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 /* Determine the data type of an ST expression.

    34  * A reference to the relevant type definition is returned.

    35  *

    36  * For example:

    37  *       2 + 3       -> returns reference to a int_type_name_c object.

    38  *       22.2 - 5    -> returns reference to a real_type_name_c object.

    39  *       etc...

    40  */

    41 

    42 /* WARNING   WARNING  WARNING

    43  *

    44  * When taking into consideration calls to functions, this search_expression_type_c

    45  * class will use internal atributes (i.e. anotation) in the function_invocation_c symbol 

    46  * in the abstract syntax tree.

    47  *

    48  * Since this anotation/atribute is only set/populated with the correct value

    49  * during stage3 (semantic verification), this class will only work correctly

    50  * after the semantic verification in stage 3 has been executed

    51  * (to be more exact, the data type checking of stage 3).

    52  */

    53 

    54 class search_expression_type_c: public search_constant_type_c {

    55 

    56   private:

    57     search_varfb_instance_type_c *search_varfb_instance_type;

    58     search_base_type_c search_base_type;

    59 

    60 

    61   public:

    62     search_expression_type_c(symbol_c *search_scope);

    63     virtual ~search_expression_type_c(void);

    64 

    65     /* A helper function... */

    66     bool is_bool_type(symbol_c *type_symbol);

    67     bool is_time_type(symbol_c *type_symbol);

    68     bool is_string_type(symbol_c *type_symbol);

    69     bool is_literal_integer_type(symbol_c *type_symbol);

    70     bool is_integer_type(symbol_c *type_symbol);

    71     bool is_literal_real_type(symbol_c *type_symbol);

    72     bool is_real_type(symbol_c *type_symbol);

    73     bool is_num_type(symbol_c *type_symbol);

    74     bool is_nbinary_type(symbol_c *type_symbol);

    75     bool is_binary_type(symbol_c *type_symbol);

    76 

    77     bool is_same_type(symbol_c *first_type, symbol_c *second_type);

    78     symbol_c* common_type(symbol_c *first_type, symbol_c *second_type);

    79     symbol_c* default_literal_type(symbol_c *symbol);

    80 

    81     /*static bool_type_name_c bool_type_name;*/

    82 

    83     /* A helper function... */

    84     void *compute_boolean_expression(symbol_c *left_type, symbol_c *right_type);

    85 

    86     /* A helper function... */

    87     void *compute_numeric_expression(symbol_c *left_type, symbol_c *right_type);

    88 

    89     /* a helper function... */

    90     symbol_c *base_type(symbol_c *symbol);

    91 

    92     /*********************/

    93     /* B 1.4 - Variables */

    94     /*********************/

    95     

    96     void *visit(symbolic_variable_c *symbol);

    97 

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

    99     /* B 1.4.1 - Directly Represented Variables */

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

   101     void *visit(direct_variable_c *symbol);

   102 

   103     /*************************************/

   104     /* B 1.4.2 - Multi-element variables */

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

   106  

   107     void *visit(array_variable_c *symbol);

   108     void *visit(structured_variable_c *symbol);

   109 

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

   111     /* B.3 - Language ST (Structured Text) */

   112     /***************************************/

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

   114     /* B 3.1 - Expressions */

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

   116     void *visit(or_expression_c *symbol);

   117     void *visit(xor_expression_c *symbol);

   118     void *visit(and_expression_c *symbol);

   119     void *visit(equ_expression_c *symbol);

   120     void *visit(notequ_expression_c *symbol);

   121     void *visit(lt_expression_c *symbol);

   122     void *visit(gt_expression_c *symbol);

   123     void *visit(le_expression_c *symbol);

   124     void *visit(ge_expression_c *symbol);

   125     

   126     void *visit(add_expression_c *symbol);

   127     void *visit(sub_expression_c *symbol);

   128     void *visit(mul_expression_c *symbol);

   129     void *visit(div_expression_c *symbol);

   130     void *visit(mod_expression_c *symbol);

   131     void *visit(power_expression_c *symbol);

   132     void *visit(neg_expression_c *symbol);

   133     void *visit(not_expression_c *symbol);

   134     void *visit(function_invocation_c *symbol);

   135 

   136 

   137     static integer_c integer;

   138 

   139 }; // search_expression_type_c

   140 

   141 

   142