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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) 2009-2012  Mario de Sousa (msousa@fe.up.pt)

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 *  Copyright (C) 2012       Manuele Conti (manuele.conti@sirius-es.it)

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 *  Copyright (C) 2012       Matteo Facchinetti (matteo.facchinetti@sirius-es.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.

    17

 *

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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.

    24

 */

    25

    26

/*

    27

 * An IEC 61131-3 compiler.

    28

 *

    29

 * 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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    34

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/* NOTE: The algorithm implemented here assumes that candidate datatype lists have already been filled!

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 *       BEFORE running this visitor, be sure to CALL the fill_candidate_datatype_c visitor!

    37

 */

    38

    39

    40

/*

    41

 *  Choose, from the list of all the possible datatypes each expression may take, the single datatype that it will in fact take.

    42

 *  The resulting (chosen) datatype, will be stored in the symbol_c.datatype variable, leaving the candidate datatype list untouched!

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 * 

    44

 *  For rvalue expressions, this decision will be based on the datatype of the lvalue expression.

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 *  For lvalue expressions, the candidate datatype list should have a single entry.

    46

 * 

    47

 *  For example, the very simple literal '0' in 'foo := 0', may represent a:

    48

 *    BOOL, BYTE, WORD, DWORD, LWORD, USINT, SINT, UINT, INT, UDINT, DINT, ULINT, LINT (as well as the SAFE versions of these data tyes too!)

    49

 * 

    50

 *  In this class, the datatype of '0' will be set to the same datatype as the 'foo' variable.

    51

 *  If the intersection of the candidate datatype lists of the left and right side expressions is empty, 

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 *  then a datatype error has been found, and the datatype is either left at NULL, or set to a pointer of an invalid_type_name_c object!

    53

 */

    54

    55

    56

#include "narrow_candidate_datatypes.hh"

    57

#include "datatype_functions.hh"

    58

#include <typeinfo>

    59

#include <list>

    60

#include <string>

    61

#include <string.h>

    62

#include <strings.h>

    63

    64

    65

/* set to 1 to see debug info during execution */

    66

static int debug = 0;

    67

    68

narrow_candidate_datatypes_c::narrow_candidate_datatypes_c(symbol_c *ignore) {

    69

	search_varfb_instance_type = NULL;

    70

	fake_prev_il_instruction = NULL;

    72

	il_operand = NULL;

    73

}

    74

    75

narrow_candidate_datatypes_c::~narrow_candidate_datatypes_c(void) {

    76

}

    77

    78

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/* Only set the symbol's desired datatype to 'datatype' if that datatype is in the candidate_datatype list */

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static void set_datatype(symbol_c *datatype, symbol_c *symbol) {

    81

    82

	/* If we are trying to set to the undefined type, and the symbol's datatype has already been set to something else, 

    83

	 * we abort the compoiler as I don't think this should ever occur. 

    84

	 * NOTE: In order to handle JMPs to labels that come before the JMP itself, we run the narrow algorithm twice.

    85

	 *       This means that this situation may legally occur, so we cannot abort the compiler here!

    86

	 */

    87

// 	if ((NULL == datatype) && (NULL != symbol->datatype)) ERROR;

    88

 	if ((NULL == datatype) && (NULL != symbol->datatype)) return;

    89

	if ((NULL == datatype) && (NULL == symbol->datatype)) return;

    90

    91

	if (search_in_candidate_datatype_list(datatype, symbol->candidate_datatypes) < 0)

    92

		symbol->datatype = &(search_constant_type_c::invalid_type_name);   

    93

	else {

    94

		if (NULL == symbol->datatype)   

    95

			/* not yet set to anything, so we set it to the requested data type */

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			symbol->datatype = datatype; 

    97

		else {

    98

			/* had already been set previously to some data type. Let's check if they are the same! */

    99

			if (!is_type_equal(symbol->datatype, datatype))

   100

				symbol->datatype = &(search_constant_type_c::invalid_type_name);

   101

// 			else 

   102

				/* we leave it unchanged, as it is the same as the requested data type! */

   103

		}

   104

	}

   105

}

   106

   107

   108

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/* Only set the symbol's desired datatype to 'datatype' if that datatype is in the candidate_datatype list */

   110

// static void set_datatype_in_prev_il_instructions(symbol_c *datatype, std::vector <symbol_c *> prev_il_instructions) {

   111

static void set_datatype_in_prev_il_instructions(symbol_c *datatype, il_instruction_c *symbol) {

   112

	if (NULL == symbol) ERROR;

   113

	for (unsigned int i = 0; i < symbol->prev_il_instruction.size(); i++)

   114

		set_datatype(datatype, symbol->prev_il_instruction[i]);

   115

}

   116

   117

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   119

bool narrow_candidate_datatypes_c::is_widening_compatible(const struct widen_entry widen_table[], symbol_c *left_type, symbol_c *right_type, symbol_c *result_type, bool *deprecated_status) {

   120

	/* NOTE: According to our algorithm, left_type and right_type should never by NULL (if they are, we have an internal compiler error!

   121

	 *       However, result_type may be NULL if the code has a data type semantic error!

   122

	 */

   123

	if ((NULL == left_type) || (NULL == right_type) || (NULL == result_type))

   124

		return false;

   125

   126

	for (int k = 0; NULL != widen_table[k].left;  k++) {

   127

		if        ((typeid(*left_type)   == typeid(*widen_table[k].left))

   128

		        && (typeid(*right_type)  == typeid(*widen_table[k].right))

   129

			&& (typeid(*result_type) == typeid(*widen_table[k].result))) {

   130

			if (NULL != deprecated_status)

   131

				*deprecated_status = (widen_table[k].status == widen_entry::deprecated);

   132

			return true;

   133

		}

   134

	}

   135

	return false;

   136

}

   137

   138

/*

   139

 * All parameters being passed to the called function MUST be in the parameter list to which f_call points to!

   140

 * This means that, for non formal function calls in IL, de current (default value) must be artificially added to the

   141

 * beginning of the parameter list BEFORE calling handle_function_call().

   142

 */

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void narrow_candidate_datatypes_c::narrow_nonformal_call(symbol_c *f_call, symbol_c *f_decl, int *ext_parm_count) {

   144

	symbol_c *call_param_value,  *param_type;

   145

	identifier_c *param_name;

   146

	function_param_iterator_c       fp_iterator(f_decl);

   147

	function_call_param_iterator_c fcp_iterator(f_call);

   148

	int extensible_parameter_highest_index = -1;

   149

	unsigned int i;

   150

   151

	if (NULL != ext_parm_count) *ext_parm_count = -1;

   152

   153

	/* Iterating through the non-formal parameters of the function call */

   154

	while((call_param_value = fcp_iterator.next_nf()) != NULL) {

   155

		/* Obtaining the type of the value being passed in the function call */

   156

		/* Iterate to the next parameter of the function being called.

   157

		 * Get the name of that parameter, and ignore if EN or ENO.

   158

		 */

   159

		do {

   160

			param_name = fp_iterator.next();

   161

			/* If there is no other parameter declared, then we are passing too many parameters... */

   162

			/* This error should have been caught in fill_candidate_datatypes_c, but may occur here again when we handle FB invocations! 

   163

			 * In this case, we carry on analysing the code in order to be able to provide relevant error messages

   164

			 * for that code too!

   165

			 */

   166

			if(param_name == NULL) break;

   167

		} while ((strcmp(param_name->value, "EN") == 0) || (strcmp(param_name->value, "ENO") == 0));

   168

   169

		/* Set the desired datatype for this parameter, and call it recursively. */

   170

		/* Note that if the call has more parameters than those declared in the function/FB declaration,

   171

		 * we may be setting this to NULL!

   172

		 */

   173

		symbol_c *desired_datatype = base_type(fp_iterator.param_type());

   174

		if ((NULL != param_name) && (NULL == desired_datatype)) ERROR;

   175

		if ((NULL == param_name) && (NULL != desired_datatype)) ERROR;

   176

   177

		/* NOTE: When we are handling a nonformal function call made from IL, the first parameter is the 'default' or 'current'

   178

		 *       il value. However, a pointer to a copy of the prev_il_instruction is pre-pended into the operand list, so 

   179

		 *       the call 

   180

		 *       call_param_value->accept(*this);

   181

		 *       may actually be calling an object of the base symbol_c .

   182

		 */

   183

		set_datatype(desired_datatype, call_param_value);

   184

		call_param_value->accept(*this);

   185

   186

		if (NULL != param_name) 

   187

			if (extensible_parameter_highest_index < fp_iterator.extensible_param_index())

   188

				extensible_parameter_highest_index = fp_iterator.extensible_param_index();

   189

	}

   190

	/* In the case of a call to an extensible function, we store the highest index 

   191

	 * of the extensible parameters this particular call uses, in the symbol_c object

   192

	 * of the function call itself!

   193

	 * In calls to non-extensible functions, this value will be set to -1.

   194

	 * This information is later used in stage4 to correctly generate the

   195

	 * output code.

   196

	 */

   197

	if ((NULL != ext_parm_count) && (extensible_parameter_highest_index >=0) /* if call to extensible function */)

   198

		*ext_parm_count = 1 + extensible_parameter_highest_index - fp_iterator.first_extensible_param_index();

   199

}

   200

   201

   202

   203

void narrow_candidate_datatypes_c::narrow_formal_call(symbol_c *f_call, symbol_c *f_decl, int *ext_parm_count) {

   204

	symbol_c *call_param_value, *call_param_name, *param_type;

   205

	symbol_c *verify_duplicate_param;

   206

	identifier_c *param_name;

   207

	function_param_iterator_c       fp_iterator(f_decl);

   208

	function_call_param_iterator_c fcp_iterator(f_call);

   209

	int extensible_parameter_highest_index = -1;

   210

	identifier_c *extensible_parameter_name;

   211

	unsigned int i;

   212

   213

	if (NULL != ext_parm_count) *ext_parm_count = -1;

   214

	/* Iterating through the formal parameters of the function call */

   215

	while((call_param_name = fcp_iterator.next_f()) != NULL) {

   216

   217

		/* Obtaining the value being passed in the function call */

   218

		call_param_value = fcp_iterator.get_current_value();

   219

		/* the following should never occur. If it does, then we have a bug in our code... */

   220

		if (NULL == call_param_value) ERROR;

   221

   222

		/* Find the corresponding parameter in function declaration */

   223

		param_name = fp_iterator.search(call_param_name);

   224

   225

		/* Set the desired datatype for this parameter, and call it recursively. */

   226

		/* NOTE: When handling a FB call, this narrow_formal_call() may be called to analyse

   227

		 *       an invalid FB call (call with parameters that do not exist on the FB declaration).

   228

		 *       For this reason, the param_name may come out as NULL!

   229

		 */

   230

		symbol_c *desired_datatype = base_type(fp_iterator.param_type());

   231

		if ((NULL != param_name) && (NULL == desired_datatype)) ERROR;

   232

		if ((NULL == param_name) && (NULL != desired_datatype)) ERROR;

   233

   234

		/* set the desired data type for this parameter */

   235

		set_datatype(desired_datatype, call_param_value);

   236

		/* And recursively call that parameter/expression, so it can propagate that info */

   237

		call_param_value->accept(*this);

   238

   239

		/* set the extensible_parameter_highest_index, which will be needed in stage 4 */

   240

		/* This value says how many extensible parameters are being passed to the standard function */

   241

		if (NULL != param_name) 

   242

			if (extensible_parameter_highest_index < fp_iterator.extensible_param_index())

   243

				extensible_parameter_highest_index = fp_iterator.extensible_param_index();

   244

	}

   245

	/* call is compatible! */

   246

   247

	/* In the case of a call to an extensible function, we store the highest index 

   248

	 * of the extensible parameters this particular call uses, in the symbol_c object

   249

	 * of the function call itself!

   250

	 * In calls to non-extensible functions, this value will be set to -1.

   251

	 * This information is later used in stage4 to correctly generate the

   252

	 * output code.

   253

	 */

   254

	if ((NULL != ext_parm_count) && (extensible_parameter_highest_index >=0) /* if call to extensible function */)

   255

		*ext_parm_count = 1 + extensible_parameter_highest_index - fp_iterator.first_extensible_param_index();

   256

}

   257

   258

   259

/*

   260

typedef struct {

   261

  symbol_c *function_name,

   262

  symbol_c *nonformal_operand_list,

   263

  symbol_c *   formal_operand_list,

   264

   265

  std::vector <symbol_c *> &candidate_functions,  

   266

  symbol_c &*called_function_declaration,

   267

  int      &extensible_param_count

   268

} generic_function_call_t;

   269

*/

   270

void narrow_candidate_datatypes_c::narrow_function_invocation(symbol_c *fcall, generic_function_call_t fcall_data) {

   271

	/* set the called_function_declaration. */

   272

	fcall_data.called_function_declaration = NULL;

   273

   274

	/* set the called_function_declaration taking into account the datatype that we need to return */

   275

	for(unsigned int i = 0; i < fcall->candidate_datatypes.size(); i++) {

   276

		if (is_type_equal(fcall->candidate_datatypes[i], fcall->datatype)) {

   277

			fcall_data.called_function_declaration = fcall_data.candidate_functions[i];

   278

			break;

   279

		}

   280

	}

   281

   282

	/* NOTE: If we can't figure out the declaration of the function being called, this is not 

   283

	 *       necessarily an internal compiler error. It could be because the symbol->datatype is NULL

   284

	 *       (because the ST code being analysed has an error _before_ this function invocation).

   285

	 *       However, we don't just give, up, we carry on recursivly analysing the code, so as to be

   286

	 *       able to print out any error messages related to the parameters being passed in this function 

   287

	 *       invocation.

   288

	 */

   289

	/* if (NULL == symbol->called_function_declaration) ERROR; */

   290

	if (fcall->candidate_datatypes.size() == 1) {

   291

		/* If only one function declaration, then we use that (even if symbol->datatypes == NULL)

   292

		 * so we can check for errors in the expressions used to pass parameters in this

   293

		 * function invocation.

   294

		 */

   295

		fcall_data.called_function_declaration = fcall_data.candidate_functions[0];

   296

	}

   297

   298

	/* If an overloaded function is being invoked, and we cannot determine which version to use,

   299

	 * then we can not meaningfully verify the expressions used inside that function invocation.

   300

	 * We simply give up!

   301

	 */

   302

	if (NULL == fcall_data.called_function_declaration)

   303

		return;

   304

   305

	if (NULL != fcall_data.nonformal_operand_list)  narrow_nonformal_call(fcall, fcall_data.called_function_declaration, &(fcall_data.extensible_param_count));

   306

	if (NULL != fcall_data.   formal_operand_list)     narrow_formal_call(fcall, fcall_data.called_function_declaration, &(fcall_data.extensible_param_count));

   307

   308

	return;

   309

}

   310

   311

   312

   313

   314

/* narrow implicit FB call in IL.

   315

 * e.g.  CLK ton_var

   316

 *        CU counter_var

   317

 *

   318

 * The algorithm will be to build a fake il_fb_call_c equivalent to the implicit IL FB call, and let 

   319

 * the visit(il_fb_call_c *) method handle it!

   320

 */

   321

void *narrow_candidate_datatypes_c::narrow_implicit_il_fb_call(symbol_c *il_instruction, const char *param_name, symbol_c *&called_fb_declaration) {

   322

   323

	/* set the datatype of the il_operand, this is, the FB being called! */

   324

	if (NULL != il_operand) {

   325

		/* only set it if it is in the candidate datatypes list! */  

   326

		set_datatype(called_fb_declaration, il_operand);

   327

		il_operand->accept(*this);

   328

	}

   329

	symbol_c *fb_decl = il_operand->datatype;

   330

   331

	if (0 == fake_prev_il_instruction->prev_il_instruction.size()) {

   332

		/* This IL implicit FB call (e.g. CLK ton_var) is not preceded by another IL instruction

   333

		 * (or list of instructions) that will set the IL current/default value.

   334

		 * We cannot proceed verifying type compatibility of something that does not exist.

   335

		 */

   336

		return NULL;

   337

	}

   338

   339

	if (NULL == fb_decl) {

   340

		/* the il_operand is a not FB instance */

   341

		/* so we simply pass on the required datatype to the prev_il_instructions */

   342

		/* The invalid FB invocation will be caught in the print_datatypes_error_c by analysing NULL value in il_operand->datatype! */

   343

		set_datatype_in_prev_il_instructions(il_instruction->datatype, fake_prev_il_instruction);

   344

		return NULL;

   345

	}

   346

   347

   348

	/* The value being passed to the 'param_name' parameter is actually the prev_il_instruction.

   349

	 * However, we do not place that object directly in the fake il_param_list_c that we will be

   350

	 * creating, since the visit(il_fb_call_c *) method will recursively call every object in that list.

   351

	 * The il_prev_intruction object will be visited once we have handled this implici IL FB call

   352

	 * (called from the instruction_list_c for() loop that works backwards). We DO NOT want to visit it twice.

   353

	 * (Anyway, if we let the visit(il_fb_call_c *) recursively visit the current prev_il_instruction, this pointer

   354

	 * would be changed to the IL instruction coming before the current prev_il_instruction! => things would get all messed up!)

   355

	 * The easiest way to work around this is to simply use a new object, and copy the relevant details to that object!

   356

	 */

   357

	symbol_c param_value = *fake_prev_il_instruction; /* copy the candidate_datatypes list ! */

   358

   359

	identifier_c variable_name(param_name);

   360

	// SYM_REF1(il_assign_operator_c, variable_name)

   361

	il_assign_operator_c il_assign_operator(&variable_name);  

   362

	// SYM_REF3(il_param_assignment_c, il_assign_operator, il_operand, simple_instr_list)

   363

	il_param_assignment_c il_param_assignment(&il_assign_operator, &param_value/*il_operand*/, NULL);

   364

	il_param_list_c il_param_list;

   365

	il_param_list.add_element(&il_param_assignment);

   366

	// SYM_REF4(il_fb_call_c, il_call_operator, fb_name, il_operand_list, il_param_list, symbol_c *called_fb_declaration)

   367

	CAL_operator_c CAL_operator;

   368

	il_fb_call_c il_fb_call(&CAL_operator, il_operand, NULL, &il_param_list);

   369

   370

	/* A FB call does not return any datatype, but the IL instructions that come after this

   371

	 * FB call may require a specific datatype in the il current/default variable, 

   372

	 * so we must pass this information up to the IL instruction before the FB call, since it will

   373

	 * be that IL instruction that will be required to produce the desired dtataype.

   374

	 *

   375

	 * The above will be done by the visit(il_fb_call_c *) method, so we must make sure to

   376

	 * correctly set up the il_fb_call.datatype variable!

   377

	 */

   378

	il_fb_call.called_fb_declaration = called_fb_declaration;

   379

	il_fb_call.accept(*this);

   380

   381

	/* set the required datatype of the previous IL instruction! */

   382

	/* NOTE:

   383

	 * When handling these implicit IL calls, the parameter_value being passed to the FB parameter

   384

	 * is actually the prev_il_instruction.

   385

	 * 

   386

	 * However, since the FB call does not change the value in the current/default IL variable, this value

   387

	 * must also be used ny the IL instruction coming after this FB call.

   388

	 *

   389

	 * This means that we have two consumers/users for the same value. 

   390

	 * We must therefore check whether the datatype required by the IL instructions following this FB call 

   391

	 * is the same as that required for the first parameter. If not, then we have a semantic error,

   392

	 * and we set it to invalid_type_name.

   393

	 *

   394

	 * However, we only do that if:

   395

	 *  - The IL instruction that comes after this IL FB call actually asked this FB call for a specific 

   396

	 *     datatype in the current/default vairable, once this IL FB call returns.

   397

	 *     However, sometimes, (for e.g., this FB call is the last in the IL list) the subsequent FB to not aks this

   398

	 *     FB call for any datatype. In that case, then the datatype required to pass to the first parameter of the

   399

	 *     FB call must be left unchanged!

   400

	 */

   401

	if ((NULL == il_instruction->datatype) || (is_type_equal(param_value.datatype, il_instruction->datatype))) {

   402

		set_datatype_in_prev_il_instructions(param_value.datatype, fake_prev_il_instruction);

   403

	} else {

   404

		set_datatype_in_prev_il_instructions(&search_constant_type_c::invalid_type_name, fake_prev_il_instruction);

   405

	}

   406

	return NULL;

   407

}

   408

   409

   410

/* a helper function... */

   411

symbol_c *narrow_candidate_datatypes_c::base_type(symbol_c *symbol) {

   412

	/* NOTE: symbol == NULL is valid. It will occur when, for e.g., an undefined/undeclared symbolic_variable is used

   413

	 *       in the code.

   414

	 */

   415

	if (symbol == NULL) return NULL;

   416

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

   417

}

   418

   419

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

   420

/* B 1.2 - Constants */

   421

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

   422

   423

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

   424

/* B 1.3 - Data types */

   425

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

   426

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

   427

/* B 1.3.3 - Derived data types */

   428

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

   429

/* simple_specification ASSIGN constant */

   430

// SYM_REF2(simple_spec_init_c, simple_specification, constant)

   431

void *narrow_candidate_datatypes_c::visit(simple_spec_init_c *symbol) {

   432

	if (symbol->candidate_datatypes.size() == 1)

   433

	  symbol->datatype = symbol->candidate_datatypes[0];

   434

   435

	if (symbol->simple_specification->candidate_datatypes.size() == 1)

   436

	  symbol->simple_specification->datatype = symbol->simple_specification->candidate_datatypes[0];

   437

   438

	if (NULL != symbol->constant) {

   439

		set_datatype(symbol->datatype, symbol->constant);

   440

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

   441

	}

   442

	return NULL;

   443

}

   444

   445

   446

   447

/*  signed_integer DOTDOT signed_integer */

   448

// SYM_REF2(subrange_c, lower_limit, upper_limit)

   449

void *narrow_candidate_datatypes_c::visit(subrange_c *symbol) {

   450

	symbol->lower_limit->datatype = symbol->datatype;

   451

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

   452

	symbol->upper_limit->datatype = symbol->datatype;

   453

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

   454

	return NULL;

   455

}

   456

   457

   458

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

   459

/* B 1.4 - Variables */

   460

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

   461

   462

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

   463

/* B 1.4.1 - Directly Represented Variables */

   464

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

   465

   466

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

   467

/* B 1.4.2 - Multi-element variables */

   468

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

   469

/*  subscripted_variable '[' subscript_list ']' */

   470

// SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

   471

void *narrow_candidate_datatypes_c::visit(array_variable_c *symbol) {

   472

	/* we need to check the data types of the expressions used for the subscripts... */

   473

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

   474

	return NULL;

   475

}

   476

   477

   478

/* subscript_list ',' subscript */

   479

// SYM_LIST(subscript_list_c)

   480

void *narrow_candidate_datatypes_c::visit(subscript_list_c *symbol) {

   481

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

   482

		for (unsigned int k = 0; k < symbol->elements[i]->candidate_datatypes.size(); k++) {

   483

			if (get_datatype_info_c::is_ANY_INT(symbol->elements[i]->candidate_datatypes[k]))

   484

				symbol->elements[i]->datatype = symbol->elements[i]->candidate_datatypes[k];

   485

		}

   486

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

   487

	}

   488

	return NULL;  

   489

}

   490

   491

   492

   493

   494

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

   495

/* B 1.4.3 - Declaration & Initialisation */

   496

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

   497

   498

void *narrow_candidate_datatypes_c::visit(var1_list_c *symbol) {

   499

#if 0   /* We don't really need to set the datatype of each variable. We just check the declaration itself! */

   500

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

   501