--- a/langs.sty	Tue Aug 13 10:23:20 2019 +0100
+++ b/langs.sty	Fri Aug 16 06:51:06 2019 +0100
@@ -3,6 +3,28 @@
 \setmonofont[Scale=.95]{Consolas}
 \newfontfamily{\consolas}{Consolas}
 
+\makeatletter
+\let\old@lstKV@SwitchCases\lstKV@SwitchCases
+\def\lstKV@SwitchCases#1#2#3{}
+\makeatother
+\usepackage{lstlinebgrd}
+\makeatletter
+\let\lstKV@SwitchCases\old@lstKV@SwitchCases
+
+\lst@Key{numbers}{none}{%
+    \def\lst@PlaceNumber{\lst@linebgrd}%
+    \lstKV@SwitchCases{#1}%
+    {none:\\%
+     left:\def\lst@PlaceNumber{\llap{\normalfont
+                \lst@numberstyle{\thelstnumber}\kern\lst@numbersep}\lst@linebgrd}\\%
+     right:\def\lst@PlaceNumber{\rlap{\normalfont
+                \kern\linewidth \kern\lst@numbersep
+                \lst@numberstyle{\thelstnumber}}\lst@linebgrd}%
+    }{\PackageError{Listings}{Numbers #1 unknown}\@ehc}}
+\makeatother
+
+
+
 \definecolor{codered}{rgb}{0.6,0,0}            % for strings
 \definecolor{codegreen}{rgb}{0.25,0.5,0.35}    % comments
 \definecolor{codepurple}{rgb}{0.5,0,0.35}      % keywords