From e0abd45dc194f7ede2b460c6e9c2c303d4321bd7 Mon Sep 17 00:00:00 2001
From: Jean-Michel Vedrine <vedrine@vedrine.org>
Date: Sun, 24 Jan 2016 13:18:38 +0100
Subject: Solve display using MathJax for all websites

---
 README.txt         |  2 +-
 displayformula.php |  9 ++++++++-
 lib.php            |  5 ++---
 parser.php         | 12 +++++++++++-
 question.php       |  1 +
 questiontype.php   |  1 +
 version.php        |  4 ++--
 7 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/README.txt b/README.txt
index 932eb51..d371985 100644
--- a/README.txt
+++ b/README.txt
@@ -26,7 +26,7 @@ Updated to Moodle 2.0 by Stefan Raffeiner <stefan.raffeiner@gmail.com>
 Updated to Moodle 2.1 by Jean-Michel Védrine <vedrine@univ-st-etienne.fr>
 
 This plugin is now maintained by Jean-Michel Védrine. This version is upgraded to
-work with Moodle 2.5.
+work with Moodle 2.8 and ulteriors versions.
 For support use the Moodle quiz forum at https://moodle.org/mod/forum/view.php?id=737
 
 Enjoy.
diff --git a/displayformula.php b/displayformula.php
index 788304b..58723f1 100644
--- a/displayformula.php
+++ b/displayformula.php
@@ -62,8 +62,15 @@ $text   = format_text($texexp, FORMAT_MOODLE, $formatoptions);
         <title>Formula</title>
         <meta http-equiv="content-type" content="text/html; charset=utf-8" />
 <?php
+
 if (!empty($CFG->additionalhtmlhead) && stripos($CFG->additionalhtmlhead, 'MathJax') !== false) {
-            echo $CFG->additionalhtmlhead;
+    // For website where Mathjax is enabled using additional HTML in head.
+    echo $CFG->additionalhtmlhead;
+} else {
+    // For other website directly include MathJax.
+    echo "<script type=\"text/javascript\" async
+  src=\"https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-MML-AM_CHTML\">
+</script>";
 }
 ?>
     </head>
diff --git a/lib.php b/lib.php
index f14538d..29cb75f 100644
--- a/lib.php
+++ b/lib.php
@@ -17,9 +17,8 @@
 /**
  * Serve question type files
  *
- * @since      2.0
- * @package    qtype
- * @subpackage algebra
+ * @since      Moodle 2.0
+ * @package    qtype_algebra
  * @copyright  Dongsheng Cai <dongsheng@moodle.com>
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
diff --git a/parser.php b/parser.php
index 6a81fe6..8a21bc3 100644
--- a/parser.php
+++ b/parser.php
@@ -1336,10 +1336,20 @@ class qtype_algebra_parser_bracket extends qtype_algebra_parser_term {
      * @return the numerical value of the term given the provided values for the variables
      */
     function evaluate($params) {
+        if($this->_sign=='-') {
+            $mult=-1;
+        } else {
+            $mult=1;
+        }
         if(count($this->_arguments)!=$this->_nargs) {
             return 0;
         }
-        return $this->_arguments[0]->evaluate($params);
+        return $mult*$this->_arguments[0]->evaluate($params);
+    }
+
+    function set_negative() {
+        // Set the sign to be a '-'
+        $this->_sign='-';
     }
 
     /**
diff --git a/question.php b/question.php
index 7d585bb..52eea54 100644
--- a/question.php
+++ b/question.php
@@ -25,6 +25,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
+require_once($CFG->dirroot . '/question/type/questionbase.php');
 require_once($CFG->dirroot . '/question/type/algebra/questiontype.php');
 require_once($CFG->dirroot . '/question/type/algebra/parser.php');
 require_once($CFG->dirroot . '/question/type/algebra/xmlrpc-utils.php');
diff --git a/questiontype.php b/questiontype.php
index d8672b9..a49698a 100644
--- a/questiontype.php
+++ b/questiontype.php
@@ -24,6 +24,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
+require_once($CFG->dirroot . '/question/type/questiontypebase.php');
 require_once($CFG->dirroot . '/question/type/algebra/question.php');
 require_once($CFG->dirroot . '/question/type/algebra/parser.php');
 require_once($CFG->dirroot . '/question/type/algebra/xmlrpc-utils.php');
diff --git a/version.php b/version.php
index 2f734d9..0b2f746 100644
--- a/version.php
+++ b/version.php
@@ -23,8 +23,8 @@
 defined('MOODLE_INTERNAL') || die();
 
 $plugin->component = 'qtype_algebra';
-$plugin->version   = 2014110800;
+$plugin->version   = 2016012400;
 
 $plugin->requires  = 2013050100;
-$plugin->release   = '1.33 for Moodle 2.5, 2.6 and 2.7';
+$plugin->release   = '1.4 for Moodle 2.8, 2.9 and 3.0';
 $plugin->maturity  = MATURITY_STABLE;
-- 
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