New Cool Features of C# 4.0

.net, c#, c#-4.0

Solution

The dynamic stuff sounds cool if you need it but I don't expect to use it very often.

The generic variance for delegates and interfaces is similar - the lack of variance is a headache at the moment, but many of the places where it's a pain won't be covered by the limited variance available in C# 4.

The COM features don't particularly interest me - I really ought to get more of a handle on what they are though.

Optional and named parameters could make a big difference when building immutable types: it enables syntax like:

Person p = new Person (name: "Jon", age: 32);

without having mammoth combinations of constructor overloads. I'd prefer a bit more support for writing immutable types in the form of readonly automatically implemented properties, but I don't expect we'll get those. (They certainly aren't in the proposed feature list at the moment.)

I'm personally actually more interested in a couple of the framework features of .NET 4.0 - in particular code contracts and parallel extensions.

Problem

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