Comma expression as tuple operator [was Tuples, C#, Java, language design]

[grauzone]

BCS wrote:
> Hello justme,
> 
>> bearophile Wrote:
>>
>>> C# will probably not follow the route of stagnation of Java for some
>>> more time, thanks to Mono too. I don't like that string interpolation
>>> syntax because it looks unsafe, and that design of tuples can be
>>> improved, but they are listening to programmes (even if they risk
>>> creating a mudball language):
>>>
>>> http://www.infoq.com/news/2009/12/Mono-CSharp-Ex
>>>
>>> More on those tuples:
>>> http://tirania.org/blog/archive/2009/Dec-23.html
>>> Eventually it will be quite useful to have some very well designed
>>> multi-return support in D (like those tuples, but better).
>>>
>> Doesn't D2 already have tuples in Phobos. D has the comma operator
>> which C# doesn't so such syntax is not possible in D, me thinks.
>>
> 
> A though on the comma operator: if the comma operator were defined to 
> give a tuple type and be implicitly castable to any suffix of it's self, 
> then you could get both the comma expression usage that Walter wants as 
> well as all the fun things that tuple expressions give.
> 
> int i = 1, j = 2;
> 
> (i, j) = (j, i); // swap
> 
> i = (j+= i, i*2 + j); // first expression gets evaluated and dropped.
> 
> Thoughts?

Why not make the programmer write tuple[$-1] instead?

i = (j += i, i*2 + j)[$-1];

There's no reason to keep the current comma operator.

>