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 /*

    27  * Seperation of type specification and default value constructs

    28  * (for e.g. simple_spec_init_c), into a type specificiation part,

    29  * and a default value part.

    30  */

    31 

    32 

    33 

    34 

    35 //#include <stdio.h>  /* required for NULL */

    36 //#include <string>

    37 //#include <iostream>

    38 

    39 //#include "../../util/symtable.hh"

    40 

    41 

    42 

    43 

    44 

    45 

    46 

    47 class spec_init_sperator_c: public null_visitor_c {

    48   private:

    49     /* this is a singleton class... */

    50     static spec_init_sperator_c *class_instance;

    51     static spec_init_sperator_c *get_class_instance(void) {

    52       if (NULL == class_instance)

    53         class_instance = new spec_init_sperator_c();

    54 

    55       if (NULL == class_instance)

    56         ERROR;

    57 

    58       return class_instance;

    59     }

    60 

    61   private:

    62     typedef enum {search_spec, search_init} search_what_t;

    63     static search_what_t search_what;

    64 

    65   public:

    66     /* the only two public functions... */

    67     static symbol_c *get_spec(symbol_c *spec_init) {

    68       search_what = search_spec;

    69       return (symbol_c *)spec_init->accept(*get_class_instance());

    70     }

    71 

    72     static symbol_c *get_init(symbol_c *spec_init) {

    73       search_what = search_init;

    74       return (symbol_c *)spec_init->accept(*get_class_instance());

    75     }

    76 

    77 //  private:

    78   public:  /* probably needs to be public so it may be visited... !! */

    79 

    80 

    81 /*******************************************/

    82 /* B 1.1 - Letters, digits and identifiers */

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

    84 // SYM_TOKEN(identifier_c)

    85 void *visit(identifier_c *symbol) {

    86   TRACE("spec_init_sperator_c::identifier_c");

    87   switch (search_what) {

    88     /* if we ever get called sith a simple identifier_c, then it must be a previously declared type... */

    89     case search_spec: return symbol;

    90     case search_init: return NULL;

    91   }

    92   ERROR; /* should never occur */

    93   return NULL;

    94 }

    95 

    96 

    97 /********************************/

    98 /* B 1.3.3 - Derived data types */

    99 /********************************/

   100 

   101 /* simple_specification ASSIGN constant */

   102 void *visit(simple_spec_init_c *symbol) {

   103   TRACE("spec_init_sperator_c::simple_spec_init_c");

   104   switch (search_what) {

   105     case search_spec: return symbol->simple_specification;

   106     case search_init: return symbol->constant;

   107   }

   108   ERROR; /* should never occur */

   109   return NULL;

   110 }

   111 

   112 /* subrange_specification ASSIGN signed_integer */

   113 void *visit(subrange_spec_init_c *symbol) {

   114   TRACE("spec_init_sperator_c::subrange_spec_init_c");

   115   switch (search_what) {

   116     case search_spec: return symbol->subrange_specification;

   117     case search_init: return symbol->signed_integer;

   118   }

   119   ERROR; /* should never occur */

   120   return NULL;

   121 }

   122 

   123 /* enumerated_specification ASSIGN enumerated_value */

   124 void *visit(enumerated_spec_init_c *symbol) {

   125   TRACE("spec_init_sperator_c::enumerated_spec_init_c");

   126   switch (search_what) {

   127     case search_spec: return symbol->enumerated_specification;

   128     case search_init: return symbol->enumerated_value;

   129   }

   130   ERROR; /* should never occur */

   131   return NULL;

   132 }

   133 

   134 /* structure_type_name ASSIGN structure_initialization */

   135 /* structure_initialization may be NULL ! */

   136 //SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)

   137 void *visit(initialized_structure_c *symbol) {

   138   TRACE("spec_init_sperator_c::initialized_structure_c");

   139   switch (search_what) {

   140     case search_spec: return symbol->structure_type_name;

   141     case search_init: return symbol->structure_initialization;

   142   }

   143   ERROR; /* should never occur */

   144   return NULL;

   145 }

   146 

   147 

   148 /******************************************/

   149 /* B 1.4.3 - Declaration & Initialisation */

   150 /******************************************/

   151 

   152 /* fb_name_list ':' function_block_type_name ASSIGN structure_initialization */

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

   154 void *visit(fb_name_decl_c *symbol) {

   155   TRACE("spec_init_sperator_c::fb_name_decl_c");

   156   switch (search_what) {

   157     case search_spec: return symbol->function_block_type_name;

   158     case search_init: return symbol->structure_initialization;

   159   }

   160   ERROR; /* should never occur */

   161   return NULL;

   162 }

   163 

   164 };   /* class spec_init_sperator_c */

   165 

   166 

   167 

   168 spec_init_sperator_c *spec_init_sperator_c ::class_instance = NULL;

   169 spec_init_sperator_c::search_what_t spec_init_sperator_c::search_what;