The stately := operator feature proposal

[Diggory]

On Thursday, 30 May 2013 at 15:05:40 UTC, monarch_dodra wrote:
> On Thursday, 30 May 2013 at 14:55:38 UTC, someone wrote:
>> Please think about the huge math and science community. Most 
>> of them I came across like D for its speed and efficiency. But 
>> D can never replace Matlab/Octave/Ipython/Scipy because ....
>>
>> .. of the messy syntax compared to almost math like syntax 
>> above languages offer.
>>
>> For example, if I want to quickly want to plot something, in 
>> Octave I would do:
>>
>> x = linspace(0, 2*pi, 1000);
>> y = sin(x);
>> plot(x, y)
>
> I could be mistaken, but those languages don't have the notion 
> of declaration, do they? (honest question)
>
> Last time I tried a similar language, basically, any variable 
> name that is not yet used is resolved to null. Which is why the 
> syntax work.
>
> D on the other hand has a strong notion of declaration, and 
> construction.
>
> I'm not sure it's just a matter of "messy syntax", and more of 
> different paradigms. In D, it is more important to make the 
> distinction of construction/assignment. The syntax is messy, 
> but the new syntax blurs that line.

There's another alternative that fits more with D style which is 
also very mathsy.

It would be possible to make storage classes work with the colon 
syntax, ie:

auto:
    x = 1;
    y = 2;
    f = a => a+1
    writeln(f(x) + y);

Also:

immutable:
    x = 3;
    y = 4;

Kind of like option explicit: off in VB