C-like static array size inference - how?

[Ali Çehreli]

On 6/6/22 17:04, arandomonlooker wrote:

 > I usually transcribe them as follows, because the previous syntax causes
 > a compiler error:
 >
 > ```d
 > int numbersINeed[] = [1, 2, 3, 4, 5];
 > ```

As you already know, the correct syntax is 'int[]' :) but it won't work 
because -betterC cannot support dynamic array.

 > it's complaining about TypeInfo being absent.

What an unfortunate error message! Trying writeln() causes equally weird 
error messages.

 > Can't i use some feature to imply that D must deduct the size
 > from the array i am assigning, like an underscore? Can't D do that?

That request comes up relatively frequently. Currently, the only way I 
know of is to use std.array.staticArray:

import std.array;

extern (C)
void main() {
   auto numbersINeed = staticArray([1, 2, 3, 4, 5]);

   import std.range;
   import std.algorithm;
   import core.stdc.stdio;

   //          |
   //          V
   numbersINeed[].each!(n => printf("%d ", n));
}

Aside: I printed the elements with a range algorithm, which is not 
necessary at all. However, the reason I had to use it is because static 
arrays are not ranges because their lengths cannot change. [] takes a 
slice to all elements, which can reduce its length, and accordingly is a 
range.

Ali