Is it possible to pass a lambda expression to a secondary AppDomain as a stream of IL bytes and then assemble it back there using DynamicMethod so it can be called? I'm not too sure this is the right way to go in the first place, so here's the (detailed) reason I ask this question... In my applications, there are a lot of cases when I ...
I need to store a big list of integers in Bigtable(db). For efficiency I am storing them as diff between 2 consecutive items. for eg: original_list = [1005, 1004, 1003, 1004, 1006] Storing the above list(which actually contains more than 1000k items) as start = 1005 diff = [-1, -1, 1, 2] The closest I could manage is, ltp = [st...
I want to be able to call a method that creates an object and sets properties of the object based on the parameters passed into the method. The number of parameters is arbitrary, but the catch is I don't want to use strings. I want to use the actual properties sort of like you do in lambda expressions. I want to be able to call the me...
Why can't you use a ref or out parameter in a lambda expression? I came across the error today and found a workaround but I was still curious why this is a compile-time error. Here's a simple example: private void Foo() { int value; Bar(out value); } private void Bar(out int value) { value ...
How I do extend an linq expression whilst keeping it an expression? I've simplified this quite a bit (to avoid pasting pages) - .e.g I working with Queryable rather than Enumerable, but the solution for this will suffice, ultimately I need to keep it as an expression whilst adding a method call to it. For exampleL var p1 = new...
Hi experts, The following codes compiled and linked fine with g++-4.0 on a Mac OSX for_each(As.begin(), As.end(), boost::lambda::if_then( boost::lambda::bind(&A::get_string, boost::lambda::_1)==" CA ", boost::lambda::bind(&std::list<A>::push_back, &As_copy, boost::lambda::_1) ) ); But when I try to populate a conta...
Hi all, I can't seem to find boost::lambda::ll for a nested ll::for_each() invocations in any header file in the boost_1_39_0 distribution. Could someone point me to the right direction? Thanks. ...
(Note the code is an example) I have the following syntax: SomeMethod(() => x.Something) What do the first brackets mean in the expression? I'm also curious how you can get the property name from argument that is being passed in. Is this posssible? ...
private void StringAction(string aString) // method to be called { return; } private void TestDelegateStatement1() // doesn't work { var stringAction = new System.Action(StringAction("a string")); // Error: "Method expected" } private void TestDelegateStatement2() // doesn't work { var stringAction = new System.Action(p...
I have a function that has the following signature... public string DoJunk(Expression<Func<bool>> expression) I'm trying to find a way to convert the "expression" parameter back to something resembling the original source code (or at least a c# representation of the original souce code). So, if someone calls the function like this... ...
Is it possible to use a lambda expression inside an object initialization expression? Please look at the code below: XDocument doc = new XDocument( new XDeclaration("1.0", "utf-8", "yes"), new XElement("data", new XElement("album", new XElement("slide1"), new XElement("slide2"), ...
Is there an application or utility that will convert LINQ to Lambda Expressions? (or an add-on to LINQPad) ...
I would like to be able to store a list of expressions to execute with IQueryable.OrderBy at a later time, something like: List<Expression<Func<MyType, object>>> list = new List<Expression<Func<MyType, object>>>(); list.Add(x => x.Date); list.Add(x => x.ID); IOrderedQueryable<MyType> qry = query.OrderBy(list[0]).ThenBy(list[1]); ...
Hello, When I call the ToString() methods on an expression, the enum value are printed as integers. Is there some format overload ? Maybe I can create an derviedclass from expression and override some ToString Method. Any thoughts ? Here is a sample : public enum LengthUnits { METRES, FEET }; Expression<Func<LengthUnits, bo...
In the first method listed below, the use method, it looks to me like :ins is an instance variable and attr is a method that provides getters and setters for :ins. What I'm not sure is what the @ins << lambda does. module Rack class Builder attr :ins def use(middleware, *args, &block) middleware.instance_variable_set "@r...
I saw the following function in a posting which allows one to order data using a generic expression: public static IOrderedQueryable<T> OrderBy<T, TKey>( this IQueryable<T> source, Expression<Func<T, TKey>> func, bool isDescending) { return isDescending ? source.OrderByDescending(func) : source.OrderBy(func); } When I try to use t...
I have a linq query that needs to pull a date column out of a row. The expression currently looks like this myObject.OrderByDescending(s=> s.MyDate).Where(s => s.CRAStatus.Description == "CheckedOut").FirstOrDefault().MyDate) The problem is that if there are no rows that are "CheckedOut", the query will return a null and attempting to...
I have a bit of code that i'd like to turn into a linq expression (preferably with lambdas) to make it easier to use as a delegate. The code looks like this: List<DateTime[]> changes = new List<DateTime[]>(); changes = PopulateChanges(); for (int i = 0; i < changes.Count; i++) { for(int j = 0; j < changes[i].Length; j++) { ...
Given the following types: class Parent { List<Child> Children {get;set;}} class Child {List<Child> GrandChildren {get;set;}} class Helper<TEntity> {List<string> Properties {get;set;}} And given the following methods on Helper... public Helper AddProps<TEntity, TProp>(Expression<Func<TEntity, TProp>> exp) { this.Properties.Add(...
def divideset(rows, column, value) split_function = nil if value.is_a?(Fixnum) || value.is_a?(Float) split_function = lambda{|row| row[column] >= value} else split_function = lambda{|row| row[column] == value} end set1 = rows.select{|row| split_function.call(row)} set2 = rows.reject{|row| split_function.call(row)} [set1, set2] end ...