!7

static L<S> verbs = toLinesFullTrim([[
  kow towed
  made
  started
  want
]]);

sclass StringTree {
  bool ok;
  new HashMap<S, StringTree> children;

  StringTree getOrAdd(S s) {
    StringTree t = children.get(s);
    if (t == null)
      children.put(s, t = new StringTree);
    ret t;
  }
}

static new StringTree tree;

p {
  tree = multiWordMap_lower(verbs);
  testAnswerFunction([[
    he kow towed before them
    i want stuff
    kow
    towed
    I WANT YOU
  ]]);
  botSleep();
}

static L<S> parse(S s) {
  ret codeTokens(nlTok4(lower(s)));
}

static StringTree multiWordMap_lower(L<S> items) {
  new StringTree tree;
  for (S s : items) {
    L<S> tok = parse(s);
    addToTree(tree, tok);
  }
  ret tree;
}

svoid addToTree(StringTree tree, L<S> tok) {
  if (empty(tok)) { tree.ok = true; ret; }
  S s = first(tok);
  StringTree t = tree.getOrAdd(s);
  addToTree(t, dropFirst(tok));
}

sS answer(S s) {
  L<S> tok = parse(s);
  new L<S> verbs;
  for i over tok: {
    StringTree tree = main.tree;
    int j = i;
    while (tree != null && j < l(tok)) {
      if (tree.ok)
        verbs.add(joinWithSpace(subList(tok, i, j)));
      tree = tree.children.get(tok.get(j));
      ++j;
    }
  }
  ret join(", ", verbs);
}