Re: How to detect if an array if dynamic or static

[Ali Çehreli via Digitalmars-d-learn]

On 02/24/2016 08:44 PM, mahdi wrote:
> On Wednesday, 24 February 2016 at 22:38:04 UTC, Adam D. Ruppe wrote:
>> On Wednesday, 24 February 2016 at 21:48:14 UTC, mahdi wrote:
>>> How can we detect is `array` is static (fixed size) or dynamic,
>>> inside the function body?
>>
>> `array` there is always dynamic because it is not of a fixed size type.
>>
>> Why do you want to know though?
>
> I thought we can simply denote `int[] x` in case we have an array
> argument in D functions. So according to your answer if a function
> expects a static array, it has to specify size of array in parameter
> declaration:
>
> void diss(int[3] array) ...  //this expects a static array of size 3
> void diss(int[] array) ...  //this expects a dynamic array
>
> is this correct?
Yes.

Note that static arrays are value types. So, if the parameter is int[3], 
then the argument will be copied. However, you can still take it by 
reference (with the ref keyword):

import std.stdio;

void diss(ref int[3] array) {
    writeln(typeof(array).stringof);
}

void diss(int[] array) {
    writeln(typeof(array).stringof);
}

void main() {
    int[3] arr;
    diss(arr);
}

Prints:

int[3]

And a reminder that rvalues cannot be bound to ref in D. So, 'ref 
int[3]' may not be usable in your case.

Ali