Equal:
// Use the type of the left operand to make the comparison
Result = CompareUsingMostPreciseType(await left(), await right()) == 0;
break;
case BinaryExpressionType.Greater:
// Use the type of the left operand to make the comparison
Result = CompareUsingMostPreciseType(await left(), await right()) > 0;
break;
case BinaryExpressionType.GreaterOrEqual:
// Use the type of the left operand to make the comparison
Result = CompareUsingMostPreciseType(await left(), await right()) >= 0;
break;
case BinaryExpressionType.Lesser:
// Use the type of the left operand to make the comparison
Result = CompareUsingMostPreciseType(await left(), await right()) < 0;
break;
case BinaryExpressionType.LesserOrEqual:
// Use the type of the left operand to make the comparison
Result = CompareUsingMostPreciseType(await left(), await right()) <= 0;
break;
case BinaryExpressionType.Minus:
Result = Checked ? Numbers.SoustractChecked(await left(), await right(), _options) : Numbers.Soustract(await left(), await right(), _options);
break;
case BinaryExpressionType.Modulo:
Result = Numbers.Modulo(await left(), await right());
break;
case BinaryExpressionType.NotEqual:
// Use the type of the left operand to make the comparison
Result = CompareUsingMostPreciseType(await left(), await right()) != 0;
break;
case BinaryExpressionType.Plus:
if (await left() is string)
{
Result = String.Concat(await left(), await right());
}
else
{
Result = Checked ? Numbers.AddChecked(await left(), await right(), _options) : Numbers.Add(await left(), await right(), _options);
}
break;
case BinaryExpressionType.Times:
Result = Checked ? Numbers.MultiplyChecked(await left(), await right(), _options) : Numbers.Multiply(await left(), await right(), _options);
break;
case BinaryExpressionType.BitwiseAnd:
Result = Convert.ToUInt16(await left()) & Convert.ToUInt16(await right());
break;
case BinaryExpressionType.BitwiseOr:
Result = Convert.ToUInt16(await left()) | Convert.ToUInt16(await right());
break;
case BinaryExpressionType.BitwiseXOr:
Result = Convert.ToUInt16(await left()) ^ Convert.ToUInt16(await right());
break;
case BinaryExpressionType.LeftShift:
Result = Convert.ToUInt16(await left()) << Convert.ToUInt16(await right());
break;
case BinaryExpressionType.RightShift:
Result = Convert.ToUInt16(await left()) >> Convert.ToUInt16(await right());
break;
}
}