diff --git a/src_main/core/pistring.h b/src_main/core/pistring.h
index 77abac57..f701263c 100755
--- a/src_main/core/pistring.h
+++ b/src_main/core/pistring.h
@@ -246,6 +246,9 @@ public:
 	 * \details All variants demonstrated in example: \snippet pistring.cpp PIString::mid
 	 * \sa \a left(), \a right() */
 	PIString mid(const int start, const int len = -1) const;
+
+	/*! \brief Return sub-string of string from symbol at index "start" and maximum length "len" */
+	PIString subString(const int start, const int len = -1) const {return mid(start, len);}
 	
 	/*! \brief Return part of string from left and maximum length "len"
 	 * \details Example: \snippet pistring.cpp PIString::left