ceph/src/boost/libs/phoenix/example/bind_goose.cpp

   1 /*=============================================================================
   2 For Boost Bind:
   3     Copyright (c) 2001-2004 Peter Dimov and Multi Media Ltd.
   4     Copyright (c) 2001 David Abrahams
   5     Copyright (c) 2005 Peter Dimov
   6 For Boost Phoenix:
   7     Copyright (c) 2001-2010 Joel de Guzman
   8     Copyright (c) 2010 Thomas Heller
   9 For the example:
  10     Copyright (c) 2011 Paul Heil
  11     Copyright (c) 2015 John Fletcher
  12
  13     Distributed under the Boost Software License, Version 1.0. (See accompanying
  14     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  15 ==============================================================================*/
  16 // bind_goose.cpp
  17 // This example is based on code by Paul Heil to be found here:
  18 // http://www.codeproject.com/Tips/248492/How-does-boost-phoenix-improve-boost-bind
  19 //
  20 // Show different ways of using boost bind and phoenix to handle deletion.
  21 //
  22
  23
  24 #include <iostream>
  25 #include <boost/function.hpp>
  26 #include <boost/bind.hpp>
  27 #include <boost/phoenix/core.hpp>
  28 #include <boost/phoenix/bind.hpp>
  29 #include <boost/phoenix/operator/comparison.hpp>
  30 #include <boost/phoenix/stl/algorithm/transformation.hpp>
  31 #include <functional>
  32 #include <string>
  33 #include <vector>
  34
  35 ////////////////////////////////////////////
  36 // Set up the list here
  37 ////////////////////////////////////////////
  38 std::vector< std::string > make_list() {
  39   std::vector< std::string > list;
  40   list.push_back( "duck" );
  41   list.push_back( "duck" );
  42   list.push_back( "goose" );
  43   return list;
  44 }
  45 //////////////////////////////////////////////
  46 // First example using standard library only
  47 //////////////////////////////////////////////
  48 bool IsGoose( const std::string& s )
  49 {
  50   return s == "goose";
  51 }
  52
  53 void delete_value1(std::vector< std::string > &list )
  54 {
  55   list.erase( std::remove_if( list.begin(), list.end(), IsGoose ), list.end() );
  56 }
  57
  58 void out_string(const std::string  &s)
  59 {
  60   std::cout << s << std::endl;
  61 }
  62
  63 void show_list1( const std::vector< std::string > &list )
  64 {
  65   std::for_each(list.begin(), list.end(), out_string);
  66 }
  67
  68 //////////////////////////////////////////////
  69 // Second example using boost bind
  70 //////////////////////////////////////////////
  71
  72 bool isValue(const std::string &s1, const std::string &s2)
  73 {
  74   return s1==s2;
  75 }
  76
  77 void delete_value2(std::vector< std::string > &list, const std::string & value)
  78 {
  79   list.erase(
  80     std::remove_if(
  81         list.begin(),
  82         list.end(),
  83         boost::bind(
  84             isValue, // &isValue works as well.
  85             _1, // Boost.Bind placeholder
  86             boost::cref( value ) ) ),
  87     list.end() );
  88 }
  89
  90 ///////////////////////////////////////////////////////
  91 // Third example using boost phoenix for the comparison
  92 ///////////////////////////////////////////////////////
  93
  94 namespace phx = boost::phoenix;
  95 using phx::placeholders::arg1;
  96 using phx::placeholders::arg2;
  97
  98 void delete_value3(std::vector< std::string > &list, const std::string & value)
  99 {
 100   list.erase( std::remove_if(
 101         list.begin(),
 102         list.end(),
 103         // This needs header boost/phoenix/operator/comparison.
 104         // arg1 is a Boost.Phoenix placeholder.
 105         arg1 == phx::cref( value ) ),
 106         list.end() );
 107 }
 108
 109 //////////////////////////////////////////////////////////////
 110 // Third example using boost phoenix for the algorithm as well
 111 //////////////////////////////////////////////////////////////
 112
 113 void delete_value4(std::vector< std::string > &list, const std::string & value)
 114 {
 115   // This need header boost/phoenix/stl/algorithm/transformation
 116   list.erase( phx::remove_if( arg1, arg2 )
 117             ( list, arg1 == phx::cref( value ) ),
 118             list.end() );
 119 }
 120
 121 int main() {
 122   std::cout << "--------------------------------" << std::endl;
 123   std::cout << "Delete the goose examples." << std::endl;
 124   std::cout << "--------------------------------" << std::endl;
 125   std::string value = "goose";
 126
 127   std::vector< std::string > list1 = make_list();
 128   delete_value1(list1);
 129   show_list1(list1);
 130   std::cout << "--------------------------------" << std::endl;
 131   std::vector< std::string > list2 = make_list();
 132   delete_value2(list2,value);
 133   show_list1(list2);
 134   std::cout << "--------------------------------" << std::endl;
 135   std::vector< std::string > list3 = make_list();
 136   delete_value3(list3,value);
 137   show_list1(list3);
 138   std::cout << "--------------------------------" << std::endl;
 139   std::vector< std::string > list4 = make_list();
 140   delete_value4(list4,value);
 141   show_list1(list4);
 142   std::cout << "--------------------------------" << std::endl;
 143   return 0;
 144 }