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

---
 parser.php | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

(limited to 'parser.php')

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='-';
     }
 
     /**
-- 
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