ceph/src/boost/libs/tti/doc/tti_introduction.qbk

   1 [/
   2   (C) Copyright Edward Diener 2011,2012
   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:tti_intro Introduction]
   9
  10 Welcome to the Boost Type Traits Introspection library, abbreviated TTI.
  11
  12 TTI is a library which provides the ability to introspect by name the elements
  13 of a type at compile time.
  14
  15 TTI works through macros generating metafunctions. Metafunctions are class
  16 templates of a particular syntax, having a nested 'type' member. So wherever
  17 in C++ class templates can occur, TTI macros can be used. The metafunctions
  18 generated by TTI are no different from any other metafunction as defined by
  19 the Boost MPL library.
  20
  21 The metafunctions generated by TTI are used to introspect elements of a type
  22 at compile time, always passing at minimum to each metafunction the enclosing
  23 type being introspected.
  24
  25 The name of the library has been chosen because the library offers
  26 compile time functionality on a type, similar to the Boost Type Traits library,
  27 and because the functionality the library offers is the ability to introspect
  28 a type about the existence of a specific element within that type.
  29
  30 I use the word "introspect" in a very broad sense here. Normally computer
  31 language introspection means initially asking for information to be returned
  32 by name, which can then further be used to introspect for more specific
  33 information. In the TTI library one must always know and supply the name, and
  34 use the functionality provided for the correct type of inner element to find
  35 out if that particular named entity exists.
  36
  37 You may prefer the term "query" instead of "introspection" to denote what this
  38 library does, but I use terminology based on the word "introspect" throughout
  39 this documentation.
  40
  41 The functionality of the library may be summed up as:
  42
  43 * Provide the means to introspect a type at compile time
  44   using a set of macros. Each macro takes the name of the
  45   type's element and generates a metafunction which can be
  46   subsequently invoked to determine whether or not the
  47   element exists within the type. These generated metafunctions
  48   will be called "macro metafunctions" in the documentation.
  49
  50 * Provide the means to create a typedef for a type which may
  51   not exist. This typedef type can be used as a type in the
  52   metafunctions of the library without producing compile-time
  53   errors.
  54
  55 The library is dependent on Boost PP, Boost MPL,
  56 Boost Type Traits, and Boost Function Types.
  57
  58 The library is also dependent on the variadic macro support
  59 of the Boost PP library if the variadic macros in the library
  60 are used.
  61
  62 The library is a header only library.
  63
  64 Since the dependencies of the library are all header only
  65 libraries, there is no need to build a library in order to use
  66 the TTI library.
  67
  68 [section:tti_headers Header Files]
  69
  70 There are is a single header file, `boost/tti/tti.hpp`,
  71 which includes all the header files in the library.
  72
  73 There are also separate specific header files for each of the elements
  74 to be introspected by the library. This allows for finer-grained inclusion
  75 of the nested elements to be introspected. These header files are:
  76
  77 [table:tbhfiles TTI Header Files
  78   [
  79     [Introspected Element]
  80     [Specific Header File]
  81   ]
  82   [
  83     [Type]
  84     [[headerref boost/tti/has_type.hpp `has_type.hpp`]]
  85   ]
  86   [
  87     [Class Template]
  88     [[headerref boost/tti/has_template.hpp `has_template.hpp`]]
  89   ]
  90   [
  91     [Member data]
  92     [[headerref boost/tti/has_member_data.hpp `has_member_data.hpp`]]
  93   ]
  94   [
  95     [Member function]
  96     [[headerref boost/tti/has_member_function.hpp `has_member_function.hpp`]]
  97   ]
  98   [
  99     [Static member data]
 100     [[headerref boost/tti/has_static_member_data.hpp `has_static_member_data.hpp`]]
 101   ]
 102   [
 103     [Static member function]
 104     [[headerref boost/tti/has_static_member_function.hpp `has_static_member_function.hpp`]]
 105   ]
 106   [
 107     [Data]
 108     [[headerref boost/tti/has_data.hpp `has_data.hpp`]]
 109   ]
 110   [
 111     [Function]
 112     [[headerref boost/tti/has_function.hpp `has_function.hpp`]]
 113   ]
 114   [
 115     [Member Type Creation]
 116     [[headerref boost/tti/member_type.hpp `member_type.hpp`]]
 117   ]
 118 ]
 119
 120 [endsect]
 121
 122 [endsect]