On Monday, 29 July 2013 at 13:30:58 UTC, bearophile wrote:
JS:
I doubt such a feature will ever get added but who knows...
It seems a cute idea, but why don't you show two or more very
different use cases? (Asking for a feature without showing use
cases is not so good.)
Bye,
bearophile
The usefulness should be obvious and I seriously doubt if someone
thinks it is not then any example I could give would convince
them otherwise.
It came up for me trying to write a ternary if to use.
struct tVariadicSplit { }
template tuple(args...) { alias tuple = args; }
template tMin(alias a, alias b)
{
static if (a < b) alias tMin = a; else alias tMin = b;
}
template tIf(alias cond, args...)
{
enum sp = std.typetuple.staticIndexOf!(tVariadicSplit, args);
static if (sp < 0) enum spp = args.length; else enum spp = sp;
static if (cond) alias tIf = args[0..tMin!($, spp)]; else
alias tIf = args[tMin!($,spp+1)..$];
}
I have to use tVariadicSplit to split the grouping(sure I could
reduce the symbol name size, which I have done).
Being able to write this as
template tIf(alias cond, tArgs..., fArgs...)
{
static if (cond)
alias tIf = tArgs;
else
alias tIf = fArgs;
}
Would be much much more elegant.
