1 /*

     2  *  matiec - a compiler for the programming languages defined in IEC 61131-3

     3  *

     4  *  Copyright (C) 2012  Mario de Sousa (msousa@fe.up.pt)

     5  *

     6  *  This program is free software: you can redistribute it and/or modify

     7  *  it under the terms of the GNU General Public License as published by

     8  *  the Free Software Foundation, either version 3 of the License, or

     9  *  (at your option) any later version.

    10  *

    11  *  This program is distributed in the hope that it will be useful,

    12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of

    13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    14  *  GNU General Public License for more details.

    15  *

    16  *  You should have received a copy of the GNU General Public License

    17  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.

    18  *

    19  *

    20  * This code is made available on the understanding that it will not be

    21  * used in safety-critical situations without a full and competent review.

    22  */

    23 

    24 /*

    25  * An IEC 61131-3 compiler.

    26  *

    27  * Based on the

    28  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)

    29  *

    30  */

    31 

    32 /*

    33  *  A small helper visitor class, that will   

    34  *  return the name (tokn_c *) of a variable, as it will

    35  *  appear in the variable declaration.

    36  */

    37 

    38 /*  For ex.:

    39  *       VAR

    40  *          A : int;

    41  *          B : ARRAY [1..9] of int;

    42  *          C : some_struct_t;

    43  *       END_VAR

    44  *

    45  *          A    := 56;

    46  *          B[8] := 99;

    47  *          C.e  := 77;

    48  *

    49  *       Calling this visitor class with symbolic_variable_c instance referencing 'A' in

    50  *       the line 'A := 56', will return the string "A".

    51  *

    52  *       Calling this visitor class with array_variable_c instance referencing 'B[8]' in

    53  *       the line 'B[8] := 99', will return the string "B".

    54  *

    55  *       Calling this visitor class with array_variable_c instance referencing 'C.e' in

    56  *       the line 'C.e := 77', will return the string "C".

    57  */

    58 

    59 

    60 

    61 

    62 class get_var_name_c : public search_visitor_c {    

    63   public:

    64     get_var_name_c(void)  {};

    65     ~get_var_name_c(void) {};  

    66     static token_c *get_name(symbol_c *symbol);

    67 

    68   private:

    69     static get_var_name_c *singleton_instance_;

    70     

    71   private:  

    72     /*************************/

    73     /* B.1 - Common elements */

    74     /*************************/

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

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

    77     /*******************************************/

    78     // SYM_TOKEN(identifier_c)

    79     void *visit(identifier_c *symbol);

    80 

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

    82     /* B 1.4 - Variables */

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

    84     // SYM_REF2(symbolic_variable_c, var_name, unused)

    85     void *visit(symbolic_variable_c *symbol);

    86 

    87     /********************************************/

    88     /* B.1.4.1   Directly Represented Variables */

    89     /********************************************/

    90     // SYM_TOKEN(direct_variable_c)

    91     // void *visit(direct_variable_c *symbol);

    92 

    93     /*************************************/

    94     /* B.1.4.2   Multi-element Variables */

    95     /*************************************/

    96     /*  subscripted_variable '[' subscript_list ']' */

    97     // SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

    98     void *visit(array_variable_c *symbol);

    99 

   100     /* subscript_list ',' subscript */

   101     // SYM_LIST(subscript_list_c)

   102     // void *visit(subscript_list_c *symbol);

   103 

   104     /*  record_variable '.' field_selector */

   105     /*  WARNING: input and/or output variables of function blocks

   106      *           may be accessed as fields of a tructured variable!

   107      *           Code handling a structured_variable_c must take

   108      *           this into account!

   109      */

   110     // SYM_REF2(structured_variable_c, record_variable, field_selector)

   111     void *visit(structured_variable_c *symbol);

   112 };

   113 

   114 

   115