// A = type of value in nodes.
// All nodes can have values, not only leaves
// Can be case-sensitive or case-insensitive
sclass StringTrie<A> {
  A value;
  TreeMap<S, StringTrie<A>> children;
  
  *() {}
  *(A *value) {}
  
  void makeCaseInsensitive() {
    children = asCIMap(children);
  }
  
  bool isCaseInsensitive() {
    ret isCIMap(children);
  }
  
  void add(S string, A value) {
    if (empty(string)) ret with this.value = value;
    
    S existingPrefix = isCaseInsensitive()
      ? longestPrefixInCISet(string, children)
      : longestPrefixInTreeSet(string, children);
      
    if (nempty(existingPrefix))
      ret with children.get(existingPrefix).add(substring(string, l(existingPrefix)), value);
    
    if (children == null) children = new TreeMap;
    children.put(string, value);
  }
}