ceph/src/boost/libs/vmd/doc/vmd_get_type.qbk

   1 [/
   2   (C) Copyright Edward Diener 2011-2015
   3   Distributed under the Boost Software License, Version 1.0.
   4   (See accompanying file LICENSE_1_0.txt or copy at
   5   http://www.boost.org/LICENSE_1_0.txt).
   6 ]
   7
   8 [section:vmd_convert_sequence Getting the type of data]
   9
  10 VMD has the ability to retrieve the type of any data which it can
  11 parse, which means any VMD sequence. The macro to do this is called
  12 BOOST_VMD_GET_TYPE and it takes a single required parameter, which
  13 is a VMD sequence.
  14
  15 It returns one of the types previously discussed when introducing
  16 v-types as an identifier subset. As explained previously in that
  17 topic a v-type is fully recognized by VMD macros and can be part
  18 of a sequence and passed as VMD data just like all the other data types
  19 VMD recognizes.
  20
  21 When BOOST_VMD_GET_TYPE returns the type of data it returns by default
  22 the most specific type that the data can be. This means that non-empty
  23 lists and arrays are returned as such, not as tuples, and numbers
  24 and types and empty lists are returned as such, not as identifiers.
  25
  26  #include <boost/vmd/get_type.hpp>
  27
  28  #define BOOST_VMD_REGISTER_ANID (ANID)
  29  #define SEQUENCE_EMPTY
  30  #define SEQUENCE_MULTI (1,2,3) 88
  31  #define SEQUENCE1 (3,(1,2,3))
  32  #define SEQUENCE2 ANID
  33  #define SEQUENCE3 (1,(2,(3,BOOST_PP_NIL)))
  34  #define SEQUENCE4 1
  35  #define SEQUENCE5 (1)(2)(3)
  36  #define SEQUENCE6 (1,2,3)
  37  #define SEQUENCE7 BOOST_VMD_TYPE_NUMBER
  38
  39  BOOST_VMD_GET_TYPE(SEQUENCE_EMPTY) will return BOOST_VMD_TYPE_EMPTY
  40  BOOST_VMD_GET_TYPE(SEQUENCE_MULTI) will return BOOST_VMD_TYPE_SEQUENCE
  41  BOOST_VMD_GET_TYPE(SEQUENCE1) will return BOOST_VMD_TYPE_ARRAY
  42  BOOST_VMD_GET_TYPE(SEQUENCE2) will return BOOST_VMD_TYPE_IDENTIFIER
  43  BOOST_VMD_GET_TYPE(SEQUENCE3) will return BOOST_VMD_TYPE_LIST
  44  BOOST_VMD_GET_TYPE(SEQUENCE4) will return BOOST_VMD_TYPE_NUMBER
  45  BOOST_VMD_GET_TYPE(SEQUENCE5) will return BOOST_VMD_TYPE_SEQ
  46  BOOST_VMD_GET_TYPE(SEQUENCE6) will return BOOST_VMD_TYPE_TUPLE
  47  BOOST_VMD_GET_TYPE(SEQUENCE7) will return BOOST_VMD_TYPE_TYPE
  48
  49 [heading Usage]
  50
  51 You can use the general header file:
  52
  53  #include <boost/vmd/vmd.hpp>
  54
  55 or you can use the individual header file:
  56
  57  #include <boost/vmd/get_type.hpp>
  58
  59 for the BOOST_VMD_GET_TYPE macro.
  60
  61 [endsect]