+ Added cache, which speeds up the repetitive calculations

+ Returned variables, because they need for cached expressions

2 files changed, 20 insertions, 1 deletions

diff --git a/src/NXP/Exception/IncorrectBracketsException.php b/src/NXP/Exception/IncorrectBracketsException.php
index 68d67c6..e2aaed9 100644
--- a/src/NXP/Exception/IncorrectBracketsException.php
+++ b/src/NXP/Exception/IncorrectBracketsException.php
@@ -12,7 +12,7 @@
 namespace NXP\Exception;
 
 /**
- * @author V@author Alexander Kiryukhin <alexander@symdev.org>
+ * @author Alexander Kiryukhin <alexander@symdev.org>
  */
 class IncorrectBracketsException extends \Exception
 {
diff --git a/src/NXP/Exception/UnknownVariableException.php b/src/NXP/Exception/UnknownVariableException.php
new file mode 100644
index 0000000..8de9493
--- /dev/null
+++ b/src/NXP/Exception/UnknownVariableException.php
@@ -0,0 +1,19 @@
+<?php
+
+/**
+ * This file is part of the MathExecutor package
+ *
+ * (c) Alexander Kiryukhin
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code
+ */
+
+namespace NXP\Exception;
+
+/**
+ * @author Alexander Kiryukhin <alexander@symdev.org>
+ */
+class UnknownVariableException extends \Exception
+{
+}