Add simple 'directories' plugin

plugins/directories.lua

@@ -0,0 +1,17 @@
+-- https://stackoverflow.com/a/3254007/704831
+function is_dir(path)
+    local f = io.open(path, "r")
+    local ok, err, code = f:read(1)
+    f:close()
+    return code == 21
+end
+
+function preprocess(path)
+    if is_dir(path) then
+        tmpfile = os.tmpname()
+        os.execute("ls -alh --color=always '" .. path .. "' > '" .. tmpfile .. "'")
+        return tmpfile
+    else
+        return path
+    end
+end