diff --git a/Data/Aeson/AutoType/CodeGen.hs b/Data/Aeson/AutoType/CodeGen.hs
--- a/Data/Aeson/AutoType/CodeGen.hs
+++ b/Data/Aeson/AutoType/CodeGen.hs
@@ -70,7 +70,7 @@
   ,"          exitSuccess"
   ,""]
 
--- Write a Haskell module to an output file, or stdout if `-` filename is given.
+-- | Write a Haskell module to an output file, or stdout if `-` filename is given.
 writeHaskellModule :: FilePath -> Map.HashMap Text Type -> IO ()
 writeHaskellModule outputFilename types =
     withFileOrHandle outputFilename WriteMode stdout $ \hOut -> do
diff --git a/Data/Aeson/AutoType/Extract.hs b/Data/Aeson/AutoType/Extract.hs
--- a/Data/Aeson/AutoType/Extract.hs
+++ b/Data/Aeson/AutoType/Extract.hs
@@ -15,6 +15,10 @@
 import           Data.Set           (Set )
 import           Data.List          (foldl1')
 
+-- | Compute total number of nodes (and leaves) within the value tree.
+-- Each simple JavaScript type (including String) is counted as of size 1,
+-- whereas both Array or object types are counted as 1+sum of the sizes
+-- of their member values.
 valueSize :: Value -> Int
 valueSize  Null      = 1
 valueSize (Bool   _) = 1
@@ -23,6 +27,12 @@
 valueSize (Array  a) = V.foldl' (+) 1 $ V.map valueSize a
 valueSize (Object o) = (1+) . sum . map valueSize . Hash.elems $ o
 
+-- | Compute total size of the type of the @Value@.
+-- For:
+-- * simple types it is always 1, 
+-- * for arrays it is just 1+_maximum_ size of the (single) element type,
+-- * for objects it is _sum_ of the sizes of fields (since each field type
+--   is assumed to be different.)
 valueTypeSize :: Value -> Int
 valueTypeSize  Null      = 1
 valueTypeSize (Bool   _) = 1
@@ -31,6 +41,10 @@
 valueTypeSize (Array  a) = (1+) . V.foldl' max 0 $ V.map valueTypeSize a
 valueTypeSize (Object o) = (1+) . sum . map valueTypeSize . Hash.elems $ o
 
+-- | Compute total depth of the value.
+-- For:
+-- * simple types it is 1
+-- * for either Array or Object, it is 1 + maximum of depths of their members
 valueDepth :: Value -> Int
 valueDepth  Null      = 1
 valueDepth (Bool   _) = 1
@@ -39,6 +53,8 @@
 valueDepth (Array  a) = (1+) . V.foldl' max 0 $ V.map valueDepth a
 valueDepth (Object o) = (1+) . maximum . (0:) . map valueDepth . Hash.elems $ o
 
+-- | Extract @Type@ from the JSON @Value@.
+-- Unifying types of array elements, if necessary.
 extractType :: Value -> Type
 extractType (Object o)                   = TObj $ Dict $ Hash.map extractType o
 extractType  Null                        = TNull
@@ -48,6 +64,8 @@
 extractType (Array  a) | V.null a        = TArray emptyType
 extractType (Array  a)                   = TArray $ V.foldl1' unifyTypes $ V.map extractType a
 
+-- | Standard unification procedure on @Type@s,
+-- with inclusion of @Type@ unions.
 unifyTypes :: Type -> Type -> Type
 unifyTypes TBool        TBool                         = TBool
 unifyTypes TNum         TNum                          = TNum
diff --git a/Data/Aeson/AutoType/Plugin/Subtype.hs b/Data/Aeson/AutoType/Plugin/Subtype.hs
--- a/Data/Aeson/AutoType/Plugin/Subtype.hs
+++ b/Data/Aeson/AutoType/Plugin/Subtype.hs
@@ -1,3 +1,4 @@
+-- | API to which @SubtypePlugin@s should conform.
 module Data.Aeson.AutoType.Plugin.Subtype (
     SubtypePlugin (..)
   , SubtypeDesc   (..)
@@ -10,8 +11,9 @@
 -- | Hmm... this should be existential type?
 type TypeDesc = String
 
+-- | Operations that @SubtypPlugin@ must implement.
 data SubtypePlugin = SubtypePlugin {
-    detect :: [Value]  -> Maybe SubtypeDesc -- | Check whether a set of values belongs to this type family
+    detect :: [Value]     -> Maybe SubtypeDesc -- | Check whether a set of values belongs to this type family
   , unify  :: SubtypeDesc -> SubtypeDesc -> Either SubtypeDesc Type
   }
 
diff --git a/GenerateJSONParser.hs b/GenerateJSONParser.hs
--- a/GenerateJSONParser.hs
+++ b/GenerateJSONParser.hs
@@ -30,12 +30,12 @@
 fst3 (a, _, _) = a
 
 -- * Command line flags
-defineFlag "outputFilename"  defaultOutputFilename "Write output to the given file"
-defineFlag "suggest"         True                  "Suggest candidates for unification"
-defineFlag "autounify"       True                  "Automatically unify suggested candidates"
-defineFlag "test"            False                 "Try to run generated parser after"
-defineFlag "debug"           False                 "Set this flag to see more debugging info"
-defineFlag "fakeFlag"        True                  "Ignore this flag - it doesn't exist!!!"
+defineFlag "o:outputFilename"  defaultOutputFilename "Write output to the given file"
+defineFlag "suggest"           True                  "Suggest candidates for unification"
+defineFlag "autounify"         True                  "Automatically unify suggested candidates"
+defineFlag "t:test"            False                 "Try to run generated parser after"
+defineFlag "d:debug"           False                 "Set this flag to see more debugging info"
+defineFlag "fakeFlag"          True                  "Ignore this flag - it doesn't exist!!! It is workaround to library problem."
 
 -- Tracing is switched off:
 myTrace :: String -> IO ()
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,9 @@
 Changelog
 =========
+    0.2.5.11  Mar 2015
+
+        * Add short versions of command line flags: -o, -d, and -t.
+
     0.2.5.10  Mar 2015
 
         * Bump up lens dependency.
diff --git a/json-autotype.cabal b/json-autotype.cabal
--- a/json-autotype.cabal
+++ b/json-autotype.cabal
@@ -1,6 +1,6 @@
 -- Build information for the package.
 name:                json-autotype
-version:             0.2.5.10
+version:             0.2.5.11
 synopsis:            Automatic type declaration for JSON input data
 description:         Generates datatype declarations with Aeson's "FromJSON" instances
                      from a set of example ".json" files.