The BOOST_PP_TUPLE_REPLACE_D macro
      replaces an element in a tuple.  It reenters BOOST_PP_WHILE
      with maximum efficiency.
    Usage
     BOOST_PP_TUPLE_REPLACE_D(
d, 
tuple,
      
i, 
elem) 
(v) 
    Arguments
    
      - d
-  The next available BOOST_PP_WHILE iteration. 
- tuple
-  A tuple to replace an element in. 
- i
-  The zero-based position in tuple of the element to be
        replaced.  Valid values range from 0 to BOOST_PP_TUPLE_SIZE(tuple)
        - 1. 
- elem
-  The replacement element. 
See Also
    
    Requirements
    
    
     © Copyright Edward Diener 2013