Dictionary – a C++ template class to emulate VBScript’s “Scripting.Dictionary” collection

CodeGuru content and product recommendations are editorially independent. We may make money when you click on links to our partners. Learn More.

Dictionary  is a C++ template designed to duplicate the functionality, and, for
the most part, the syntax of the Scripting.Dictionary ActiveX object built into VBA and
VBScript.  It derives from an STL map<> template, so any of the STL algorithms
will also work with it.  All of it’s member functions are inlined, so there’s only a
Dictionary.h file.  There is no Dictionary.cpp.

In the examples below, the left side are taken directly from Microsoft published
documentation for the Scripting.Dictionary ActiveX.  The right side is the equivalent
C++ code using the Dictionary<> template.  As you can see, the syntax is nearly
identical, with the only significant different is that the data types of the dictionary
must to predefined, and the C++ methods require parentheses where the VBScript methods
don’t.

Summary of Public Interface:

// Dictionary.h: interface/implementation for the Dictionary class.
//
// Dictionary is a templatized class which is a direct copy of
// the VBScript Scripting.Dictionary object.  All methods
// and properties are provided with a syntax that is either
// identical to the VBS implementation, or with only trivial
// differences (mainly, C++ member functions require parentheses
// where VBScript methods don't)
//
// Copyright 1998, James M. Curran, All Rights reserved.
//  May be used freely, provided copyright noticed remains.
//  May not be sold in source code form.
//
// email: JamesCurran@Mvps.org
//   WWW: http://www.NJTheater.Com/JamesCurran
//////////////////////////////////////////////////////////////////////

template<typename KEY, typename ITEM>
class Dictionary  : std::map<KEY, ITEM>
{
public:
	Dictionary() {};
	virtual ~Dictionary(){};
	void			Add(KEY k, ITEM i);
	bool 			Exists(KEY k) 	const;
	size_type 		Count() 	const;
	void 			Remove(KEY k);
	void 			RemoveAll();
	std::vector<KEY>	Keys() 		const;
	std::vector<ITEM>	Items()		const;
	DKH			Key(KEY k);
	DIH			Item(KEY k);
	DIH 			operator[](KEY k);
	DIH 			operator()(KEY k);
	friend std::ostream& 	operator<<(std::ostream& os, const DIH& dih);
};

Note:  
Anything above the returns a DIH or DKH can appear on either the right or
left side of an assignment,  (although Key() is a bit pointless on the right hand
side).  eg:

are all legal (and equivalent).

Demo is included with header file.  Just compile & link a source file with the
following three lines:

#define DICTIONARY_TEST
#include "dictionary.h"
void main()	{ dictionary_test();	}