stage4/generate_cc/search_var_instance_decl.cc
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     1 /*
       
     2  * (c) 2003 Mario de Sousa
       
     3  *
       
     4  * Offered to the public under the terms of the GNU General Public License
       
     5  * as published by the Free Software Foundation; either version 2 of the
       
     6  * License, or (at your option) any later version.
       
     7  *
       
     8  * This program is distributed in the hope that it will be useful, but
       
     9  * WITHOUT ANY WARRANTY; without even the implied warranty of
       
    10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
       
    11  * Public License for more details.
       
    12  *
       
    13  * This code is made available on the understanding that it will not be
       
    14  * used in safety-critical situations without a full and competent review.
       
    15  */
       
    16 
       
    17 /*
       
    18  * An IEC 61131-3 IL and ST compiler.
       
    19  *
       
    20  * Based on the
       
    21  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
       
    22  *
       
    23  */
       
    24 
       
    25 /* Determine the data type of a specific variable instance, including
       
    26  * function block instances.
       
    27  * A reference to the relevant variable declaration is returned.
       
    28  * The variable instance may NOT be a member of a structure of a memeber
       
    29  * of a structure of an element of an array of ...
       
    30  *
       
    31  * example:
       
    32  *    window.points[1].coordinate.x
       
    33  *    window.points[1].colour
       
    34  *    etc... ARE NOT ALLOWED!
       
    35  *
       
    36  * This class must only be passed the name of the variable that will appear
       
    37  * in the variable declaration. In the above examples, this would be
       
    38  *   'window' !!
       
    39  *
       
    40  *
       
    41  * If you need to pass a complete name of a variable instance (such as
       
    42  * 'window.points[1].coordinate.x') use the search_varfb_instance_type_c instead!
       
    43  */
       
    44 /* Note that current_type_decl that this class returns may reference the
       
    45  * name of a type, or the type declaration itself!
       
    46  * For an example of the first, consider a variable declared as ...
       
    47  * x : AAA;
       
    48  * where the AAA type is previously declared as whatever.
       
    49  * For an example of the second, consider a variable declared as ...
       
    50  * x : array of int [10];  ---->  is allowed
       
    51  *
       
    52  * If it is the first, we will return a reference to the name, if the second
       
    53  * we return a reference to the declaration!!
       
    54  */
       
    55 class search_var_instance_decl_c: public search_visitor_c {
       
    56 
       
    57   private:
       
    58     symbol_c *search_scope;
       
    59     symbol_c *search_name;
       
    60     symbol_c *current_type_decl;
       
    61 
       
    62   public:
       
    63     search_var_instance_decl_c(symbol_c *search_scope) {
       
    64       this->search_scope = search_scope;
       
    65       this->search_name = NULL;
       
    66       this->current_type_decl = NULL;
       
    67     }
       
    68 
       
    69     symbol_c *get_decl(symbol_c *variable_instance_name) {
       
    70       this->search_name = variable_instance_name;
       
    71       return (symbol_c *)search_scope->accept(*this);
       
    72     }
       
    73 
       
    74   public:
       
    75 /***************************/
       
    76 /* B 0 - Programming Model */
       
    77 /***************************/
       
    78     void *visit(library_c *symbol) {
       
    79       /* we do not want to search multiple declaration scopes,
       
    80        * so we do not visit all the functions, fucntion blocks, etc...
       
    81        */
       
    82       return NULL;
       
    83     }
       
    84 
       
    85 
       
    86 
       
    87 /******************************************/
       
    88 /* B 1.4.3 - Declaration & Initialisation */
       
    89 /******************************************/
       
    90 /* edge -> The F_EDGE or R_EDGE directive */
       
    91 // SYM_REF2(edge_declaration_c, edge, var1_list)
       
    92 // TODO
       
    93 
       
    94 /* var1_list is one of the following...
       
    95  *    simple_spec_init_c *
       
    96  *    subrange_spec_init_c *
       
    97  *    enumerated_spec_init_c *
       
    98  */
       
    99 // SYM_REF2(var1_init_decl_c, var1_list, spec_init)
       
   100     void *visit(var1_init_decl_c *symbol) {
       
   101       current_type_decl = symbol->spec_init;
       
   102       return symbol->var1_list->accept(*this);
       
   103     }
       
   104 
       
   105 /* var1_list ',' variable_name */
       
   106 // SYM_LIST(var1_list_c)
       
   107     void *visit(var1_list_c *symbol) {
       
   108       list_c *list = symbol;
       
   109       for(int i = 0; i < list->n; i++) {
       
   110         if (compare_identifiers(list->elements[i], search_name) == 0)
       
   111 	  /* by now, current_type_decl should be != NULL */
       
   112           return current_type_decl;
       
   113       }
       
   114       return NULL;
       
   115     }
       
   116 
       
   117 /* name_list ':' function_block_type_name ASSIGN structure_initialization */
       
   118 /* structure_initialization -> may be NULL ! */
       
   119     void *visit(fb_name_decl_c *symbol) {
       
   120       current_type_decl = symbol->function_block_type_name;
       
   121       return symbol->fb_name_list->accept(*this);
       
   122     }
       
   123 
       
   124 /* name_list ',' fb_name */
       
   125     void *visit(fb_name_list_c *symbol) {
       
   126       list_c *list = symbol;
       
   127       for(int i = 0; i < list->n; i++) {
       
   128         if (compare_identifiers(list->elements[i], search_name) == 0)
       
   129 	  /* by now, current_fb_declaration should be != NULL */
       
   130           return current_type_decl;
       
   131       }
       
   132       return NULL;
       
   133     }
       
   134 
       
   135 /* var1_list ':' array_spec_init */
       
   136 // SYM_REF2(array_var_init_decl_c, var1_list, array_spec_init)
       
   137     void *visit(array_var_init_decl_c *symbol) {
       
   138       current_type_decl = symbol->array_spec_init;
       
   139       return symbol->var1_list->accept(*this);
       
   140     }
       
   141 
       
   142 /*  var1_list ':' initialized_structure */
       
   143 // SYM_REF2(structured_var_init_decl_c, var1_list, initialized_structure)
       
   144     void *visit(structured_var_init_decl_c *symbol) {
       
   145       current_type_decl = symbol->initialized_structure;
       
   146       return symbol->var1_list->accept(*this);
       
   147     }
       
   148 
       
   149 /*  var1_list ':' array_specification */
       
   150 // SYM_REF2(array_var_declaration_c, var1_list, array_specification)
       
   151     void *visit(array_var_declaration_c *symbol) {
       
   152       current_type_decl = symbol->array_specification;
       
   153       return symbol->var1_list->accept(*this);
       
   154     }
       
   155 
       
   156 /*  var1_list ':' structure_type_name */
       
   157 // SYM_REF2(structured_var_declaration_c, var1_list, structure_type_name)
       
   158     void *visit(structured_var_declaration_c *symbol) {
       
   159       current_type_decl = symbol->structure_type_name;
       
   160       return symbol->var1_list->accept(*this);
       
   161     }
       
   162 
       
   163 /*  [variable_name] location ':' located_var_spec_init */
       
   164 /* variable_name -> may be NULL ! */
       
   165 // SYM_REF4(located_var_decl_c, variable_name, location, located_var_spec_init, unused)
       
   166 // TODO!!
       
   167 
       
   168 /*  global_var_name ':' (simple_specification|subrange_specification|enumerated_specification|array_specification|prev_declared_structure_type_name|function_block_type_name */
       
   169 // SYM_REF2(external_declaration_c, global_var_name, specification)
       
   170     void *visit(external_declaration_c *symbol) {
       
   171       if (compare_identifiers(symbol->global_var_name, search_name) == 0)
       
   172           return symbol->specification;
       
   173       return NULL;
       
   174     }
       
   175 
       
   176 /*| global_var_spec ':' [located_var_spec_init|function_block_type_name] */
       
   177 /* type_specification ->may be NULL ! */
       
   178 // SYM_REF2(global_var_decl_c, global_var_spec, type_specification)
       
   179 // TODO!!
       
   180 
       
   181 /*| global_var_name location */
       
   182 // SYM_REF2(global_var_spec_c, global_var_name, location)
       
   183 // TODO!!
       
   184 
       
   185 /*  AT direct_variable */
       
   186 // SYM_REF2(location_c, direct_variable, unused)
       
   187 // TODO!!
       
   188 
       
   189 /*| global_var_list ',' global_var_name */
       
   190 // SYM_LIST(global_var_list_c)
       
   191 // TODO!!
       
   192 
       
   193 /*  var1_list ':' single_byte_string_spec */
       
   194 // SYM_REF2(single_byte_string_var_declaration_c, var1_list, single_byte_string_spec)
       
   195     void *visit(single_byte_string_var_declaration_c *symbol) {
       
   196       current_type_decl = symbol->single_byte_string_spec;
       
   197       return symbol->var1_list->accept(*this);
       
   198     }
       
   199 
       
   200 /*  STRING ['[' integer ']'] [ASSIGN single_byte_character_string] */
       
   201 /* integer ->may be NULL ! */
       
   202 /* single_byte_character_string ->may be NULL ! */
       
   203 // SYM_REF2(single_byte_string_spec_c, integer, single_byte_character_string)
       
   204 // TODO!!
       
   205 
       
   206 /*  var1_list ':' double_byte_string_spec */
       
   207 // SYM_REF2(double_byte_string_var_declaration_c, var1_list, double_byte_string_spec)
       
   208     void *visit(double_byte_string_var_declaration_c *symbol) {
       
   209       current_type_decl = symbol->double_byte_string_spec;
       
   210       return symbol->var1_list->accept(*this);
       
   211     }
       
   212 
       
   213 /*  WSTRING ['[' integer ']'] [ASSIGN double_byte_character_string] */
       
   214 /* integer ->may be NULL ! */
       
   215 /* double_byte_character_string ->may be NULL ! */
       
   216 // SYM_REF2(double_byte_string_spec_c, integer, double_byte_character_string)
       
   217 // TODO!!
       
   218 
       
   219 /*  variable_name incompl_location ':' var_spec */
       
   220 // SYM_REF4(incompl_located_var_decl_c, variable_name, incompl_location, var_spec, unused)
       
   221 // TODO!!
       
   222 
       
   223 /*  AT incompl_location_token */
       
   224 // SYM_TOKEN(incompl_location_c)
       
   225 // TODO!!
       
   226 
       
   227 
       
   228 /**************************************/
       
   229 /* B.1.5 - Program organization units */
       
   230 /**************************************/
       
   231 /***********************/
       
   232 /* B 1.5.1 - Functions */
       
   233 /***********************/
       
   234 // SYM_REF4(function_declaration_c, derived_function_name, type_name, var_declarations_list, function_body)
       
   235     void *visit(function_declaration_c *symbol) {
       
   236       /* functions have a variable named after themselves, to store
       
   237        * the variable that will be returned!!
       
   238        */
       
   239       if (compare_identifiers(symbol->derived_function_name, search_name) == 0)
       
   240           return symbol->type_name;
       
   241 
       
   242       /* no need to search through all the body, so we only
       
   243        * visit the variable declarations...!
       
   244        */
       
   245       return symbol->var_declarations_list->accept(*this);
       
   246     }
       
   247 
       
   248 /*****************************/
       
   249 /* B 1.5.2 - Function Blocks */
       
   250 /*****************************/
       
   251     void *visit(function_block_declaration_c *symbol) {
       
   252       /* no need to search through all the body, so we only
       
   253        * visit the variable declarations...!
       
   254        */
       
   255       return symbol->var_declarations->accept(*this);
       
   256     }
       
   257 
       
   258 /**********************/
       
   259 /* B 1.5.3 - Programs */
       
   260 /**********************/
       
   261     void *visit(program_declaration_c *symbol) {
       
   262       /* no need to search through all the body, so we only
       
   263        * visit the variable declarations...!
       
   264        */
       
   265       return symbol->var_declarations->accept(*this);
       
   266     }
       
   267 
       
   268 
       
   269 #if 0
       
   270 /*********************/
       
   271 /* B 1.4 - Variables */
       
   272 /*********************/
       
   273 SYM_REF2(symbolic_variable_c, var_name, unused)
       
   274 
       
   275 /********************************************/
       
   276 /* B.1.4.1   Directly Represented Variables */
       
   277 /********************************************/
       
   278 SYM_TOKEN(direct_variable_c)
       
   279 
       
   280 /*************************************/
       
   281 /* B.1.4.2   Multi-element Variables */
       
   282 /*************************************/
       
   283 /*  subscripted_variable '[' subscript_list ']' */
       
   284 SYM_REF2(array_variable_c, subscripted_variable, subscript_list)
       
   285 
       
   286 /* subscript_list ',' subscript */
       
   287 SYM_LIST(subscript_list_c)
       
   288 
       
   289 /*  record_variable '.' field_selector */
       
   290 /*  WARNING: input and/or output variables of function blocks
       
   291  *           may be accessed as fields of a tructured variable!
       
   292  *           Code handling a structured_variable_c must take
       
   293  *           this into account!
       
   294  */
       
   295 SYM_REF2(structured_variable_c, record_variable, field_selector)
       
   296 
       
   297 
       
   298 #endif
       
   299 };
       
   300 
       
   301 
       
   302 
       
   303 
       
   304