+ Added cache, which speeds up the repetitive calculations

+ Returned variables, because they need for cached expressions

1 files changed, 18 insertions, 1 deletions

diff --git a/README.md b/README.md
index 9bc06e3..8000e35 100644
--- a/README.md
+++ b/README.md
@@ -99,4 +99,21 @@ And adding to executor:
 
 ```php
 $executor->addOperator('MyNamespace\ModulusToken');
-```
\ No newline at end of file
+```
+
+## Variables:
+
+Default variables:
+
+$pi = 3.14159265359
+$e = 2.71828182846
+
+You can add own variable to executor:
+
+```php
+$executor->setVars(array(
+    'var1' => 0.15,
+    'var2' => 0.22
+));
+
+$executor->execute("$var1 + $var2");
\ No newline at end of file