From 10add04b9138b13ba36a53a20e990bfe82d343ee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcel=20Fabian=20Kr=C3=BCger?= <zauguin@gmail.com>
Date: Tue, 25 Aug 2020 00:20:23 +0200
Subject: [PATCH] Handle token.to_string returning nil for empty

---
 luametalatex-firstcode.lua | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/luametalatex-firstcode.lua b/luametalatex-firstcode.lua
index e02e6b5..7039c92 100644
--- a/luametalatex-firstcode.lua
+++ b/luametalatex-firstcode.lua
@@ -135,7 +135,8 @@ token.luacmd("closein", function(_, prefix)
 end, "value")
 
 local function do_write(p)
-  local content = token.to_string(p.data) .. '\n'
+  local data = token.to_string(p.data)
+  local content = data and data .. '\n' or '\n'
   local file = ofiles[p.file]
   if file then
     file:write(content)