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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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    25

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/*

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 * Conversion of st statements (i.e. ST code).

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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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class generate_cc_st_c: public generate_cc_typedecl_c {

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  private:

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    /* When calling a function block, we must first find it's type,

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     * by searching through the declarations of the variables currently

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     * in scope.

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     * This class does just that...

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     * A new class is instantiated whenever we begin generating the code

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     * for a function block type declaration, or a program declaration.

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     * This object instance will then later be called while the

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     * function block's or the program's body is being handled.

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     *

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     * Note that functions cannot contain calls to function blocks,

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     * so we do not create an object instance when handling

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     * a function declaration.

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     */

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    search_fb_instance_decl_c *search_fb_instance_decl;

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  public:

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    generate_cc_st_c(stage4out_c *s4o_ptr, symbol_c *scope, const char *variable_prefix = NULL)

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    : generate_cc_typedecl_c(s4o_ptr) {

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      search_fb_instance_decl = new search_fb_instance_decl_c(scope);

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      this->set_variable_prefix(variable_prefix);

    62

    }

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    virtual ~generate_cc_st_c(void) {

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      delete search_fb_instance_decl;

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    }

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    68

    69

  private:

    70

    /* Some function calls in the body of functions or function blocks

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     * may leave some parameters to their default values, and

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     * ignore some output parameters of the function being called.

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     * Our conversion of ST functions to C++ does not contemplate that,

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     * i.e. each called function must get all it's input and output

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     * parameters set correctly.

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     * For input parameters we merely need to call the function with

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     * the apropriate default value, but for output parameters

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     * we must create temporary variables to hold the output value.

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     *

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     * We declare all the temporary output variables at the begining of

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     * the body of each function or function block, and use them as

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     * in function calls later on as they become necessary...

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     * Note that we cannot create these variables just before a function

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     * call, as the function call itself may be integrated within an

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     * expression, or another function call!

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     *

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     * The variables are declared in the exact same order in which they

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     * will be used later on during the function calls, which allows us

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     * to simply re-create the name that was used for the temporary variable

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     * instead of keeping it in some list.

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     * The names are recreated by the temp_var_name_factory, after reset()

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     * has been called!

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     *

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     * This function will genertae code similar to...

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     *

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     *     INT __TMP_0 = 23;

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     *     REAL __TMP_1 = 45.5;

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     *     ...

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     */

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    temp_var_name_c temp_var_name_factory;

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  public:

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    void generate(statement_list_c *stl) {

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      generate_cc_tempvardecl_c generate_cc_tempvardecl(&s4o);

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      generate_cc_tempvardecl.generate(stl, &temp_var_name_factory);

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      stl->accept(*this);

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    }

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  private:

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

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/* B.3 - Language ST (Structured Text) */

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

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

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/* B 3.1 - Expressions */

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

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void *visit(or_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " || ");}

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/* TODO ...  XOR expression... */

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void *visit(xor_expression_c *symbol) {ERROR; return print_binary_expression(symbol->l_exp, symbol->r_exp, " XOR ");}

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void *visit(and_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " && ");}

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void *visit(equ_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " == ");}

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void *visit(notequ_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " != ");}

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void *visit(lt_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " < ");}

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void *visit(gt_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " > ");}

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void *visit(le_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " <= ");}

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void *visit(ge_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " >= ");}

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void *visit(add_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " + ");}

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void *visit(sub_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " - ");}

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void *visit(mul_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " * ");}

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void *visit(div_expression_c *symbol) {return print_binary_expression(symbol->l_exp, symbol->r_exp, " / ");}

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void *visit(mod_expression_c *symbol) {

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  s4o.print("((");

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  symbol->r_exp->accept(*this);

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  s4o.print(" == 0)?0:");

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  print_binary_expression(symbol->l_exp, symbol->r_exp, " % ");

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  s4o.print(")");

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  return NULL;

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}

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/* TODO: power expression... */

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void *visit(power_expression_c *symbol) {ERROR; return print_binary_expression(symbol->l_exp, symbol->r_exp, " ** ");}

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void *visit(neg_expression_c *symbol) {return print_unary_expression(symbol->exp, " -");}

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void *visit(not_expression_c *symbol) {return print_unary_expression(symbol->exp, "!");}

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void *visit(function_invocation_c *symbol) {

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  function_declaration_c *f_decl = function_symtable.find_value(symbol->function_name);

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  if (f_decl == function_symtable.end_value())

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    /* should never occur. The function being called MUST be in the symtable... */

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    ERROR;

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  symbol->function_name->accept(*this);

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  s4o.print("(");

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  /* loop through each function parameter, find the value we should pass

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   * to it, and then output the c equivalent...

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   */

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   158

  function_param_iterator_c fp_iterator(f_decl);

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  identifier_c *param_name;

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  function_call_param_iterator_c function_call_param_iterator(symbol);

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  for(int i = 1; (param_name = fp_iterator.next()) != NULL; i++) {

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    if (i != 1)

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      s4o.print(", ");

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    symbol_c *param_type = fp_iterator.param_type();

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    if (param_type == NULL) ERROR;

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    function_param_iterator_c::param_direction_t param_direction = fp_iterator.param_direction();

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    /* Get the value from a foo(<param_name> = <param_value>) style call */

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    symbol_c *param_value = function_call_param_iterator.search(param_name);

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    /* Get the value from a foo(<param_value>) style call */

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    if (param_value == NULL)

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      param_value = function_call_param_iterator.next();

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    switch (param_direction) {

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      case function_param_iterator_c::direction_in:

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        if (param_value == NULL) {

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          /* No value given for parameter, so we must use the default... */

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          /* First check whether default value specified in function declaration...*/

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          param_value = fp_iterator.default_value();

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        }

   184

        if (param_value == NULL) {

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          /* If not, get the default value of this variable's type */

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          param_value = (symbol_c *)param_type->accept(*type_initial_value_c::instance());

   187

        }

   188

        if (param_value == NULL) ERROR;

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        param_value->accept(*this);

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	break;

   191

      case function_param_iterator_c::direction_out:

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      case function_param_iterator_c::direction_inout:

   193

        if (param_value == NULL) {

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	  /* no parameter value given, so we pass a previously declared temporary variable. */

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          std::string *temp_var_name = temp_var_name_factory.new_name();

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          s4o.print(*temp_var_name);

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          delete temp_var_name;

   198

	} else {

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          param_value->accept(*this);

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	}

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	break;

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      case function_param_iterator_c::direction_extref:

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        /* TODO! */

   204

        ERROR;

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        break;

   206

    } /* switch */

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  } /* for(...) */

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   209

  // symbol->parameter_assignment->accept(*this);

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  s4o.print(")");

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  return NULL;

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}

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

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/* B 3.2 Statements */

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

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void *visit(statement_list_c *symbol) {

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  return print_list(symbol, s4o.indent_spaces, ";\n" + s4o.indent_spaces, ";\n");

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}

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

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/* B 3.2.1 Assignment Statements */

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

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void *visit(assignment_statement_c *symbol) {

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  symbol->l_exp->accept(*this);

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  s4o.print(" = ");

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  symbol->r_exp->accept(*this);

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  return NULL;

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}

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

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/* B 3.2.2 Subprogram Control Statements */

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

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/* fb_name '(' [param_assignment_list] ')' */

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/* param_assignment_list -> may be NULL ! */

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//SYM_REF2(fb_invocation_c, fb_name, param_assignment_list)

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void *visit(fb_invocation_c *symbol) {

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  TRACE("fb_invocation_c");

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  /* first figure out what is the name of the function block type of the function block being called... */

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  symbol_c *function_block_type_name = this->search_fb_instance_decl->get_type_name(symbol->fb_name);

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    /* should never occur. The function block instance MUST have been declared... */

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  if (function_block_type_name == NULL) ERROR;

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  /* Now find the declaration of the function block type being called... */

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  function_block_declaration_c *fb_decl = function_block_type_symtable.find_value(function_block_type_name);

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    /* should never occur. The function block type being called MUST be in the symtable... */

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  if (fb_decl == function_block_type_symtable.end_value()) ERROR;

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  /* loop through each function block parameter, find the value we should pass

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   * to it, and then output the c equivalent...

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   */

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  function_param_iterator_c fp_iterator(fb_decl);

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  identifier_c *param_name;

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  function_call_param_iterator_c function_call_param_iterator(symbol);

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  for(int i = 1; (param_name = fp_iterator.next()) != NULL; i++) {

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    function_param_iterator_c::param_direction_t param_direction = fp_iterator.param_direction();

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   259

    /* Get the value from a foo(<param_name> = <param_value>) style call */

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    symbol_c *param_value = function_call_param_iterator.search(param_name);

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   262

    /* Get the value from a foo(<param_value>) style call */

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    if (param_value == NULL)

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      param_value = function_call_param_iterator.next();

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   266

    /* now output the value assignment */

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    if (param_value != NULL)

   268

      if ((param_direction == function_param_iterator_c::direction_in) ||

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          (param_direction == function_param_iterator_c::direction_inout)) {

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        symbol->fb_name->accept(*this);

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        s4o.print(".");

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        param_name->accept(*this);

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        s4o.print(" = ");

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        param_value->accept(*this);

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        s4o.print(";\n" + s4o.indent_spaces);

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      }

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  } /* for(...) */

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  /* now call the function... */

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  function_block_type_name->accept(*this);

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  s4o.print(FB_FUNCTION_SUFFIX);

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  s4o.print("(&");

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  symbol->fb_name->accept(*this);

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  s4o.print(")");

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  /* loop through each function parameter, find the variable to which

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   * we should atribute the value of all output or inoutput parameters.

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   */

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  fp_iterator.reset();

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  function_call_param_iterator.reset();

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  for(int i = 1; (param_name = fp_iterator.next()) != NULL; i++) {

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    function_param_iterator_c::param_direction_t param_direction = fp_iterator.param_direction();

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    /* Get the value from a foo(<param_name> = <param_value>) style call */

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    symbol_c *param_value = function_call_param_iterator.search(param_name);

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   297

    /* Get the value from a foo(<param_value>) style call */

   298

    if (param_value == NULL)

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      param_value = function_call_param_iterator.next();

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   301

    /* now output the value assignment */

   302

    if (param_value != NULL)

   303

      if ((param_direction == function_param_iterator_c::direction_out) ||

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          (param_direction == function_param_iterator_c::direction_inout)) {

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        s4o.print(";\n"+ s4o.indent_spaces);

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        param_value->accept(*this);

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        s4o.print(" = ");

   308

        symbol->fb_name->accept(*this);

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        s4o.print(".");

   310

        param_name->accept(*this);

   311

      }

   312

  } /* for(...) */

   313

   314

  return NULL;

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}

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/* helper symbol for fb_invocation */

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/* param_assignment_list ',' param_assignment */

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void *visit(param_assignment_list_c *symbol) {

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  TRACE("param_assignment_list_c");

   324

  /* this should never be called... */

   325

  ERROR;

   326

  return NULL;

   327

//  return print_list(symbol, "", ", ");

   328

}

   329

   330

   331

void *visit(input_variable_param_assignment_c *symbol) {

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  TRACE("input_variable_param_assignment_c");

   333

  /* this should never be called... */

   334

  ERROR;

   335

  return NULL;

   336

/*

   337

  symbol->variable_name->accept(*this);

   338

  s4o.print(" = ");

   339

  symbol->expression->accept(*this);

   340

  return NULL;

   341

*/

   342

}

   343

   344

void *visit(output_variable_param_assignment_c *symbol) {

   345

  TRACE("output_variable_param_assignment_c");

   346

  /* this should never be called... */

   347

  ERROR;

   348

  return NULL;

   349

/*

   350

  s4o.print(s4o.indent_spaces);

   351

  if (symbol->not_param != NULL)

   352

    symbol->not_param->accept(*this);

   353

  symbol->variable_name->accept(*this);

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  s4o.print(" => ");

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  symbol->variable->accept(*this);

   356

  return NULL;

   357

*/

   358

}

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   360

// TODO: the NOT symbol in function (block) calls...

   361

void *visit(not_paramassign_c *symbol) {

   362

  TRACE("not_paramassign_c");

   363

  /* this should never be called... */

   364

  ERROR;

   365

  return NULL;

   366

/*

   367

  s4o.print("NOT ");

   368

  return NULL;

   369

*/

   370

}

   371

   372

   373

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

   374

/* B 3.2.3 Selection Statements */

   375

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

   376

void *visit(if_statement_c *symbol) {

   377

  s4o.print("if (");

   378

  symbol->expression->accept(*this);

   379

  s4o.print(") {\n");

   380

  s4o.indent_right();

   381

  symbol->statement_list->accept(*this);

   382

  s4o.indent_left();

   383

  symbol->elseif_statement_list->accept(*this);

   384

   385

  if (symbol->else_statement_list != NULL) {

   386

    s4o.print(s4o.indent_spaces); s4o.print("} else {\n");

   387

    s4o.indent_right();

   388

    symbol->else_statement_list->accept(*this);

   389

    s4o.indent_left();

   390

  }

   391

  s4o.print(s4o.indent_spaces); s4o.print("}");

   392

  return NULL;

   393

}

   394

   395

/* helper symbol for if_statement */

   396

void *visit(elseif_statement_list_c *symbol) {return print_list(symbol);}

   397

   398

/* helper symbol for elseif_statement_list */

   399

void *visit(elseif_statement_c *symbol) {

   400

  s4o.print(s4o.indent_spaces); s4o.print("} else if (");

   401

  symbol->expression->accept(*this);

   402

  s4o.print(") {\n");

   403

  s4o.indent_right();

   404

  symbol->statement_list->accept(*this);

   405

  s4o.indent_left();

   406

  return NULL;

   407

}

   408

   409

void *visit(case_statement_c *symbol) {

   410

  s4o.print("switch(");

   411

  symbol->expression->accept(*this);

   412

  s4o.print(") {\n");

   413

  s4o.indent_right();

   414

  symbol->case_element_list->accept(*this);

   415

  if (symbol->statement_list != NULL) {

   416

    s4o.print(s4o.indent_spaces + "default:\n");

   417

    s4o.indent_right();

   418

    symbol->statement_list->accept(*this);

   419

    s4o.print(s4o.indent_spaces + "break;\n");

   420

    s4o.indent_left();

   421

  }

   422

  s4o.indent_left();

   423

  s4o.print(s4o.indent_spaces + "}");

   424

  return NULL;

   425

}

   426

   427

/* helper symbol for case_statement */

   428

void *visit(case_element_list_c *symbol) {return print_list(symbol);}

   429

   430

void *visit(case_element_c *symbol) {

   431

  s4o.print(s4o.indent_spaces + "case ");

   432

  symbol->case_list->accept(*this);

   433

  s4o.print(" :\n");

   434

  s4o.indent_right();

   435

  symbol->statement_list->accept(*this);

   436

  s4o.print(s4o.indent_spaces + "break;\n");

   437

  s4o.indent_left();

   438

  return NULL;

   439

}

   440

   441

void *visit(case_list_c *symbol) {return print_list(symbol, "", ", ");}

   442

   443

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

   444

/* B 3.2.4 Iteration Statements */

   445

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

   446

void *visit(for_statement_c *symbol) {

   447

  s4o.print("for(");

   448

  symbol->control_variable->accept(*this);

   449

  s4o.print(" = ");

   450

  symbol->beg_expression->accept(*this);

   451

  s4o.print("; ");

   452

  symbol->control_variable->accept(*this);

   453

  s4o.print(" != ");

   454

  symbol->end_expression->accept(*this);

   455

  s4o.print("; ");

   456

  symbol->control_variable->accept(*this);

   457

  if (symbol->by_expression != NULL) {

   458

    s4o.print(" += ");

   459

    symbol->by_expression->accept(*this);

   460

  } else {

   461

    s4o.print("++");

   462

  }

   463

  s4o.print(") {\n");

   464

  s4o.indent_right();

   465

  symbol->statement_list->accept(*this);

   466

  s4o.indent_left();

   467

  s4o.print(s4o.indent_spaces); s4o.print("}");

   468

  return NULL;

   469

}

   470

void *visit(while_statement_c *symbol) {

   471

  s4o.print("while (");

   472

  symbol->expression->accept(*this);

   473

  s4o.print(") {\n");

   474

  s4o.indent_right();

   475

  symbol->statement_list->accept(*this);

   476

  s4o.indent_left();

   477

  s4o.print(s4o.indent_spaces); s4o.print("}");

   478

  return NULL;

   479

}

   480

void *visit(repeat_statement_c *symbol) {

   481

  s4o.print("do {\n");

   482

  s4o.indent_right();

   483

  symbol->statement_list->accept(*this);

   484

  s4o.indent_left();

   485

  s4o.print(s4o.indent_spaces); s4o.print("} while(");

   486

  symbol->expression->accept(*this);

   487

  s4o.print(")");

   488

  return NULL;

   489

}

   490

void *visit(exit_statement_c *symbol) {

   491

  s4o.print("exit(0)");

   492

  return NULL;

   493

}

   494

   495

   496

   497

}; /* generate_cc_st_c */

   498

   499

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   501

   502

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   504

   505

   506