public static IQueryable <TResult> Select <TSource, TResult>(this IAqlModifiable <TSource> source, Expression <Func <TSource, TSource, TResult> > selector)
{
var newSelector = ExpressionParameterRewriter.RewriteParameters(selector, "NEW", "OLD");
return(source.Provider.CreateQuery <TResult>(
Expression.Call(
FindExtention("SelectModification", typeof(TSource), typeof(TResult)),
source.Expression,
Expression.Quote(newSelector))));
}
public static Expression <T> Compose <T>(this Expression <T> first, Expression <T> second,
Func <Expression, Expression, Expression> merge)
{
// build parameter map (from parameters of second to parameters of first)
var map = first.Parameters.Select((f, i) => new { f, s = second.Parameters[i] })
.ToDictionary(p => p.s, p => p.f);
// replace parameters in the second lambda expression with parameters from the first
var secondBody = ExpressionParameterRewriter.ReplaceParameters(map, second.Body);
// apply composition of lambda expression bodies to parameters from the first expression
return(Expression.Lambda <T>(merge(first.Body, secondBody), first.Parameters));
}
internal static IAqlModifiable <TSource> InternalUpsert <TSource, TOld>(this IQueryable <TSource> source, Expression <Func <TSource, object> > searchExpression,
Expression <Func <TSource, object> > insertExpression, Expression <Func <TSource, TOld, object> > updateExpression, Type updateType)
{
var newUpdateExp = ExpressionParameterRewriter.RewriteParameterAt(updateExpression, 1, "OLD");
return(source.Provider.CreateQuery <TSource>(
Expression.Call(
FindExtention("InternalUpsert", typeof(TSource), typeof(TOld)),
source.Expression,
Expression.Quote(searchExpression),
Expression.Quote(insertExpression),
Expression.Quote(newUpdateExp),
Expression.Constant(updateType)
)) as IAqlModifiable <TSource>);
}
