Re: Variadic template with template arguments in pairs

[Paul Backus via Digitalmars-d-learn]

On Wednesday, 12 September 2018 at 15:12:16 UTC, Anonymouse wrote:
void doByPair(Args...)(Args args)
if (Args.length)
{
    foreach (pair; args.pairwise)
    {
        static assert(is(typeof(pair[0]) == string));
        static assert(isPointer!(pair[1]));
        assert(pair[1] !is null);
        string desc = pair[0];
        auto value = *pair[1];
        writefln("%s %s: %s", typeof(value).stringof, desc, 
value);
    }
}

The easiest way is probably to iterate using indices with an 
increment of 2, e.g.:

static foreach(i; iota(0, args.length, 2))
{
    static assert(is(typeof(args[i]) == string));
    static assert(isPointer!(args[i+1]));

    // etc.
}

Another alternative is to write the function recursively:

void doByPair(T, Rest...)(string desc, T* valuePtr, Rest rest)
{
    writefln("%s %s: %s", T.stringof, desc, *valuePtr);
    if (rest.length) doByPair(rest);
}