1 | // see also C++ investigation in ~/plg2/cfa2/mycode/string/raii/ctor-calls.cpp |
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2 | |
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3 | #include <string.hfa> |
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4 | #include <string_res.hfa> |
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5 | |
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6 | /* |
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7 | call_substrOfPart: |
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8 | In all cases, of both HL and LL, there is a temporary object. |
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9 | It represents narrowing the range, from full-string, to [1..3]. |
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10 | The only matter to control is whether that temporary shares edits with the string from which it was created. |
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11 | In HL, two knobs control it, and the |
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12 | */ |
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13 | |
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14 | void calltest_HL() { |
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15 | |
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16 | #define HELPER_BODY(param) \ |
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17 | sout | "early in helper with " | param; \ |
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18 | param[0] = '+'; \ |
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19 | sout | "late in helper with " | param; |
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20 | |
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21 | void helper1( string q ) { HELPER_BODY(q) } |
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22 | void helper2( string & q ) { HELPER_BODY(q) } |
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23 | #undef HELPER_BODY |
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24 | |
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25 | string fred; |
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26 | |
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27 | |
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28 | sout | "==="; |
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29 | sout | "HL: substring of part"; |
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30 | |
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31 | sout | "---"; |
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32 | // Calling a by-val function, the only way it supports, in which it gets a private logical copy. |
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33 | fred = "abcd"; |
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34 | sout | "before helper with " | fred; |
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35 | helper1( fred(1,3) ); |
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36 | sout | "after helper with " | fred; |
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37 | |
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38 | sout | "---"; |
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39 | // Calling a by-ref function, sys-style, in which we want to gets its changes as side effects. |
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40 | fred = "abcd"; |
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41 | sout | "before helper with " | fred; |
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42 | helper2( fred(1,3) ); |
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43 | sout | "after helper with " | fred; |
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44 | |
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45 | sout | "---"; |
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46 | // Calling a by-ref function, trans-style, in which we give it a logical copy, to prevent it from pulluting our gold one. |
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47 | fred = "abcd"; |
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48 | sout | "before helper with " | fred; |
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49 | helper2( (string){ fred(1,3) } ); |
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50 | sout | "after helper with " | fred; |
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51 | |
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52 | |
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53 | sout | "==="; |
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54 | sout | "HL: substring of whole"; |
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55 | |
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56 | sout | "---"; |
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57 | // Calling a by-val function, the only way it supports, in which it gets a private logical copy. |
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58 | fred = "abcd"; |
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59 | sout | "before helper with " | fred; |
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60 | helper1( fred(0,4) ); |
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61 | sout | "after helper with " | fred; |
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62 | |
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63 | sout | "---"; |
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64 | // Calling a by-ref function, sys-style, in which we want to gets its changes as side effects. |
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65 | fred = "abcd"; |
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66 | sout | "before helper with " | fred; |
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67 | helper2( fred(0,4) ); |
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68 | sout | "after helper with " | fred; |
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69 | |
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70 | sout | "---"; |
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71 | // Calling a by-ref function, trans-style, in which we give it a logical copy, to prevent it from pulluting our gold one. |
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72 | fred = "abcd"; |
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73 | sout | "before helper with " | fred; |
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74 | helper2( (string){ fred(0,4) } ); |
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75 | sout | "after helper with " | fred; |
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76 | |
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77 | |
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78 | |
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79 | sout | "==="; |
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80 | sout | "HL: whole original string"; |
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81 | |
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82 | sout | "---"; |
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83 | // Calling a by-val function, the only way it supports, in which it gets a private logical copy. |
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84 | fred = "abcd"; |
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85 | sout | "before helper with " | fred; |
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86 | helper1( fred ); |
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87 | sout | "after helper with " | fred; |
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88 | |
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89 | sout | "---"; |
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90 | // Calling a by-ref function, sys-style, in which we want to gets its changes as side effects. |
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91 | fred = "abcd"; |
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92 | sout | "before helper with " | fred; |
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93 | helper2( fred ); |
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94 | sout | "after helper with " | fred; |
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95 | |
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96 | sout | "---"; |
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97 | // Calling a by-ref function, trans-style, in which we give it a logical copy, to prevent it from pulluting our gold one. |
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98 | fred = "abcd"; |
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99 | sout | "before helper with " | fred; |
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100 | helper2( (string){ fred } ); |
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101 | sout | "after helper with " | fred; |
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102 | } |
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103 | |
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104 | void calltest_LL() { |
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105 | |
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106 | #define HELPER_BODY(param) \ |
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107 | sout | "early in helper with " | param; \ |
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108 | assignAt(param, 0, '+'); \ |
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109 | sout | "late in helper with " | param; |
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110 | |
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111 | void helper1( string_res & q ) { HELPER_BODY(q) } // arg should always be a temporary constructed with COPY_VALUE |
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112 | void helper2( string_res & q ) { HELPER_BODY(q) } // arg can refer to whatever you want |
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113 | #undef HELPER_BODY |
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114 | |
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115 | /* |
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116 | In LL, both functions are translated to the same thing. |
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117 | "The only allowed call of #1" becomes respecting the restriction of the comment at helper1. |
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118 | A sys call of #2 is different from the only allowed call of #1. |
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119 | A trans call of #2 is the same as the only allowed call of #1. |
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120 | */ |
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121 | |
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122 | string_res fred; |
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123 | |
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124 | sout | "==="; |
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125 | sout | "LL: substring of part"; |
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126 | |
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127 | sout | "---"; |
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128 | // Calling a by-val function, the only way it supports, in which it gets a private logical copy. |
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129 | fred = "abcd"; |
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130 | sout | "before helper with " | fred; |
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131 | helper1( (string_res){ fred, COPY_VALUE, 1, 3 } ); |
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132 | sout | "after helper with " | fred; |
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133 | |
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134 | sout | "---"; |
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135 | // Calling a by-ref function, sys-style, in which we want to gets its changes as side effects. |
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136 | fred = "abcd"; |
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137 | sout | "before helper with " | fred; |
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138 | helper2( (string_res){ fred, SHARE_EDITS, 1, 3 } ); |
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139 | sout | "after helper with " | fred; |
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140 | |
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141 | sout | "---"; |
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142 | // Calling a by-ref function, trans-style, in which we give it a logical copy, to prevent it from pulluting our gold one. |
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143 | fred = "abcd"; |
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144 | sout | "before helper with " | fred; |
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145 | helper2( (string_res){ fred, COPY_VALUE, 1, 3 } ); |
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146 | sout | "after helper with " | fred; |
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147 | |
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148 | |
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149 | sout | "==="; |
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150 | sout | "LL: substring of whole"; |
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151 | |
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152 | sout | "---"; |
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153 | // Calling a by-val function, the only way it supports, in which it gets a private logical copy. |
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154 | fred = "abcd"; |
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155 | sout | "before helper with " | fred; |
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156 | helper1( (string_res){ fred, COPY_VALUE, 0, 4 } ); |
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157 | sout | "after helper with " | fred; |
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158 | |
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159 | sout | "---"; |
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160 | // Calling a by-ref function, sys-style, in which we want to gets its changes as side effects. |
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161 | fred = "abcd"; |
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162 | sout | "before helper with " | fred; |
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163 | helper2( (string_res){ fred, SHARE_EDITS, 0, 4 } ); |
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164 | sout | "after helper with " | fred; |
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165 | |
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166 | sout | "---"; |
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167 | // Calling a by-ref function, trans-style, in which we give it a logical copy, to prevent it from pulluting our gold one. |
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168 | fred = "abcd"; |
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169 | sout | "before helper with " | fred; |
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170 | helper2( (string_res){ fred, COPY_VALUE, 0, 4 } ); |
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171 | sout | "after helper with " | fred; |
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172 | |
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173 | |
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174 | sout | "==="; |
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175 | sout | "LL: whole original string"; |
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176 | |
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177 | sout | "---"; |
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178 | // Calling a by-val function, the only way it supports, in which it gets a private logical copy. |
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179 | fred = "abcd"; |
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180 | sout | "before helper with " | fred; |
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181 | helper1( (string_res){ fred, COPY_VALUE } ); |
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182 | sout | "after helper with " | fred; |
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183 | |
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184 | sout | "---"; |
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185 | // Calling a by-ref function, sys-style, in which we want to gets its changes as side effects. |
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186 | fred = "abcd"; |
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187 | sout | "before helper with " | fred; |
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188 | helper2( fred ); |
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189 | sout | "after helper with " | fred; |
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190 | |
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191 | sout | "---"; |
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192 | // Calling a by-ref function, trans-style, in which we give it a logical copy, to prevent it from pulluting our gold one. |
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193 | fred = "abcd"; |
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194 | sout | "before helper with " | fred; |
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195 | helper2( (string_res){ fred, COPY_VALUE } ); |
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196 | sout | "after helper with " | fred; |
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197 | } |
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198 | |
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199 | |
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200 | |
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201 | int main() { |
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202 | |
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203 | calltest_HL(); |
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204 | calltest_LL(); |
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205 | |
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206 | } |
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