_Student

Hierarchy

Expanded class hierarchy of _Student

Properties

NameDescription
_Student::$array_settings
_Student::$list_courses_taken
_Student::$list_standardized_tests
_Student::$list_transfer_eqvs_unassigned
_Student::$student_id

Functions & methods

NameDescription
_Student::calculate_cumulative_hours_and_gpaThis function will look at the courses which the student has taken, to calculate the cumulative hours and gpa, rather than just load them from the db table.
_Student::determine_terms_to_hide_gradesThis is a stub function. If you are planning on hiding course grades for a term at a time, you should override this method in /custom/classes and place that logic here.
_Student::get_degree_planReturns a student's degree plan object.
_Student::get_major_and_track_codeEnter description here... Returns the major code and trackCode, if it exists in this form: MAJOR|CONC_TRACK Though usually it will be: MAJR|_TRCK Asumes you have already called "load_settings()";
_Student::get_rank_descriptionGiven a rank_code like FR, SO, etc., get the english description. For example: Freshman, Sophomore, etc.
_Student::get_transfer_course_eqvFind a transfer eqv for this student, for this course in question.
_Student::init_semester_courses_added
_Student::load_courses_taken
_Student::load_settings
_Student::load_significant_courses
_Student::load_significant_courses_from_list_courses_taken
_Student::load_student
_Student::load_student_dataThis loads a student's personal data, like name and so forth.
_Student::load_student_substitutions
_Student::load_test_scores
_Student::load_transfer_eqvs_unassigned
_Student::load_unassignments
_Student::to_string
_Student::__construct

File

classes/_Student.php, line 4

View source
class _Student {
  public $student_id, $name, $major_code, $gpa, $cumulative_hours, $catalog_year;
  public $list_courses_taken, $list_courses_advised, $list_courses_added, $db, $rank;
  public $list_standardized_tests, $list_substitutions;
  public $list_transfer_eqvs_unassigned;
  public $array_settings, $array_significant_courses, $array_hide_grades_terms;

  function __construct($student_id = "", DatabaseHandler $db = NULL) {

    $this->student_id = $student_id;
    $this->array_hide_grades_terms = array();
    $this->array_significant_courses = array(); // array of course_ids
    // the student has taken, or has subs for (or transfer eqv's).
    // used later to help speed up assignCoursesToList in FlightPath.

    $this->db = $db;
    if ($db == NULL) {
      $this->db = get_global_database_handler();
    }

    // Go ahead and load and assemble
    // all information in the database on this student.
    $this->load_student();

  }


  /**
   * This is a stub function.  If you are planning on hiding course grades
   * for a term at a time, you should override this method in /custom/classes
   * and place that logic here.
   *
   * For example,
   * at ULM, students cannot see their final grades for a term until they
   * have completed their course evaluations for every course they took that
   * term, OR, until 2 weeks have passed.
   *
   *
   *
   */
  function determine_terms_to_hide_grades() {
    return;
  }


  function load_student() {

    $this->list_transfer_eqvs_unassigned = new CourseList();
    $this->list_courses_taken = new CourseList();
    $this->list_courses_added = new CourseList();

    $this->list_substitutions = new SubstitutionList();

    $this->list_standardized_tests = new ObjList();
    $this->array_settings = array();

    if ($this->student_id != "") {
      $this->determine_terms_to_hide_grades();
      $this->load_transfer_eqvs_unassigned();
      $this->load_courses_taken();
      $this->load_student_data();
      $this->load_test_scores();
      $this->load_settings();
      $this->load_significant_courses();
      //$this->load_unassignments();
      //$this->load_student_substitutions();

      // If we are supposed to set cumulative hours and gpa, perform that
      // operation now.
      if (variable_get("calculate_cumulative_hours_and_gpa", FALSE)) {
        $arr = $this->calculate_cumulative_hours_and_gpa();
        $this->cumulative_hours = $arr["cumulative_total_hours"];
        $this->gpa = $arr["cumulative_gpa"];
      }


    }


    // When we load this student, let's also check for any hooks relating
    // to loading this student.
    // Since this class might be used outside of FP, only do this if we know
    // that the bootstrap.inc file has been executed.
    if ($GLOBALS["fp_bootstrap_loaded"] == TRUE) {
      invoke_hook("student_load", array(&$this));
    }

  }

  function load_significant_courses() {
    // This will attempt to add as much to the array_significant_courses
    // as we can, which was not previously determined.
    // For example: courses we were advised to take and/or
    // substitutions.

    // Now, when this gets called, it's actually *before* we
    // write any subs or advisings to the database, so what we
    // actually need to do is go through the POST
    // and add any course_id's we find.
    // In the future, perhaps it would be more efficient
    // to have just one POST variable to look at, perhaps
    // comma-seperated.


    // Look in the database of advised courses for ANY course advised in
    // the range of advisingTermIDs.
    $advising_term_ids = variable_get("available_advising_term_ids", "0");

    $temp = explode(",", $advising_term_ids);
    foreach ($temp as $term_id) {
      $term_id = trim($term_id);
      $res = $this->db->db_query("SELECT * FROM advising_sessions a,
							advised_courses b
							WHERE a.student_id='?'
							AND a.advising_session_id = b.advising_session_id
							AND a.term_id = '?' 
							AND a.is_draft = '0' ", $this->student_id, $term_id);
      while ($cur = $this->db->db_fetch_array($res)) {
        $this->array_significant_courses[$cur["course_id"]] = true;
      }
    }


    // Now, look for any course which a substitution might have been
    // performed for...
    $res = $this->db->db_query("SELECT * FROM student_substitutions
										WHERE student_id='?' ", $this->student_id);
    while ($cur = $this->db->db_fetch_array($res)) {
      $this->array_significant_courses[$cur["required_course_id"]] = true;
    }


  }

  function load_significant_courses_from_list_courses_taken() {
    // Build the array_significant_courses
    // entriely from list_courses_taken.
    $this->list_courses_taken->reset_counter();
    while ($this->list_courses_taken->has_more()) {
      $c = $this->list_courses_taken->get_next();
      $this->array_significant_courses[$c->course_id] = true;
    }
  }


  function load_settings() {
    // This will load & set up the array_settings variable for this
    // student.
    $res = $this->db->db_query("SELECT * FROM student_settings
									WHERE 
									student_id='?' ", $this->student_id);
    $cur = $this->db->db_fetch_array($res);

    if ($arr = unserialize($cur["settings"])) {
      $this->array_settings = $arr;
    }

  }

  function load_transfer_eqvs_unassigned() {
    $res = $this->db->db_query("SELECT * FROM student_unassign_transfer_eqv
									WHERE
									student_id='?' 
									AND delete_flag='0'
									ORDER BY id ", $this->student_id);
    while ($cur = $this->db->db_fetch_array($res)) {
      extract($cur, 3, "db");
      $new_course = new Course();
      $new_course->bool_transfer = true;
      $new_course->course_id = $db_transfer_course_id;
      $new_course->db_unassign_transfer_id = $db_id;

      $this->list_transfer_eqvs_unassigned->add($new_course);

    }
  }


  function init_semester_courses_added() {
    // The "Add a Course" box on screen is really just a
    // semester, with the number -88, with a single group,
    // also numbered -88.
    $this->semester_courses_added = new Semester(-88);
    $this->semester_courses_added->title = "Courses Added by Advisor";

    // Now, we want to add the Add a Course group...
    $g = new Group();
    $g->group_id = -88;
    // Since it would take a long time during page load, we will
    // leave this empty of courses for now.  It doesn't matter anyway,
    // as we will not be checking this group for course membership
    // anyway.  We only need to load it in the popup.
    $g->hours_required = 99999; // Nearly infinite selections may be made.
    $g->assigned_to_semester_num = -88;
    $g->title = "Add an Additional Course";

    $this->semester_courses_added->list_groups->add($g);

  }


  function load_unassignments() {
    // Load courses which have been unassigned from groups
    // or the bare degree plan.
    $res = $this->db->db_query("SELECT * FROM student_unassign_group
							WHERE 
								student_id='?' 
								AND delete_flag='0' ", $this->student_id);
    while ($cur = $this->db->db_fetch_array($res)) {
      extract($cur, 3, "db");

      if ($taken_course = $this->list_courses_taken->find_specific_course($db_course_id, $db_term_id, (bool) $db_transfer_flag, true)) {
        // Add the group_id to this courses' list of unassigned groups.
        $new_group = new Group();
        $new_group->group_id = $db_group_id;
        $new_group->db_unassign_group_id = $db_id;


        $taken_course->group_list_unassigned->add($new_group);
      }

    }



  }



  function load_test_scores() {
    // If the student has any scores (from standardized tests)
    // then load them here.

    $st = null;

    $res = db_query("		          
		          SELECT * FROM student_tests
		          WHERE 
								  student_id = '?' 								
							ORDER BY date_taken DESC ", $this->student_id);
    while ($cur = db_fetch_array($res)) {

      $c++;

      extract($cur, 3, "db");


      // Get the test's description, if available.

      $res2 = db_query("SELECT * FROM standardized_tests
                        WHERE test_id = '?'
                        AND category_id = '?'
                        ORDER BY position", $db_test_id, $db_category_id);
      $cur2 = db_fetch_array($res2);
      $db_test_description = trim($cur2["test_description"]);
      $db_category_description = trim($cur2["category_description"]);

      // Did we find anything in the table?  If not, just use the codes themselves
      if ($db_test_description == "") {
        $db_test_description = t("Test code:") . " " . $db_test_id;
      }
      if ($db_category_description == "") {
        $db_category_description = $db_category_id;
      }



      if (!(($db_date_taken . $db_test_id) == $old_row)) {
        // We are at a new test.  Add the old test to our list.
        if ($st != null) {
          $this->list_standardized_tests->add($st);

        }

        $st = new StandardizedTest();
        $st->test_id = $db_test_id;
        $st->date_taken = $db_date_taken;
        $st->description = $db_test_description;
        $old_row = $db_date_taken . $db_test_id;

      }

      $st->categories[$db_position . $c]["description"] = $db_category_description;
      $st->categories[$db_position . $c]["category_id"] = $db_category_id;
      $st->categories[$db_position . $c]["score"] = $db_score;

    }

    // Add the last one created.
    if ($st != null) {
      $this->list_standardized_tests->add($st);
    }


  }


  function load_student_substitutions() {
    // Load the substitutions which have been made for
    // this student.

    // Meant to be called AFTER load_courses_taken.
    $this->list_substitutions = new SubstitutionList();

    $res = $this->db->db_query("SELECT * FROM
						student_substitutions
						WHERE student_id='?'
						AND delete_flag='0' ", $this->student_id);
    while ($cur = $this->db->db_fetch_array($res)) {

      $sub_id = $cur["id"];
      $sub_course_id = $cur["sub_course_id"];
      $sub_term_id = $cur["sub_term_id"];
      $sub_bool_transfer = (bool) $cur["sub_transfer_flag"];
      $sub_hours = $cur["sub_hours"] * 1;
      $sub_remarks = trim($cur["sub_remarks"]);
      $faculty_id = $cur["faculty_id"];

      if (strstr($sub_term_id, "9999")) {
        // was an unknown semester.  Let's set it lower so
        // it doesn't screw up my sorting.
        $sub_term_id = 11111;
      }


      // Okay, look to see if we can find the course specified by this
      // courseSubstitution within the list of courses which the student
      // has taken.  If the subHours is less than the hours_awarded for the
      // particular course, it means the course has been split up!

      if ($taken_course = $this->list_courses_taken->find_specific_course($sub_course_id, $sub_term_id, $sub_bool_transfer, true)) {


        // If this takenCourse is a transfer credit, then we want to remove
        // any automatic eqv it may have set.
        // We can do this easily by setting its course_id to 0.
        if ($sub_bool_transfer == true) {
          $taken_course->temp_old_course_id = $taken_course->course_id;
          $taken_course->course_id = 0;
        }

        if ($sub_hours == 0) { // If none specified, assume its the full amount.				  
          $sub_hours = $taken_course->hours_awarded;
        }


        if (($taken_course->hours_awarded > $sub_hours)) {


          // Okay, now this means that the course which we are
          // using in the substitution-- the course which the student
          // has actually taken-- is being split up in the substitution.
          // We are only using a portion of its hours.
          // We MUST round, because if there is a decimal place, we might run into
          // trouble.  Because, for example, 2.001 - 2 actually gets .00009999999 instead of .001.
          // The most decimals we can have is 4, so let's round to 6 decimal places, just to give
          // us some breathing room.  That should take care of us without losing too much precision.
          $remaining_hours = round(($taken_course->hours_awarded - $sub_hours), 6);

          // Create a clone of the course with the leftover hours, and add
          // it back into the list_courses_taken.
          $new_course_string = $taken_course->to_data_string();
          $new_course = new Course();
          $new_course->load_course_from_data_string($new_course_string);

          $new_course->bool_substitution_split = true;
          $new_course->bool_substitution_new_from_split = true;

          $new_course->subject_id = $taken_course->subject_id;
          $new_course->course_num = $taken_course->course_num;

          $new_course->hours_awarded = $remaining_hours;
          if (is_object($new_course->course_transfer)) {
            $new_course->course_transfer->hours_awarded = $remaining_hours;
          }

          $taken_course->bool_substitution_split = true;
          $taken_course->hours_awarded = $sub_hours;
          if (is_object($taken_course->course_transfer)) {
            $taken_course->course_transfer->hours_awarded = $sub_hours;
          }


          // Add the newCourse back into the student's list_courses_taken.
          $this->list_courses_taken->add($new_course);

        }


        $taken_course->substitution_hours = $sub_hours;
        $taken_course->bool_substitution = true;
        $taken_course->display_status = "completed";
        $taken_course->db_substitution_id = $sub_id;


        $substitution = new Substitution();

        if ($cur["required_course_id"] > 0) {
          $course_requirement = new Course($cur["required_course_id"]);

          $this->array_significant_courses[$course_requirement->course_id] = true;

        }
        else {
          // This is a group addition!
          $course_requirement = new Course($sub_course_id, $sub_bool_transfer);
          $this->array_significant_courses[$sub_course_id] = true;
          $substitution->bool_group_addition = true;
        }

        $course_requirement->assigned_to_group_id = $cur["required_group_id"];
        $course_requirement->assigned_to_semester_num = $cur["required_semester_num"];
        $taken_course->assigned_to_group_id = $cur["required_group_id"];
        $taken_course->assigned_to_semester_num = $cur["required_semester_num"];

        $substitution->course_requirement = $course_requirement;


        $substitution->course_list_substitutions->add($taken_course);


        $substitution->remarks = $sub_remarks;
        $substitution->faculty_id = $faculty_id;
        $this->list_substitutions->add($substitution);



      }

    }

  }


  /**
   * This loads a student's personal data, like name and so forth.
   *
   */
  function load_student_data() {

    $this->cumulative_hours = $this->db->get_student_cumulative_hours($this->student_id);
    $this->gpa = $this->db->get_student_gpa($this->student_id);
    $this->rank = $this->get_rank_description($this->db->get_student_rank($this->student_id));
    $this->major_code = $this->db->get_student_major_from_db($this->student_id);
    $this->catalog_year = $this->db->get_student_catalog_year($this->student_id);
    $this->name = $this->db->get_student_name($this->student_id);


  }

  /**
   * This function will look at the courses which the student has taken, to calculate
   * the cumulative hours and gpa, rather than just load them from the db table.
   *
   * It will then return the values in an assoc array for later use.  For example, you
   * may want to set $this->cumulative_hours and $this->gpa to them.
   *
   */
  function calculate_cumulative_hours_and_gpa() {

    $cumulative_hours = 0;
    $cumulative_points = 0;

    $cumulative_total_hours = $this->list_courses_taken->count_credit_hours("", FALSE, TRUE, FALSE);
    $cumulative_quality_hours = $this->list_courses_taken->count_credit_hours("", FALSE, TRUE, TRUE);
    $cumulative_quality_points = $this->list_courses_taken->count_credit_quality_points("", FALSE, TRUE);

    $cgpa = FALSE;
    if ($cumulative_quality_hours > 0) {
      $cgpa = fp_truncate_decimals($cumulative_quality_points / $cumulative_quality_hours, 3);
    }

    fpm("This student: <b>$cumulative_total_hours total hours</b>, 
		            $cumulative_quality_hours qual hours, $cumulative_quality_points cpoints. <b>gpa: $cgpa</b>");


    return array(
      "cumulative_total_hours" => $cumulative_total_hours,
      "cumulative_quality_hours" => $cumulative_quality_hours,
      "cumulative_quality_points" => $cumulative_quality_points,
      "cumulative_gpa" => $cgpa,
    );

  }



  /**
   * Given a rank_code like FR, SO, etc., get the english
   * description. For example: Freshman, Sophomore, etc.
   *
   */
  function get_rank_description($rank_code = "") {
    // TODO:  Maybe this should be a setting somewhere instead of hard-coded?
    $rank_array = array(
      "FR" => t("Freshman"),
      "SO" => t("Sophomore"),
      "JR" => t("Junior"),
      "SR" => t("Senior"),
      "PR" => t("Professional"),
    );

    return $rank_array[$rank_code];

  }



  /**
   * Returns a student's degree plan object.
   *
   */
  function get_degree_plan($bool_load_full = true, $bool_ignore_settings = false) {

    $t_major_code = $this->get_major_and_track_code($bool_ignore_settings);
    $degree_id = $this->db->get_degree_id($t_major_code, $this->catalog_year);
    if ($bool_load_full) {
      $degree_plan = new DegreePlan($degree_id, $this->db);
    }
    else {
      $degree_plan = new DegreePlan();
      $degree_plan->degree_id = $degree_id;
      $degree_plan->load_descriptive_data();
    }

    return $degree_plan;
  }


  /**
   * Enter description here...
   * Returns the major code and trackCode, if it exists in this form:
   *  MAJOR|CONC_TRACK
   *  Though usually it will be:
   * MAJR|_TRCK
   * Asumes you have already called "load_settings()";
   */
  function get_major_and_track_code($bool_ignore_settings = false) {

    $rtn = "";
    $major_code = "";

    if ($this->array_settings["major_code"] != "") { // If they have settings saved, use those...
      if ($this->array_settings["track_code"] != "") {
        // if it does NOT have a | in it already....
        if (!strstr($this->array_settings["major_code"], "|")) {
          $rtn = $this->array_settings["major_code"] . "|_" . $this->array_settings["track_code"];
        }
        else {
          // it DOES have a | already, so we join with just a _.  This would
          // be the case if we have a track AND an concentration.
          $rtn = $this->array_settings["major_code"] . "_" . $this->array_settings["track_code"];
        }
      }
      else {
        $rtn = $this->array_settings["major_code"];
      }
      $major_code = $this->array_settings["major_code"];
    }
    else {
      $rtn = $this->major_code;
    }


    if ($bool_ignore_settings == true) {
      $rtn = $this->major_code;
    }


    return $rtn;

  }



  function load_courses_taken($bool_load_transfer_credits = true) {

    $retake_grades = csv_to_array($GLOBALS["fp_system_settings"]["retake_grades"]);

    $not_released_grades_terms = csv_to_array(variable_get("not_released_grades_terms"));

    // This will create and load the list_courses_taken list.
    // contains SQL queries to fully create the list_courses_taken.
    $res = $this->db->db_query("SELECT *	FROM student_courses									
                							 WHERE 
                								student_id = '?' ", $this->student_id);

    while ($cur = $this->db->db_fetch_array($res)) {

      // Create a course object for this course...
      $is_transfer = false;
      $course_id = $this->db->get_course_id($cur["subject_id"], $cur["course_num"]);

      if (!$course_id) {
        fpm("Course not found while trying to load student data: {$cur["subject_id"]} {$cur["course_num"]}");
        continue;
      }

      // Are these grades (terms) not released yet?
      if (in_array($cur["term_id"], $not_released_grades_terms)) {
        $cur["grade"] = "";
      }

      $new_course = new Course();
      $new_course->course_id = $course_id;

      // Load descriptive data for this course from the catalog (so we can get min, max, and repeat hours)
      $new_course->load_descriptive_data();

      // Now, over-write whatever we got from the descriptive data with what the course was called
      // when the student took it.
      $new_course->subject_id = $cur["subject_id"];
      $new_course->course_num = $cur["course_num"];
      $new_course->grade = $cur["grade"];
      $new_course->term_id = $cur["term_id"];

      // Is this grade supposed to be hidden from students (and this user is probably
      // a student)
      if (in_array($new_course->term_id, $this->array_hide_grades_terms) && !user_has_permission("can_advise_students")) {
        $new_course->bool_hide_grade = true;
      }

      $new_course->hours_awarded = $cur["hours_awarded"] * 1;
      $new_course->display_status = "completed";
      $new_course->bool_taken = true;

      // Was this course worth 0 hours but they didn't fail it?
      // If so, we need to set it to actually be 1 hour, and
      // indicate this is a "ghost hour."
      if (!in_array($new_course->grade, $retake_grades) && $new_course->hours_awarded == 0) {
        $new_course->hours_awarded = 1;
        $new_course->bool_ghost_hour = TRUE;
      }

      // Now, add the course to the list_courses_taken...
      $this->list_courses_taken->add($new_course);
      $this->array_significant_courses[$course_id] = true;

    }



    if ($bool_load_transfer_credits == false) {
      return;
    }


    // Tranfer credits?  Get those too...

    $res = $this->db->db_query("
                  			SELECT *
                  			FROM student_transfer_courses a, 
                  			     transfer_courses b 
                  			WHERE a.transfer_course_id = b.transfer_course_id
                  			AND a.student_id = '?' ", $this->student_id);

    while ($cur = $this->db->db_fetch_array($res)) {
      $transfer_course_id = $cur['transfer_course_id'];
      $institution_id = $cur["institution_id"];

      $new_course = new Course();

      // Find out if this course has an eqv.
      if ($course_id = $this->get_transfer_course_eqv($transfer_course_id, false)) {
        $new_course = new Course($course_id);
        $this->array_significant_courses[$course_id] = true;
      }



      $t_course = new Course();
      $t_course->subject_id = $cur['subject_id'];
      $t_course->course_num = $cur['course_num'];
      $t_course->course_id = $transfer_course_id;
      $t_course->bool_transfer = true;
      $t_course->institution_id = $institution_id;

      $new_course->bool_transfer = true;

      $new_course->course_transfer = $t_course;
      $new_course->grade = $cur['grade'];
      $t_course->grade = $cur['grade'];

      $new_course->hours_awarded = $cur['hours_awarded'] * 1;
      $t_course->hours_awarded = $cur['hours_awarded'] * 1;


      // Was this course worth 0 hours but they didn't fail it?
      // If so, we need to set it to actually be 1 hour, and
      // indicate this is a "ghost hour."
      if (!in_array($new_course->grade, $retake_grades) && $new_course->hours_awarded == 0) {
        $new_course->hours_awarded = 1;
        $new_course->bool_ghost_hour = TRUE;
        $t_course->hours_awarded = 1;
        $t_course->bool_ghost_hour = TRUE;
      }

      $new_course->bool_taken = true;
      $t_course->bool_taken = true;


      $new_course->term_id = $cur['term_id'];
      if (strstr($new_course->term_id, "9999")) {
        // was an unknown semester.  Let's set it lower so
        // it doesn't screw up my sorting.
        $new_course->term_id = 11111;
      }
      $t_course->term_id = $new_course->term_id;
      $new_course->display_status = "completed";

      $this->list_courses_taken->add($new_course);
    }
    //		print_pre($this->list_courses_taken->to_string());

  }




  /**
   * Find a transfer eqv for this student, for this course in question.
   *
   */
  function get_transfer_course_eqv($transfer_course_id, $bool_ignore_unassigned = false, $require_valid_term_id = "") {

    // First, make sure that this transfer course hasn't
    // been unassigned.  Do this by checking through
    // the student's courseListUnassignedTransferEQVs.
    $temp_course = new Course();
    $temp_course->course_id = $transfer_course_id;
    if ($bool_ignore_unassigned == false && $this->list_transfer_eqvs_unassigned->find_match($temp_course)) {
      // The transfer course in question has had its eqv removed,
      // so skip it!
      return false;
    }



    $valid_term_line = "";
    if ($require_valid_term_id != "") {
      // We are requesting eqv's only from a particular valid term, so, amend
      // the query.
      $valid_term_line = "AND valid_term_id = $require_valid_term_id ";
    }


    // Does the supplied transfer course ID have an eqv?
    $res = $this->db->db_query("
			SELECT * FROM transfer_eqv_per_student
			WHERE transfer_course_id = '?'
			AND student_id = '?'
			AND broken_id = '0'
			$valid_term_line 	", $transfer_course_id, $this->student_id);

    if ($cur = $this->db->db_fetch_array($res)) {
      return $cur['local_course_id'];
    }

    return false;

  }


  function to_string() {
    $rtn = "Student Information:\n";
    $rtn .= " Courses Taken:\n";
    $rtn .= $this->list_courses_taken->to_string();
    return $rtn;
  }

}