/*
 *  matiec - a compiler for the programming languages defined in IEC 61131-3
 *
 *  Copyright (C) 2003-2011  Mario de Sousa (msousa@fe.up.pt)
 *  Copyright (C) 2007-2011  Laurent Bessard and Edouard Tisserant
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 * This code is made available on the understanding that it will not be
 * used in safety-critical situations without a full and competent review.
 */

/*
 * An IEC 61131-3 compiler.
 *
 * Based on the
 * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
 *
 */



/* Determine the data type of a variable.
 * The variable may be a simple variable, a function block instance, a
 * struture element within a data structured type (a struct or a fb), or
 * an array element.
 * A mixture of array element of a structure element of a structure element
 * of a .... is also suported!
 *
 *  example:
 *    window.points[1].coordinate.x
 *    window.points[1].colour
 *    etc... ARE ALLOWED!
 *
 * This class must be passed the scope within which the
 * variable was declared, and the variable name...
 *
 *
 *
 *
 *
 * This class has several members, depending on the exact data the caller
 * is looking for...
 *
 *    - item i: we can get either the name of the data type(A),
 *              or it's declaration (B)
 *             (notice however that some variables belong to a data type that does
 *              not have a name, only a declaration as in
 *              VAR a: ARRAY [1..3] of INT; END_VAR
 *             )
 *    - item ii: we can get either the direct data type (1), 
 *               or the base type (2)
 * 
 *   By direct type, I mean the data type of the variable. By base type, I 
 * mean the data type on which the direct type is based on. For example, in 
 * a subrange on INT, the direct type is the subrange itself, while the 
 * base type is INT.
 * e.g.
 *   This means that if we find that the variable is of type MY_INT,
 *   which was previously declared to be
 *   TYPE MY_INT: INT := 9;
 *   option (1) will return MY_INT
 *   option (2) will return INT
 * 
 *
 * Member functions:
 * ================
 *   get_basetype_decl()  ---> returns 2B 
 *   get_type_id()        ---> returns 1A
 * 
 *   Since we haven't yet needed them, we don't yet implement
 *   get_basetype_id()    ----> would return 2A
 *   get_type_decl()      ----> would return 1B
 */ 

class search_varfb_instance_type_c: public search_base_type_c {

  private:
    search_var_instance_decl_c search_var_instance_decl;
    decompose_var_instance_name_c *decompose_var_instance_name;
    symbol_c *current_structelement_name;
    symbol_c *current_typeid;
    symbol_c *current_basetypeid;
    bool is_complex;

  public:
    search_varfb_instance_type_c(symbol_c *search_scope);
    symbol_c *get_basetype_decl(symbol_c *variable_name);
    symbol_c *get_type_decl(symbol_c *variable_name);
    symbol_c *get_type_id(symbol_c *variable_name);

    /* NOTE: this function should be remvoed/deleted.
     *       However, it is currently used in stage 4, and before deleting it
     *       requires that the stage4 code be analysed and fixed (i.e. replace by 
     *       a call to one of the above functions get_basetype_decl(), 
     *       get_type_decl(), get_type_id().
     *
     *      At the moment, I have a feeling that this whole class search_varfb_instance_type_c
     *      will not be needed in the future (i.e. when we finish implementing type checking
     *      in stage 3 correctly, where we store on each symbol in the abstract syntax
     *      tree it's data type, so stage4 implementations will not need to deduce the data
     *      types again), so it does not make much sense to spend more time on it.
     */
    unsigned int get_vartype(symbol_c *variable_name);
    bool type_is_complex(void);

  private:
    /* a helper function... */
    void *visit_list(list_c *list);

    /* a helper function... */
    void *base_type(symbol_c *symbol);


  private:
    /* We override the base class' visitor to identifier_c.
     * This is so because the base class does not consider a function block
     * to be a type, unlike this class that allows a variable instance
     * of a function block type...
     */
    void *visit(identifier_c *type_name);

    /********************************/
    /* B 1.3.3 - Derived data types */
    /********************************/
    
    /*  identifier ':' array_spec_init */
    void *visit(array_type_declaration_c *symbol);
    
    /* array_specification [ASSIGN array_initialization} */
    /* array_initialization may be NULL ! */
    void *visit(array_spec_init_c *symbol);
    
    /* ARRAY '[' array_subrange_list ']' OF non_generic_type_name */
    void *visit(array_specification_c *symbol);

    /*  structure_type_name ':' structure_specification */
    void *visit(structure_type_declaration_c *symbol);

    /* structure_type_name ASSIGN structure_initialization */
    /* structure_initialization may be NULL ! */
    // SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)
    void *visit(initialized_structure_c *symbol);

    /* helper symbol for structure_declaration */
    /* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */
    /* structure_element_declaration_list structure_element_declaration ';' */
    void *visit(structure_element_declaration_list_c *symbol);

    /*  structure_element_name ':' spec_init */
    void *visit(structure_element_declaration_c *symbol);

    /* helper symbol for structure_initialization */
    /* structure_initialization: '(' structure_element_initialization_list ')' */
    /* structure_element_initialization_list ',' structure_element_initialization */
    void *visit(structure_element_initialization_list_c *symbol); /* should never get called... */
    /*  structure_element_name ASSIGN value */
    void *visit(structure_element_initialization_c *symbol); /* should never get called... */



    /**************************************/
    /* B.1.5 - Program organization units */
    /**************************************/
    /*****************************/
    /* B 1.5.2 - Function Blocks */
    /*****************************/
    /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */
    // SYM_REF4(function_block_declaration_c, fblock_name, var_declarations, fblock_body, unused)
    void *visit(function_block_declaration_c *symbol);

}; // search_varfb_instance_type_c