CTFE - filling an array

[The Anh Tran]

Hi,
I would like to pre-create a double array, each element is calculated by 
a function.


//-
import std.stdio;
import std.conv;
import std.string;

template f(int N)
{
bool fn(double[] tb)
{
for (int i = 1; i < N; i++)
tb[i] = 1.0/i;
return true;
}
}

void main(string[] args)
{
const int N = 200;
static double[N] dd = void;
static auto tmp = f!(N).fn(dd);

int n = toInt(args[1]);

writefln("test array[%d] = %f", n, dd[n]);
}
//--

dmd.2021 says: cannot evaluate "static auto tmp = f!(N).fn(dd);" at 
compile-time.


How can i fix it?
Thanks.

Re: CTFE - filling an array

[Christopher Wright]

The Anh Tran wrote:

static double[N] dd = void;


dd is not a compile-time constant.


static auto tmp = f!(N).fn(dd);


The initializer of tmp must be a compile-time constant, but since dd is 
not a compile-time constant, you can't use CTFE on fn.