private static TResult CompileExpressionItem <TResult>(Expression expression)
{
var visitor = new TestExpressionVisitor();
var body = visitor.Visit(expression);
var f = Expression.Lambda <Func <TResult> >(body ?? throw new InvalidOperationException($"{nameof(body)} is null"), (IEnumerable <ParameterExpression>)null);
return(f.Compile()());
}
private static TResult CompileExpressionItem <TResult>(Expression expression)
{
var rewriter = new TestExpressionVisitor();
var body = rewriter.Visit(expression);
var f = Expression.Lambda <Func <TResult> >(body, (IEnumerable <ParameterExpression>)null);
return(f.Compile()());
}
public async Task SimpleVisitor()
{
var visitor = new TestExpressionVisitor();
var service = TcpTestService.Create(QbservableServiceOptions.Default.Add(visitor), Observable.Range(1, 5));
var results = await service.QueryAsync(source => from value in source
where value % 2 == 0
select value);
QactiveAssert.AreEqual(results, OnNext(2), OnNext(4), OnCompleted <int>());
QactiveAssert.AreEqual(visitor.Visited,
Call <int>(typeof(Qbservable), "Where", Any.ExpressionOfType <IQbservable <int> >(), Any.LambdaExpression <Func <int, bool> >(Any.ParameterExpression <int>())),
Any.ExpressionOfType <IQbservable <int> >(ExpressionType.Constant),
Any.QuotedLambdaExpression <Func <int, bool> >(Any.ParameterExpression <int>()),
Any.LambdaExpression <Func <int, bool> >(Any.ParameterExpression <int>()),
Any.ExpressionOfType(ExpressionType.Equal),
Any.ExpressionOfType(ExpressionType.Modulo),
Any.ParameterExpression <int>(),
Expression.Constant(2),
Expression.Constant(0),
Any.ParameterExpression <int>());
}
