diff --git a/lua/csv.lua b/lua/csv.lua
index a7dffc7..d01c7b1 100644
--- a/lua/csv.lua
+++ b/lua/csv.lua
@@ -150,13 +150,9 @@ end
 --  the buffer.
 local function separated_values_iterator(file, parameters)
   local buffer_size = parameters.buffer_size or DEFAULT_BUFFER_SIZE
-  local filename = parameters.filename or "<unknown>"
   local buffer = ""
   local anchor_pos = 1
-  local line, line_start = 1, 1
-  local column_name_map = parameters.columns and
-    build_column_name_map(parameters.columns)
-  local column_index_map
+  local line_start = 1
 
 
   -- Cut the front off the buffer if we've already read it
@@ -208,6 +204,13 @@ local function separated_values_iterator(file, parameters)
   end
 
 
+  local filename = parameters.filename or "<unknown>"
+  local line = 1
+  local column_name_map = parameters.columns and
+    build_column_name_map(parameters.columns)
+  local column_index_map
+
+
   -- If the user hasn't specified a separator, try to work out what it is.
   local sep = parameters.separator
   if not sep then