diff --git a/getopt-generics.cabal b/getopt-generics.cabal
--- a/getopt-generics.cabal
+++ b/getopt-generics.cabal
@@ -1,17 +1,20 @@
 -- This file has been generated from package.yaml by Cabalize.
-name: getopt-generics
-version: 0.4
-synopsis: Simple command line argument parsing
+--
+-- see: https://github.com/sol/cabalize
+
+name:           getopt-generics
+version:        0.4.1
+synopsis:       Simple command line argument parsing
 description:
   "getopt-generics" tries to make it very simple to create command line argument parsers. An introductory example can be found in the <https://github.com/zalora/getopt-generics#getopt-generics README>.
-category: Console, System
-author: Linh Nguyen, Sönke Hahn
-maintainer: linh.nguyen@zalora.com, soenke.hahn@zalora.com
-copyright: Zalora South East Asia Pte Ltd
-license: BSD3
-license-file: LICENSE
-build-type: Simple
-cabal-version: >= 1.10
+category:       Console, System
+author:         Linh Nguyen, Sönke Hahn
+maintainer:     linh.nguyen@zalora.com, soenke.hahn@zalora.com
+copyright:      Zalora South East Asia Pte Ltd
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+cabal-version:  >= 1.10
 
 source-repository head
   type: git
@@ -38,13 +41,14 @@
   hs-source-dirs: src, test, examples
   main-is: Spec.hs
   build-depends:
-      QuickCheck
-    , base == 4.*
+      base == 4.*
     , base-compat >= 0.7
     , generics-sop
+    , tagged
+
     , hspec
     , hspec-expectations
+    , QuickCheck
     , silently
-    , tagged
   ghc-options: -Wall -fno-warn-name-shadowing -threaded -O0 -pgmL markdown-unlit
   default-language: Haskell2010
diff --git a/src/System/Console/GetOpt/Generics/Modifier.hs b/src/System/Console/GetOpt/Generics/Modifier.hs
--- a/src/System/Console/GetOpt/Generics/Modifier.hs
+++ b/src/System/Console/GetOpt/Generics/Modifier.hs
@@ -36,6 +36,9 @@
     -- ^ @RenameOption fieldName customName@ renames the option generated
     --   through the @fieldName@ by @customName@.
   | UseForPositionalArguments String
+    -- ^ @UseForPositionalArguments fieldName@ fills the field addressed by
+    --   @fieldName@ with the positional arguments (i.e. arguments that don't
+    --   correspond to a flag). The field has to have type @['String']@.
   deriving (Show, Eq, Ord)
 
 data Modifiers = Modifiers {