internal void QWhere <TSource>(Expression <Func <TSource, bool> > predicate)
{
LambdaExpression fixedPredicate = predicate;
if (GroupByKeySelector != null)
{
throw new NotSupportedException("Pomona LINQ provider does not support calling Where() after GroupBy()");
}
if (SelectExpression != null)
{
fixedPredicate = MergeWhereAfterSelect(fixedPredicate);
}
this.whereExpressions.Add(fixedPredicate);
if (WherePredicate == null)
{
WherePredicate = fixedPredicate;
}
else
{
var replacer = new LamdbaParameterReplacer(fixedPredicate.Parameters[0],
WherePredicate.Parameters[0]);
var rewrittenPredicateBody = replacer.Visit(fixedPredicate.Body);
WherePredicate = Expression.Lambda(
WherePredicate.Type,
Expression.AndAlso(WherePredicate.Body, rewrittenPredicateBody),
WherePredicate.Parameters);
}
}
private LambdaExpression MergeWhereAfterSelect(LambdaExpression predicate)
{
var parameter = Expression.Parameter(SelectExpression.Parameters[0].Type,
SelectExpression.Parameters[0].Name);
var fixedSelectExpr = LamdbaParameterReplacer.Replace(SelectExpression.Body,
SelectExpression.Parameters[0],
parameter);
var expandedBody = LamdbaParameterReplacer.Replace(predicate.Body, predicate.Parameters[0], fixedSelectExpr);
var newBody = new CollapseDisplayObjectsVisitor().Visit(expandedBody);
return(Expression.Lambda(newBody, parameter));
}
internal void QOfType <TResult>()
{
if (!ElementType.IsAssignableFrom(typeof(TResult)))
{
throw new NotSupportedException("Only supports OfType'ing to inherited type.");
}
if (SelectExpression != null)
{
throw new NotSupportedException("Does only support OfType at start of query.");
}
if (WherePredicate != null)
{
var newParam = Expression.Parameter(typeof(TResult), WherePredicate.Parameters[0].Name);
var replacer = new LamdbaParameterReplacer(WherePredicate.Parameters[0], newParam);
WherePredicate = Expression.Lambda(replacer.Visit(WherePredicate.Body), newParam);
}
ElementType = typeof(TResult);
}
