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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

     5

 * as published by the Free Software Foundation; either version 2 of the

     6

 * License, or (at your option) any later version.

     7

 *

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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

    10

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General

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 * Public License for more details.

    12

 *

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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.

    15

 */

    16

    17

/*

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 * An IEC 61131-3 IL and ST compiler.

    19

 *

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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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 */

    24

    25

    26

/* Determine the data type of an ST expression.

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 * A reference to the relevant type definition is returned.

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 *

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 * For example:

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 *       2 + 3       -> returns reference to a int_type_name_c object.

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 *       22.2 - 5    -> returns reference to a real_type_name_c object.

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 *       etc...

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 */

    34

    35

#include "function_type_decl.h"

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#include "get_function_type_decl.c"

    37

    38

#if 0

    39

typedef enum {function_add,

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              function_sub,

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              function_and,

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              function_or,

    43

              function_sqrt,

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              function_none} function_type_t;

    45

    46

    47

function_type_t get_function_type(identifier_c *function_name) {

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  if (!strcasecmp(function_name->value, "ADD"))

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    return function_add;

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  else if (!strcasecmp(function_name->value, "SUB"))

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    return function_sub;

    52

  else if (!strcasecmp(function_name->value, "AND"))

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    return function_and;

    54

  else if (!strcasecmp(function_name->value, "OR"))

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    return function_or;

    56

  else if (!strcasecmp(function_name->value, "SQRT"))

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    return function_sqrt;

    58

  else return function_none;

    59

}

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#endif

    61

    62

    63

symbol_c *generate_param_name(const char *name) {

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  symbol_c *param_name = new identifier_c(name);

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  return param_name;

    66

}

    67

    68

    69

symbol_c *generate_param_name(const char *format, int number) {

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  char name[10];

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  sprintf(name, format, number);

    72

  symbol_c *param_name = new identifier_c(name);

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  return param_name;

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}

    75

    76

    77

class search_expression_type_c: public search_constant_type_c {

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  private:

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    search_varfb_instance_type_c *search_varfb_instance_type;

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    search_base_type_c search_base_type;

    81

    82

  public:

    83

    search_expression_type_c(symbol_c *search_scope) {

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      search_varfb_instance_type = new search_varfb_instance_type_c(search_scope);

    85

    }

    86

    87

    virtual ~search_expression_type_c(void) {

    88

      delete search_varfb_instance_type;

    89

    }

    90

    91

    /* A helper function... */

    92

    bool is_bool_type(symbol_c *type_symbol) {

    93

      return (typeid(*type_symbol) == typeid(bool_type_name_c));

    94

    }

    95

    96

    /* A helper function... */

    97

    bool is_time_type(symbol_c *type_symbol) {

    98

      if (typeid(*type_symbol) == typeid(time_type_name_c)) {return true;}

    99

      if (typeid(*type_symbol) == typeid(date_type_name_c)) {return true;}

   100

      if (typeid(*type_symbol) == typeid(tod_type_name_c)) {return true;}

   101

      if (typeid(*type_symbol) == typeid(dt_type_name_c)) {return true;}

   102

      return false;

   103

    }

   104

   105

    /* A helper function... */

   106

    bool is_integer_type(symbol_c *type_symbol) {

   107

      if (typeid(*type_symbol) == typeid(sint_type_name_c)) {return true;}

   108

      if (typeid(*type_symbol) == typeid(int_type_name_c)) {return true;}

   109

      if (typeid(*type_symbol) == typeid(dint_type_name_c)) {return true;}

   110

      if (typeid(*type_symbol) == typeid(lint_type_name_c)) {return true;}

   111

      if (typeid(*type_symbol) == typeid(usint_type_name_c)) {return true;}

   112

      if (typeid(*type_symbol) == typeid(uint_type_name_c)) {return true;}

   113

      if (typeid(*type_symbol) == typeid(udint_type_name_c)) {return true;}

   114

      if (typeid(*type_symbol) == typeid(ulint_type_name_c)) {return true;}

   115

      if (typeid(*type_symbol) == typeid(constant_int_type_name_c)) {return true;}

   116

      return false;

   117

    }

   118

   119

    bool is_real_type(symbol_c *type_symbol) {

   120

      if (typeid(*type_symbol) == typeid(real_type_name_c)) {return true;}

   121

      if (typeid(*type_symbol) == typeid(lreal_type_name_c)) {return true;}

   122

      if (typeid(*type_symbol) == typeid(constant_real_type_name_c)) {return true;}

   123

      return false;

   124

    }

   125

   126

    bool is_num_type(symbol_c *type_symbol) {

   127

      return is_real_type(type_symbol) || is_integer_type(type_symbol);

   128

    }

   129

   130

    bool is_binary_type(symbol_c *type_symbol) {

   131

      if (typeid(*type_symbol) == typeid(bool_type_name_c)) {return true;}

   132

      if (typeid(*type_symbol) == typeid(byte_type_name_c)) {return true;}

   133

      if (typeid(*type_symbol) == typeid(word_type_name_c)) {return true;}

   134

      if (typeid(*type_symbol) == typeid(dword_type_name_c)) {return true;}

   135

      if (typeid(*type_symbol) == typeid(lword_type_name_c)) {return true;}

   136

      if (typeid(*type_symbol) == typeid(constant_int_type_name_c)) {return true;}

   137

      return false;

   138

    }

   139

   140

    bool is_same_type(symbol_c *first_type, symbol_c *second_type) {

   141

      if (typeid(*first_type) == typeid(*second_type)) {return true;}

   142

      if (is_integer_type(first_type) && (typeid(*second_type) == typeid(constant_int_type_name_c))) {return true;}

   143

      if ((typeid(*first_type) == typeid(constant_int_type_name_c) && is_integer_type(second_type))) {return true;}

   144

      if (is_binary_type(first_type) && (typeid(*second_type) == typeid(constant_int_type_name_c))) {return true;}

   145

      if ((typeid(*first_type) == typeid(constant_int_type_name_c) && is_binary_type(second_type))) {return true;}

   146

      if (is_real_type(first_type) && (typeid(*second_type) == typeid(constant_real_type_name_c))) {return true;}

   147

      if ((typeid(*first_type) == typeid(constant_real_type_name_c) && is_real_type(second_type))) {return true;}

   148

      return false;

   149

    }

   150

   151

    symbol_c* common_type(symbol_c *first_type, symbol_c *second_type) {

   152

      if (typeid(*first_type) == typeid(*second_type)) {return first_type;}

   153

      if (is_integer_type(first_type) && (typeid(*second_type) == typeid(constant_int_type_name_c))) {return first_type;}

   154

      if ((typeid(*first_type) == typeid(constant_int_type_name_c) && is_integer_type(second_type))) {return second_type;}

   155

      if (is_binary_type(first_type) && (typeid(*second_type) == typeid(constant_int_type_name_c))) {return first_type;}

   156

      if ((typeid(*first_type) == typeid(constant_int_type_name_c) && is_binary_type(second_type))) {return second_type;}

   157

      if (is_real_type(first_type) && (typeid(*second_type) == typeid(constant_real_type_name_c))) {return first_type;}

   158

      if ((typeid(*first_type) == typeid(constant_real_type_name_c) && is_real_type(second_type))) {return second_type;}

   159

      return NULL;

   160

    }

   165

  void *compute_standard_function_st(function_invocation_c *symbol) {

   166

    symbol_c *current_type = NULL;

   167

    symbol_c *return_type = NULL;

   168

   169

    function_type_t current_function_type = get_function_type((identifier_c *)symbol->function_name);

   170

    function_call_param_iterator_c function_call_param_iterator(symbol);

   171

    search_expression_type_c* search_expression_type = this;

   173

    for(int current_param = 0; current_param < ((list_c *)symbol->parameter_assignment_list)->n; current_param++) {

   174

      symbol_c *param_name = NULL;

   175

      switch (current_function_type) {

   176

        case function_add:

   177

        case function_and:

   178

        case function_or:

   179

          param_name = generate_param_name("IN%d", current_param + 1);

   180

          break;

   181

        case function_sub:

   182

          if (current_param < 2)

   183

            param_name = generate_param_name("IN%d", current_param + 1);

   184

          else ERROR;

   185

          break;

   186

        default: ERROR;

   187

      }

   188

   189

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

   190

      symbol_c *param_value = function_call_param_iterator.search(param_name);

   191

      delete param_name;

   192

   193

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

   194

      if (param_value == NULL)

   195

        param_value = function_call_param_iterator.next();

   196

   197

      if (param_value == NULL) ERROR;

   198

   199

      symbol_c *param_type = (symbol_c *)param_value->accept(*this);

   200

   201

      switch (current_function_type) {

   202

        case function_add:

   203

          if (current_param == 0)

   204

            current_type = param_type;

   205

          else if (current_param == 1) {

   206

            if ((is_integer_type(current_type) && is_same_type(current_type, param_type)) ||

   207

                (is_real_type(current_type) && is_same_type(current_type, param_type))) {

   208

              current_type = common_type(current_type, param_type);

   209

              return_type = current_type;

   210

            }

   211

            else if (is_time_type(current_type)) {

   212

              if ((typeid(*current_type) == typeid(time_type_name_c)) && (typeid(*param_type) == typeid(time_type_name_c))) {return_type = (symbol_c *)&time_type_name;}

   213

              else if (typeid(*current_type) == typeid(tod_type_name_c) && typeid(*param_type) == typeid(time_type_name_c)) {return_type = (symbol_c *)&tod_type_name;}

   214

              else if (typeid(*current_type) == typeid(dt_type_name_c) && typeid(*param_type) == typeid(time_type_name_c)) {return_type = (symbol_c *)&dt_type_name;}

   215

              else ERROR;

   216

            }

   217

            else ERROR;

   218

          }

   219

          else if (!is_time_type(current_type) && is_same_type(current_type, param_type)) {

   220

            current_type = common_type(current_type, param_type);

   221

            return_type = current_type;

   222

          }

   223

          else ERROR;

   224

          break;

   225

        case function_sub:

   226

          if (current_param == 0)

   227

            current_type = param_type;

   228

          else if (current_param == 1) {

   229

            if ((is_integer_type(current_type) && is_same_type(current_type, param_type)) ||

   230

                (is_real_type(current_type) && is_same_type(current_type, param_type)))

   231

              return_type = common_type(current_type, param_type);

   232

            else if (is_time_type(current_type)) {

   233

              if (typeid(*current_type) == typeid(time_type_name_c) && typeid(*param_type) == typeid(time_type_name_c)) {return_type = (symbol_c *)&time_type_name;}

   234

              else if (typeid(*current_type) == typeid(date_type_name_c) && typeid(*param_type) == typeid(date_type_name_c)) {return_type = (symbol_c *)&time_type_name;}

   235

              else if (typeid(*current_type) == typeid(tod_type_name_c) && typeid(*param_type) == typeid(time_type_name_c)) {return_type = (symbol_c *)&tod_type_name;}

   236

              else if (typeid(*current_type) == typeid(tod_type_name_c) && typeid(*param_type) == typeid(tod_type_name_c)) {return_type = (symbol_c *)&time_type_name;}

   237

              else if (typeid(*current_type) == typeid(dt_type_name_c) && typeid(*param_type) == typeid(time_type_name_c)) {return_type = (symbol_c *)&dt_type_name;}

   238

              else if (typeid(*current_type) == typeid(dt_type_name_c) && typeid(*param_type) == typeid(dt_type_name_c)) {return_type = (symbol_c *)&time_type_name;}

   239

              else ERROR;

   240

            }

   241

            else ERROR;

   242

          }

   243

          else ERROR;

   244

          break;

   245

        case function_and:

   246

        case function_or:

   247

          if (current_param == 0)

   248

            if (is_binary_type(param_type))

   249

              current_type = param_type;

   250

            else ERROR;

   251

          else if (is_same_type(current_type, param_type))

   252

            return_type = common_type(current_type, param_type);

   253

          else ERROR;

   254

          break;

   255

        default: ERROR;

   256

      }

   257

    }

   258

    return (void *)return_type;

   260

   261

  void *compute_standard_function_il(il_function_call_c *symbol, symbol_c *param_type) {

   262

    /*symbol_c *current_type = NULL;*/

   263

    symbol_c *return_type = NULL;

   264

    function_type_t current_function_type = get_function_type((identifier_c *)symbol->function_name);

   265

    if (current_function_type == function_none) ERROR;

   266

   267

    function_call_param_iterator_c function_call_param_iterator(symbol);

   268

   269

    int nb_param = 1;

   270

    if (symbol->il_operand_list != NULL)

   271

      nb_param += ((list_c *)symbol->il_operand_list)->n;

   272

   273

    for(int current_param = 0; current_param < nb_param; current_param++) {

   274

   275

      if (current_param != 0) {

   276

        symbol_c *param_name = NULL;

   277

        switch (current_function_type) {

   278

          default: ERROR;

   279

        }

   280

   281

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

   282

        symbol_c *param_value = function_call_param_iterator.search(param_name);

   283

        delete param_name;

   284

   285

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

   286

        if (param_value == NULL)

   287

          param_value = function_call_param_iterator.next();

   288

   289

        if (param_value == NULL) ERROR;

   290

   291

        param_type = (symbol_c *)param_value->accept(*this);

   292

      }

   293

   294

      switch (current_function_type) {

   295

        case function_sqrt:

   296

          if (current_param == 0 && is_real_type(param_type))

   297

            return_type = param_type;

   298

          else ERROR;

   299

          break;

   300

        default: ERROR;

   301

      }

   302

    }

   303

   304

    return (void *)return_type;

   305

  }

   307

   308

  /*static bool_type_name_c bool_type_name;*/

   309

   310

  /* A helper function... */

   311

  void *compute_boolean_expression(symbol_c *left_type, symbol_c *right_type) {

   312

    if (!is_same_type(left_type, right_type))

   313

      ERROR;

   314

    if (!is_bool_type(left_type) && !is_binary_type(left_type))

   315

      ERROR;

   316

    if (typeid(*left_type) == typeid(constant_int_type_name_c)) {return (void *)right_type;}

   317

    else {return (void *)left_type;}

   318

  }

   319

   320

  /* A helper function... */

   321

  void *compute_numeric_expression(symbol_c *left_type, symbol_c *right_type) {

   322

    if (!is_same_type(left_type, right_type))

   323

      ERROR;

   324

    if (!is_integer_type(left_type) && !is_real_type(left_type))

   325

      ERROR;

   326

    if ((typeid(*left_type) == typeid(constant_int_type_name_c)) || (typeid(*left_type) == typeid(constant_real_type_name_c))) {return (void *)right_type;}

   327

    else {return (void *)left_type;}

   328

    return NULL;

   329

  }

   330

   331

  /* a helper function... */

   332

  symbol_c *base_type(symbol_c *symbol) {

   333

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

   334

  }

   335

   336

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

   337

/* B 1.4 - Variables */

   338

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

   339

   340

  void *visit(symbolic_variable_c *symbol) {

   341

    symbol_c *res;

   342

   343

    /* Nope, now we assume it is a variable, and determine its type... */

   344

    res = search_varfb_instance_type->get_type(symbol);

   345

    if (NULL != res) return res;

   346

   347

    return NULL;

   348

  }

   349

   350

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

   351

/* B 1.4.2 - Multi-element variables */

   352

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

   353

   354

  void *visit(array_variable_c *symbol) {

   355

    symbol_c *res;

   356

   357

    /* Nope, now we assume it is a variable, and determine its type... */

   358

    res = search_varfb_instance_type->get_type(symbol);

   359

    if (NULL != res) return res;

   360

   361

    return NULL;

   362

  }

   363

   364

  void *visit(structured_variable_c *symbol) {

   365

    symbol_c *res;

   366

   367

    /* Nope, now we assume it is a variable, and determine its type... */

   368

    res = search_varfb_instance_type->get_type(symbol);

   369

    if (NULL != res) return res;

   370

   371

    return NULL;

   372

  }

   373

   374

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

   375

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

   376

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

   377

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

   378

/* B 3.1 - Expressions */

   379

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

   380

  void *visit(or_expression_c *symbol) {

   381

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   382

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   383

    return compute_boolean_expression(left_type, right_type);

   384

  }

   385

   386

  void *visit(xor_expression_c *symbol) {

   387

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   388

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   389

    return compute_boolean_expression(left_type, right_type);

   390

  }

   391

   392

  void *visit(and_expression_c *symbol) {

   393

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   394

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   395

    return compute_boolean_expression(left_type, right_type); 

   396

  }

   397

   398

  void *visit(equ_expression_c *symbol) {return (void *)&bool_type_name;}

   399

  void *visit(notequ_expression_c *symbol) {return (void *)&bool_type_name;}

   400

  void *visit(lt_expression_c *symbol) {return (void *)&bool_type_name;}

   401

  void *visit(gt_expression_c *symbol) {return (void *)&bool_type_name;}

   402

  void *visit(le_expression_c *symbol) {return (void *)&bool_type_name;}

   403

  void *visit(ge_expression_c *symbol) {return (void *)&bool_type_name;}

   404

   405

  void *visit(add_expression_c *symbol) {

   406

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   407

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   408

    if (typeid(*left_type) == typeid(time_type_name_c) && typeid(*right_type) == typeid(time_type_name_c)) {return (void *)&time_type_name;}

   409

    if (typeid(*left_type) == typeid(tod_type_name_c) && typeid(*right_type) == typeid(time_type_name_c)) {return (void *)&tod_type_name;}

   410

    if (typeid(*left_type) == typeid(dt_type_name_c) && typeid(*right_type) == typeid(time_type_name_c)) {return (void *)&dt_type_name;}

   411

    return compute_numeric_expression(left_type, right_type);

   412

  }

   413

   414

  void *visit(sub_expression_c *symbol) {

   415

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   416

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   417

    if (typeid(*left_type) == typeid(time_type_name_c) && typeid(*right_type) == typeid(time_type_name_c)) {return (void *)&time_type_name;}

   418

    if (typeid(*left_type) == typeid(date_type_name_c) && typeid(*right_type) == typeid(date_type_name_c)) {return (void *)&time_type_name;}

   419

    if (typeid(*left_type) == typeid(tod_type_name_c) && typeid(*right_type) == typeid(time_type_name_c)) {return (void *)&tod_type_name;}

   420

    if (typeid(*left_type) == typeid(tod_type_name_c) && typeid(*right_type) == typeid(tod_type_name_c)) {return (void *)&time_type_name;}

   421

    if (typeid(*left_type) == typeid(dt_type_name_c) && typeid(*right_type) == typeid(time_type_name_c)) {return (void *)&dt_type_name;}

   422

    if (typeid(*left_type) == typeid(dt_type_name_c) && typeid(*right_type) == typeid(dt_type_name_c)) {return (void *)&time_type_name;}

   423

    return compute_numeric_expression(left_type, right_type);

   424

  }

   425

   426

  void *visit(mul_expression_c *symbol) {

   427

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   428

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   429

    if (typeid(*left_type) == typeid(time_type_name_c) && is_integer_type(right_type)) {return (void *)&time_type_name;}

   430

    if (typeid(*left_type) == typeid(time_type_name_c) && is_real_type(right_type)) {return (void *)&time_type_name;}

   431

    return compute_numeric_expression(left_type, right_type);

   432

  }

   433

   434

  void *visit(div_expression_c *symbol) {

   435

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   436

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   437

    if (typeid(*left_type) == typeid(time_type_name_c) && is_integer_type(right_type)) {return (void *)&time_type_name;}

   438

    if (typeid(*left_type) == typeid(time_type_name_c) && is_real_type(right_type)) {return (void *)&time_type_name;}

   439

    return compute_numeric_expression(left_type, right_type);

   440

  }

   441

   442

  void *visit(mod_expression_c *symbol) {

   443

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   444

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   445

    return compute_numeric_expression(left_type, right_type);

   446

  }

   447

   448

  void *visit(power_expression_c *symbol) {

   449

    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

   450

    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

   451

    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(sint_type_name_c)) {return (void *)left_type;}

   452

    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(int_type_name_c)) {return (void *)left_type;}

   453

    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(dint_type_name_c)) {return (void *)left_type;}

   454

    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(lint_type_name_c)) {return (void *)left_type;}

   455

    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(usint_type_name_c)) {return (void *)left_type;}

   456

    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(uint_type_name_c)) {return (void *)left_type;}

   457

    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(udint_type_name_c)) {return (void *)left_type;}

   458

    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(ulint_type_name_c)) {return (void *)left_type;}

   459

    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(sint_type_name_c)) {return (void *)left_type;}

   460

    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(int_type_name_c)) {return (void *)left_type;}

   461

    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(dint_type_name_c)) {return (void *)left_type;}

   462

    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(lint_type_name_c)) {return (void *)left_type;}

   463

    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(usint_type_name_c)) {return (void *)left_type;}

   464

    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(uint_type_name_c)) {return (void *)left_type;}

   465

    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(udint_type_name_c)) {return (void *)left_type;}

   466

    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(ulint_type_name_c)) {return (void *)left_type;}

   467

    ERROR;

   468

    return NULL;

   469

  }

   470

   471

  void *visit(neg_expression_c *symbol) {

   472

    symbol_c *exp_type = base_type((symbol_c *)symbol->exp->accept(*this));

   473

    if (typeid(*exp_type) == typeid(sint_type_name_c)) {return (void *)exp_type;}

   474

    if (typeid(*exp_type) == typeid(int_type_name_c)) {return (void *)exp_type;}

   475

    if (typeid(*exp_type) == typeid(dint_type_name_c)) {return (void *)exp_type;}

   476

    if (typeid(*exp_type) == typeid(lint_type_name_c)) {return (void *)exp_type;}

   477

    if (typeid(*exp_type) == typeid(usint_type_name_c)) {return (void *)exp_type;}

   478

    if (typeid(*exp_type) == typeid(uint_type_name_c)) {return (void *)exp_type;}

   479

    if (typeid(*exp_type) == typeid(udint_type_name_c)) {return (void *)exp_type;}

   480

    if (typeid(*exp_type) == typeid(ulint_type_name_c)) {return (void *)exp_type;}

   481

    if (typeid(*exp_type) == typeid(real_type_name_c)) {return (void *)exp_type;}

   482

    if (typeid(*exp_type) == typeid(lreal_type_name_c)) {return (void *)exp_type;}

   483

    if (typeid(*exp_type) == typeid(time_type_name_c)) {return (void *)exp_type;}

   484

    ERROR;

   485

    return NULL;

   486

  }

   487

   488

  void *visit(not_expression_c *symbol) {

   489

    symbol_c *exp_type = base_type((symbol_c *)symbol->exp->accept(*this));

   490

    if (typeid(*exp_type) == typeid(bool_type_name_c)) {return (void *)exp_type;}

   491

    ERROR;

   492

    return NULL;

   493

  }

   494

   495

  void *visit(function_invocation_c *symbol) {

   496

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

   497

   498

	  if (f_decl == function_symtable.end_value()) {

   499

      void *res = compute_standard_function_st(symbol);

   500

	    if (res == NULL)

   501

        ERROR;

   502

      return res;

   503

    }

   504

   505

    return base_type(f_decl->type_name);

   506

  }

   507