1 files changed, 16 insertions, 0 deletions

diff --git a/arabluatex.lua b/arabluatex.lua
index 07968c0..527be3b 100644
--- a/arabluatex.lua
+++ b/arabluatex.lua
@@ -128,6 +128,21 @@ local function indnum(str)
    return str
 end
 
+local function processarbnull(str, scheme)
+   if scheme == "buckwalter" then
+      str = string.gsub(str, "(\\arbnull.?)(%b{})", function(tag, body)
+                           body = string.sub(body, 2, -2)
+                           return string.format("P%sP", body)
+      end)
+   else
+      str = string.gsub(str, "(\\arbnull.?)(%b{})", function(tag, body)
+                           body = string.sub(body, 2, -2)
+                           return string.format("o%so", body)
+      end)
+   end
+   return str
+end
+
 local function takeoutabjad(str)
    str = string.gsub(str, "(\\abjad.?)(%b{})", function(tag, body)
                         body = string.sub(body, 2, -2)
@@ -543,6 +558,7 @@ end
 
 function processtrans(str, mode, rules, scheme)
    str = "\\arb{".. str.."}"
+   str = processarbnull(str, scheme)
    str = takeoutabjad(str)
    str = protectarb(str)
    str = breakcmd(str)