generic-variance Questions
2
Solved
Could you please explain using small and simple TypeScript examples what is Variance, Covariance, Contravariance, Bivariance and Invariance?
Goober asked 28/2, 2021 at 14:30
2
Solved
Recently I ran into a problem where I had a function which had to return an Array of Is, in form of all values of enum E, with E implementing interface I, with every code that came to my mind compi...
Breathtaking asked 15/1, 2019 at 14:27
1
I've been recently learning Kotlin, while having some questions with covariant type.
The sample code is here.
I have Option and Option2 both having a type parameter T and a run extension.
I coul...
Kopans asked 19/4, 2019 at 16:50
2
Solved
I'm new to Kotlin.
When I learn Storing Properties in a Map. I try following usage.
class User(val map: MutableMap<String, String>) {
val name: String by map
}
class User(val map: Mutab...
Arginine asked 21/6, 2017 at 1:27
1
Solved
In the following sample, I can pass a Consumer<Optional<Integer> to foo, but not a Consumer<Optional<Number>>. On the other hand, I can pass either type to foo2, but then I can...
Ballonet asked 30/6, 2017 at 8:3
1
Solved
In coursera functional programming course, I came across a subtle concept.
If A2 <: A1 and B1 <: B2, then (A1 => B1) <: (A2 => B2)
Justification
when we pass an argument to A2 and beca...
Lyallpur asked 12/12, 2016 at 9:52
3
Solved
The following raises complaints:
interface IInvariant<TInv> {}
interface ICovariant<out TCov> {
IInvariant<TCov> M(); // The covariant type parameter `TCov'
// must be invarian...
Connective asked 17/5, 2016 at 14:27
3
Solved
Assume I have an interface such as
public interface IInterface<in TIn, out TOut> {
IInterface<TIn, TOut> DoSomething(TIn input);
}
TIn being contra-variant, and TOut being co-varian...
Sitter asked 18/2, 2016 at 11:51
2
Solved
Take this small LINQPad example:
void Main()
{
Foo<object> foo = new Foo<string>();
Console.WriteLine(foo.Get());
}
class Foo<out T>
{
public T Get()
{
return default...
Declaim asked 20/3, 2015 at 13:37
2
Solved
The codes below are exactly the same, except that one is C# and the other one is VB.Net.
C# compiles just fine, but VB.Net throws the warning:
Interface 'System.IObserver(Of Foo)' is ambiguous w...
Copro asked 27/12, 2011 at 18:2
2
Solved
Currently I'm preparing a presentation of the new generic variance features in C# for my colleagues. To cut the story short I wrote following lines:
IList<Form> formsList = new List<Form&...
Tabbie asked 26/10, 2011 at 18:45
3
Solved
First, sorry for the vague question title. I couldn't come up with a more precise one.
Given these types:
{ TCommand : ICommand }
«interface» «interface» /
+-----------+ +--------------------...
Cecilycecity asked 10/8, 2011 at 11:43
1
Solved
Inspired by Real-world examples of co- and contravariance in Scala I thought a better question would be:
When designing a library, are there a specific set of questions you should ask yourself whe...
Candelabrum asked 11/3, 2011 at 23:34
2
Solved
I didn't attend PDC 2008, but I heard some news that C# 4.0 is announced to support Generic covariance and contra-variance. That is, List<string> can be assigned to List<object>. How co...
Relations asked 29/10, 2008 at 2:27
3
Solved
Generic Variance in C# 4.0 has been implemented in such a way that it's possible to write the following without an exception (which is what would happen in C# 3.0):
List<int> intList = new ...
Pauwles asked 5/2, 2010 at 14:58
1
© 2022 - 2024 — McMap. All rights reserved.