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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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 *  Copyright (C) 2012       Manuele Conti  (conti.ma@alice.it)

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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 characteristics of a specific data type

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 *  e.g., is it an enumeration, is it an array, is it ANY_INT, etc...

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 *

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 * The methods of this class may be passed either:

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 *  - a data type declaration symbol_c, 

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 *   OR

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 *  - the name of a data type (identifier_c)

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 *    In this case, we shall first serach for the basetype declaration using search_base_type_c, and then 

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 *    run the normal process.

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 */

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#include "absyntax_utils.hh"

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#include "../main.hh" // required for ERROR() and ERROR_MSG() macros.

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#include <typeinfo>  // required for typeid

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

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

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

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

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

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/*****           Some helper classes                  *****/

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

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

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

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

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

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

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

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/* Return the identifier (name) of a datatype, typically declared in a TYPE .. END_TYPE declaration */

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

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

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class get_datatype_id_c: null_visitor_c {

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  private:

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    static get_datatype_id_c *singleton;

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  public:

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    static symbol_c *get_id(symbol_c *symbol) {

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      if (NULL == singleton) singleton = new  get_datatype_id_c();

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      if (NULL == singleton) ERROR;

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      return (symbol_c *)symbol->accept(*singleton);

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    }

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  protected:

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

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    /* B 1.3.1 - Elementary Data Types */

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

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    void *visit(time_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(bool_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(sint_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(int_type_name_c         *symbol) {return (void *)symbol;};

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    void *visit(dint_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(lint_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(usint_type_name_c       *symbol) {return (void *)symbol;};

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    void *visit(uint_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(udint_type_name_c       *symbol) {return (void *)symbol;};

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    void *visit(ulint_type_name_c       *symbol) {return (void *)symbol;};

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    void *visit(real_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(lreal_type_name_c       *symbol) {return (void *)symbol;};

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    void *visit(date_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(tod_type_name_c         *symbol) {return (void *)symbol;};

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    void *visit(dt_type_name_c          *symbol) {return (void *)symbol;};

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    void *visit(byte_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(word_type_name_c        *symbol) {return (void *)symbol;};

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    void *visit(lword_type_name_c       *symbol) {return (void *)symbol;};

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    void *visit(dword_type_name_c       *symbol) {return (void *)symbol;};

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    void *visit(string_type_name_c      *symbol) {return (void *)symbol;};

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    void *visit(wstring_type_name_c     *symbol) {return (void *)symbol;};

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    void *visit(safetime_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safebool_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safesint_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safeint_type_name_c     *symbol) {return (void *)symbol;};

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    void *visit(safedint_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safelint_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safeusint_type_name_c   *symbol) {return (void *)symbol;};

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    void *visit(safeuint_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safeudint_type_name_c   *symbol) {return (void *)symbol;};

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    void *visit(safeulint_type_name_c   *symbol) {return (void *)symbol;};

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    void *visit(safereal_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safelreal_type_name_c   *symbol) {return (void *)symbol;};

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    void *visit(safedate_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safetod_type_name_c     *symbol) {return (void *)symbol;};

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    void *visit(safedt_type_name_c      *symbol) {return (void *)symbol;};

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    void *visit(safebyte_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safeword_type_name_c    *symbol) {return (void *)symbol;};

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    void *visit(safelword_type_name_c   *symbol) {return (void *)symbol;};

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    void *visit(safedword_type_name_c   *symbol) {return (void *)symbol;};

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    void *visit(safestring_type_name_c  *symbol) {return (void *)symbol;};

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    void *visit(safewstring_type_name_c *symbol) {return (void *)symbol;};

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

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    /* B 1.3.3 - Derived data types */

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

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    /*  simple_type_name ':' simple_spec_init */

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    void *visit(simple_type_declaration_c     *symbol)  {return symbol->simple_type_name;}

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    /*  subrange_type_name ':' subrange_spec_init */

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    void *visit(subrange_type_declaration_c   *symbol)  {return symbol->subrange_type_name;}

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    /*  enumerated_type_name ':' enumerated_spec_init */

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    void *visit(enumerated_type_declaration_c *symbol)  {return symbol->enumerated_type_name;}

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    /*  identifier ':' array_spec_init */

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    void *visit(array_type_declaration_c      *symbol)  {return symbol->identifier;}

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    /*  structure_type_name ':' structure_specification */

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    void *visit(structure_type_declaration_c  *symbol)  {return symbol->structure_type_name;}

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    /*  string_type_name ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init */

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    void *visit(string_type_declaration_c     *symbol)  {return symbol->string_type_name;}

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    /* ref_type_decl: identifier ':' ref_spec_init */

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    void *visit(ref_type_decl_c               *symbol)  {return symbol->ref_type_name;}

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    /* NOTE: DO NOT place any code here that references symbol->anotations_map["generate_c_annotaton__implicit_type_id"] !!

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     *       All anotations in the symbol->anotations_map[] are considered a stage4 construct. In the above example,

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     *       That anotation is specific to the generate_c stage4 code, and must therefore NOT be referenced

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     *       in the absyntax_utils code, as this last code should be independent of the stage4 version!

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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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    void *visit(function_block_declaration_c  *symbol)  {return symbol->fblock_name;}

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}; // get_datatype_id_c 

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get_datatype_id_c *get_datatype_id_c::singleton = NULL;

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

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

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/* transform elementary data type class to string */

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

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

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/* A small helper class, to transform elementary data type to string.

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 * this allows us to generate more relevant error messages...

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 */

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class get_datatype_id_str_c: public null_visitor_c {

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  protected:

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     get_datatype_id_str_c(void)  {};

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    ~get_datatype_id_str_c(void) {};

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  private:

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    /* singleton class! */

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    static get_datatype_id_str_c *singleton;

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  public:

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    static const char *get_id_str(symbol_c *symbol) {

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      if (NULL == singleton)    singleton = new get_datatype_id_str_c;

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      if (NULL == singleton)    ERROR;

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      const char *res           = (const char *)symbol->accept(*singleton);

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      if (NULL == res)          ERROR;

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      return 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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    void *visit(identifier_c *symbol) {return (void *)symbol->value;};

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

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    /* B 1.3.1 - Elementary Data Types */

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

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    void *visit(time_type_name_c        *symbol) {return (void *)"TIME";        };

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    void *visit(bool_type_name_c        *symbol) {return (void *)"BOOL";        };

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    void *visit(sint_type_name_c        *symbol) {return (void *)"SINT";        };

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    void *visit(int_type_name_c         *symbol) {return (void *)"INT";         };

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    void *visit(dint_type_name_c        *symbol) {return (void *)"DINT";        };

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    void *visit(lint_type_name_c        *symbol) {return (void *)"LINT";        };

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    void *visit(usint_type_name_c       *symbol) {return (void *)"USINT";       };

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    void *visit(uint_type_name_c        *symbol) {return (void *)"UINT";        };

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    void *visit(udint_type_name_c       *symbol) {return (void *)"UDINT";       };

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    void *visit(ulint_type_name_c       *symbol) {return (void *)"ULINT";       };

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    void *visit(real_type_name_c        *symbol) {return (void *)"REAL";        };

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    void *visit(lreal_type_name_c       *symbol) {return (void *)"LREAL";       };

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    void *visit(date_type_name_c        *symbol) {return (void *)"DATE";        };

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    void *visit(tod_type_name_c         *symbol) {return (void *)"TOD";         };

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    void *visit(dt_type_name_c          *symbol) {return (void *)"DT";          };

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    void *visit(byte_type_name_c        *symbol) {return (void *)"BYTE";        };

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    void *visit(word_type_name_c        *symbol) {return (void *)"WORD";        };

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    void *visit(lword_type_name_c       *symbol) {return (void *)"LWORD";       };

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    void *visit(dword_type_name_c       *symbol) {return (void *)"DWORD";       };

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    void *visit(string_type_name_c      *symbol) {return (void *)"STRING";      };

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    void *visit(wstring_type_name_c     *symbol) {return (void *)"WSTRING";     };

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    void *visit(safetime_type_name_c    *symbol) {return (void *)"SAFETIME";    };

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    void *visit(safebool_type_name_c    *symbol) {return (void *)"SAFEBOOL";    };

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    void *visit(safesint_type_name_c    *symbol) {return (void *)"SAFESINT";    };

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    void *visit(safeint_type_name_c     *symbol) {return (void *)"SAFEINT";     };

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    void *visit(safedint_type_name_c    *symbol) {return (void *)"SAFEDINT";    };

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    void *visit(safelint_type_name_c    *symbol) {return (void *)"SAFELINT";    };

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    void *visit(safeusint_type_name_c   *symbol) {return (void *)"SAFEUSINT";   };

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    void *visit(safeuint_type_name_c    *symbol) {return (void *)"SAFEUINT";    };

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    void *visit(safeudint_type_name_c   *symbol) {return (void *)"SAFEUDINT";   };

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    void *visit(safeulint_type_name_c   *symbol) {return (void *)"SAFEULINT";   };

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    void *visit(safereal_type_name_c    *symbol) {return (void *)"SAFEREAL";    };

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    void *visit(safelreal_type_name_c   *symbol) {return (void *)"SAFELREAL";   };

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    void *visit(safedate_type_name_c    *symbol) {return (void *)"SAFEDATE";    };

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    void *visit(safetod_type_name_c     *symbol) {return (void *)"SAFETOD";     };

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    void *visit(safedt_type_name_c      *symbol) {return (void *)"SAFEDT";      };

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    void *visit(safebyte_type_name_c    *symbol) {return (void *)"SAFEBYTE";    };

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    void *visit(safeword_type_name_c    *symbol) {return (void *)"SAFEWORD";    };

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    void *visit(safelword_type_name_c   *symbol) {return (void *)"SAFELWORD";   };

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    void *visit(safedword_type_name_c   *symbol) {return (void *)"SAFEDWORD";   };

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    void *visit(safestring_type_name_c  *symbol) {return (void *)"SAFESTRING";  };

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    void *visit(safewstring_type_name_c *symbol) {return (void *)"SAFEWSTRING"; };

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

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    /* B 1.3.3 - Derived data types */

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

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    /*  simple_type_name ':' simple_spec_init */

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    void *visit(simple_type_declaration_c     *symbol)  {return symbol->simple_type_name->accept(*this);}

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    /*  subrange_type_name ':' subrange_spec_init */

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    void *visit(subrange_type_declaration_c   *symbol)  {return symbol->subrange_type_name->accept(*this);}

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    /*  enumerated_type_name ':' enumerated_spec_init */

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    void *visit(enumerated_type_declaration_c *symbol)  {return symbol->enumerated_type_name->accept(*this);}

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    /*  identifier ':' array_spec_init */

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    void *visit(array_type_declaration_c      *symbol)  {return symbol->identifier->accept(*this);}

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    /*  structure_type_name ':' structure_specification */

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    void *visit(structure_type_declaration_c  *symbol)  {return symbol->structure_type_name->accept(*this);}

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    /*  string_type_name ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init */

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    void *visit(string_type_declaration_c     *symbol)  {return symbol->string_type_name->accept(*this);}

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    /* ref_type_decl: identifier ':' ref_spec_init */

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    void *visit(ref_type_decl_c               *symbol)  {return symbol->ref_type_name->accept(*this);}

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    /* NOTE: DO NOT place any code here that references symbol->anotations_map["generate_c_annotaton__implicit_type_id"] !!

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     *       All anotations in the symbol->anotations_map[] are considered a stage4 construct. In the above example,

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     *       That anotation is specific to the generate_c stage4 code, and must therefore NOT be referenced

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     *       in the absyntax_utils code, as this last code should be independent of the stage4 version!

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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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    void *visit(function_block_declaration_c  *symbol)  {return symbol->fblock_name->accept(*this);}    

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};

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get_datatype_id_str_c *get_datatype_id_str_c::singleton = NULL;

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

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

   287

/* get the datatype of a field inside a struct data type */

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

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

   290

   291

class get_struct_info_c : null_visitor_c {

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  private:

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    symbol_c *current_field;

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    /* singleton class! */

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    static get_struct_info_c *singleton;

   296

   297

  public:

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    get_struct_info_c(void) {current_field = NULL;}

   299

   300

    static symbol_c *get_field_type_id(symbol_c *struct_type, symbol_c *field_name) {

   301

      if (NULL == singleton)    singleton = new get_struct_info_c;

   302

      if (NULL == singleton)    ERROR;

   303

      singleton->current_field = field_name;

   304

      return (symbol_c *)struct_type->accept(*singleton);

   305

    }

   306

   307

   308

  private:

   309

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

   310

    /* B.1 - Common elements */

   311

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

   312

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

   313

    /* B 1.3.3 - Derived data types */

   314

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

   315

    /*  structure_type_name ':' structure_specification */

   316

    /* NOTE: this is only used inside a TYPE ... END_TYPE declaration.  It is never used directly when declaring a new variable! */

   317

    /* NOTE: structure_specification will point to either initialized_structure_c  OR  structure_element_declaration_list_c */

   318

    void *visit(structure_type_declaration_c *symbol) {return symbol->structure_specification->accept(*this);}

   319

   320

    /* structure_type_name ASSIGN structure_initialization */

   321

    /* structure_initialization may be NULL ! */

   322

    // SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)

   323

    /* NOTE: only the initialized structure is never used when declaring a new variable instance */

   324

    void *visit(initialized_structure_c *symbol) {return symbol->structure_type_name->accept(*this);}

   325

   326

    /* helper symbol for structure_declaration */

   327

    /* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */

   328

    /* structure_element_declaration_list structure_element_declaration ';' */

   329

    void *visit(structure_element_declaration_list_c *symbol) {

   330

      /* now search the structure declaration */

   331

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

   332

        void *tmp = symbol->elements[i]->accept(*this);

   333

        if (NULL != tmp) return tmp;

   334

      }

   335

      return NULL; // not found!!

   336

    }  

   337

   338

    /*  structure_element_name ':' spec_init */

   339

    void *visit(structure_element_declaration_c *symbol) {

   340

      if (compare_identifiers(symbol->structure_element_name, current_field) == 0)

   341

        return symbol->spec_init; /* found the type of the element we were looking for! */

   342

      return NULL;   /* not the element we are looking for! */

   343

    }

   344

   345

   346

    /* helper symbol for structure_initialization */

   347

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

   348

    /* structure_element_initialization_list ',' structure_element_initialization */

   349

    void *visit(structure_element_initialization_list_c *symbol) {ERROR; return NULL;} /* should never get called... */

   350

    /*  structure_element_name ASSIGN value */

   351

    void *visit(structure_element_initialization_c *symbol) {ERROR; return NULL;} /* should never get called... */

   352

   353

   354

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

   355

    /* B.1.5 - Program organization units */

   356

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

   357

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

   358

    /* B 1.5.2 - Function Blocks */

   359

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

   360

    /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */

   361

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

   362

    void *visit(function_block_declaration_c *symbol) {

   363

      /* now search the function block declaration for the variable... */

   364

      search_var_instance_decl_c search_decl(symbol);

   365

      return search_decl.get_decl(current_field);

   366

    }

   367

   368

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

   369

    /* B.1.6  Sequential function chart elements */

   370

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

   371

    /* INITIAL_STEP step_name ':' action_association_list END_STEP */

   372

    // SYM_REF2(initial_step_c, step_name, action_association_list)

   373

    void *visit(initial_step_c *symbol) {

   374

      identifier_c T("T");  identifier_c X("X");

   375

      /* Hard code the datatypes of the implicit variables Stepname.X and Stepname.T */

   376

      if (compare_identifiers(&T, current_field) == 0)  return &get_datatype_info_c::time_type_name;

   377

      if (compare_identifiers(&X, current_field) == 0)  return &get_datatype_info_c::bool_type_name;

   378

      return NULL;

   379

    }

   380

   381

    /* STEP step_name ':' action_association_list END_STEP */

   382

    // SYM_REF2(step_c, step_name, action_association_list)

   383

    /* The code here should be identicial to the code in the visit(initial_step_c *) visitor! So we simply call the other visitor! */

   384

    void *visit(step_c *symbol) {initial_step_c initial_step(NULL, NULL); return initial_step.accept(*this);}

   385

   386

}; // get_struct_info_c

   387

   388

get_struct_info_c *get_struct_info_c::singleton = NULL;

   389

   390

   391

   392

   393

   394

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

   395

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

   396

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

   397

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

   398

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

   399

/*****        GET_DATATYPE_INFO_C                     *****/

   400

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

   401

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

   402

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

   403

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

   404

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

   405

   406

const char *get_datatype_info_c::get_id_str(symbol_c *datatype) {

   407

  return get_datatype_id_str_c::get_id_str(datatype);

   408

}

   409

   410

   411

symbol_c *get_datatype_info_c::get_id(symbol_c *datatype) {

   412

  return get_datatype_id_c::get_id(datatype);

   413

}

   414

   415

   416

symbol_c *get_datatype_info_c::get_struct_field_type_id(symbol_c *struct_datatype, symbol_c *struct_fieldname) {

   417

  return get_struct_info_c::get_field_type_id(struct_datatype, struct_fieldname);

   418

}

   419

   420

symbol_c *get_datatype_info_c::get_array_storedtype_id(symbol_c *type_symbol) {

   421

  // returns the datatype of the variables stored in the array

   422

  symbol_c *basetype = search_base_type_c::get_basetype_decl(type_symbol);

   423

  array_specification_c *symbol = dynamic_cast<array_specification_c *>(basetype);

   424

   425

  if (NULL != symbol) 

   426

    return symbol->non_generic_type_name;

   427

  return NULL; // this is not an array!

   428

}

   429

   430

   431

/* Returns true if both datatypes are equivalent (not necessarily equal!).

   432

 * WARNING: May return true even though the datatypes are not the same/identicial!!!

   433

 *          This occurs when at least one of the datatypes is of a generic

   434

 *          datatype (or a REF_TO a generic datatype). 

   435

 *          (Generic dataypes: ANY, ANY_INT, ANY_NUM, ...)

   436

 * NOTE: Currently only the ANY generic datatype is implemented!

   437

 * NOTE: Currently stage1_2 only allows the use of the ANY keyword when in conjuntion with

   438

 *       the REF_TO keyword (i.e. REF_TO ANY), so when handling non REF_TO datatypes,

   439

 *       this function will currently only return true if the dataypes are identicial.

   440

 */

   441

   442

/* NOTE: Currently the datatype model used by matiec considers any implicitly defined datatype

   443

 *       (e.g. an array datatype defined in the variable declaration itself, instead of inside a TYPE ... END_TYPE

   444

 *       construct) to be different (i.e. not the same datatype, and therefore not compatible) to any other

   445

 *       datatype, including with datatypes declared identically to the implicit datatype.

   446

 *       e.g.

   447

 *         TYPE my_array_t: ARRAY [1..3] OF INT; END_TYPE;

   448

 *         FUNCTION_BLOCK FOO

   449

 *          VAR my_array:  ARRAY [1..3] OF INT; END_VAR

   450

 *         ...

   451

 *         END_FUNCTION_BLOCK

   452

 * 

   453

 *         In the abive code, my_array is NOT considered to te compatible with my_Array_t !!!

   454

 * 

   455

 *       In essence, the currently supported datatype model considers all datatypes to be different to each other,

   456

 *       even though the stored data is the same (Let us call this rule (0))!

   457

 *       There are 2 exceptions to the above rule:

   458

 *        (1) Datatypes that are directly derived from other datatypes.

   459

 *              (this rule is specified in the standard, so we follow it!)

   460

 *        (2) REF_TO datatypes that reference the same datatype

   461

 *              (I dont think the standard says anything about this!)

   462

 *

   463

 *         TYPE 

   464

 *          my_array_1_t: ARRAY [1..3] OF INT; 

   465

 *          my_array_2_t: ARRAY [1..3] OF INT; 

   466

 *          my_array_3_t: my_array_1_t; 

   467

 *          A_ref_t: REF_TO my_array_1_t;

   468

 *          B_ref_t: REF_TO my_array_1_t;

   469

 *          C_ref_t: A_ref_t;

   470

 *         END_TYPE;

   471

 *                 

   472

 *         In the above code, my_array_1_t is a distinct datatype to my_array_2_t

   473

 *           (this is different to C and C++, where they would be considered the same datatype!)

   474

 *           (following rule (0))

   475

 *         In the above code, my_array_3_t is the same datatype as my_array_1_t

   476

 *           (following rule (1))

   477

 *         In the above code, A_ref_t is the same datatype as B_ref_t

   478

 *           (following rule (2))

   479

 *         In the above code, A_ref_t is the same datatype as C_ref_t

   480

 *           (following rule (1))

   481

 *

   482

 *       Note that rule (0) means that a function/FB with a parameter whose datatype is implicitly defined

   483

 *       can never be passed a value!

   484

 *         FUNCTION_BLOCK FOO

   485

 *          VAR_INPUT my_array:  ARRAY [1..3] OF INT; END_VAR

   486

 *         ...

   487

 *         END_FUNCTION_BLOCK

   488

 *

   489

 *       Any call to FB foo can never pass a value to parameter my_array, as its datatype is distinct

   490

 *       to all other datatypes, and therefore passing any other variable to my_array will result in an

   491

 *       'incompatible datatypes' error!

   492

 *       The above seems natural o me (Mario) in a programming language that is very strongly typed.

   493

 * 

   494

 *       However, if we did not have exception (2), the following would also be invalid:

   495

 *         TYPE my_array_t: ARRAY [1..3] OF INT; END_TYPE;

   496

 *         FUNCTION_BLOCK FOO_t

   497