gistfile1.txt

var typeToNameSetMap=new Map<String,NameSet>();
class NameSet {
  static const int MAX_ENTRIES=16;
  var keys=new List(MAX_ENTRIES);
  var hashCodes=new Int32List(MAX_ENTRIES);
  var currentSize=0;
  int getIndex(key) {
     int hashCode=key.hashCode;
     int index=-1;
     for (int i=0, j=currentSize-1; j>=i; i++, j--) {
        if (hashCodes[i]==hashCode) {index = i; break; }
        if (hashCodes[j]==hashCode) {index = j; break; };
     }

     if (index>=0) {
        return keys[index]==key ? index :-1; 
     } else if (currentSize<MAX_ENTRIES) {
       keys[currentSize]=key;
       hashCodes[currentSize]=hashCode;
       return currentSize++;
     } else {
       return -1;
     }  
  }
}
class TypedMap {
  NameSet nameSet;
  var values=new List(NameSet.MAX_ENTRIES);
  var fallbackMap;
  TypedMap(String type) { // "type" is a string that identifies named set
    nameSet=typeToNameSetMap.putIfAbsent(type,()=>new NameSet());
  }
  operator [](key) {
     if (fallbackMap!=null) {
       return fallbackMap[key];
     }
     int index=nameSet.getIndex(key);
     return index>=0 ? values[index] : null;
  }
  operator []=(key,value) {
    if (fallbackMap!=null) {
      fallbackMap[key]=value;
      return;
    }
    int index=nameSet.getIndex(key);
    if (index>=0) {
      values[index]=value;
    } else {
      _createFallback();
       fallbackMap[key]=value;
    }
  } 
  _createFallback() {
     print ("creating fallback!");
     fallbackMap=new Map();
     for (int i=0; i<nameSet.currentSize; i++) {
       fallbackMap[nameSet.keys[i]]=values[i];
     }
   }
}