+ Added cache, which speeds up the repetitive calculations

+ Returned variables, because they need for cached expressions

4 files changed, 70 insertions, 4 deletions

diff --git a/src/NXP/Classes/Calculator.php b/src/NXP/Classes/Calculator.php
index e74b7ab..41e0d9f 100644
--- a/src/NXP/Classes/Calculator.php
+++ b/src/NXP/Classes/Calculator.php
@@ -13,7 +13,9 @@ namespace NXP\Classes;
 use NXP\Classes\Token\InterfaceOperator;
 use NXP\Classes\Token\TokenFunction;
 use NXP\Classes\Token\TokenNumber;
+use NXP\Classes\Token\TokenVariable;
 use NXP\Exception\IncorrectExpressionException;
+use NXP\Exception\UnknownVariableException;
 
 /**
  * @author Alexander Kiryukhin <alexander@symdev.org>
@@ -21,17 +23,28 @@ use NXP\Exception\IncorrectExpressionException;
 class Calculator
 {
     /**
-     * @param  array                                       $tokens Tokens in reverse polish notation
-     * @return number
+     * Calculate array of tokens in reverse polish notation
+     * @param  array                                       $tokens    Array of tokens
+     * @param  array                                       $variables Array of variables
+     * @return number                                      Result
      * @throws \NXP\Exception\IncorrectExpressionException
+     * @throws \NXP\Exception\UnknownVariableException
      */
-    public function calculate($tokens)
+    public function calculate($tokens, $variables)
     {
         $stack = array();
         foreach ($tokens as $token) {
             if ($token instanceof TokenNumber) {
                 array_push($stack, $token);
             }
+            if ($token instanceof TokenVariable) {
+                $variable = $token->getValue();
+                if (!array_key_exists($variable, $variables)) {
+                    throw new UnknownVariableException();
+                }
+                $value = $variables[$variable];
+                array_push($stack, new TokenNumber($value));
+            }
             if ($token instanceof InterfaceOperator || $token instanceof TokenFunction) {
                 array_push($stack, $token->execute($stack));
             }
diff --git a/src/NXP/Classes/Lexer.php b/src/NXP/Classes/Lexer.php
index 676962d..63a87b2 100644
--- a/src/NXP/Classes/Lexer.php
+++ b/src/NXP/Classes/Lexer.php
@@ -16,6 +16,7 @@ use NXP\Classes\Token\TokenFunction;
 use NXP\Classes\Token\TokenLeftBracket;
 use NXP\Classes\Token\TokenNumber;
 use NXP\Classes\Token\TokenRightBracket;
+use NXP\Classes\Token\TokenVariable;
 use NXP\Exception\IncorrectBracketsException;
 use NXP\Exception\IncorrectExpressionException;
 
@@ -67,6 +68,9 @@ class Lexer
             if ($token instanceof TokenNumber) {
                 $output[] = $token;
             }
+            if ($token instanceof TokenVariable) {
+                $output[] = $token;
+            }
             if ($token instanceof TokenFunction) {
                 array_push($stack, $token);
             }
diff --git a/src/NXP/Classes/Token/TokenVariable.php b/src/NXP/Classes/Token/TokenVariable.php
new file mode 100644
index 0000000..ccd7c83
--- /dev/null
+++ b/src/NXP/Classes/Token/TokenVariable.php
@@ -0,0 +1,25 @@
+<?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\Classes\Token;
+
+/**
+ * @author Alexander Kiryukhin <alexander@symdev.org>
+ */
+class TokenVariable extends AbstractContainerToken
+{
+    /**
+     * @return string
+     */
+    public static function getRegex()
+    {
+        return '\$[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*';
+    }
+}
diff --git a/src/NXP/Classes/TokenFactory.php b/src/NXP/Classes/TokenFactory.php
index 924203d..19ba1cf 100644
--- a/src/NXP/Classes/TokenFactory.php
+++ b/src/NXP/Classes/TokenFactory.php
@@ -16,6 +16,7 @@ use NXP\Classes\Token\TokenFunction;
 use NXP\Classes\Token\TokenLeftBracket;
 use NXP\Classes\Token\TokenNumber;
 use NXP\Classes\Token\TokenRightBracket;
+use NXP\Classes\Token\TokenVariable;
 use NXP\Exception\UnknownFunctionException;
 use NXP\Exception\UnknownOperatorException;
 use NXP\Exception\UnknownTokenException;
@@ -40,6 +41,7 @@ class TokenFactory
     protected $functions = array();
 
     /**
+     * Add function
      * @param $name
      * @param $function
      * @param $places
@@ -49,6 +51,11 @@ class TokenFactory
         $this->functions[$name] = array($places, $function);
     }
 
+    /**
+     * Add operator
+     * @param  string                                  $operatorClass
+     * @throws \NXP\Exception\UnknownOperatorException
+     */
     public function addOperator($operatorClass)
     {
         $class = new \ReflectionClass($operatorClass);
@@ -62,6 +69,16 @@ class TokenFactory
     }
 
     /**
+     * Add variable
+     * @param string $name
+     * @param mixed  $value
+     */
+    public function addVariable($name, $value)
+    {
+
+    }
+
+    /**
      * @return string
      */
     public function getTokenParserRegex()
@@ -72,10 +89,11 @@ class TokenFactory
         }
 
         return sprintf(
-            '/(%s)|([%s])|(%s)|([%s%s%s])/i',
+            '/(%s)|([%s])|(%s)|(%s)|([%s%s%s])/i',
             TokenNumber::getRegex(),
             $operatorsRegex,
             TokenFunction::getRegex(),
+            TokenVariable::getRegex(),
             TokenLeftBracket::getRegex(),
             TokenRightBracket::getRegex(),
             TokenComma::getRegex()
@@ -112,6 +130,11 @@ class TokenFactory
             }
         }
 
+        $regex = sprintf('/%s/i', TokenVariable::getRegex());
+        if (preg_match($regex, $token)) {
+            return new TokenVariable(substr($token,1));
+        }
+
         $regex = sprintf('/%s/i', TokenFunction::getRegex());
         if (preg_match($regex, $token)) {
             if (isset($this->functions[$token])) {
@@ -120,6 +143,7 @@ class TokenFactory
                 throw new UnknownFunctionException();
             }
         }
+
         throw new UnknownTokenException();
     }
 }