Mercurial > hg > octave-nkf
annotate liboctave/lo-traits.h @ 9685:e793865ede63
implement builtin_type
| author | Jaroslav Hajek <highegg@gmail.com> |
|---|---|
| date | Fri, 02 Oct 2009 08:27:44 +0200 |
| parents | 0f6683a8150a |
| children | 192d94cff6c1 |
| rev | line source |
|---|---|
| 8725 | 1 /* |
| 2 | |
| 3 Copyright (C) 2009 John W. Eaton | |
| 4 | |
| 5 This file is part of Octave. | |
| 6 | |
| 7 Octave is free software; you can redistribute it and/or modify it | |
| 8 under the terms of the GNU General Public License as published by the | |
| 9 Free Software Foundation; either version 3 of the License, or (at your | |
| 10 option) any later version. | |
| 11 | |
| 12 Octave is distributed in the hope that it will be useful, but WITHOUT | |
| 13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 15 for more details. | |
| 16 | |
| 17 You should have received a copy of the GNU General Public License | |
| 18 along with Octave; see the file COPYING. If not, see | |
| 19 <http://www.gnu.org/licenses/>. | |
| 20 | |
| 21 */ | |
| 22 | |
| 23 #if !defined (octave_liboctave_traits_h) | |
| 24 #define octave_liboctave_traits_h 1 | |
| 25 | |
|
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0f6683a8150a
some comments for lo-traits.h
John W. Eaton <jwe@octave.org>
parents:
8725
diff
changeset
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26 // Ideas for these classes taken from C++ Templates, The Complete |
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parents:
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27 // Guide by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley |
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parents:
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28 // (2003). |
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some comments for lo-traits.h
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parents:
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29 |
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some comments for lo-traits.h
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parents:
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changeset
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30 // Select a type based on the value of a constant expression. |
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0f6683a8150a
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parents:
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changeset
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31 |
| 8725 | 32 template <bool cond, typename T1, typename T2> |
| 33 class if_then_else; | |
| 34 | |
| 35 template<typename T1, typename T2> | |
| 36 class if_then_else<true, T1, T2> | |
| 37 { | |
| 38 public: | |
| 39 | |
| 40 typedef T1 result; | |
| 41 }; | |
| 42 | |
| 43 template<typename T1, typename T2> | |
| 44 class if_then_else<false, T1, T2> | |
| 45 { | |
| 46 public: | |
| 47 | |
| 48 typedef T2 result; | |
| 49 }; | |
| 50 | |
|
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some comments for lo-traits.h
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parents:
8725
diff
changeset
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51 // Determine whether a template paramter is a class type. |
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parents:
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changeset
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52 |
| 8725 | 53 template<typename T1> |
| 54 class is_class_type | |
| 55 { | |
| 56 private: | |
| 57 | |
| 58 typedef char one; | |
| 59 typedef struct { char c[2]; } two; | |
| 60 | |
| 61 // Classes can have pointers to members. | |
| 62 template<typename T2> static one is_class_type_test (int T2::*); | |
| 63 | |
| 64 // Catch everything else. | |
| 65 template<typename T2> static two is_class_type_test (...); | |
| 66 | |
| 67 public: | |
| 68 | |
| 69 enum { yes = sizeof (is_class_type_test<T1> (0)) == 1 }; | |
| 70 enum { no = ! yes }; | |
| 71 }; | |
| 72 | |
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some comments for lo-traits.h
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parents:
8725
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changeset
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73 // Define typename ref_param<T>::type as T const& if T is a class |
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parents:
8725
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74 // type. Otherwise, define it to be T. |
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0f6683a8150a
some comments for lo-traits.h
John W. Eaton <jwe@octave.org>
parents:
8725
diff
changeset
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75 |
| 8725 | 76 template<typename T> |
| 77 class ref_param | |
| 78 { | |
| 79 public: | |
| 80 | |
| 81 typedef typename if_then_else<is_class_type<T>::no, T, T const&>::result type; | |
| 82 }; | |
| 83 | |
| 9685 | 84 // Will turn TemplatedClass<T> to T, leave T otherwise. |
| 85 // Useful for stripping wrapper classes, like octave_int. | |
| 86 | |
| 87 template<template<typename> class TemplatedClass, typename T> | |
| 88 class strip_template_param | |
| 89 { | |
| 90 public: | |
| 91 typedef T type; | |
| 92 }; | |
| 93 | |
| 94 template<template<typename> class TemplatedClass, typename T> | |
| 95 class strip_template_param<TemplatedClass, TemplatedClass<T> > | |
| 96 { | |
| 97 public: | |
| 98 typedef T type; | |
| 99 }; | |
| 100 | |
| 8725 | 101 #endif |
| 102 | |
| 103 /* | |
| 104 ;;; Local Variables: *** | |
| 105 ;;; mode: C *** | |
| 106 ;;; page-delimiter: "^/\\*" *** | |
| 107 ;;; End: *** | |
| 108 */ |