varargs.pl6

use v6.c;
use NativeCall;

# A proof of concept for NativeCall "varargs" calls,
my $printf = cglobal(Str,'printf',Pointer);
my @sxa := (
    (Nil => :(Str --> int32)).Map, # arity 0
    (Str => :(Str,Str --> int32), Int => :(Str,Int --> int32)).Map # arity 1
);

sub choose-sig(Capture \c) {
    @sxa[c-1]{c.list[1].^name};
}

sub make-callable(Pointer \sym, Capture \c) {
    my \sig = choose-sig(c);
    nativecast(sig, sym);
}

for (\("hi\n"), \("Hello %s\n","perl6"), \("Age: %d\n", 10)) -> \c {
    my &fun = make-callable($printf, c);
    fun(|c);
}