TempAlloc review starts now

[bearophile]

Andrej Mitrovic:

> I wish "newVoid" was a language feature. If we have:
> int x = void;
> 
> It'd also be nice to have a similar form for the new operator:
> int[] x = void new int[](size);
> x[] = 1;
> 
> "int x = void" might not save too much cycles, but initializing a
> large array twice.. that's another thing.
> 
> newVoid seems to only work for 1-dimensional arrays. I could use
> something of this form:
> double[][] arr = newVoid!(double[][])(16, 100);
> 
> Not a big deal, I could write something like this for my own projects.
> I'm just commenting.
> 
> I used GC.malloc before but I never once thought about setting the
> NO_SCAN flag. Heh. :)

This is kind of off-topic.
There is a very simple syntax, nice and clean:

// doesn't initialize foo1
auto foo1 = new uint[5] = void;

// initializes the dynamic array to 5, avoiding a double initialization
auto foo2 = new uint[5] = 10;

// works for nD arrays too
auto mat1 = new double[][][](n1,n2,n3) = 0.0;

That syntax is inspired by fixed-sized array syntax, so I don't think it will take lot of time to people to learn it, quite the opposite:

uint[5] a1 = void;
uint[5] a2 = 10;
double[n1][n2][n3] mat2 = 0.0;

The increase of language complexity for the programmer is minimal.

But its usage as expression is not the most nice, so it's probably better to disallow this usage:

void foo(int[] a) {}
main() {
    foo(new[5] = 5);
}

Bye,
bearophile