projects / ceph.git / blame
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| 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_sequence_convert Converting sequences] | |
| 9 | ||
| 10 | The easiest way to work with a sequence is to convert it to a Boost PP | |
| 11 | data type. Likewise you can also convert a sequence to variadic data even though the | |
| 12 | Boost PP data types have much greater functionality than variadic data in Boost PP. | |
| 13 | ||
| 14 | To convert a sequence to a Boost PP data type or variadic data the macros to be used are: | |
| 15 | ||
| 16 | * BOOST_VMD_TO_ARRAY(sequence) to convert the sequence to an array | |
| 17 | * BOOST_VMD_TO_LIST(sequence) to convert the sequence to a list | |
| 18 | * BOOST_VMD_TO_SEQ(sequence) to convert the sequence to a seq | |
| 19 | * BOOST_VMD_TO_TUPLE(sequence) to convert the sequence to a tuple | |
| 20 | * BOOST_VMD_ENUM(sequence) to convert the sequence to variadic data | |
| 21 | ||
| 22 | After the conversion the elements of a sequence become the elements | |
| 23 | of the corresponding composite data type. | |
| 24 | ||
| 25 | Once the elements of the sequence have been converted to the elements | |
| 26 | of the composite data type the full power of that composite data type can be used | |
| 27 | to process each element. Furthermore the programmer can use VMD to discover | |
| 28 | the type of an individual element for further processing. | |
| 29 | ||
| 30 | For single element sequences the result is always a single element composite | |
| 31 | data type. For multi-element sequences the result is always a composite data | |
| 32 | type of more than one element. | |
| 33 | ||
| 34 | For a sequence that is empty the result is emptiness when converting to | |
| 35 | a seq, tuple, or variadic data; the result is an empty array or list when | |
| 36 | converting to each of those composite data types respectively. | |
| 37 | ||
| 38 | #include <boost/vmd/enum.hpp> | |
| 39 | #include <boost/vmd/to_array.hpp> | |
| 40 | #include <boost/vmd/to_list.hpp> | |
| 41 | #include <boost/vmd/to_seq.hpp> | |
| 42 | #include <boost/vmd/to_tuple.hpp> | |
| 43 | ||
| 44 | #define BOOST_VMD_REGISTER_ANID (ANID) | |
| 45 | ||
| 46 | #define SEQUENCE_EMPTY | |
| 47 | #define SEQUENCE_SINGLE 35 | |
| 48 | #define SEQUENCE_SINGLE_2 ANID | |
| 49 | #define SEQUENCE_MULTI (0,1) (2)(3)(4) | |
| 50 | #define SEQUENCE_MULTI_2 BOOST_VMD_TYPE_SEQ (2,(5,6)) | |
| 51 | ||
| 52 | BOOST_VMD_TO_ARRAY(SEQUENCE_EMPTY) will return an empty array '(0,())' | |
| 53 | BOOST_VMD_TO_LIST(SEQUENCE_SINGLE) will return a one-element list '(35,BOOST_PP_NIL)' | |
| 54 | BOOST_VMD_TO_SEQ(SEQUENCE_SINGLE_2) will return a one-element seq '(ANID)' | |
| 55 | BOOST_VMD_TO_TUPLE(SEQUENCE_MULTI) will return a multi-element tuple '((0,1),(2)(3)(4))' | |
| 56 | BOOST_VMD_ENUM(SEQUENCE_MULTI_2) will return multi-element variadic data 'BOOST_VMD_TYPE_SEQ,(2,(5,6))' | |
| 57 | ||
| 58 | [heading Usage] | |
| 59 | ||
| 60 | You can use the general header file: | |
| 61 | ||
| 62 | #include <boost/vmd/vmd.hpp> | |
| 63 | ||
| 64 | or you can use individual header files for each of these macros. | |
| 65 | The individual header files are: | |
| 66 | ||
| 67 | #include <boost/vmd/to_array.hpp> // for the BOOST_VMD_TO_ARRAY macro | |
| 68 | #include <boost/vmd/to_list.hpp> // for the BOOST_VMD_TO_LIST macro | |
| 69 | #include <boost/vmd/to_seq.hpp> // for the BOOST_VMD_TO_SEQ macro | |
| 70 | #include <boost/vmd/to_tuple.hpp> // for the BOOST_VMD_TO_TUPLE macro. | |
| 71 | #include <boost/vmd/enum.hpp> // for the BOOST_VMD_ENUM macro. | |
| 72 | ||
| 73 | [endsect] |