Re: C#7 features

[maik klein via Digitalmars-d-announce]

On Monday, 9 May 2016 at 13:09:24 UTC, Jacob Carlborg wrote:

On 2016-05-09 14:46, John wrote:

C# 7's tuples are something different though. They don't even 
map to

System.Tuple. The syntax is:

   (int x, int y) GetPoint() {
 return (500, 400);
   }

   var p = GetPoint();
   Console.WriteLine($"{p.x}, {p.y}");


Would be nice to have in D. Both with and without named fields.


I mean it is not much shorter than in D

alias Point = Tuple!(int, "x", int, "y");
Point getPoint(){
return Point(500, 400);
}

What would be nice though if tuples would be implicitly 
convertible to named tuples, if the types matches.


Tuple!(int, "x", int, "y") getPoint(){
return tuple(500, 400);
}

Re: C#7 features

[Jacob Carlborg via Digitalmars-d-announce]

On 2016-05-09 14:46, John wrote:


C# 7's tuples are something different though. They don't even map to
System.Tuple. The syntax is:

   (int x, int y) GetPoint() {
 return (500, 400);
   }

   var p = GetPoint();
   Console.WriteLine($"{p.x}, {p.y}");


Would be nice to have in D. Both with and without named fields.

--
/Jacob Carlborg

Re: C#7 features

[John 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


C# 7's tuples are something different though. They don't even map 
to System.Tuple. The syntax is:


  (int x, int y) GetPoint() {
return (500, 400);
  }

  var p = GetPoint();
  Console.WriteLine($"{p.x}, {p.y}");

Re: C#7 features

[Kagamin via Digitalmars-d-announce]

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


You can also use anonymous types: http://ideone.com/WBRunL they 
are predated by tuples.

Re: 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 through 
Tuple 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(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.

Re: C#7 features

[Peter Häggman via Digitalmars-d-announce]

On Friday, 6 May 2016 at 14:33:22 UTC, Andrei Alexandrescu wrote:

Most of them are also present in D, yay.

https://www.reddit.com/r/programming/comments/4i3h77/some_new_c7_features/

Added a comment:

https://www.reddit.com/r/programming/comments/4i3h77/some_new_c7_features/d2v5lu6


Andrei


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.

Re: C#7 features

[Nick Treleaven via Digitalmars-d-announce]

On Friday, 6 May 2016 at 23:51:59 UTC, Steven Schveighoffer wrote:


Of COURSE D supports local ref variables:

struct RefVar(T)
{
  private T * var;
  this(ref T v) { var =  }
  auto get() { return *var; }
  alias this get;
}


ref get() return {...

Which is unsafe even if the ctor is marked trusted, the struct 
could be moved to a higher scope. But like in another thread, you 
can have a ref property in @safe code:


T v;
@property ref myRef(){return v;}

So why are ref locals disallowed? Now we have the return 
attribute on functions that take myRef by ref, can it still 
escape?


ref myRef = v;

Re: C#7 features

[Steven Schveighoffer via Digitalmars-d-announce]

On 5/7/16 1:29 AM, Timon Gehr wrote:

On 06.05.2016 18:58, Kagamin wrote:

On Friday, 6 May 2016 at 14:33:22 UTC, Andrei Alexandrescu wrote:

Added a comment:

https://www.reddit.com/r/programming/comments/4i3h77/some_new_c7_features/d2v5lu6




D has ref variables? Not for a long time though.


D actually does not support ref local variables in most contexts (one
can have ref locals declared by foreach). There is an explicit check
ruling them out, but I'm pretty sure DMD supports them internally, they
are useful for lowering.


Of COURSE D supports local ref variables:

struct RefVar(T)
{
  private T * var;
  this(ref T v) { var =  }
  auto get() { return *var; }
  alias this get;
}

;)

-Steve

Re: C#7 features

[Timon Gehr via Digitalmars-d-announce]

On 06.05.2016 18:58, Kagamin wrote:

On Friday, 6 May 2016 at 14:33:22 UTC, Andrei Alexandrescu wrote:

Added a comment:

https://www.reddit.com/r/programming/comments/4i3h77/some_new_c7_features/d2v5lu6



D has ref variables? Not for a long time though.


D actually does not support ref local variables in most contexts (one 
can have ref locals declared by foreach). There is an explicit check 
ruling them out, but I'm pretty sure DMD supports them internally, they 
are useful for lowering.

Re: C#7 features

[Kagamin via Digitalmars-d-announce]

On Friday, 6 May 2016 at 14:33:22 UTC, Andrei Alexandrescu wrote:

Added a comment:

https://www.reddit.com/r/programming/comments/4i3h77/some_new_c7_features/d2v5lu6


D has ref variables? Not for a long time though.

C#7 features

[Andrei Alexandrescu via Digitalmars-d-announce]

Most of them are also present in D, yay.

https://www.reddit.com/r/programming/comments/4i3h77/some_new_c7_features/

Added a comment:

https://www.reddit.com/r/programming/comments/4i3h77/some_new_c7_features/d2v5lu6


Andrei