new get_viewer_from_env function

git-svn-id: svn://tug.org/texlive/trunk@9448 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 12 insertions, 3 deletions

diff --git a/Master/texmf/scripts/texlive/texdoc.tlu b/Master/texmf/scripts/texlive/texdoc.tlu
index 45862a73088..0f12822ebdf 100755
--- a/Master/texmf/scripts/texlive/texdoc.tlu
+++ b/Master/texmf/scripts/texlive/texdoc.tlu
@@ -268,11 +268,20 @@ function setup_config ()
     end
 end
 
+function get_viewer_from_env (variable)
+    local viewer = os.getenv(variable)
+    if viewer then
+        return "("..viewer.." %s)"
+    else
+        return nil
+    end
+end
+
 -- with intermediate priority, we shall make use of some environment variables
 set_config_list {
-    viewer_html = os.getenv("BROWSER"),
-    viewer_tex  = os.getenv("PAGER"),
-    viewer_txt  = os.getenv("PAGER")
+    viewer_html = get_viewer_from_env ("BROWSER"),
+    viewer_tex  = get_viewer_from_env ("PAGER"),
+    viewer_txt  = get_viewer_from_env ("PAGER")
 }
 
 -- for default viewer on general Unix, we use a list