Re: how to do this meta-programming? print the address of random element's address of a variable length of arrays?

[Paul Backus via Digitalmars-d-learn]

On Saturday, 12 September 2020 at 03:19:23 UTC, mw wrote:
I.e. I want to learn the generic meta-programming way to 
assemble such parameter list (&(x[i], &(y[j])) at compile time, 
it is possible?

It's possible if you use a helper function. Here's how:

import std.meta: allSatisfy;
import std.traits: isArray;

void printRandomElemAddr(Arrays...)(Arrays arrays)
    if (allSatisfy!(isArray, Arrays))
{
    auto randomElemAddr(size_t i)()
        if (i < arrays.length)
    {
        import std.random: uniform;

        return &arrays[i][uniform(0, $)];
    }

    import std.stdio: writeln;
    import std.meta: staticMap, aliasSeqOf;
    import std.range: iota;

    writeln(staticMap!(randomElemAddr, 
aliasSeqOf!(iota(arrays.length))));
}

void main()
{
    int[] a = [1];
    int[] b = [2, 3];
    double[] c = [4, 5, 6];

    printRandomElemAddr(a);
    printRandomElemAddr(a, b);
    printRandomElemAddr(a, b, c);
}