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

Header:  <boost/preprocessor/repetition/enum.hpp>

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
   */

© Copyright Housemarque Oy 2002
© Copyright Paul Mensonides 2002

Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at www.boost.org/LICENSE_1_0.txt)