1 /*

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

     3  *

     4  *  Copyright (C) 2003-2011  Mario de Sousa (msousa@fe.up.pt)

     5  *  Copyright (C) 2007-2011  Laurent Bessard and Edouard Tisserant

     6  *

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

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

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

    10  *  (at your option) any later version.

    11  *

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

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

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

    15  *  GNU General Public License for more details.

    16  *

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

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

    19  *

    20  *

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

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

    23  */

    24 

    25 /*

    26  * An IEC 61131-3 compiler.

    27  *

    28  * Based on the

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

    30  *

    31  */

    32 

    33 

    34 /*

    35  * Case element iterator.

    36  * Iterate through the elements of a case list.

    37  *

    38  * This is part of the 4th stage that generates

    39  * a c++ source program equivalent to the IL and ST

    40  * code.

    41  */

    42 

    43 /* Given a case_list_c and a type of element, iterate through

    44  * each element, returning the symbol of each element if from

    45  * the good type...case_element_iterator_c

    46  */

    47 

    48 

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

    50 

    51 

    52 class case_element_iterator_c : public null_visitor_c {

    53   public:

    54     /* A type to specify the type of element.

    55      */

    56     typedef enum {

    57       element_single,

    58       element_subrange,

    59     } case_element_t ;

    60 

    61 

    62   private:

    63     /* a pointer to the function_block_declaration_c

    64      * or function_declaration_c currently being analysed.

    65      */

    66     symbol_c *case_list;

    67     /* used when called to iterate() for a parameter */

    68     symbol_c *current_case_element;

    69 

    70     /* used to indicate the type of case element on which iterate */

    71     case_element_t wanted_element_type;

    72 

    73   private:

    74     void* handle_case_element(symbol_c *case_element);

    75 

    76     void* iterate_list(list_c *list);

    77 

    78   public:

    79     /* start off at the first case element once again... */

    80     void reset(void);

    81 

    82     /* initialise the iterator object.

    83      * We must be given a reference to a case_list_c that will be analysed...

    84      */

    85     case_element_iterator_c(symbol_c *list, case_element_t element_type);

    86 

    87     /* Skip to the next case element of type chosen. After object creation,

    88      * the object references on case element _before_ the first, so

    89      * this function must be called once to get the object to

    90      * reference the first element...

    91      *

    92      * Returns the case element's symbol!

    93      */

    94     symbol_c *next(void);

    95 

    96     private:

    97     

    98     /******************************/

    99     /* B 1.2.1 - Numeric Literals */

   100     /******************************/

   101     void *visit(integer_c *symbol);

   102     void *visit(neg_integer_c *symbol);

   103 

   104     /********************************/

   105     /* B 1.3.3 - Derived data types */

   106     /********************************/

   107     /*  signed_integer DOTDOT signed_integer */

   108     void *visit(subrange_c *symbol);

   109 

   110     /* enumerated_type_name '#' identifier */

   111     void *visit(enumerated_value_c *symbol);

   112 

   113     /********************************/

   114     /* B 3.2.3 Selection Statements */

   115     /********************************/

   116     void *visit(case_list_c *symbol);

   117 

   118     

   119 

   120 }; // function_param_iterator_c

   121 

   122 

   123 

   124 

   125 

   126 

   127