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locallib.php
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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Serve question type files
*
* @since 2.0
* @package qtype_regexp
* @copyright Joseph REZEAU
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
/**
* Expand regexp.
* @param string $myregexp
*/
function expand_regexp($myregexp) {
global $regexporiginal;
// JR 16 DEC 2011 add parentheses if necessary; still need to detect un-parenthesized pipe.
// JR 04 OCT 2019 removed this feature which caused a bug.
$regexporiginal = $myregexp;
$charlist = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
// Change [a-c] to [abc] NOTE: ^ metacharacter is not processed inside [].
$pattern = '/\\[\w-\w\\]/'; // Find [a-c] in $myregexp.
while (preg_match($pattern, $myregexp, $matches, PREG_OFFSET_CAPTURE) ) {
$result = $matches[0][0];
$offset = $matches[0][1];
$stringleft = substr($myregexp, 0, $offset + 1);
$stringright = substr($myregexp, $offset + strlen($result) - 1);
$c1 = $result[1];
$c3 = $result[3];
$rs = '';
for ($c = strrpos($charlist, $c1); $c < strrpos($charlist, $c3) + 1; $c++) {
$rs .= $charlist[$c];
}
$myregexp = $stringleft.$rs.$stringright;
}
// Provisionally replace existing escaped [] before processing the change [abc] to (a|b|c) JR 11-9-2007.
// See Oleg http://moodle.org/mod/forum/discuss.php?d=38542&parent=354095.
// See https://moodle.org/mod/forum/discuss.php?d=251510#p1090642
// Replacement character changed to Unicode character Halloween 2018.
$pattern = '/\\\\\[/';
// Replace \[ with Unicode Character 'LEFT WHITE SQUARE BRACKET' (U+301A).
$replacement = '〚';
$count = 0;
$myregexp = preg_replace ($pattern, $replacement, $myregexp, -1, $count);
$pattern = '/\\\\\]/';
// Replace \] with Unicode Character 'RIGHT WHITE SQUARE BRACKET' (U+301B).
$replacement = '〛';
$myregexp = preg_replace ($pattern, $replacement, $myregexp, -1, $count);
// Halloween 2018 version: added similar treatment for excaped parentheses.
$pattern = '/\\\\\(/';
// Replace \( with Unicode Character 'FULLWIDTH LEFT PARENTHESIS' (U+FF08).
$replacement = '（';
$count = 0;
$myregexp = preg_replace ($pattern, $replacement, $myregexp, -1, $count);
$pattern = '/\\\\\)/';
// Replace \) with Unicode Character 'FULLWIDTH RIGHT PARENTHESIS' (U+FF09).
$replacement = '）';
$myregexp = preg_replace ($pattern, $replacement, $myregexp, -1, $count);
// Change [abc] to (a|b|c).
$pattern = '/\[.*?\]/'; // Find [abc] in $myregexp.
// Added core_text to deal with utf8 accents etc.
while (preg_match($pattern, $myregexp, $matches, PREG_OFFSET_CAPTURE) ) {
$result = $matches[0][0];
// Fixed utf8 problem in lengths.
$offset = core_text::strlen(substr($myregexp, 0, $matches[0][1]));
$stringleft = core_text::substr($myregexp, 0, $offset);
$stringright = core_text::substr($myregexp, $offset + core_text::strlen($result));
$rs = core_text::substr($result, 1, core_text::strlen($result) - 2);
$r = '';
$l = core_text::strlen($rs);
for ($i = 0; $i < $l; $i++) {
$r .= core_text::substr($rs, $i, 1).'|';
}
$rs = '('.core_text::substr($r, 0, core_text::strlen($r) - 1).')';
$myregexp = $stringleft.$rs.$stringright;
}
// We can now safely restore the previously replaced escaped square brakets.
$pattern = '/〚/';
$replacement = '\[';
$count = 0;
$myregexp = preg_replace ($pattern, $replacement, $myregexp, -1, $count);
$pattern = '/〛/';
$replacement = '\]';
$myregexp = preg_replace ($pattern, $replacement, $myregexp, -1, $count);
// Process ? in regexp (zero or one occurrence of preceding char).
while (strpos($myregexp, '?')) {
$c1 = strpos($myregexp, '?');
$c0 = $myregexp[$c1 - 1];
// If \? -> escaped ?, treat as literal char (replace with ¬ char temporarily).
// This ¬ char chosen because non-alphanumeric & rarely used...
if ($c0 == '\\') {
$myregexp = substr($myregexp, 0, $c1 - 1 ) .'¬' .substr($myregexp, $c1 + 1);
continue;
}
// If )? -> meta ? action upon parens (), replace with ¤ char temporarily.
// This ¤ char chosen because non-alphanumeric & rarely used...
if ($c0 == ')') {
$myregexp = substr( $myregexp, 0, $c1 - 1 ) .'¤' .substr($myregexp, $c1 + 1);
continue;
}
// If ? metacharacter acts upon an escaped char, put it in $c2.
if ($myregexp[$c1 - 2] == '\\') {
$c0 = '\\'.$c0;
}
$c2 = '('.$c0.'|)';
$myregexp = str_replace($c0.'?', $c2, $myregexp);
}
// Replaces possible temporary ¬ char with escaped question mark.
if (strpos( $myregexp, '¬') != - 1) {
$myregexp = str_replace('¬', '\?', $myregexp);
$regexporiginal = $myregexp;
}
// Replaces possible temporary ¤ char with escaped question mark.
if (strpos( $myregexp, '¤') != - 1) {
$myregexp = str_replace('¤', ')?', $myregexp);
}
// Process ? metacharacter acting upon a set of parentheses \(.*?\)\?
$myregexp = str_replace(')?', '|)', $myregexp);
// Replace escaped characters with their escape code.
while ($c = strpos($myregexp, '\\')) {
$s1 = substr($myregexp, $c, 2);
$s2 = $myregexp[$c + 1];
$s2 = rawurlencode($s2);
// Alaphanumeric chars can't be escaped; escape codes useful here are:
// . = %2e ; + = %2b ; * = %2a
// Add any others as needed & modify below accordingly.
switch ($s2) {
case '.' : $s2 = '%2e';
break;
case '+' : $s2 = '%2b';
break;
case '*' : $s2 = '%2a';
break;
}
$myregexp = str_replace($s1, $s2, $myregexp);
}
// Remove starting and trailing metacharacters; not used for generation but useful for testing regexp.
if (strpos($myregexp, '^')) {
$myregexp = substr($myregexp, 1);
}
if (strpos($myregexp, '$') == strlen($myregexp) - 1) {
$myregexp = substr( $myregexp, 0, strlen($myregexp) - 1);
}
$mynewregexp = find_nested_ors($myregexp); // Check $myregexp for nested parentheses.
if ($mynewregexp != null) {
$myregexp = $mynewregexp;
}
$result = find_ors($myregexp); // Expand parenthesis contents.
// We can now restore any previously replaced escaped parentheses.
if ( !is_array($result) ) {
$results[0] = $result;
} else {
$results = $result;
}
$i = 0;
foreach ($results as $result) {
$toreplace = ['（', '）'];
$replacewith = ['(', ')'];
$results[$i] = strtr($result, array_combine($toreplace, $replacewith));
$i++;
}
return $results; // Returns array of alternate strings.
}
/**
* Find individual $nestedors expressions in $myregexp.
* @param string $mystring
*
*/
function is_nested_ors ($mystring) {
$orsstart = 0; $orsend = 0; $isnested = false; $parens = 0; $result = '';
for ($i = 0; $i < strlen($mystring); $i++) {
switch ($mystring[$i]) {
case '(':
$parens++;
if ($parens == 1) {
$orsstart = $i;
}
if ($parens == 2) {
$isnested = true;
}
break;
case ')':
$parens--;
if ($parens == 0) {
if ($isnested == true) {
$orsend = $i + 1;
$i = strlen($mystring);
break;
}
}
break;
}
}
if ($isnested == true) {
$result = substr( $mystring, $orsstart, $orsend - $orsstart);
return $result;
}
return false;
}
/**
* Find nested parentheses in $myregexp.
* @param string $myregexp
*/
function is_parents ($myregexp) {
$finalresult = null;
$pattern = '/[^(|)]*\\(([^(|)]*\\|[^(|)]*)+\\)[^(|)]*/';
if (preg_match_all($pattern, $myregexp, $matches, PREG_OFFSET_CAPTURE)) {
$matches = $matches[0];
for ($i = 0; $i < count($matches); $i++) {
$thisresult = $matches[$i][0];
$leftchar = $thisresult[0];
$rightchar = $thisresult[strlen($thisresult) - 1];
$outerchars = $leftchar .$rightchar;
if ($outerchars !== '()') {
$finalresult = $thisresult;
break;
}
}
}
return $finalresult;
}
/**
* Find ((a|b)c).
* @param string $myregexp
*/
function find_nested_ors ($myregexp) {
// Find next nested parentheses in $myregexp.
while ($nestedors = is_nested_ors ($myregexp)) {
$nestedorsoriginal = $nestedors;
// Find what?
while ($myparent = is_parents ($nestedors)) {
$leftchar = $nestedors[strpos($nestedors, $myparent) - 1];
$rightchar = $nestedors[strpos($nestedors, $myparent) + strlen($myparent)];
$outerchars = $leftchar.$rightchar;
// Fixed DECEMBER 2018.
$leftpar = '';
$rightpar = '';
// End fix.
switch ($outerchars) {
case '||':
case '()':
$leftpar = '';
$rightpar = '';
break;
case '((':
case '))':
case '(|':
case '|(':
case ')|':
case '|)':
$leftpar = '('; $rightpar = ')';
break;
default:
break;
}
$t1 = find_ors ($myparent);
$t = implode('|', $t1);
$myresult = $leftpar.$t.$rightpar;
$nestedors = str_replace( $myparent, $myresult, $nestedors);
}
// Detect sequence of ((*|*)|(*|*)) within parentheses or |) or (| and remove all INSIDE parentheses.
$pattern = '/(\\(|\\|)\\([^(|)]*\\|[^(|)]*\\)(\\|\\([^(|)]*\\|[^(|)]*\\))*(\\)|\\|)/';
while (preg_match($pattern, $nestedors, $matches, PREG_OFFSET_CAPTURE)) {
$plainors = $matches[0][0];
$leftchar = $plainors[0];
$rightchar = $plainors[strlen($plainors) - 1];
// Remove leading & trailing chars.
$plainors2 = substr($plainors, 1, strlen($plainors) - 2);
$plainors2 = str_replace( '(', '', $plainors2);
$plainors2 = str_replace( ')', '', $plainors2);
$plainors2 = $leftchar .$plainors2 .$rightchar;
$nestedors = str_replace( $plainors, $plainors2, $nestedors);
if (is_parents($nestedors)) {
$myregexp = str_replace( $nestedorsoriginal, $nestedors, $myregexp);
continue;
}
}
// Any sequence of (|)(|) in $nestedors? process them all.
$pattern = '/(\\([^(]*?\\|*?\\)){2,99}/';
while (preg_match($pattern, $nestedors, $matches, PREG_OFFSET_CAPTURE)) {
$parensseq = $matches[0][0];
$myresult = find_ors ($parensseq);
$myresult = implode('|', $myresult);
$nestedors = str_replace( $parensseq, $myresult, $nestedors);
}
// Test if we have reached the singleOrs stage.
if (is_parents ($nestedors) != null) {
$myregexp = str_replace( $nestedorsoriginal, $nestedors, $myregexp);
continue;
}
// No parents left in $nestedors, ...
// Find all single (*|*|*|*) and remove parentheses.
$patternsingleors = '/\\([^()]*\\)/';
$patternsingleorstotal = '/^\\([^()]*\\)$/';
while ($p = preg_match($patternsingleors, $nestedors, $matches, PREG_OFFSET_CAPTURE)) {
$r = preg_match($patternsingleorstotal, $nestedors, $matches, PREG_OFFSET_CAPTURE);
if ($r) {
if ($matches[0][0] == $nestedors) {
break;
} // We have reached top of $nestedors: keep ( )!
}
$r = preg_match($patternsingleors, $nestedors, $matches, PREG_OFFSET_CAPTURE);
$singleparens = $matches[0][0];
$myresult = substr($singleparens, 1, strlen($singleparens) - 2);
$nestedors = str_replace( $singleparens, $myresult, $nestedors);
if (is_parents ($nestedors) != null) {
$myregexp = str_replace( $nestedorsoriginal, $nestedors, $myregexp);
continue;
}
}
$myregexp = str_replace( $nestedorsoriginal, $nestedors, $myregexp);
}
return $myregexp;
}
/**
* Find ors.
* @param string $mystring
*/
function find_ors ($mystring) {
global $regexporiginal;
// Add extra space between consecutive parentheses (that extra space will be removed later on).
$pattern = '/\\(.*?\\|.*?\\)/';
while (strpos($mystring, ')(')) {
$mystring = str_replace( ')(', ')µ(', $mystring);
}
if (strpos($mystring, ')(')) {
$mystring = str_replace( ')(', ')£(', $mystring);
}
// In $mystring, find the parts outside of parentheses ($plainparts).
$plainparts = preg_split($pattern, $mystring);
if ($plainparts) {
$plainparts = index_plain_parts ($mystring, $plainparts);
}
$a = preg_match_all($pattern, $mystring, $matches, PREG_OFFSET_CAPTURE);
if (!$a) {
$regexporiginal = stripslashes($regexporiginal);
return $regexporiginal;
}
$plainors = index_ors($mystring, $matches);
// Send $list of $plainparts and $plainors to expand_ors () function.
return(expand_ors ($plainparts, $plainors));
}
/**
* This function expands a chunk of words containing a single set of parenthesized alternatives
* of the type: <(aaa|bbb)> OR <ccc (aaa|bbb)> OR <ccc (aaa|bbb) ddd> etc.
* into a LIST of possible alternatives,
* e.g. <ccc (aaa|bbb|)> -> <ccc aaa>, <ccc bbb>, <ccc>.
* @param string $plainparts
* @param string $plainors
*/
function expand_ors ($plainparts, $plainors) {
$expandedors = [];
$expandedors[] = '';
$slen = count($expandedors);
$expandedors[$slen - 1] = '';
if (isset($plainparts[0]) && $plainparts[0] == 0) { // If chunk begins with $plainparts.
$expandedors[$slen - 1] = $plainparts[1];
array_splice($plainparts, 0, 2);
}
while ((count($plainparts) != 0) || (count($plainors) != 0)) { // Go through sentence $plainparts.
$l = count($expandedors);
for ($k = 0; $k < $l; $k++) {
for ($m = 0; $m < count($plainors[1]); $m++) {
$expandedors[] = '';
$slen = count($expandedors) - 1;
$expandedors[$slen] = $expandedors[0].$plainors[1][$m];
if (count($plainparts)) {
if ($plainparts[1]) {
$expandedors[$slen] .= $plainparts[1];
}
}
$expandedors[$slen] = rawurldecode($expandedors[$slen]);
}
array_splice($expandedors, 0, 1); // Remove current "model" sentence from Sentences.
}
array_splice($plainors, 0, 2); // Remove current $plainors.
array_splice($plainparts, 0, 2); // Remove current $plainparts.
}
// Eliminate all extra µ signs which have been placed to replace consecutive parentheses by )µ(.
$n = count ($expandedors);
for ($i = 0; $i < $n; $i++) {
if (is_int(strpos($expandedors[$i], 'µ') ) ) { // Corrects strpos for 1st char of a string found!
$expandedors[$i] = str_replace('µ', '', $expandedors[$i]);
}
}
return ($expandedors);
}
/**
* Index plain parts.
* @param string $mystring
* @param array $plainparts
*/
function index_plain_parts($mystring, $plainparts) {
$indexedplainparts = [];
if (is_array($plainparts) ) {
foreach ($plainparts as $parts) {
if ($parts) {
$index = strpos($mystring, $parts);
$indexedplainparts[] = $index;
$indexedplainparts[] = $parts;
}
}
}
return ($indexedplainparts);
}
/**
* Index plain ors.
* @param string $mystring
* @param array $plainors
*/
function index_ors($mystring, $plainors) {
$indexedplainors = [];
foreach ($plainors as $ors) {
foreach ($ors as $or) {
$indexedplainors[] = $or[1];
$o = substr($or[0], 1, strlen($or[0]) - 2);
$o = explode('|', $o);
$indexedplainors[] = $o;
}
}
return ($indexedplainors);
}
/**
* Function adapted from Hot Potatoes.
* Check beginning
* @param string $guess
* @param string $answer
* @param boolean $ignorecase
* @return string $outstring
*/
function check_beginning( $guess, $answer, $ignorecase) {
$outstring = '';
if ($ignorecase) {
$guessoriginal = $guess;
$guess = strtoupper($guess);
$answer = strtoupper($answer);
}
$i1 = core_text::strlen($guess);
$i2 = core_text::strlen($answer);
for ($i = 0; ( $i < $i1 && $i < $i2); $i++) {
if (strlen($answer) < $i ) {
break;
}
if (core_text::substr($guess, $i, 1) == core_text::substr($answer, $i , 1)) {
$outstring .= core_text::substr($guess, $i, 1);
} else {
break;
}
}
if ($ignorecase) {
$outstring = core_text::substr($guessoriginal, 0, core_text::strlen($outstring));
}
return $outstring;
}
/**
* Function adapted from Hot Potatoes.
* Get closest.
* @param string $guess
* @param string $answers
* @param boolean $ignorecase
* @param int $ishint
* @return array $closest
*/
function get_closest( $guess, $answers, $ignorecase, $ishint) {
$closest[0] = ''; // Closest answer to be displayed as input field value.
$closest[1] = ''; // Closest answer to be displayed in feedback line.
$closest[2] = ''; // Hint state :: plus (added 1 letter), minus (removed extra chars & added 1 letter),
// Complete (correct response achieved), nil (beginning of sentence).
$closest[3] = ''; // Student's guess (rest of).
$closest[4] = ''; // Added letter or word (according to Help mode).
$closest[5] = ''; // Flag the type of errors: [0]wrong; [1]misplaced.
$closesta = '';
$l = core_text::strlen($guess);
$ignorebegin = '';
if ($ishint) {
$closest[2] = 'nil';
}
$rightbits = [];
foreach ($answers as $answer) {
$rightbits[0][] = $answer;
$rightbits[1][] = check_beginning($guess, $answer, $ignorecase, $ishint);
}
$longestanswerlen = max(array_map('core_text::strlen', $rightbits[1]));
// Function get_max located at the end of this locallib.
$indexoflongest = get_max($rightbits[1], 0, 0);
if ($longestanswerlen) {
// Var $a = alternative correct answer.
// Var $g = current best student answer so far.
$a = $rightbits[0][$indexoflongest];
$g = $rightbits[1][$indexoflongest];
$closesta = trim($g);
$closestahint = '';
if ($ishint) {
$closest[2] = 'plus';
$closestahint = $closesta;
}
switch ($ishint) {
case 1: // Get or buy one character (letter of punctuation mark).
$closestahint = $closesta;
$closestahint .= core_text::substr($a, $longestanswerlen, 1);
$lenguess = core_text::strlen($guess);
$lenclosestahint = core_text::strlen($closestahint);
if ($lenguess > $lenclosestahint) {
$closest[2] = 'minus';
}
if (core_text::substr($a, $longestanswerlen, 1) == ' ') { // If hint letter is a space, add next one.
$closestahint .= core_text::substr($a, $longestanswerlen + 1, 1);
}
break;
case 2: // Get or buy one word (including punctuation).
$pattern = '/\s.*/';
if (preg_match($pattern, $a, $matches, PREG_OFFSET_CAPTURE, strlen($g) + 1) ) {
$closestahint = substr($a, 0, $matches[0][1]);
} else {
$pattern = '/.*$/'; // End of sentence.
if (preg_match($pattern, $a, $matches, PREG_OFFSET_CAPTURE, core_text::strlen($g)) ) {
$closestahint = $a;
$closest[2] = 'complete'; // Hint gives a complete correct answer.
}
}
break;
case 3: // Get or buy one word OR one punctuation mark.
$pattern = '/(\s|(?<!\w)[\p{P}]|[\p{P}](?!\w))/';
if (preg_match($pattern, $a, $matches, PREG_OFFSET_CAPTURE, strlen($g) + 1) ) {
$index = 0;
$pattern = '/\s[\p{P}]/';
if (preg_match($pattern, $a, $ma, PREG_OFFSET_CAPTURE, strlen($g)) ) {
if ($matches[0][1] == $ma[0][1] + 1) {
$index = 1;
}
}
$closestahint = substr($a, 0, $matches[0][1] + $index);
} else {
$pattern = '/.*$/'; // End of sentence.
if (preg_match($pattern, $a, $matches, PREG_OFFSET_CAPTURE, core_text::strlen($g)) ) {
$closestahint = $a;
$closest[2] = 'complete'; // Hint gives a complete correct answer.
}
}
}
// JR 13 OCT 2012 to fix potential html format tags inside correct answer.
$aa = preg_replace("/\//", "\/", $a);
if ( preg_match('/^'.$aa.'$/'.$ignorecase, $closestahint)) {
$closest[2] = 'complete'; // Hint gives a complete correct answer.
$state = new stdClass(); // Instantiate $state explicitely for PHP 5.3 compliance.
$state->raw_grade = 0;
}
}
// Student clicked the help button with an empty answer.
$a = $rightbits[0][$indexoflongest];
if ($closesta == '' && $ishint) {
$closest[2] = 'plus';
$answer = $answers[0];
switch ($ishint) {
case 1: // Add letter.
$closestahint = core_text::substr($a, 0, 1);
break;
case 2: // Add word.
$words = explode(' ', $answer);
$closestahint = $words[0];
break;
case 3: // Add word or punctuation.
// Return fist word OR punctuation sign (e.g. Spanish inverted ? or !).
$pattern = '/^([\p{P}]|\s*([a-zA-Z0-9]+))/u';
preg_match ($pattern, $a, $matches, PREG_OFFSET_CAPTURE);
$closestahint = $matches[0][0];
}
}
// Type of hint state.
switch ($closest[2]) {
case 'plus':
$closest[0] = $closestahint;
$closest[1] = $guess;
if ($ignorebegin) {
$closest[1] = '';
}
$closest[4] = substr ($closestahint, strlen($closesta));
break;
case 'minus':
case 'complete':
$closest[1] = $closesta;
$closest[4] = substr ($closestahint, strlen($closesta));
case 'minus':
$closest[0] = $closestahint;
break;
case 'complete':
$closest[0] = $a;
break;
default:
$closest[0] = $closesta;
$closest[1] = $closest[0];
}
// Search for correct *words* in student's guess, after closest answer has been found
// and even if closest answer is null JR 26 FEB 2012.
// JR DEC 2020 If word was bought, response can be complete but with extra text, so we need to look for rest of answer.
$lenclosesta = strlen($closest[0]) - strlen($closest[4]);
$closest[1] = substr($closest[0], 0, $lenclosesta);
$restofanswer = substr($guess, $lenclosesta);
$restofanswer = implode(' ', explode(' ', $restofanswer));
// Local function get_max at end of this l ocallib.
$indexoflongest = get_max($rightbits[1], 0, 0);
$restofanswers = $rightbits[0][$indexoflongest];
if ($restofanswer) {
unset($array1, $array2);
// Count punctuation marks as words - except within within words themselves.
// Does not work for French number format (space separator).
$pattern = "/(\s|(?<!\w)[\p{P}]|[\p{P}](?!\w))/";
$flags = PREG_SPLIT_DELIM_CAPTURE;
$array1 = preg_split($pattern, $restofanswer, - 1, $flags);
$array2 = preg_split($pattern, $restofanswers, - 1, $flags);
// Filter arrays to remove empty values.
$array1 = array_filter(array_map('trim', $array1));
$array2 = array_filter(array_map('trim', $array2));
$misplacedwords = array_intersect($array1, $array2);
// Remove potential duplicate words.
$misplacedwords = array_unique($misplacedwords);
foreach ($misplacedwords as $key => $value) {
$misplacedwords[$key] = '<span class="misplacedword"> '.$value.' </span>';
}
$wrongwords = array_diff($array1, $array2);
$closest[5] = (count($misplacedwords) !== 0);
if (count($wrongwords) !== 0) {
$closest[5] = $closest[5] + 10;
}
foreach ($wrongwords as $key => $value) {
$wrongwords[$key] = '<span class="wrongword"> '.$value.' </span> ';
}
unset ($result);
$result = $misplacedwords + $wrongwords;
ksort($result);
$result = implode (' ', $result);
$closest[3] = $result;
unset ($result);
}
return $closest;
}
/**
* Find whether student's response matches at least the beginning of one of the correct answers.
* @param array $question
* @param string $currentanswer
* @param boolean $correctresponse
* @param boolean $hintadded
* @return array $closest
*/
function find_closest($question, $currentanswer, $correctresponse = false, $hintadded = false) {
global $CFG;
// JR dec 2011 moved get alternate answers to new function.
$alternateanswers = get_alternateanswers($question);
$alternatecorrectanswers = [];
// JR jan 2012 changed contents of alternateanswers.
if (isset($question->id)) {
$qid = $question->id;
if (!isset ($SESSION->qtype_regexp_question->alternatecorrectanswers[$qid])) {
foreach ($alternateanswers as $key => $alternateanswer) {
foreach ($alternateanswer['answers'] as $alternate) {
$alternatecorrectanswers[] = $alternate;
}
}
}
}
// Testing ignorecase.
$ignorecase = 'i';
if ($question->usecase) {
$ignorecase = '';
};
// Only use ishint value if hint button has been clicked.
$ishint = $question->usehint * $hintadded;
// Find closest answer matching student response.
if (!isset($currentanswer) && !$correctresponse) {
return null;
}
if ($correctresponse) {
return $alternatecorrectanswers;
}
$closest = get_closest( $currentanswer, $alternatecorrectanswers, $ignorecase, $ishint);
if ($closest[2] == 'complete') {
return $closest;
}
return $closest;
}
/**
* Remove extra blank spaces from student's response.
* @param string $text
* @return string $text
*/
function remove_blanks($text) {
// Finds 2 successive spaces (note: \s does not work with French 'à' character!
$pattern = "/ /";
// Added (string) before $text for PHP 8.1 compatibility.
while ($w = preg_match($pattern, (string) $text, $matches, PREG_OFFSET_CAPTURE) ) {
$text = substr($text, 0, $matches[0][1]) .substr($text, $matches[0][1] + 1);
}
// Remove potential final extra blank. 31 AUG 2024.
$text = $text !== null ? trim($text) : '';
return $text;
}
/**
* Check that parentheses and square brackets are balanced, including nested ones.
* @param string $myregexp
* @param string $markedline
* @return string
*/
function check_my_parens($myregexp, $markedline) {
$parens = [];
$sqbrackets = [];
// Walk the $myregexp string to find parentheses and square brackets.
for ($i = 0; $i < strlen($myregexp); $i++) {
$escaped = false;
if ($i > 0 && $myregexp[$i - 1] == "\\") {
$escaped = true;
}
if (!$escaped) {
switch ($myregexp[$i]) {
case '(': $parens[$i] = 'open';
break;
case ')': $parens[$i] = 'close';
break;
case '[': $sqbrackets[$i] = 'open';
break;
case ']': $sqbrackets[$i] = 'close';
break;
default:
break;
}
}
}
// Check for parentheses.
$tags['open'] = '(';
$tags['close'] = ')';
$markedline2 = check_balanced($parens, $tags, $markedline);
// Check for square brackets.
$tags['open'] = '[';
$tags['close'] = ']';
$markedline2 = check_balanced($sqbrackets, $tags, $markedline2);
if ($markedline2 != $markedline) {
return $markedline2;
} else {
return;
}
}
/**
* Check that parentheses and square brackets are balanced.
* @param array $bracketstype
* @param array $tags
* @param string $markedline
* @return string
*/
function check_balanced ($bracketstype, $tags, $markedline) {
$open = [];
foreach ($bracketstype as $key => $value) {
switch ($value) {
case 'open':
$open[] = $key;
break;
case 'close':
if ($open) {
$index = array_pop ($open);
$bracketstype[$index] = null;
$bracketstype[$key] = null;
}
break;
}
}
foreach ($bracketstype as $key => $value) {
if ($value) {
if ($value == 'open') {
$mark = $tags['open'];
}
if ($value == 'close') {
$mark = $tags['close'];
}
$markedline[$key] = $mark;
}
}
return $markedline;
}
/**
* Detect un-escaped metacharacters.
* Full list of metacharacters used in regular expressions syntax.
* ALL these characters can be used as metacharacters in INCORRECT Answers (grade = None)
* . ^ $ * ( ) [ ] + ? | { } \ *
* Characters which can NOT be used as metacharacters in an accepted Answer (grade > 0)
* and MUST be escaped if used for their LITERAL value: . ^ $ * + { } \
* Characters which CAN be used as metacharacters in an accepted Answer (grade > 0)
* and must be escaped IF used for their LITERAL value: use of those characters
* must lead to alternative CORRECT answers ( ) [ ] | ?
* @param string $myregexp
* @param string $markedline
* @return string
*/
function check_unescaped_metachars ($myregexp, $markedline) {
$markedline2 = $markedline;
// All metacharacters must be escaped.
// Check for unescaped metacharacters, except for backslash itself.
$unescapedregex = '/(?<!\\\\)[\.\^\$\*\+\{\}]/';
// 1 (?<!\\\\) NO backslash preceding (this is a negative lookahead assertion)
// 2 [\.\^\$\*\+\{\}] list of metacharacters which can NOT be used in context of accepted Answer (grade > 0).
$unescapedmetachars = preg_match_all($unescapedregex, $myregexp, $matches, PREG_OFFSET_CAPTURE);
if ($unescapedmetachars) {
foreach ($matches as $v1) {
// In marked line, replace blank spaces with the unescaped metacharacter.
foreach ($v1 as $v2) {
$markedline2[$v2[1]] = $v2[0];
}
}
}
// Now check for unescaped backslashes.
$unescapedregex = '/(^|[^\\\])\\\[^\.|\*|\(|\\[\]\{\}\/)\+\?\^\|\$\.]/';
/* First part of regexp: beginning of sentence OR no backslash.
Second part of regexp: followed by backslash.
This is the third part of regexp: NOT followed by a metacharacter.
*/
$unescapedmetachars = preg_match_all($unescapedregex, $myregexp, $matches, PREG_OFFSET_CAPTURE);
if ($unescapedmetachars) {
$foundbackslash = substr($matches[0][0][0], 1, 3);
// We must skip a valid escaped backslash.
if ($foundbackslash != "\\\\") {
foreach ($matches as $v1) {
// In marked line, replace blank spaces with the unescaped backslash \.
foreach ($v1 as $v2) {
$markedline2[$v2[1] + 1] = '\\';
}
}
}
}
if ($markedline2 != $markedline) {
return $markedline2;
} else {
return;
}
}
/**
* When displaying unescaped_metachars or unbalanced brackets, too long strings need to be cut up into chunks.
* Change $maxlen if necessary (e.g. to fit smaller width screens).
* @param string $longstring
* @param int $maxlen
*/
function splitstring ($longstring, $maxlen = 75) {
$len = core_text::strlen($longstring);
$stringchunks = [];
if ($len < $maxlen) {
$stringchunks[] = $longstring;
} else {
for ($i = 0; $i < $len; $i += $maxlen) {
$stringchunks[] = core_text::substr($longstring, $i, $maxlen);
}
}
return $stringchunks;
}
/**
* Expand regexp.
* @param array $question
*/
function get_alternateanswers($question) {
global $CFG, $SESSION;
$qid = '';
if (isset($question->id)) {
$qid = $question->id;
if (isset ($SESSION->qtype_regexp_question->alternateanswers[$qid])) {
return $SESSION->qtype_regexp_question->alternateanswers[$qid];
}
}
$alternateanswers = [];
$i = 1;
foreach ($question->answers as $answer) {
if ($answer->fraction != 0) {
// This is Answer 1 :: do not process as regular expression.
if ($i == 1) {
$alternateanswers[$i]['fraction'] = ($answer->fraction * 100).'%';
$alternateanswers[$i]['regexp'] = $answer->answer;
$alternateanswers[$i]['answers'][] = $answer->answer;
} else {
// JR added permutations OCT 2012.
$answer->answer = has_permutations($answer->answer);
// End permutations.
$r = expand_regexp($answer->answer);
if ($r) {
$alternateanswers[$i]['fraction'] = ($answer->fraction * 100).'%';
$alternateanswers[$i]['regexp'] = $answer->answer;
if (is_array($r)) {
$alternateanswers[$i]['answers'] = $r; // Normal alternateanswers (expanded).
} else {
$alternateanswers[$i]['answers'][] = $r; // Regexp was not expanded.
}
}
}
}
$i++;
}
// Store alternate answers in SESSION for caching effect DEC 2011.
// Added isset check DEC 2020 to avoid error message (strict syntax).
if (isset($SESSION->qtype_regexp_question->alternateanswers)) {
$SESSION->qtype_regexp_question->alternateanswers[$qid] = $alternateanswers;
$SESSION->qtype_regexp_question->alternatecorrectanswers[$qid] = '';
}
return $alternateanswers;
}
/**
* Check permutations.
* @param string $ans
*/
function check_permutations($ans) {
$p = preg_match_all("/\[\[(.*)\]\]/U", $ans, $matches);
if ($p === 0) {
return;
}
if ($p > 2) {
return get_string("regexperrortoomanypermutations", "qtype_regexp");
}
$nbpermuted = count($matches[1]);
for ($i = 0; $i < $nbpermuted; $i++) {
$ans = $matches[1][$i];
$p = preg_match_all("/(.*)_(.*)_.*/U", $ans, $matchesp);
if ($p === 0) {
return get_string("regexperrornopermutations", "qtype_regexp");
}
$p = preg_match_all("/_/", $ans, $matchesp);
$n = count($matchesp[0]);