Variadic grouping
JS
js.mdnq at gmail.com
Tue Jul 30 00:06:59 PDT 2013
On Monday, 29 July 2013 at 15:02:13 UTC, Robert Clipsham wrote:
> On Monday, 29 July 2013 at 14:46:02 UTC, Robert Clipsham wrote:
>> You can achieve this like so:
>> ----
>> template Outer(T...) {
>> template Inner(U...) {
>> // Do something with T and U
>> }
>> }
>> Outer!(a, b, c).Inner!(d, e, f);
>> ----
>>
>> You can see an example of it in action here (type tuple
>> intersection):
>> https://github.com/mrmonday/misc/blob/master/misc/misc.d#L5
>>
>> Robert
>
> What would be more interesting would be to have the ability to
> have variadic variadics, so you could use something like:
> ----
> template Outer(T...) {
> template Inner(U... ...) {
> // Do something with T, U[0], U[1], U[2..$]
> }
> }
> Outer!(a, b, c).Inner!(d, e, f).Inner!(g, h, i); // Etc
> ----
> Of course that raises the question of variadic variadic
> variadics
> and variadic variadic variadic variadics and so on, and my
> proposed syntax is already silly............
I don't think so, this seems similar:
It would be cool if we could nest templates to get grouping
template tIF(alias cond)
{
template tIF(alias T...)
{
template tIF(alias F...)
{
....
}
}
then do
tIF!(cond)!(t1,t2,t3)!(f1,..,fn)
which would allow for a natural grouping of variadics. The
notation may seem silly but only because it is not common.
which could have a short hand notation of
tIF!(cond; t1, t2, t3; f1, ..., fn);
(this way, if you can't keep track of your ';'s then you can use
the long form)
More information about the Digitalmars-d
mailing list