#ifndef DICTIONARY_DOT_H
#define DICTIONARY_DOT_H

// The Dictionary class is just a wrapper for the STL "map" class.
// The interface here is small and understandable, hence the value.

#include <vector>
#include <map>
#include "util.h"

class NoSuchKeyException : public Exception {
public:
   string what() const { return "Dictionary: no such key"; }
};

template <class K, class V>
class Dictionary {
      map<K,V> d;
   public:
      void put( const K& key, const V& value );     // destructive put
      void remove( const K& key );           // pre: contains
      V at( const K& key ) const;            // pre: contains
      bool contains( const K& key ) const;

      bool is_empty() const { return d.empty(); }

      vector<K> keys() const;
};

template <class K, class V>
void Dictionary<K,V>::put( const K& key, const V& value ) {
   d[key] = value;
}
   
template <class K, class V>
void Dictionary<K,V>::remove( const K& key ) {
   if( !contains(key) )
      throw NoSuchKeyException();
   d.erase(key);
}

template <class K, class V>
V Dictionary<K,V>::at( const K& key ) const {
   if( !contains(key) )
      throw NoSuchKeyException();
   return d.find(key)->second;
}

template <class K, class V>
bool Dictionary<K,V>::contains( const K& key ) const {
   return d.count(key) == 1;
}

template <class K, class V>
vector<K> Dictionary<K,V>::keys() const {
   vector<K> temp;
   for( map<K,V>::const_iterator i=d.begin(); i!=d.end(); ++i )
      temp.push_back( i->first );
   return temp;
}

#endif