public static bool IsAccumulator(this AstUnaryOperator @operator, out AstAccumulatorOperator accumulatorOperator)
{
switch (@operator)
{
case AstUnaryOperator.AddToSet: accumulatorOperator = AstAccumulatorOperator.AddToSet; return(true);
case AstUnaryOperator.Avg: accumulatorOperator = AstAccumulatorOperator.Avg; return(true);
case AstUnaryOperator.First: accumulatorOperator = AstAccumulatorOperator.First; return(true);
case AstUnaryOperator.Last: accumulatorOperator = AstAccumulatorOperator.Last; return(true);
case AstUnaryOperator.Max: accumulatorOperator = AstAccumulatorOperator.Max; return(true);
case AstUnaryOperator.Min: accumulatorOperator = AstAccumulatorOperator.Min; return(true);
case AstUnaryOperator.Push: accumulatorOperator = AstAccumulatorOperator.Push; return(true);
case AstUnaryOperator.StdDevPop: accumulatorOperator = AstAccumulatorOperator.StdDevPop; return(true);
case AstUnaryOperator.StdDevSamp: accumulatorOperator = AstAccumulatorOperator.StdDevSamp; return(true);
case AstUnaryOperator.Sum: accumulatorOperator = AstAccumulatorOperator.Sum; return(true);
default: accumulatorOperator = default; return(false);
}
}
public static string Render(this AstAccumulatorOperator @operator)
{
return(@operator switch
{
AstAccumulatorOperator.AddToSet => "$addToSet",
AstAccumulatorOperator.Avg => "$avg",
AstAccumulatorOperator.First => "$first",
AstAccumulatorOperator.Last => "$last",
AstAccumulatorOperator.Max => "$max",
AstAccumulatorOperator.MergeObjects => "$mergeObjects",
AstAccumulatorOperator.Min => "$min",
AstAccumulatorOperator.Push => "$push",
AstAccumulatorOperator.StdDevPop => "$stdDevPop",
AstAccumulatorOperator.StdDevSamp => "$stdDevSamp",
AstAccumulatorOperator.Sum => "$sum",
_ => throw new InvalidOperationException($"Unexpected accumulator operator: {@operator}.")
});
public static AstAccumulatorField AccumulatorField(string name, AstAccumulatorOperator @operator, AstExpression arg)
{
var value = new AstAccumulatorExpression(@operator, arg);
return(new AstAccumulatorField(name, value));
}
public static AstAccumulatorExpression AccumulatorExpression(AstAccumulatorOperator @operator, AstExpression arg)
{
return(new AstAccumulatorExpression(@operator, arg));
}
public AstAccumulatorExpression(AstAccumulatorOperator @operator, AstExpression arg)
{
_operator = @operator;
_arg = Ensure.IsNotNull(arg, nameof(arg));
}
