Dogcows Code - chaz/yoink/blob - src/Moof/cml/core/meta/switch.h

   1 /* -*- C++ -*- ------------------------------------------------------------
   2
   3 Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
   4
   5 The Configurable Math Library (CML) is distributed under the terms of the
   6 Boost Software License, v1.0 (see cml/LICENSE for details).
   7
   8  *-----------------------------------------------------------------------*/
   9 /** @file
  10  *  @brief
  11  */
  12
  13 #ifndef meta_switch_h
  14 #define meta_switch_h
  15
  16 #include <cml/core/meta/common.h>
  17 #include <cml/core/meta/if.h>
  18
  19 namespace cml {
  20
  21 struct NilCase {};      /* For terminating the case list. */
  22 struct Default {};      /* For indicating the default result. */
  23
  24 /* The working parts of the meta-switch go into namespace meta: */
  25 namespace meta {
  26
  27 /* "Interior" case statements: */
  28 template<typename Case, typename Result, typename NextCase>
  29 struct select_case
  30 {
  31     template<typename Find> struct match {
  32         typedef typename select_if<
  33             same_type<Find,Case>::is_true,
  34             Result,
  35             typename NextCase::template match<Find>::result
  36         >::result result;
  37     };
  38 };
  39
  40 /* Default case, returned when no match is found in a previous case: */
  41 template<typename Result>
  42 struct select_case<Default,Result,NilCase>
  43 {
  44     template<typename Find> struct match {
  45         typedef Result result;
  46     };
  47 };
  48
  49 /* The last case statement (if no match until now, the result is 'void'): */
  50 template<typename Case, typename Result>
  51 struct select_case<Case,Result,NilCase>
  52 {
  53     template<typename Find> struct match {
  54         typedef typename select_if<
  55             same_type<Find,Case>::is_true,
  56             Result,
  57             void
  58         >::result result;
  59     };
  60 };
  61
  62 } // namespace meta
  63
  64 /** Return the matched type (like a switch/case statement).
  65  *
  66  * This is a convenience wrapper to avoid having to explicitly type out
  67  * select_case for each case in the list of types to match against.
  68  */
  69 template<typename Find
  70 , typename T1,           typename R1
  71 , typename T2 = NilCase, typename R2 = void
  72 , typename T3 = NilCase, typename R3 = void
  73 , typename T4 = NilCase, typename R4 = void
  74 , typename T5 = NilCase, typename R5 = void
  75 , typename T6 = NilCase, typename R6 = void
  76 , typename T7 = NilCase, typename R7 = void
  77 , typename T8 = NilCase, typename R8 = void
  78 , typename T9 = NilCase, typename R9 = void
  79 , typename T10 = NilCase, typename R10 = void
  80 , typename T11 = NilCase, typename R11 = void
  81 , typename T12 = NilCase, typename R12 = void
  82 , typename T13 = NilCase, typename R13 = void
  83 , typename T14 = NilCase, typename R14 = void
  84 , typename T15 = NilCase, typename R15 = void
  85 , typename T16 = NilCase, typename R16 = void
  86 #if !defined(_MSC_VER)
  87 , typename T17 = NilCase, typename R17 = void
  88 , typename T18 = NilCase, typename R18 = void
  89 , typename T19 = NilCase, typename R19 = void
  90 , typename T20 = NilCase, typename R20 = void
  91 , typename T21 = NilCase, typename R21 = void
  92 , typename T22 = NilCase, typename R22 = void
  93 , typename T23 = NilCase, typename R23 = void
  94 , typename T24 = NilCase, typename R24 = void
  95 , typename T25 = NilCase, typename R25 = void
  96 , typename T26 = NilCase, typename R26 = void
  97 , typename T27 = NilCase, typename R27 = void
  98 , typename T28 = NilCase, typename R28 = void
  99 , typename T29 = NilCase, typename R29 = void
 100 , typename T30 = NilCase, typename R30 = void
 101 , typename T31 = NilCase, typename R31 = void
 102 , typename T32 = NilCase, typename R32 = void
 103 , typename T33 = NilCase, typename R33 = void
 104 , typename T34 = NilCase, typename R34 = void
 105 , typename T35 = NilCase, typename R35 = void
 106 , typename T36 = NilCase, typename R36 = void
 107 , typename T37 = NilCase, typename R37 = void
 108 , typename T38 = NilCase, typename R38 = void
 109 , typename T39 = NilCase, typename R39 = void
 110 , typename T40 = NilCase, typename R40 = void
 111 #endif
 112 > struct select_switch
 113 {
 114     typedef typename
 115           meta::select_case< T1,R1
 116         , meta::select_case< T2,R2
 117         , meta::select_case< T3,R3
 118         , meta::select_case< T4,R4
 119         , meta::select_case< T5,R5
 120         , meta::select_case< T6,R6
 121         , meta::select_case< T7,R7
 122         , meta::select_case< T8,R8
 123         , meta::select_case< T9,R9
 124         , meta::select_case< T10,R10
 125         , meta::select_case< T11,R11
 126         , meta::select_case< T12,R12
 127         , meta::select_case< T13,R13
 128         , meta::select_case< T14,R14
 129         , meta::select_case< T15,R15
 130         , meta::select_case< T16,R16
 131 #if !defined(_MSC_VER)
 132         , meta::select_case< T17,R17
 133         , meta::select_case< T18,R18
 134         , meta::select_case< T19,R19
 135         , meta::select_case< T20,R20
 136         , meta::select_case< T21,R21
 137         , meta::select_case< T22,R22
 138         , meta::select_case< T23,R23
 139         , meta::select_case< T24,R24
 140         , meta::select_case< T25,R25
 141         , meta::select_case< T26,R26
 142         , meta::select_case< T27,R27
 143         , meta::select_case< T28,R28
 144         , meta::select_case< T29,R29
 145         , meta::select_case< T30,R30
 146         , meta::select_case< T31,R31
 147         , meta::select_case< T32,R32
 148         , meta::select_case< T33,R33
 149         , meta::select_case< T34,R34
 150         , meta::select_case< T35,R35
 151         , meta::select_case< T36,R36
 152         , meta::select_case< T37,R37
 153         , meta::select_case< T38,R38
 154         , meta::select_case< T39,R39
 155         , meta::select_case< T40,R40
 156         , NilCase
 157         > > > > > > > > > >     /* 10 */
 158         > > > > > > > > > >     /* 10 */
 159         > > > >    /* 4 */
 160 #else
 161         , NilCase
 162 #endif
 163         > > > > > >     /* 6 */
 164         > > > > > > > > > >     /* 10 */
 165         ::template match<Find>::result result;
 166 };
 167
 168 } // namespace cml
 169
 170 #endif
 171
 172 // -------------------------------------------------------------------------
 173 // vim:ft=cpp