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 /* Decomposes a variable instance name into its constituents,

    28  * example:

    29  *    window.points[1].coordinate.x

    30  *

    31  *  will succesfully return

    32  *        - window

    33  *        - points

    34  *        - coordinate

    35  *        - x

    36  * on succesive calls to decompose_var_instance_name_c::next_part()

    37  */

    38 

    39 

    40 

    41 #include "../absyntax/visitor.hh"

    42 

    43 

    44 

    45 class decompose_var_instance_name_c: null_visitor_c {

    46 

    47   private:

    48     symbol_c *variable_name;

    49     symbol_c *next_variable_name;

    50     symbol_c *current_recursive_variable_name;

    51     symbol_c *previously_returned_variable_name;

    52 

    53   public:

    54     decompose_var_instance_name_c(symbol_c *variable_instance_name);

    55 

    56     symbol_c *next_part(void);

    57 

    58   private:

    59   /*********************/

    60   /* B 1.4 - Variables */

    61   /*********************/

    62     void *visit(symbolic_variable_c *symbol);

    63   

    64   /********************************************/

    65   /* B.1.4.1   Directly Represented Variables */

    66   /********************************************/

    67     void *visit(direct_variable_c *symbol);

    68   

    69   /*************************************/

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

    71   /*************************************/

    72   /*  subscripted_variable '[' subscript_list ']' */

    73   // SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

    74     void *visit(array_variable_c *symbol);

    75   

    76   /*  record_variable '.' field_selector */

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

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

    79    *           Code handling a structured_variable_c must take

    80    *           this into account!

    81    */

    82   //SYM_REF2(structured_variable_c, record_variable, field_selector)

    83     void *visit(structured_variable_c *symbol);

    84 

    85 }; // decompose_var_instance_name_c

    86 

    87 

    88 

    89