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/*

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 *

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

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

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 */

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/*

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 *

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 * Based on the

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

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 *

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 */

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/* Verify whether the semantic rules of data type compatibility are being followed.

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 *

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 * For example:

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 */

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#include "../absyntax_utils/absyntax_utils.hh"

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class visit_expression_type_c: public search_constant_type_c {

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  private:

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    search_varfb_instance_type_c *search_varfb_instance_type;

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    search_base_type_c search_base_type;

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    /* When calling a function block, we must first find it's type,

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     * by searching through the declarations of the variables currently

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     * in scope.

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     * This class does just that...

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     * A new bject instance is instantiated whenever we start checking semantics

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     * for a function block type declaration, or a program declaration.

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     * This object instance will then later be called while the

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     * function block's or the program's body is being handled.

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     *

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     * Note that functions cannot contain calls to function blocks,

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     * so we do not create an object instance when handling

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     * a function declaration.

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     */

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//     search_var_instance_decl_c *search_var_instance_decl;

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     /* This variable was created to pass information from

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      * visit_expression_type_c::visit(case_statement_c *symbol) function to

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      * visit_expression_type_c::visit(case_list_c *symbol) function.

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      */

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      symbol_c *case_expression_type;

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    /* In IL code, once we find a type mismatch error, it is best to

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     * ignore any further errors until the end of the logicl operation,

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     * i.e. until the next LD.

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     * However, we cannot clear the il_error flag on all LD operations,

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     * as these may also be used within parenthesis. LD operations

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     * within parenthesis may not clear the error flag.

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     * We therefore need a counter to know how deep inside a parenthesis 

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     * structure we are.

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     */

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    int  il_parenthesis_level;

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    bool il_error;

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    bool error_found;

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    /* the current data type of the data stored in the IL stack, i.e. the default variable */

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    symbol_c *il_default_variable_type;

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    /* the current IL operand being analysed - its symbol and its data type */

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    symbol_c *il_operand_type;

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    symbol_c *il_operand;

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  public:

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    visit_expression_type_c(symbol_c *ignore);

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    virtual ~visit_expression_type_c(void);

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    bool get_error_found(void);

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    typedef struct {

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      symbol_c *value;

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      symbol_c *type;

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    } value_and_type_t; 

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    /* A helper function... */

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    bool is_ANY_ELEMENTARY_type         (symbol_c *type_symbol);

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    bool is_ANY_SAFEELEMENTARY_type     (symbol_c *type_symbol);

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    bool is_ANY_ELEMENTARY_compatible   (symbol_c *type_symbol);

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    bool is_ANY_MAGNITUDE_type          (symbol_c *type_symbol);

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    bool is_ANY_SAFEMAGNITUDE_type      (symbol_c *type_symbol);

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    bool is_ANY_MAGNITUDE_compatible    (symbol_c *type_symbol);

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    bool is_ANY_DATE_type               (symbol_c *type_symbol);

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    bool is_ANY_SAFEDATE_type           (symbol_c *type_symbol);

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    bool is_ANY_DATE_compatible         (symbol_c *type_symbol);

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    bool is_ANY_STRING_type             (symbol_c *type_symbol);

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    bool is_ANY_SAFESTRING_type         (symbol_c *type_symbol);

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    bool is_ANY_STRING_compatible       (symbol_c *type_symbol);   

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    bool is_ANY_INT_type                (symbol_c *type_symbol);

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    bool is_ANY_SAFEINT_type            (symbol_c *type_symbol);

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    bool is_ANY_INT_compatible          (symbol_c *type_symbol);

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    bool is_ANY_REAL_type               (symbol_c *type_symbol);

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    bool is_ANY_SAFEREAL_type           (symbol_c *type_symbol);

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    bool is_ANY_REAL_compatible         (symbol_c *type_symbol);

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    bool is_ANY_NUM_type                (symbol_c *type_symbol);

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    bool is_ANY_SAFENUM_type            (symbol_c *type_symbol);

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    bool is_ANY_NUM_compatible          (symbol_c *type_symbol);

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    bool is_ANY_BIT_type                (symbol_c *type_symbol);

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    bool is_ANY_SAFEBIT_type            (symbol_c *type_symbol);

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    bool is_ANY_BIT_compatible          (symbol_c *type_symbol);

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    bool is_BOOL_type                   (symbol_c *type_symbol);

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    bool is_SAFEBOOL_type               (symbol_c *type_symbol);

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    bool is_ANY_BOOL_compatible         (symbol_c *type_symbol);

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    bool is_nonneg_literal_integer_type (symbol_c *type_symbol);

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    bool is_literal_integer_type        (symbol_c *type_symbol);

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    bool is_literal_real_type           (symbol_c *type_symbol);

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    bool is_literal_bool_type           (symbol_c *type_symbol);

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    /* Determine the common data type between two data types.

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     * If no common data type found, return NULL.

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     *

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     * If data types are identical, return the first (any would do...).

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     * If any of the datat types is a literal, we confirm that 

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     *   the literal uses less bits than the fixed size data type.

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     *   e.g. BYTE and 1024 returns NULL

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     *        BYTE and 255  returns BYTE

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     *

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     * If two literals, then return the literal that requires more bits...

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     */

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    symbol_c *common_type__(symbol_c *first_type, symbol_c *second_type);

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    /* Determine the common data type between two data types.

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     * Unlike the common_type__() function, we stop the compiler with an ERROR

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     *  if no common data type is found.

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     */

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

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/* Return TRUE if the second (value) data type may be assigned to a variable of the first (variable) data type

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 * such as: 

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 *     var_type     value_type

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 *    BOOL           BYTE#7     -> returns false

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 *    INT            INT#7      -> returns true

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 *    INT            7          -> returns true

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 *    REAL           7.89       -> returns true

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 *    REAL           7          -> returns true

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 *    INT            7.89       -> returns false

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 *    SAFEBOOL       BOOL#1     -> returns false   !!!

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 *   etc...

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 *

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 * NOTE: It is assumed that the var_type is the data type of an lvalue

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 */

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    bool is_valid_assignment(symbol_c *var_type, symbol_c *value_type);

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/* Return TRUE if there is a common data type, otherwise return FALSE

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 * i.e., return TRUE if both data types may be used simultaneously in an expression

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 * such as:

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 *    BOOL#0     AND BYTE#7  -> returns false

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 *    0          AND BYTE#7  -> returns true

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 *    INT#10     AND INT#7   -> returns true

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 *    INT#10     AND 7       -> returns true

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 *    REAL#34.3  AND 7.89    -> returns true

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 *    REAL#34.3  AND 7       -> returns true

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 *    INT#10     AND 7.89    -> returns false

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 *    SAFEBOOL#0 AND BOOL#1  -> returns true   !!!

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 *   etc...

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 */

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    bool is_compatible_type(symbol_c *first_type, symbol_c *second_type);

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    void compute_input_operatores(symbol_c *symbol, const char *input_operator);

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    void check_formal_parameter(symbol_c *call_param_name, symbol_c *call_param_type, symbol_c *f_decl);

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    /* check the semantics of a FB or Function non-formal call */

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    /* e.g. foo(1, 2, 3, 4);  */

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    void check_nonformal_call(symbol_c *f_call, symbol_c *f_decl, bool use_il_defvar = false);

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    /* check the semantics of a FB or Function formal call */

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    /* e.g. foo(IN1 := 1, OUT1 =>x, EN := true);  */

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    void check_formal_call(symbol_c *f_call, symbol_c *f_decl);

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    void *compute_standard_function_default(function_invocation_c *st_symbol, il_formal_funct_call_c *il_symbol);

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    void *compute_standard_function_il(il_function_call_c *symbol, symbol_c *param_data_type);

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    /* A helper function... */

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    typedef bool (visit_expression_type_c::*is_data_type_t)(symbol_c *type_symbol);  /* a pointer to a function! */

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//    symbol_c *compute_boolean_expression(symbol_c *left_exp, symbol_c *right_exp, is_data_type_t is_data_type);

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//    symbol_c *compute_numeric_expression(symbol_c *left_exp, symbol_c *right_exp, is_data_type_t is_data_type);

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//    symbol_c *compute_expression(symbol_c *left_exp, symbol_c *right_exp, is_data_type_t is_data_type);

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    symbol_c *compute_expression(symbol_c *left_type, symbol_c *right_type, is_data_type_t is_data_type,

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                                 symbol_c *left_expr=NULL, symbol_c *right_expr=NULL);

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    /* a helper function... */

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    symbol_c *base_type(symbol_c *symbol);

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    /* a helper function... */

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    void *verify_null(symbol_c *symbol);

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    /*********************/

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    /* B 1.4 - Variables */

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    /*********************/

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    void *visit(symbolic_variable_c *symbol);

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    /********************************************/

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    /* B 1.4.1 - Directly Represented Variables */

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    /********************************************/

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    void *visit(direct_variable_c *symbol);

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    /*************************************/

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    /* B 1.4.2 - Multi-element variables */

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    /*************************************/

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    void *visit(array_variable_c *symbol);

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    void *visit(structured_variable_c *symbol);

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    /****************************************/

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    /* B.2 - Language IL (Instruction List) */

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    /****************************************/

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    /***********************************/

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    /* B 2.1 Instructions and Operands */

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    /***********************************/

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    // void *visit(instruction_list_c *symbol);

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    void *visit(il_simple_operation_c *symbol);

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    void *visit(il_function_call_c *symbol);

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    void *visit(il_expression_c *symbol);

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//     void *visit(il_jump_operation_c *symbol);

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    void *visit(il_fb_call_c *symbol);

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    void *visit(il_formal_funct_call_c *symbol);

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    /*

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    void *visit(il_operand_list_c *symbol);

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    void *visit(simple_instr_list_c *symbol);

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    void *visit(il_param_list_c *symbol);

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    void *visit(il_param_assignment_c *symbol);

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    void *visit(il_param_out_assignment_c *symbol);

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    */

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    /*******************/

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    /* B 2.2 Operators */

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    /*******************/

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    void *visit(LD_operator_c *symbol);

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    void *visit(LDN_operator_c *symbol);

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    void *visit(ST_operator_c *symbol);

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    void *visit(STN_operator_c *symbol);

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    void *visit(NOT_operator_c *symbol);

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    void *visit(S_operator_c *symbol);

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    void *visit(R_operator_c *symbol);

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    void *visit(S1_operator_c *symbol);

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    void *visit(R1_operator_c *symbol);

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    void *visit(CLK_operator_c *symbol);

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    void *visit(CU_operator_c *symbol);

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    void *visit(CD_operator_c *symbol);

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    void *visit(PV_operator_c *symbol);

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    void *visit(IN_operator_c *symbol);

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    void *visit(PT_operator_c *symbol);

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    void *visit(AND_operator_c *symbol);

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    void *visit(OR_operator_c *symbol);

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    void *visit(XOR_operator_c *symbol);

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    void *visit(ANDN_operator_c *symbol);

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    void *visit(ORN_operator_c *symbol);

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    void *visit(XORN_operator_c *symbol);

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    void *visit(ADD_operator_c *symbol);

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    void *visit(SUB_operator_c *symbol);

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    void *visit(MUL_operator_c *symbol);

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    void *visit(DIV_operator_c *symbol);

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    void *visit(MOD_operator_c *symbol);

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    void *visit(GT_operator_c *symbol);

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    void *visit(GE_operator_c *symbol);

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    void *visit(EQ_operator_c *symbol);

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    void *visit(LT_operator_c *symbol);

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    void *visit(LE_operator_c *symbol);

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    void *visit(NE_operator_c *symbol);

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    void *visit(CAL_operator_c *symbol);

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    void *visit(CALC_operator_c *symbol);

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    void *visit(CALCN_operator_c *symbol);

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    void *visit(RET_operator_c *symbol);

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    void *visit(RETC_operator_c *symbol);

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    void *visit(RETCN_operator_c *symbol);

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    void *visit(JMP_operator_c *symbol);

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    void *visit(JMPC_operator_c *symbol);

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    void *visit(JMPCN_operator_c *symbol);

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    /* Symbol class handled together with function call checks */

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    // void *visit(il_assign_operator_c *symbol, variable_name);

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    /* Symbol class handled together with function call checks */

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    // void *visit(il_assign_operator_c *symbol, option, variable_name);

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    /***************************************/

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

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    /***************************************/

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    /***********************/

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    /* B 3.1 - Expressions */

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    /***********************/

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    void *visit(or_expression_c *symbol);

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    void *visit(xor_expression_c *symbol);

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    void *visit(and_expression_c *symbol);

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    void *visit(equ_expression_c *symbol);

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    void *visit(notequ_expression_c *symbol);

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    void *visit(lt_expression_c *symbol);

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    void *visit(gt_expression_c *symbol);

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    void *visit(le_expression_c *symbol);

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    void *visit(ge_expression_c *symbol);    

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    void *visit(add_expression_c *symbol);

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    void *visit(sub_expression_c *symbol);

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    void *visit(mul_expression_c *symbol);

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    void *visit(div_expression_c *symbol);

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    void *visit(mod_expression_c *symbol);

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    void *visit(power_expression_c *symbol);

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    void *visit(neg_expression_c *symbol);

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    void *visit(not_expression_c *symbol);

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    void *visit(function_invocation_c *symbol);

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    /*********************************/

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    /* B 3.2.1 Assignment Statements */

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    /*********************************/

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    void *visit(assignment_statement_c *symbol);

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    /*****************************************/

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    /* B 3.2.2 Subprogram Control Statements */

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    /*****************************************/

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    void *visit(fb_invocation_c *symbol);

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    /********************************/

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    /* B 3.2.3 Selection Statements */

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    /********************************/

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    void *visit(if_statement_c *symbol);    

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//     void *visit(elseif_statement_list_c *symbol);

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    void *visit(elseif_statement_c *symbol);

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    void *visit(case_statement_c *symbol);

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//     void *visit(case_element_list_c *symbol);

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//     void *visit(case_element_c *symbol);   

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   void *visit(case_list_c *symbol);

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    /********************************/

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    /* B 3.2.4 Iteration Statements */

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    /********************************/

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    void *visit(for_statement_c *symbol);

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    void *visit(while_statement_c *symbol);

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    void *visit(repeat_statement_c *symbol);

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//TODO: delete this functions. Why are they needed?

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void *visit(program_declaration_c *symbol);

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void *visit(function_declaration_c *symbol);

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void *visit(function_block_declaration_c *symbol);

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}; // visit_expression_type_c

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