// Yes the nomenclature is a bit illogical

static <A> Chain<A> chainPlus(Chain<A> chain, A a) {
  ret Chain<A>(a, chain);
}

static <A> Chain<A> chainPlus(Chain<A> chain, A... l) {
  fOr (A a : l)
    chain = chainPlus(chain, a);
  ret chain;
}

static <A> ReverseChain<A> chainPlus(ReverseChain<A> chain, A a) {
  ret ReverseChain<A>(chain, a);
}

static <A> ReverseChain<A> chainPlus(ReverseChain<A> chain, A... l) {
  fOr (A a : l)
    chain = chainPlus(chain, a);
  ret chain;
}

ifclass AppendableChain
static <A> AppendableChain<A> chainPlus(AppendableChain<A> chain, A a) {
  if (chain == null) ret new AppendableChain<A>(a);
  chain.add(a);
  ret chain;
}

static <A> AppendableChain<A> chainPlus(AppendableChain<A> chain, A... l) {
  fOr (A a : l)
    chain = chainPlus(chain, a);
  ret chain;
}
endif

Began life as a copy of #1027932