The BOOST_PP_ENUM_z macro represents a reentry into the BOOST_PP_ENUM repetition construct.
	
	Usage
		
			BOOST_PP_ENUM_ ## z(count, macro, data)
		
	Arguments
		
			- z
- 
				The next available BOOST_PP_REPEAT dimension.
			
- count
- 
				The number of repetitious calls to macro. 
				Valid values range from 0 to BOOST_PP_LIMIT_REPEAT.
			
- macro
- 
				A ternary operation of the form macro(z, n, data). 
				This macro is expanded by BOOST_PP_ENUM with the next available repetition depth,
				the current repetition number, and the auxiliary data argument. 
			
- data
- 
				Auxiliary data passed to macro.
			
Remarks
		
			This macro expands to the sequence:
			
				macro(z, 0, data), macro(z, 1, data), ... macro(z, count - 1, data)
			
		
			At certain times, it may be necessary to perform the concatenation with 
BOOST_PP_CAT rather than the preprocessor token-pasting operator. 
			This happens when the 
z value is a macro invocation itself. 
			It needs a delay to allow it to expand. 
			The syntax in such a scenario becomes:
			
				BOOST_PP_CAT(BOOST_PP_ENUM_, z)(count, macro, data)
			
		See Also
		
	Requirements
		
	Sample Code
#include <boost/preprocessor/arithmetic/inc.hpp>
#include <boost/preprocessor/repetition/enum.hpp>
#define TEXT(z, n, text) text
#define TTP(z, n, _) \
   template< \
      BOOST_PP_ENUM_ ## z(BOOST_PP_INC(n), TEXT, class) \
   > \
   class T ## n \
   /**/
BOOST_PP_ENUM(3, TTP, nil)
   /*
      expands to...
      template<class> class T0,
      template<class, class> class T1,
      template<class, class, class> class T2
   */