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1 /* |
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2 |
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3 Copyright (C) 1996, 1997 John W. Eaton |
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4 |
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5 This file is part of Octave. |
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6 |
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7 Octave is free software; you can redistribute it and/or modify it |
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8 under the terms of the GNU General Public License as published by the |
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9 Free Software Foundation; either version 2, or (at your option) any |
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10 later version. |
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11 |
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12 Octave is distributed in the hope that it will be useful, but WITHOUT |
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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15 for more details. |
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16 |
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17 You should have received a copy of the GNU General Public License |
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18 along with Octave; see the file COPYING. If not, write to the Free |
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19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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20 |
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21 */ |
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22 |
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23 #if defined (__GNUG__) |
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24 #pragma implementation |
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25 #endif |
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26 |
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27 #ifdef HAVE_CONFIG_H |
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28 #include <config.h> |
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29 #endif |
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30 |
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31 #include "defun.h" |
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32 #include "error.h" |
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33 #include "pt-cmd.h" |
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34 #include "ov.h" |
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35 #include "oct-lvalue.h" |
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36 #include "pt-decl.h" |
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37 #include "pt-exp.h" |
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38 #include "pt-id.h" |
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39 #include "pt-walk.h" |
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40 #include "utils.h" |
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41 #include "variables.h" |
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42 |
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43 // Control whether otherwise uninitialized global variables are |
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44 // given a default value. |
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45 static int Vinitialize_global_variables; |
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46 |
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47 // Declarations (global, static, etc.). |
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48 |
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49 tree_decl_elt::~tree_decl_elt (void) |
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50 { |
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51 delete id; |
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52 delete expr; |
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53 } |
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54 |
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55 void |
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56 tree_decl_elt::accept (tree_walker& tw) |
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57 { |
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58 tw.visit_decl_elt (*this); |
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59 } |
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60 |
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61 // Initializer lists for declaration statements. |
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62 |
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63 void |
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64 tree_decl_init_list::eval (tree_decl_elt::eval_fcn f) |
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65 { |
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66 for (Pix p = first (); p != 0; next (p)) |
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67 { |
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68 f (*(this->operator () (p))); |
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69 |
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70 if (error_state) |
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71 break; |
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72 } |
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73 } |
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74 |
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75 void |
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76 tree_decl_init_list::accept (tree_walker& tw) |
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77 { |
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78 tw.visit_decl_init_list (*this); |
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79 } |
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80 |
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81 // Base class for declaration commands (global, static). |
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82 |
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83 tree_decl_command::~tree_decl_command (void) |
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84 { |
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85 delete init_list; |
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86 } |
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87 |
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88 void |
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89 tree_decl_command::accept (tree_walker& tw) |
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90 { |
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91 tw.visit_decl_command (*this); |
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92 } |
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93 |
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94 // Global. |
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95 |
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96 void |
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97 tree_global_command::do_init (tree_decl_elt& elt) |
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98 { |
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99 tree_identifier *id = elt.ident (); |
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100 |
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101 if (id) |
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102 { |
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103 id->link_to_global (); |
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104 |
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105 octave_lvalue ult = id->lvalue (); |
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106 |
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107 if (ult.is_undefined ()) |
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108 { |
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109 tree_expression *expr = elt.expression (); |
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110 |
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111 octave_value init_val; |
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112 |
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113 if (expr) |
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114 init_val = expr->rvalue (); |
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115 else if (Vinitialize_global_variables) |
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116 init_val = builtin_any_variable ("default_global_variable_value"); |
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117 |
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118 ult.assign (octave_value::asn_eq, init_val); |
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119 } |
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120 } |
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121 } |
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122 |
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123 void |
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124 tree_global_command::eval (void) |
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125 { |
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126 if (init_list) |
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127 { |
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128 init_list->eval (do_init); |
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129 |
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130 initialized = true; |
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131 } |
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132 |
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133 if (error_state > 0) |
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134 ::error ("evaluating global command near line %d, column %d", |
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135 line (), column ()); |
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136 } |
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137 |
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138 // Static. |
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139 |
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140 void |
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141 tree_static_command::do_init (tree_decl_elt& elt) |
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142 { |
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143 tree_identifier *id = elt.ident (); |
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144 |
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145 if (id) |
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146 { |
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147 id->mark_as_static (); |
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148 |
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149 tree_expression *expr = elt.expression (); |
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150 |
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151 if (expr) |
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152 { |
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153 octave_value init_val = expr->rvalue (); |
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154 |
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155 octave_lvalue ult = id->lvalue (); |
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156 |
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157 ult.assign (octave_value::asn_eq, init_val); |
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158 } |
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159 } |
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160 } |
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161 |
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162 void |
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163 tree_static_command::eval (void) |
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164 { |
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165 // Static variables only need to be marked and initialized once. |
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166 |
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167 if (init_list && ! initialized) |
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168 { |
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169 init_list->eval (do_init); |
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170 |
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171 initialized = true; |
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172 |
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173 if (error_state > 0) |
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174 ::error ("evaluating static command near line %d, column %d", |
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175 line (), column ()); |
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176 } |
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177 } |
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178 |
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179 static int |
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180 initialize_global_variables (void) |
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181 { |
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182 Vinitialize_global_variables |
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183 = check_preference ("initialize_global_variables"); |
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184 |
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185 return 0; |
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186 } |
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187 |
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188 void |
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189 symbols_of_pt_decl (void) |
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190 { |
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191 DEFVAR (default_global_variable_value, , 0, |
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192 "-*- texinfo -*-\n\ |
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193 @defvr {Built-in Variable} default_global_variable_value\n\ |
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194 The default for value for otherwise uninitialized global variables.\n\ |
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195 Only used if the variable initialize_global_variables is nonzero.\n\ |
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196 If @code{initialize_global_variables} is nonzero, the value of\n\ |
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197 @code{default_glbaol_variable_value} is used as the initial value of\n\ |
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198 global variables that are not explicitly initialized. for example,\n\ |
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199 \n\ |
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200 @example\n\ |
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201 @group\n\ |
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202 initialize_global_variables = 1;\n\ |
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203 default_global_variable_value = 13;\n\ |
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204 global foo;\n\ |
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205 foo\n\ |
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206 @result{} 13\n\ |
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207 @end group\n\ |
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208 @end example\n\ |
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209 \n\ |
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210 the variable @code{default_global_variable_value} is initially undefined.\n\ |
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211 @end defvr"); |
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212 |
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213 DEFVAR (initialize_global_variables, 0.0, initialize_global_variables, |
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214 "-*- texinfo -*-\n\ |
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215 @defvr initialize_global_variables\n\ |
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216 If the value of this variable is nonzero, global variables are given\n\ |
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217 the default initial value specified by the built-in variable\n\ |
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218 @code{default_global_variable_value}.\n\ |
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219 @end defvr"); |
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220 |
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221 } |
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222 |
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223 /* |
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224 ;;; Local Variables: *** |
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225 ;;; mode: C++ *** |
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226 ;;; End: *** |
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227 */ |
