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 

    26 /* Returns the function block type declaration

    27  * of a specific function block instance.

    28  */

    29 

    30 

    31 

    32 /* Returns the type name of a specific function block

    33  * instance. This class will search the variable

    34  * declarations inside the scope given to it

    35  * searching for the declaration of the function

    36  * block instance.

    37  *

    38  * The class constructor must be given the search scope

    39  * (function, function block or program within which

    40  * the function block instance was declared).

    41  *

    42  * This class will search the tree from the root given to the

    43  * constructor. Another option would be to build a symbol table,

    44  * and search that instead. Building the symbol table would be done

    45  * while visiting the variable declaration objects in the parse

    46  * tree. Unfortuantely, generate_cc_c does not visit these

    47  * objects, delegating it to another class. This means that

    48  * we would need another specialised class just to build the

    49  * symbol table. We might just as well have a specialised class

    50  * that searches the tree itself for the relevant info. This

    51  * class is exactly that...!

    52  */

    53 class search_fb_instance_decl_c: public search_visitor_c {

    54 

    55   private:

    56     symbol_c *search_scope;

    57 

    58     symbol_c *search_name;

    59     symbol_c *current_fb_type_name;

    60 

    61   public:

    62     search_fb_instance_decl_c(symbol_c *search_scope) {

    63       this->search_scope = search_scope;

    64       this->current_fb_type_name = NULL;

    65     }

    66 

    67     symbol_c *get_type_name(symbol_c *fb_instance_name) {

    68       this->search_name = fb_instance_name;

    69       return (symbol_c *)search_scope->accept(*this);

    70     }

    71 

    72   public:

    73 /***************************/

    74 /* B 0 - Programming Model */

    75 /***************************/

    76     void *visit(library_c *symbol) {

    77       /* we do not want to search multiple declaration scopes,

    78        * so we do not visit all the functions, fucntion blocks, etc...

    79        */

    80       return NULL;

    81     }

    82 

    83 /******************************************/

    84 /* B 1.4.3 - Declaration & Initialisation */

    85 /******************************************/

    86 

    87 /* name_list ':' function_block_type_name ASSIGN structure_initialization */

    88 /* structure_initialization -> may be NULL ! */

    89     void *visit(fb_name_decl_c *symbol) {

    90       current_fb_type_name = symbol->function_block_type_name;

    91       return symbol->fb_name_list->accept(*this);

    92     }

    93 

    94 /* name_list ',' fb_name */

    95     void *visit(fb_name_list_c *symbol) {

    96       list_c *list = symbol;

    97       for(int i = 0; i < list->n; i++) {

    98         if (compare_identifiers(list->elements[i], search_name) == 0)

    99 	  /* by now, current_fb_declaration should be != NULL */

   100           return current_fb_type_name;

   101       }

   102       return NULL;

   103     }

   104 

   105 /**************************************/

   106 /* B.1.5 - Program organization units */

   107 /**************************************/

   108 /***********************/

   109 /* B 1.5.1 - Functions */

   110 /***********************/

   111     void *visit(function_declaration_c *symbol) {

   112       /* no need to search through all the body, so we only

   113        * visit the variable declarations...!

   114        */

   115       return symbol->var_declarations_list->accept(*this);

   116     }

   117 

   118 /*****************************/

   119 /* B 1.5.2 - Function Blocks */

   120 /*****************************/

   121     void *visit(function_block_declaration_c *symbol) {

   122       /* no need to search through all the body, so we only

   123        * visit the variable declarations...!

   124        */

   125       return symbol->var_declarations->accept(*this);

   126     }

   127 

   128 /**********************/

   129 /* B 1.5.3 - Programs */

   130 /**********************/

   131     void *visit(program_declaration_c *symbol) {

   132       /* no need to search through all the body, so we only

   133        * visit the variable declarations...!

   134        */

   135       return symbol->var_declarations->accept(*this);

   136     }

   137 };

   138 

   139 

   140 

   141