     end
   end
 
-  @doc "Retuns the source code and filename for the given `source_file_or_source`."
+  @doc "Returns the source code and filename for the given `source_file_or_source`."
   def source_and_filename(source_file_or_source, default_filename \\ "nofilename")
 
   def source_and_filename(%__MODULE__{filename: filename} = source_file, _default_filename) do

    end
  end

  @doc "Retuns the lines of source code for the given `source_file`."
  def lines(source_file)

  def lines(%__MODULE__{filename: filename}) do

    }
  end

  @doc "Returns the AST for the given `source_file`."
  def ast(source_file)

  def ast(%__MODULE__{filename: filename}) do
