| [08ed947] | 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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