@defstx @mycontainerof(p, tn, f)
{
	#`{
	{
		@local fld, _tn, type, tmp;
		_tn = #,tn;
		tmp = #,p;
		type = looktype(domof(tmp), _tn);
		if(isnil(type))
			error("undefined type %t", _tn);
		fld = lookfield(type, #,(#val(stxid(f))));
		if(isnil(fld))
			error("undefined field %a", #,(#val(stxid(f))));
		type = mkctype_ptr(type, nsptr(domof(tmp)));
		{type}((void*)tmp - fieldoff(fld));
	}
	};
}

ns = @names c64le {
	struct X {
		@0x0 int x;
		@0x4 int y;
		@0x8 int z;
		@0xc;
	};
};

dom = mkdom(ns, mknas());

p = (struct X*){dom}0;
printf("p is %t 0x%x\n", @typeof(p), p);
q = &p->y;
printf("q is %t 0x%x\n", @typeof(q), q);
r = @mycontainerof(q, @typename(struct X), y);
printf("r is %t 0x%x\n", @typeof(r), r);

//p = (struct X*){dom}0;
//printf("p is %t 0x%x\n", @typeof(p), p);
//q = &p->y;
//printf("q is %t 0x%x\n", @typeof(q), q);
//r = @mycontainerof(q, struct dom`X, y);
//printf("r is %t 0x%x\n", @typeof(r), r);

//p = (struct X*){dom}0;
//printf("p is %t 0x%x\n", @typeof(p), p);
//q = &p->z;
//printf("q is %t 0x%x\n", @typeof(q), q);
//r = @mycontainerof(q, struct dom`X, y);
//printf("r is %t 0x%x\n", @typeof(r), r);