C#7 features

[Simen Kjaeraas via Digitalmars-d-announce]

On Monday, 9 May 2016 at 00:44:09 UTC, Peter Häggman wrote:

> Their tuples seem to be a complete DIY:
>
> https://msdn.microsoft.com/en-us/library/system.tuple(v=vs.110).aspx
>
> I wouldn't be surpised to see in the implementation an array of 
> variant or something like that, explaining why it's limited to 
> octuples [1]. Sharp tuples look weak compared to D tuple-ish 
> things: Tuple, TList, AliasSeq, variadics, ...
>
> [1] Also I think that the param-"variadicity" is simply 
> emulated via a set of overloaded constructor, explaining why 
> they stop at 8.

C#'s tuples are actually 8 different templated classes - one for 
each arity. There's a lot of duplicated code to make that work. 
Wait, it's actually 9 classes - in addition to Tuple<T1> through 
Tuple<T1, ..., T8> there's the humble Tuple - a non-generic class 
that cannot be instantiated and only exists to be a namespace for 
the Tuple.Create function. The example code on gooroo seems to 
have eaten the template arguments for the constructor example - 
to instantiate a tuple you use one of these syntaxen:

   var t1 = new Tuple<int, string>(1, "foo");
   var t2 = Tuple.Create(2, "bar");

The 'templates' in C# are (much) more limited than old C++ 
templates, and have nothing on D's templates. That's not 
necessarily a bad thing, though - the language is different and 
fills a different niche. It does mean some things that are very 
elegant in D end up very inelegant in C#, though.