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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) 2014  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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 * Re-oder the POUs in te library so that no forward references occur.

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 * 

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 * Since stage1_2 now suppport POUs that contain references to POUS that are only declared later,

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 * (e.g. a variable of FB1_t is declared, before the FB1_T function block is itself declared!)

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 * we may need to re-order all the POUs in the library so that these forward references do not occur.

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 * 

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 * This utility class will do just that. However, it does not destroy the original abstract syntax 

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 * tree (AST). It instead creates a new re-ordered AST, by instantiating a new library_c object.

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 * This new library_c object will however point to the *same* objects of the original AST, just in 

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 * a new order. 

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 * This means that the new and original AST share all the object instances, and only use a distinct

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 * library_c object!

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 */

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

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

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

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#include <set>

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class   find_forward_dependencies_c;

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typedef symtable_c<symbol_c *> identifiers_symbtable_t;

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class remove_forward_dependencies_c: public search_visitor_c {

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  private:

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    /* The level of detail that the user wants us to display error messages. */

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    #define error_level_default (1)

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    #define error_level_nagging (4)

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    unsigned int    current_display_error_level;

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    int             error_count;

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    bool            warning_found;

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    library_c      *new_tree;

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    int             cycle_count; // main algorithm runs in a loop. The nuber of the current cycle...

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    // NOTE: we need two lists in order to correctly handle overloaded functions

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    identifiers_symbtable_t      declared_identifiers; // list of identifiers already declared by the symbols in the new tree

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    std::set <symbol_c *>        inserted_symbols;     // list of symbols already inserted in the new tree 

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    symbol_c       *current_code_generation_pragma;    // points to any currently 'active' enable_code_generation_pragma_c

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    find_forward_dependencies_c    *find_forward_dependencies;  

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  public:

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     remove_forward_dependencies_c(void);

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    ~remove_forward_dependencies_c(void);

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    library_c *create_new_tree(symbol_c *old_tree);  // create a new tree with POUs ordered so it does not contain forward dependencies...

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    int        get_error_count(void);

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  private:

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    void *handle_library_symbol(symbol_c *symbol, symbol_c *name, symbol_c *search1, symbol_c *search2 = NULL, symbol_c *search3 = NULL);

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    void  print_circ_error(library_c *symbol);

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

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    /* B 0 - Programming Model */

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

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    void *visit(library_c *symbol);

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

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    /* B.1.5 - Program organization units */

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

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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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    void *visit(program_declaration_c *symbol);

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

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    /* B 1.7 Configuration elements */

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

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    void *visit(configuration_declaration_c *symbol);

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

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    /* 2.1.6 - Pragmas  */

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

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    void *visit(disable_code_generation_pragma_c *symbol);

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    void *visit(enable_code_generation_pragma_c *symbol);

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    void *visit(pragma_c *symbol);

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};   /* class remove_forward_dependencies_c */

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