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/*

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 * (c) 2003 Mario de Sousa

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 *

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 * Offered to the public under the terms of the GNU General Public License

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 * as published by the Free Software Foundation; either version 2 of the

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 * License, or (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, but

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 * WITHOUT ANY WARRANTY; without even the implied warranty of

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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General

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 * Public License for more details.

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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 IL and ST 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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/*

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 * Function parameter iterator.

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 * Iterate through the in/out parameters of a function declaration.

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 * Function blocks are also suported.

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 *

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 * This is part of the 4th stage that generates

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

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 * code.

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 */

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//#include <stdio.h>  /* required for NULL */

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//#include <string>

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//#include <iostream>

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//#include "../../util/symtable.hh"

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//#include "generate_cc.hh"

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

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/* given a function_declaration_c, iterate through each

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 * function in/out/inout parameter, returning the name

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 * of each parameter...function_param_iterator_c

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 */

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class function_param_iterator_c : public null_visitor_c {

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  public:

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    /* A type to specify the type of parameter.

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     * VAR_INPUT => direction_in

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     * VAR_OUTPUT => direction_out

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     * VAR_IN_OUT => direction_inout

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     * VAR_EXTERNAL => direction_extref

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     *

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     * Note that VAR_EXTERNAL declares variables that are in reality references

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     * to global variables. This is used only inside programs!

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     * These references to external variables must be correctly initialised to refer

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     * to the correct global variable. Note that the user may define which variable is to be

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     * referenced in a CONFIGURATION, and that different instantiations of a program

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     * may have the same external variable reference diffenrent global variables!

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     * The references must therefore be correctly initialised when the program instance

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     * is created. This may be done by the PROGRAM class constructor since the ST and IL

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     * languages do not allow the VAR_EXTERNAL reference to change at runtime

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     * for a specific instance.

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     *

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     * We therefore need to call a PROGRAM class constructor with the variables

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     * that should be refernced by the VAR_EXTERNAL variables. The direction_extref will

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     * be used to identify these parameters!

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     */

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    typedef enum {direction_in, direction_out, direction_inout, direction_extref} param_direction_t ;

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  private:

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      /* a pointer to the function_block_declaration_c

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       * or function_declaration_c currently being analysed.

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       */

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    symbol_c *f_decl;

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    int next_param, param_count;

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    identifier_c *current_param_name;

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    symbol_c *current_param_type;

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    symbol_c *current_param_default_value;

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    param_direction_t current_param_direction;

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  private:

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    void* handle_param_list(list_c *list) {

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      if (next_param <= param_count + list->n)

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        return list->elements[next_param - param_count - 1];

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      /* the desired param is not on this list... */

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      param_count += list->n;

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     return NULL;

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    }

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    void* handle_single_param(symbol_c *var_name) {

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      param_count++;

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      if (next_param == param_count)

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        return var_name;

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      /* not yet the desired param... */

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     return NULL;

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    }

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    void* iterate_list(list_c *list) {

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      void *res;

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      for (int i = 0; i < list->n; i++) {

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        res = list->elements[i]->accept(*this);

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	if (res != NULL)

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	  return res;

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      }

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      return NULL;

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   }

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  public:

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    /* start off at the first parameter once again... */

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    void reset(void) {

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      next_param = param_count = 0;

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      current_param_name = NULL;

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      current_param_type = current_param_default_value = NULL;

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    }

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    /* initialise the iterator object.

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     * We must be given a reference to the function declaration

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     * that will be analysed...

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     */

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    function_param_iterator_c(function_declaration_c *f_decl) {

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      this->f_decl = f_decl;

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      reset();

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    }

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    /* initialise the iterator object.

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     * We must be given a reference to the function block declaration

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     * that will be analysed...

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     */

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    function_param_iterator_c(function_block_declaration_c *fb_decl) {

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      this->f_decl = fb_decl;

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      reset();

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    }

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    /* initialise the iterator object.

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     * We must be given a reference to the program declaration

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     * that will be analysed...

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     */

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    function_param_iterator_c(program_declaration_c *p_decl) {

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      this->f_decl = p_decl;

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      reset();

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    }

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    /* Skip to the next parameter. After object creation,

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     * the object references on parameter _before_ the first, so

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

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     * reference the first parameter...

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     *

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     * Returns the parameter's name!

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     */

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    identifier_c *next(void) {

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      void *res;

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      param_count = 0;

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      next_param++;

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      res = f_decl->accept(*this);

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      if (res == NULL)

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        return NULL;

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      symbol_c *sym = (symbol_c *)res;

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      identifier_c *identifier = dynamic_cast<identifier_c *>(sym);

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      if (identifier == NULL)

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        ERROR;

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      current_param_name = identifier;

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      return current_param_name;

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    }

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    /* Returns the currently referenced parameter's default value,

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     * or NULL if none is specified in the function declrataion itself.

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     */

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    symbol_c *default_value(void) {

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      return current_param_default_value;

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    }

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    /* Returns the currently referenced parameter's type name. */

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    symbol_c *param_type(void) {

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      return current_param_type;

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    }

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    /* Returns the currently referenced parameter's data passing direction.

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     * i.e. VAR_INPUT, VAR_OUTPUT or VAR_INOUT

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     */

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    param_direction_t param_direction(void) {

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      return current_param_direction;

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    }

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

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/* B 1.4.3 - Declaration & Initialisation */

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

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    void *visit(input_declarations_c *symbol) {

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      TRACE("input_declarations_c");

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      current_param_direction = direction_in;

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      return symbol->input_declaration_list->accept(*this);

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    }

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    void *visit(input_declaration_list_c *symbol) {TRACE("input_declaration_list_c"); return iterate_list(symbol);}

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    void *visit(edge_declaration_c *symbol) {TRACE("edge_declaration_c"); return symbol->var1_list->accept(*this);}

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#if 0

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/* var1_list ':' array_spec_init */

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SYM_REF2(array_var_init_decl_c, var1_list, array_spec_init)

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/*  var1_list ':' initialized_structure */

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SYM_REF2(structured_var_init_decl_c, var1_list, initialized_structure)

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/* name_list ':' function_block_type_name ASSIGN structure_initialization */

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/* structure_initialization -> may be NULL ! */

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SYM_REF4(fb_name_decl_c, fb_name_list, function_block_type_name, structure_initialization, unused)

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/* name_list ',' fb_name */

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SYM_LIST(fb_name_list_c)

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#endif

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    void *visit(output_declarations_c *symbol) {

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      TRACE("output_declarations_c");

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      current_param_direction = direction_out;

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      return symbol->var_init_decl_list->accept(*this);

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    }

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    void *visit(input_output_declarations_c *symbol) {

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      TRACE("input_output_declarations_c");

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      current_param_direction = direction_inout;

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      return symbol->var_declaration_list->accept(*this);

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    }

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    void *visit(var_declaration_list_c *symbol) {TRACE("var_declaration_list_c"); return iterate_list(symbol);}

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#if 0

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/*  var1_list ':' array_specification */

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SYM_REF2(array_var_declaration_c, var1_list, array_specification)

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/*  var1_list ':' structure_type_name */

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SYM_REF2(structured_var_declaration_c, var1_list, structure_type_name)

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#endif

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/* VAR [CONSTANT] var_init_decl_list END_VAR */

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    void *visit(var_declarations_c *symbol) {TRACE("var_declarations_c"); return NULL;}

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#if 0

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/*  VAR RETAIN var_init_decl_list END_VAR */

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SYM_REF2(retentive_var_declarations_c, var_init_decl_list, unused)

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/*  VAR [CONSTANT|RETAIN|NON_RETAIN] located_var_decl_list END_VAR */

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/* option -> may be NULL ! */

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SYM_REF2(located_var_declarations_c, option, located_var_decl_list)

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/* helper symbol for located_var_declarations */

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/* located_var_decl_list located_var_decl ';' */

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SYM_LIST(located_var_decl_list_c)

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/*  [variable_name] location ':' located_var_spec_init */

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/* variable_name -> may be NULL ! */

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SYM_REF4(located_var_decl_c, variable_name, location, located_var_spec_init, unused)

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#endif

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/*| VAR_EXTERNAL [CONSTANT] external_declaration_list END_VAR */

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/* option -> may be NULL ! */

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// SYM_REF2(external_var_declarations_c, option, external_declaration_list)

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    void *visit(external_var_declarations_c *symbol) {

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      TRACE("external_var_declarations_c");

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      current_param_direction = direction_extref;

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      return symbol->external_declaration_list->accept(*this);

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    }

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/* helper symbol for external_var_declarations */

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/*| external_declaration_list external_declaration';' */

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// SYM_LIST(external_declaration_list_c)

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    void *visit(external_declaration_list_c *symbol) {TRACE("external_declaration_list_c"); return iterate_list(symbol);}

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/*  global_var_name ':' (simple_specification|subrange_specification|enumerated_specification|array_specification|prev_declared_structure_type_name|function_block_type_name */

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//SYM_REF2(external_declaration_c, global_var_name, specification)

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    void *visit(external_declaration_c *symbol) {

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      TRACE("external_declaration_c");

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      /* It is OK to store these values in the current_param_XXX

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       * variables, because if the desired parameter is not in the

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       * variable list we will be analysing, the current_param_XXXX

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       * variables will get overwritten when we visit the next

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       * var1_init_decl_c list!

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       */

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      current_param_default_value = spec_init_sperator_c::get_init(symbol->specification);

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      current_param_type = spec_init_sperator_c::get_spec(symbol->specification);

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      return handle_single_param(symbol->global_var_name);

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    }

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#if 0

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/*| VAR_GLOBAL [CONSTANT|RETAIN] global_var_decl_list END_VAR */

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/* option -> may be NULL ! */

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SYM_REF2(global_var_declarations_c, option, global_var_decl_list)

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/* helper symbol for global_var_declarations */

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/*| global_var_decl_list global_var_decl ';' */

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SYM_LIST(global_var_decl_list_c)

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/*| global_var_spec ':' [located_var_spec_init|function_block_type_name] */

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/* type_specification ->may be NULL ! */

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SYM_REF2(global_var_decl_c, global_var_spec, type_specification)

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/*| global_var_name location */

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SYM_REF2(global_var_spec_c, global_var_name, location)

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/*  AT direct_variable */

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SYM_REF2(location_c, direct_variable, unused)

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/*| global_var_list ',' global_var_name */

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SYM_LIST(global_var_list_c)

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/*  var1_list ':' single_byte_string_spec */

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SYM_REF2(single_byte_string_var_declaration_c, var1_list, single_byte_string_spec)

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/*  STRING ['[' integer ']'] [ASSIGN single_byte_character_string] */

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/* integer ->may be NULL ! */

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/* single_byte_character_string ->may be NULL ! */

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SYM_REF2(single_byte_string_spec_c, integer, single_byte_character_string)

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/*  var1_list ':' double_byte_string_spec */

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SYM_REF2(double_byte_string_var_declaration_c, var1_list, double_byte_string_spec)

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/*  WSTRING ['[' integer ']'] [ASSIGN double_byte_character_string] */

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/* integer ->may be NULL ! */

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/* double_byte_character_string ->may be NULL ! */

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SYM_REF2(double_byte_string_spec_c, integer, double_byte_character_string)

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/*| VAR [RETAIN|NON_RETAIN] incompl_located_var_decl_list END_VAR */

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/* option ->may be NULL ! */

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SYM_REF2(incompl_located_var_declarations_c, option, incompl_located_var_decl_list)

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/* helper symbol for incompl_located_var_declarations */

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/*| incompl_located_var_decl_list incompl_located_var_decl ';' */

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SYM_LIST(incompl_located_var_decl_list_c)

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/*  variable_name incompl_location ':' var_spec */

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SYM_REF4(incompl_located_var_decl_c, variable_name, incompl_location, var_spec, unused)

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/*  AT incompl_location_token */

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SYM_TOKEN(incompl_location_c)

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#endif

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    void *visit(var1_init_decl_c *symbol) {

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      TRACE("var1_init_decl_c");

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      /* It is OK to store these values in the current_param_XXX

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       * variables, because if the desired parameter is not in the

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       * variable list we will be analysing, the current_param_XXXX

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       * variables will get overwritten when we visit the next

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       * var1_init_decl_c list!

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       */

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      current_param_default_value = spec_init_sperator_c::get_init(symbol->spec_init);

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      current_param_type = spec_init_sperator_c::get_spec(symbol->spec_init);

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      return symbol->var1_list->accept(*this);

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    }

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    void *visit(var1_list_c *symbol) {

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      TRACE("var1_list_c");

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      return handle_param_list(symbol);

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    }

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    void *visit(var_init_decl_list_c *symbol) {TRACE("var_init_decl_list_c"); return iterate_list(symbol);}

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

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/* B 1.5.1 - Functions */

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

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    void *visit(function_declaration_c *symbol) {TRACE("function_declaration_c"); return symbol->var_declarations_list->accept(*this);}

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    /* intermediate helper symbol for function_declaration */

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    void *visit(var_declarations_list_c *symbol) {TRACE("var_declarations_list_c"); return iterate_list(symbol);}

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    void *visit(function_var_decls_c *symbol) {TRACE("function_var_decls_c"); /* ignore */ return NULL;}

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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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    void *visit(function_block_declaration_c *symbol) {TRACE("function_block_declaration_c"); return symbol->var_declarations->accept(*this);}

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/* intermediate helper symbol for function_declaration */

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/*  { io_var_declarations | other_var_declarations }   */

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/*

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 * NOTE: we re-use the var_declarations_list_c

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 */

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/*  VAR_TEMP temp_var_decl_list END_VAR */

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    void *visit(temp_var_decls_c *symbol) {TRACE("temp_var_decls_c"); /* ignore */ return NULL;}

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    void *visit(temp_var_decls_list_c *symbol) {TRACE("temp_var_decls_list_c"); /* ignore */ return NULL;}

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   402

/*  VAR NON_RETAIN var_init_decl_list END_VAR */

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    void *visit(non_retentive_var_decls_c *symbol) {TRACE("non_retentive_var_decls_c"); /* ignore */ return NULL;}

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

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/* B 1.5.3 - Programs */

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

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/*  PROGRAM program_type_name program_var_declarations_list function_block_body END_PROGRAM */

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// SYM_REF4(program_declaration_c, program_type_name, var_declarations, function_block_body, unused)

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    void *visit(program_declaration_c *symbol) {TRACE("program_declaration_c"); return symbol->var_declarations->accept(*this);}

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/* intermediate helper symbol for program_declaration_c */

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/*  { io_var_declarations | other_var_declarations }   */

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/*

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 * NOTE: we re-use the var_declarations_list_c

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 */

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};

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