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/*

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

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 *

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 *  Copyright (C) 2003-2012  Mario de Sousa (msousa@fe.up.pt)

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

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 *

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

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

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

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 *  (at your option) any later version.

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 *

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

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

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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

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 *  GNU General Public License for more details.

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 *

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

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

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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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 * An IEC 61131-3 compiler.

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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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/* Determine the data type of a variable.

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 * The variable may be a simple variable, a function block instance, a

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 * struture element within a data structured type (a struct or a fb), or

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 * an array element.

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 * A mixture of array element of a structure element of a structure element

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 * of a .... is also suported!

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 *

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 *  example:

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 *    window.points[1].coordinate.x

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 *    window.points[1].colour

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 *    etc... ARE ALLOWED!

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 *

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 * This class must be passed the scope within which the

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 * variable was declared, and the variable name...

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 *

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 *

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 *

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 *

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 *

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 * This class has several members, depending on the exact data the caller

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 * is looking for...

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 *

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 *    - item i: we can get either the name of the data type(A),

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 *              or it's declaration (B)

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 *             (notice however that some variables belong to a data type that does

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 *              not have a name, only a declaration as in

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 *              VAR a: ARRAY [1..3] of INT; END_VAR

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 *             )

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 *    - item ii: we can get either the direct data type (1), 

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 *               or the base type (2)

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 * 

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 *   By direct type, I mean the data type of the variable. By base type, I 

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 * mean the data type on which the direct type is based on. For example, in 

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 * a subrange on INT, the direct type is the subrange itself, while the 

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 * base type is INT.

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 * e.g.

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 *   This means that if we find that the variable is of type MY_INT,

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 *   which was previously declared to be

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 *   TYPE MY_INT: INT := 9;

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 *   option (1) will return MY_INT

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 *   option (2) will return INT

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 * 

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 *

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 * Member functions:

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 * ================

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 *   get_basetype_id()    ---> returns 2A   (implemented, although currently it is not needed! )

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 *   get_basetype_decl()  ---> returns 2B 

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 *   get_type_id()        ---> returns 1A

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 * 

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 *   Since we haven't yet needed it, we don't yet implement

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 *   get_type_decl()      ---> returns 1B 

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 */ 

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class search_varfb_instance_type_c : null_visitor_c {

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  private:

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    search_var_instance_decl_c search_var_instance_decl;

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    search_base_type_c         search_base_type;

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//  symbol_c *current_type_decl;

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    symbol_c *current_type_id;

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    symbol_c *current_basetype_decl;

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    symbol_c *current_basetype_id;

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    symbol_c *current_field_selector;

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    bool is_complex;

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    /* sets all the above variables to NULL, or false */

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    void init(void);

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  public:

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    search_varfb_instance_type_c(symbol_c *search_scope);

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    symbol_c *get_basetype_decl(symbol_c *variable_name);

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    symbol_c *get_basetype_id  (symbol_c *variable_name);

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//     symbol_c *get_type_decl(symbol_c *variable_name);

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    symbol_c *get_type_id(symbol_c *variable_name);

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    /* NOTE: I have a feeling that this function should be remvoed/deleted.

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     *       However, it is currently used in stage 4, and before deleting it

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     *       requires that the stage4 code be analysed and fixed (i.e. replace by 

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     *       a call to one of the above functions get_basetype_decl(), 

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     *       get_type_decl(), get_type_id().

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     */

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    unsigned int get_vartype(symbol_c *variable_name);

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    bool type_is_complex(void);

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  private:

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    /* a helper function... */

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    void *visit_list(list_c *list);

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    /* a helper function... */

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    void *base_type(symbol_c *symbol);

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  private:

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

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    /* B.1 - Common elements */

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

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

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

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

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    void *visit(identifier_c *variable_name);

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

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    /* B 1.3.3 - Derived data types */

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

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    /*  identifier ':' array_spec_init */

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    void *visit(array_type_declaration_c *symbol);

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    /* array_specification [ASSIGN array_initialization} */

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    /* array_initialization may be NULL ! */

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    void *visit(array_spec_init_c *symbol);

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    /* ARRAY '[' array_subrange_list ']' OF non_generic_type_name */

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    void *visit(array_specification_c *symbol);

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    /*  structure_type_name ':' structure_specification */

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    void *visit(structure_type_declaration_c *symbol);

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    /* structure_type_name ASSIGN structure_initialization */

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    /* structure_initialization may be NULL ! */

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    // SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)

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    void *visit(initialized_structure_c *symbol);

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    /* helper symbol for structure_declaration */

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    /* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */

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    /* structure_element_declaration_list structure_element_declaration ';' */

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    void *visit(structure_element_declaration_list_c *symbol);

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    /*  structure_element_name ':' spec_init */

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    void *visit(structure_element_declaration_c *symbol);

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    /* helper symbol for structure_initialization */

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    /* structure_initialization: '(' structure_element_initialization_list ')' */

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    /* structure_element_initialization_list ',' structure_element_initialization */

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    void *visit(structure_element_initialization_list_c *symbol); /* should never get called... */

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    /*  structure_element_name ASSIGN value */

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    void *visit(structure_element_initialization_c *symbol); /* should never get called... */

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

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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.1.5 - Program organization units */

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

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

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    /* B 1.5.2 - Function Blocks */

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

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    /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */

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    // SYM_REF4(function_block_declaration_c, fblock_name, var_declarations, fblock_body, unused)

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    void *visit(function_block_declaration_c *symbol);

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}; // search_varfb_instance_type_c

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