/// <summary>
/// Deal with the aggregate operator coming in here.
/// </summary>
/// <param name="resultOperator"></param>
/// <param name="queryModel"></param>
/// <param name="_codeEnv"></param>
/// <returns></returns>
public Expression ProcessResultOperator(ResultOperatorBase resultOperator, QueryModel queryModel, IGeneratedQueryCode _codeEnv, ICodeContext context, CompositionContainer container)
{
///
/// Basic code checks
///
AggregateFromSeedResultOperator a = resultOperator as AggregateFromSeedResultOperator;
if (a == null)
{
throw new ArgumentNullException("result Operator must not be null and must be of type AggregateFromSeedResultOperator!");
}
if (a.Func.Parameters.Count != 1)
{
throw new InvalidOperationException("Aggregate only allows for a function with one parameters!");
}
if (a.OptionalResultSelector != null)
{
throw new NotImplementedException("Can't do a selector function yet");
}
// We need to declare a variable to hold the seed and its updates - the accumulator
// We then need to write the code that does the update to the seed.
// Finally, if there is a final function, we need to call that after the loop is done!
var accumulator = DeclarableParameter.CreateDeclarableParameterExpression(a.Seed.Type);
var newGC = new GeneratedCode(blockShouldBeBraced: false);
var newCC = new CodeContext();
accumulator.InitialValue = ExpressionToCPP.GetExpression(a.Seed, newGC, newCC, container);
if (newGC.CodeBody.Statements.Count() > 0)
{
accumulator.InitialValueCode = newGC;
}
_codeEnv.QueueForTransferFromGC(newGC);
///
/// Now, parse the lambda expression, doing a substitution with this guy! Note that the only argument is our
/// accumulator - the other arguments have all been replaced with subqueryexpressions and the like!
///
var p1 = context.Add(a.Func.Parameters[0].Name, accumulator);
var funcResolved = ExpressionToCPP.GetExpression(a.Func.Body, _codeEnv, context, container);
p1.Pop();
if (accumulator.RawValue != funcResolved.RawValue)
{
_codeEnv.Add(new Statements.StatementAggregate(accumulator, funcResolved));
}
return(accumulator);
}