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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) 2012  Mario de Sousa (msousa@fe.up.pt)

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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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/*

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 *  A small helper visitor class, that will   

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 *  return the name (tokn_c *) of a variable, as it will

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 *  appear in the variable declaration.

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 */

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#include "absyntax_utils.hh"

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get_var_name_c *get_var_name_c::singleton_instance_ = NULL;

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/*  For ex.:

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 *       VAR

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 *          A : int;

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 *          B : ARRAY [1..9] of int;

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 *          C : some_struct_t;

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 *       END_VAR

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 *

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 *          A    := 56;

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 *          B[8] := 99;

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 *          C.e  := 77;

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 *

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 *       Calling this method with symbolic_variable_c instance referencing 'A' in

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 *       the line 'A := 56', will return the string "A".

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 *

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 *       Calling this method with array_variable_c instance referencing 'B[8]' in

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 *       the line 'B[8] := 99', will return the string "B".

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 *

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 *       Calling this method with array_variable_c instance referencing 'C.e' in

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 *       the line 'C.e := 77', will return the string "C".

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 */

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token_c *get_var_name_c::get_name(symbol_c *symbol) {

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  if (NULL == singleton_instance_) singleton_instance_ = new get_var_name_c(); 

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  if (NULL == singleton_instance_) ERROR; 

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  return (token_c *)(symbol->accept(*singleton_instance_));

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}

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/*  Return the last field of a structured variable...

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 * 

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 *          A    := 56;   --> returns A

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 *          B[8] := 99;   --> returns B

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 *          C.e  := 77;   --> returns e   !!!

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 */

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symbol_c *get_var_name_c::get_last_field(symbol_c *symbol) {

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  if (NULL == singleton_instance_) singleton_instance_ = new get_var_name_c(); 

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  if (NULL == singleton_instance_) ERROR; 

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  singleton_instance_->last_field = NULL;

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  symbol_c *res = (symbol_c*)(symbol->accept(*singleton_instance_));

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  return (NULL != singleton_instance_->last_field)? singleton_instance_->last_field : res;

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}

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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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// SYM_TOKEN(identifier_c)

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void *get_var_name_c::visit(identifier_c *symbol) {return (void *)symbol;}

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

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/* B 1.4 - Variables */

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

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// SYM_REF2(symbolic_variable_c, var_name, unused)

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void *get_var_name_c::visit(symbolic_variable_c *symbol) {return symbol->var_name->accept(*this);}

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

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/* B.1.4.1   Directly Represented Variables */

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

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// SYM_TOKEN(direct_variable_c)

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

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/* B.1.4.2   Multi-element Variables */

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

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/*  subscripted_variable '[' subscript_list ']' */

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// SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

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void *get_var_name_c::visit(array_variable_c *symbol) {return symbol->subscripted_variable->accept(*this);}

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/* subscript_list ',' subscript */

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// SYM_LIST(subscript_list_c)

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/*  record_variable '.' field_selector */

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/*  WARNING: input and/or output variables of function blocks

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 *           may be accessed as fields of a tructured variable!

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 *           Code handling a structured_variable_c must take

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 *           this into account!

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 */

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// SYM_REF2(structured_variable_c, record_variable, field_selector)

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void *get_var_name_c::visit(structured_variable_c *symbol) {

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  void *res = symbol->record_variable->accept(*this);

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  last_field = symbol->field_selector;

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  return res;

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}

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