diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,18 @@
 
+## 4.1.0.0
+
+*   Fix a regression which arose in 4.0, whereby excess spaces would be inserted for unusual strings like dates and IP addresses.
+    [#105](https://github.com/cdepillabout/pretty-simple/pull/105)
+*   Attach warnings to debugging functions, so that they're easy to find and remove.
+    [#103](https://github.com/cdepillabout/pretty-simple/pull/103)
+*   Some minor improvements to the CLI tool:
+    *   Add a `--version`/`-v` flag.
+        [#83](https://github.com/cdepillabout/pretty-simple/pull/83)
+    *   Add a trailing newline.
+        [#87](https://github.com/cdepillabout/pretty-simple/pull/87)
+    *   Install by default, without requiring a flag.
+        [#94](https://github.com/cdepillabout/pretty-simple/pull/94)
+
 ## 4.0.0.0
 
 *   Expand `OutputOptions`:
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -44,12 +44,18 @@
 `pretty-simple` can be easily used from `ghci` when debugging.
 
 When using `stack` to run `ghci`, just append the `--package` flag to
-the command line to load `pretty-simple`.
+the command line to load `pretty-simple`:
 
 ```sh
 $ stack ghci --package pretty-simple
 ```
 
+Or, with cabal:
+
+```sh
+$ cabal repl --build-depends pretty-simple
+```
+
 Once you get a prompt in `ghci`, you can use `import` to get `pretty-simple`'s
 [`pPrint`](https://hackage.haskell.org/package/pretty-simple/docs/Text-Pretty-Simple.html#v:pPrint)
 function in scope.
@@ -81,7 +87,7 @@
     - Easy to understand deeply nested data types.
 - Configurable
     - Indentation, compactness, colors and more are configurable with the
-      [`pPrintOpt`](https://hackage.haskell.org/package/pretty-simple/docs/Text-Pretty-Simple.html#v:pPrintOpt)
+      [`pPrintOpt`](https://hackage.haskell.org/package/pretty-simple-1.0.0.6/docs/Text-Pretty-Simple.html#v:pPrintOpt)
       function.
 - Fast
     - No problem pretty-printing data types thousands of lines long.
@@ -106,11 +112,14 @@
 
 The `pPrint` function can be used as the default output function in GHCi.
 
-All you need to do is run GHCi like this:
+All you need to do is run GHCi with a command like one of these:
 
 ```sh
 $ stack ghci --ghci-options "-interactive-print=Text.Pretty.Simple.pPrint" --package pretty-simple
 ```
+```sh
+$ cabal repl --repl-options "-interactive-print=Text.Pretty.Simple.pPrint" --build-depends pretty-simple
+```
 
 Now, whenever you make GHCi evaluate an expression, GHCi will pretty-print the
 result using `pPrint`!  See
@@ -181,7 +190,7 @@
 must enable the `buildexe` flag, since it will not be built by default:
 
 ```sh
-$ stack install pretty-simple-4.0.0.0 --flag pretty-simple:buildexe
+$ stack install pretty-simple-2.2.0.1 --flag pretty-simple:buildexe
 ```
 
 When run on the command line, you can paste in the Haskell datatype you want to
diff --git a/app/Main.hs b/app/Main.hs
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -23,14 +23,16 @@
 --   ]
 -- @
 
+import Data.Monoid ((<>))
 import Data.Text (unpack)
 import qualified Data.Text.IO as T
 import qualified Data.Text.Lazy.IO as LT
-import Options.Applicative 
-       ( Parser, ReadM, execParser, fullDesc, help, helper, info, long
-       , option, progDesc, readerError, short, showDefaultWith, str, value, (<**>))
-import Data.Monoid ((<>))
-import Text.Pretty.Simple 
+import Data.Version (showVersion)
+import Options.Applicative
+       ( Parser, ReadM, execParser, fullDesc, help, helper, info, infoOption, long
+       , option, progDesc, readerError, short, showDefaultWith, str, value)
+import Paths_pretty_simple (version)
+import Text.Pretty.Simple
        ( pStringOpt, OutputOptions
        , defaultOutputOptionsDarkBg
        , defaultOutputOptionsLightBg
@@ -41,7 +43,9 @@
            | LightBg
            | NoColor
 
-newtype Args = Args { color :: Color }
+newtype Args = Args
+  { color :: Color
+  }
 
 colorReader :: ReadM Color
 colorReader = do
@@ -58,19 +62,28 @@
         ( long "color"
        <> short 'c'
        <> help "Select printing color. Available options: dark-bg (default), light-bg, no-color."
-       <> showDefaultWith (\_ -> "dark-bg")
+       <> showDefaultWith (const "dark-bg")
        <> value DarkBg
         )
 
+versionOption :: Parser (a -> a)
+versionOption =
+  infoOption
+    (showVersion version)
+    ( long "version"
+   <> short 'V'
+   <> help "Show version"
+    )
+
 main :: IO ()
 main = do
   args' <- execParser opts
   input <- T.getContents
   let printOpt = getPrintOpt $ color args'
       output = pStringOpt printOpt $ unpack input
-  LT.putStr output
+  LT.putStrLn output
   where
-    opts = info (args <**> helper)
+    opts = info (helper <*> versionOption <*> args)
       ( fullDesc
      <> progDesc "Format Haskell data types with indentation and highlighting"
       )
diff --git a/pretty-simple.cabal b/pretty-simple.cabal
--- a/pretty-simple.cabal
+++ b/pretty-simple.cabal
@@ -1,5 +1,5 @@
 name:                pretty-simple
-version:             4.0.0.0
+version:             4.1.0.0
 synopsis:            pretty printer for data types with a 'Show' instance.
 description:         Please see <https://github.com/cdepillabout/pretty-simple#readme README.md>.
 homepage:            https://github.com/cdepillabout/pretty-simple
@@ -22,7 +22,7 @@
 
 flag buildexe
   description: Build an small command line program that pretty-print anything from stdin.
-  default:     False
+  default:     True
 
 flag buildexample
   description: Build a small example program showing how to use the pPrint function
@@ -50,6 +50,7 @@
 
 executable pretty-simple
   main-is:             Main.hs
+  other-modules:       Paths_pretty_simple
   hs-source-dirs:      app
   build-depends:       base
                      , pretty-simple
diff --git a/src/Debug/Pretty/Simple.hs b/src/Debug/Pretty/Simple.hs
--- a/src/Debug/Pretty/Simple.hs
+++ b/src/Debug/Pretty/Simple.hs
@@ -95,6 +95,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceIO "'pTraceIO' remains in code" #-}
 pTraceIO :: String -> IO ()
 pTraceIO = pTraceOptIO CheckColorTty defaultOutputOptionsDarkBg
 
@@ -113,6 +114,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTrace "'pTrace' remains in code" #-}
 pTrace :: String -> a -> a
 pTrace = pTraceOpt CheckColorTty defaultOutputOptionsDarkBg
 
@@ -121,6 +123,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceId "'pTraceId' remains in code" #-}
 pTraceId :: String -> String
 pTraceId = pTraceIdOpt CheckColorTty defaultOutputOptionsDarkBg
 
@@ -139,6 +142,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceShow "'pTraceShow' remains in code" #-}
 pTraceShow :: (Show a) => a -> b -> b
 pTraceShow = pTraceShowOpt CheckColorTty defaultOutputOptionsDarkBg
 
@@ -147,6 +151,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceShowId "'pTraceShowId' remains in code" #-}
 pTraceShowId :: (Show a) => a -> a
 pTraceShowId = pTraceShowIdOpt CheckColorTty defaultOutputOptionsDarkBg
 {-|
@@ -168,6 +173,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceM "'pTraceM' remains in code" #-}
 #if __GLASGOW_HASKELL__ < 800
 pTraceM :: (Monad f) => String -> f ()
 #else
@@ -185,6 +191,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceShowM "'pTraceShowM' remains in code" #-}
 #if __GLASGOW_HASKELL__ < 800
 pTraceShowM :: (Show a, Monad f) => a -> f ()
 #else
@@ -204,6 +211,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceStack "'pTraceStack' remains in code" #-}
 pTraceStack :: String -> a -> a
 pTraceStack = pTraceStackOpt CheckColorTty defaultOutputOptionsDarkBg
 
@@ -221,6 +229,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceEvent "'pTraceEvent' remains in code" #-}
 pTraceEvent :: String -> a -> a
 pTraceEvent = pTraceEventOpt CheckColorTty defaultOutputOptionsDarkBg
 
@@ -233,6 +242,7 @@
 
 @since 2.0.1.0
 -}
+{-# WARNING pTraceEventIO "'pTraceEventIO' remains in code" #-}
 pTraceEventIO :: String -> IO ()
 pTraceEventIO = pTraceEventOptIO CheckColorTty defaultOutputOptionsDarkBg
 
@@ -249,6 +259,7 @@
 -- that uses 'pTraceMarker'.
 --
 -- @since 2.0.1.0
+{-# WARNING pTraceMarker "'pTraceMarker' remains in code" #-}
 pTraceMarker :: String -> a -> a
 pTraceMarker = pTraceMarkerOpt CheckColorTty defaultOutputOptionsDarkBg
 
@@ -259,12 +270,14 @@
 -- to other IO actions.
 --
 -- @since 2.0.1.0
+{-# WARNING pTraceMarkerIO "'pTraceMarkerIO' remains in code" #-}
 pTraceMarkerIO :: String -> IO ()
 pTraceMarkerIO = pTraceMarkerOptIO CheckColorTty defaultOutputOptionsDarkBg
 
 ------------------------------------------
 -- Helpers
 ------------------------------------------
+{-# WARNING pStringTTYOptIO "'pStringTTYOptIO' remains in code" #-}
 pStringTTYOptIO :: CheckColorTty -> OutputOptions -> String -> IO Text
 pStringTTYOptIO checkColorTty outputOptions v = do
   realOutputOpts <-
@@ -273,14 +286,17 @@
       NoCheckColorTty -> pure outputOptions
   pure $ pStringOpt realOutputOpts v
 
+{-# WARNING pStringTTYOpt "'pStringTTYOpt' remains in code" #-}
 pStringTTYOpt :: CheckColorTty -> OutputOptions -> String -> Text
 pStringTTYOpt checkColorTty outputOptions =
   unsafePerformIO . pStringTTYOptIO checkColorTty outputOptions
 
+{-# WARNING pShowTTYOptIO "'pShowTTYOptIO' remains in code" #-}
 pShowTTYOptIO :: Show a => CheckColorTty -> OutputOptions -> a -> IO Text
 pShowTTYOptIO checkColorTty outputOptions =
   pStringTTYOptIO checkColorTty outputOptions . show
 
+{-# WARNING pShowTTYOpt "'pShowTTYOpt' remains in code" #-}
 pShowTTYOpt :: Show a => CheckColorTty -> OutputOptions -> a -> Text
 pShowTTYOpt checkColorTty outputOptions =
   unsafePerformIO . pShowTTYOptIO checkColorTty outputOptions
@@ -289,22 +305,27 @@
 -- Traces forcing color
 ------------------------------------------
 -- | Similar to 'pTrace', but forcing color.
+{-# WARNING pTraceForceColor "'pTraceForceColor' remains in code" #-}
 pTraceForceColor :: String -> a -> a
 pTraceForceColor = pTraceOpt NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceId', but forcing color.
+{-# WARNING pTraceIdForceColor "'pTraceIdForceColor' remains in code" #-}
 pTraceIdForceColor :: String -> String
 pTraceIdForceColor = pTraceIdOpt NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceShow', but forcing color.
+{-# WARNING pTraceShowForceColor "'pTraceShowForceColor' remains in code" #-}
 pTraceShowForceColor :: (Show a) => a -> b -> b
 pTraceShowForceColor = pTraceShowOpt NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceShowId', but forcing color.
+{-# WARNING pTraceShowIdForceColor "'pTraceShowIdForceColor' remains in code" #-}
 pTraceShowIdForceColor :: (Show a) => a -> a
 pTraceShowIdForceColor =
   pTraceShowIdOpt NoCheckColorTty defaultOutputOptionsDarkBg
 -- | Similar to 'pTraceM', but forcing color.
+{-# WARNING pTraceMForceColor "'pTraceMForceColor' remains in code" #-}
 #if __GLASGOW_HASKELL__ < 800
 pTraceMForceColor :: (Monad f) => String -> f ()
 #else
@@ -312,6 +333,7 @@
 #endif
 pTraceMForceColor = pTraceOptM NoCheckColorTty defaultOutputOptionsDarkBg
 -- | Similar to 'pTraceShowM', but forcing color.
+{-# WARNING pTraceShowMForceColor "'pTraceShowMForceColor' remains in code" #-}
 #if __GLASGOW_HASKELL__ < 800
 pTraceShowMForceColor :: (Show a, Monad f) => a -> f ()
 #else
@@ -321,31 +343,37 @@
   pTraceShowOptM NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceStack', but forcing color.
+{-# WARNING pTraceStackForceColor "'pTraceStackForceColor' remains in code" #-}
 pTraceStackForceColor :: String -> a -> a
 pTraceStackForceColor =
   pTraceStackOpt NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceEvent', but forcing color.
+{-# WARNING pTraceEventForceColor "'pTraceEventForceColor' remains in code" #-}
 pTraceEventForceColor :: String -> a -> a
 pTraceEventForceColor =
   pTraceEventOpt NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceEventIO', but forcing color.
+{-# WARNING pTraceEventIOForceColor "'pTraceEventIOForceColor' remains in code" #-}
 pTraceEventIOForceColor :: String -> IO ()
 pTraceEventIOForceColor =
   pTraceEventOptIO NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceMarker', but forcing color.
+{-# WARNING pTraceMarkerForceColor "'pTraceMarkerForceColor' remains in code" #-}
 pTraceMarkerForceColor :: String -> a -> a
 pTraceMarkerForceColor =
   pTraceMarkerOpt NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceMarkerIO', but forcing color.
+{-# WARNING pTraceMarkerIOForceColor "'pTraceMarkerIOForceColor' remains in code" #-}
 pTraceMarkerIOForceColor :: String -> IO ()
 pTraceMarkerIOForceColor =
   pTraceMarkerOptIO NoCheckColorTty defaultOutputOptionsDarkBg
 
 -- | Similar to 'pTraceIO', but forcing color.
+{-# WARNING pTraceIOForceColor "'pTraceIOForceColor' remains in code" #-}
 pTraceIOForceColor :: String -> IO ()
 pTraceIOForceColor = pTraceOptIO NoCheckColorTty defaultOutputOptionsDarkBg
 
@@ -359,6 +387,7 @@
 -- ()
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceNoColor "'pTraceNoColor' remains in code" #-}
 pTraceNoColor :: String -> a -> a
 pTraceNoColor = pTraceOpt NoCheckColorTty defaultOutputOptionsNoColor
 
@@ -372,6 +401,7 @@
 -- ()
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceIdNoColor "'pTraceIdNoColor' remains in code" #-}
 pTraceIdNoColor :: String -> String
 pTraceIdNoColor = pTraceIdOpt NoCheckColorTty defaultOutputOptionsNoColor
 
@@ -388,6 +418,7 @@
 -- ()
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceShowNoColor "'pTraceShowNoColor' remains in code" #-}
 pTraceShowNoColor :: (Show a) => a -> b -> b
 pTraceShowNoColor = pTraceShowOpt NoCheckColorTty defaultOutputOptionsNoColor
 
@@ -404,6 +435,7 @@
 -- ()
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceShowIdNoColor "'pTraceShowIdNoColor' remains in code" #-}
 pTraceShowIdNoColor :: (Show a) => a -> a
 pTraceShowIdNoColor =
   pTraceShowIdOpt NoCheckColorTty defaultOutputOptionsNoColor
@@ -413,6 +445,7 @@
 -- wow
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceMNoColor "'pTraceMNoColor' remains in code" #-}
 #if __GLASGOW_HASKELL__ < 800
 pTraceMNoColor :: (Monad f) => String -> f ()
 #else
@@ -428,6 +461,7 @@
 -- ]
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceShowMNoColor "'pTraceShowMNoColor' remains in code" #-}
 #if __GLASGOW_HASKELL__ < 800
 pTraceShowMNoColor :: (Show a, Monad f) => a -> f ()
 #else
@@ -442,18 +476,21 @@
 -- ()
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceStackNoColor "'pTraceStackNoColor' remains in code" #-}
 pTraceStackNoColor :: String -> a -> a
 pTraceStackNoColor = pTraceStackOpt NoCheckColorTty defaultOutputOptionsNoColor
 
 -- | Similar to 'pTraceEvent', but without color.
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceEventNoColor "'pTraceEventNoColor' remains in code" #-}
 pTraceEventNoColor :: String -> a -> a
 pTraceEventNoColor = pTraceEventOpt NoCheckColorTty defaultOutputOptionsNoColor
 
 -- | Similar to 'pTraceEventIO', but without color.
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceEventIONoColor "'pTraceEventIONoColor' remains in code" #-}
 pTraceEventIONoColor :: String -> IO ()
 pTraceEventIONoColor =
   pTraceEventOptIO NoCheckColorTty defaultOutputOptionsNoColor
@@ -461,6 +498,7 @@
 -- | Similar to 'pTraceMarker', but without color.
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceMarkerNoColor "'pTraceMarkerNoColor' remains in code" #-}
 pTraceMarkerNoColor :: String -> a -> a
 pTraceMarkerNoColor =
   pTraceMarkerOpt NoCheckColorTty defaultOutputOptionsNoColor
@@ -468,6 +506,7 @@
 -- | Similar to 'pTraceMarkerIO', but without color.
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceMarkerIONoColor "'pTraceMarkerIONoColor' remains in code" #-}
 pTraceMarkerIONoColor :: String -> IO ()
 pTraceMarkerIONoColor =
   pTraceMarkerOptIO NoCheckColorTty defaultOutputOptionsNoColor
@@ -481,6 +520,7 @@
 -- )
 --
 -- @since 2.0.2.0
+{-# WARNING pTraceIONoColor "'pTraceIONoColor' remains in code" #-}
 pTraceIONoColor :: String -> IO ()
 pTraceIONoColor = pTraceOptIO NoCheckColorTty defaultOutputOptionsNoColor
 
@@ -490,6 +530,7 @@
 {-|
 Like 'pTrace' but takes OutputOptions.
 -}
+{-# WARNING pTraceOpt "'pTraceOpt' remains in code" #-}
 pTraceOpt :: CheckColorTty -> OutputOptions -> String -> a -> a
 pTraceOpt checkColorTty outputOptions =
   trace . unpack . pStringTTYOpt checkColorTty outputOptions
@@ -497,6 +538,7 @@
 {-|
 Like 'pTraceId' but takes OutputOptions.
 -}
+{-# WARNING pTraceIdOpt "'pTraceIdOpt' remains in code" #-}
 pTraceIdOpt :: CheckColorTty -> OutputOptions -> String -> String
 pTraceIdOpt checkColorTty outputOptions a =
   pTraceOpt checkColorTty outputOptions a a
@@ -504,6 +546,7 @@
 {-|
 Like 'pTraceShow' but takes OutputOptions.
 -}
+{-# WARNING pTraceShowOpt "'pTraceShowOpt' remains in code" #-}
 pTraceShowOpt :: (Show a) => CheckColorTty -> OutputOptions -> a -> b -> b
 pTraceShowOpt checkColorTty outputOptions =
   trace . unpack . pShowTTYOpt checkColorTty outputOptions
@@ -511,6 +554,7 @@
 {-|
 Like 'pTraceShowId' but takes OutputOptions.
 -}
+{-# WARNING pTraceShowIdOpt "'pTraceShowIdOpt' remains in code" #-}
 pTraceShowIdOpt :: (Show a) => CheckColorTty -> OutputOptions -> a -> a
 pTraceShowIdOpt checkColorTty outputOptions a =
   trace (unpack $ pShowTTYOpt checkColorTty outputOptions a) a
@@ -518,12 +562,14 @@
 {-|
 Like 'pTraceIO' but takes OutputOptions.
 -}
+{-# WARNING pTraceOptIO "'pTraceOptIO' remains in code" #-}
 pTraceOptIO :: CheckColorTty -> OutputOptions -> String -> IO ()
 pTraceOptIO checkColorTty outputOptions =
   traceIO . unpack <=< pStringTTYOptIO checkColorTty outputOptions
 {-|
 Like 'pTraceM' but takes OutputOptions.
 -}
+{-# WARNING pTraceOptM "'pTraceOptM' remains in code" #-}
 #if __GLASGOW_HASKELL__ < 800
 pTraceOptM :: (Monad f) => CheckColorTty -> OutputOptions -> String -> f ()
 #else
@@ -535,6 +581,7 @@
 {-|
 Like 'pTraceShowM' but takes OutputOptions.
 -}
+{-# WARNING pTraceShowOptM "'pTraceShowOptM' remains in code" #-}
 #if __GLASGOW_HASKELL__ < 800
 pTraceShowOptM ::
      (Show a, Monad f) => CheckColorTty -> OutputOptions -> a -> f ()
@@ -548,6 +595,7 @@
 {-|
 Like 'pTraceStack' but takes OutputOptions.
 -}
+{-# WARNING pTraceStackOpt "'pTraceStackOpt' remains in code" #-}
 pTraceStackOpt :: CheckColorTty -> OutputOptions -> String -> a -> a
 pTraceStackOpt checkColorTty outputOptions =
   traceStack . unpack . pStringTTYOpt checkColorTty outputOptions
@@ -555,6 +603,7 @@
 {-|
 Like 'pTraceEvent' but takes OutputOptions.
 -}
+{-# WARNING pTraceEventOpt "'pTraceEventOpt' remains in code" #-}
 pTraceEventOpt :: CheckColorTty -> OutputOptions -> String -> a -> a
 pTraceEventOpt checkColorTty outputOptions =
   traceEvent . unpack . pStringTTYOpt checkColorTty outputOptions
@@ -562,6 +611,7 @@
 {-|
 Like 'pTraceEventIO' but takes OutputOptions.
 -}
+{-# WARNING pTraceEventOptIO "'pTraceEventOptIO' remains in code" #-}
 pTraceEventOptIO :: CheckColorTty -> OutputOptions -> String -> IO ()
 pTraceEventOptIO checkColorTty outputOptions =
   traceEventIO . unpack <=< pStringTTYOptIO checkColorTty outputOptions
@@ -569,6 +619,7 @@
 {-|
 Like 'pTraceMarker' but takes OutputOptions.
 -}
+{-# WARNING pTraceMarkerOpt "'pTraceMarkerOpt' remains in code" #-}
 pTraceMarkerOpt :: CheckColorTty -> OutputOptions -> String -> a -> a
 pTraceMarkerOpt checkColorTty outputOptions =
   traceMarker . unpack . pStringTTYOpt checkColorTty outputOptions
@@ -576,6 +627,7 @@
 {-|
 Like 'pTraceMarkerIO' but takes OutputOptions.
 -}
+{-# WARNING pTraceMarkerOptIO "'pTraceMarkerOptIO' remains in code" #-}
 pTraceMarkerOptIO :: CheckColorTty -> OutputOptions -> String -> IO ()
 pTraceMarkerOptIO checkColorTty outputOptions =
   traceMarkerIO . unpack <=< pStringTTYOptIO checkColorTty outputOptions
diff --git a/src/Text/Pretty/Simple.hs b/src/Text/Pretty/Simple.hs
--- a/src/Text/Pretty/Simple.hs
+++ b/src/Text/Pretty/Simple.hs
@@ -1,12 +1,8 @@
 {-# LANGUAGE CPP #-}
-{-# LANGUAGE DeriveDataTypeable #-}
-{-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TemplateHaskell #-}
 
 {-|
 Module      : Text.Pretty.Simple
@@ -691,6 +687,29 @@
 --        ( B
 --            ( B ( B A ) )
 --        )
+--
+-- __Weird/illegal show instances__
+--
+-- >>> pPrintString "2019-02-18 20:56:24.265489 UTC"
+-- 2019-02-18 20:56:24.265489 UTC
+--
+-- >>> pPrintString "a7ed86f7-7f2c-4be5-a760-46a3950c2abf"
+-- a7ed86f7-7f2c-4be5-a760-46a3950c2abf
+--
+-- >>> pPrintString "192.168.0.1:8000"
+-- 192.168.0.1:8000
+--
+-- >>> pPrintString "A @\"type\" 1"
+-- A @"type" 1
+--
+-- >>> pPrintString "2+2"
+-- 2+2
+--
+-- >>> pPrintString "1.0e-2"
+-- 1.0e-2
+--
+-- >>> pPrintString "0x1b"
+-- 0x1b
 --
 -- __Other__
 --
diff --git a/src/Text/Pretty/Simple/Internal/Color.hs b/src/Text/Pretty/Simple/Internal/Color.hs
--- a/src/Text/Pretty/Simple/Internal/Color.hs
+++ b/src/Text/Pretty/Simple/Internal/Color.hs
@@ -7,7 +7,6 @@
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TemplateHaskell #-}
 
 {-|
 Module      : Text.Pretty.Simple.Internal.Color
diff --git a/src/Text/Pretty/Simple/Internal/Expr.hs b/src/Text/Pretty/Simple/Internal/Expr.hs
--- a/src/Text/Pretty/Simple/Internal/Expr.hs
+++ b/src/Text/Pretty/Simple/Internal/Expr.hs
@@ -4,7 +4,6 @@
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TemplateHaskell #-}
 
 {-|
 Module      : Text.Pretty.Simple.Internal.Expr
diff --git a/src/Text/Pretty/Simple/Internal/ExprParser.hs b/src/Text/Pretty/Simple/Internal/ExprParser.hs
--- a/src/Text/Pretty/Simple/Internal/ExprParser.hs
+++ b/src/Text/Pretty/Simple/Internal/ExprParser.hs
@@ -1,10 +1,7 @@
 {-# LANGUAGE CPP #-}
-{-# LANGUAGE DeriveDataTypeable #-}
-{-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE TemplateHaskell #-}
 
 {-|
 Module      : Text.Pretty.Simple.Internal.ExprParser
diff --git a/src/Text/Pretty/Simple/Internal/Printer.hs b/src/Text/Pretty/Simple/Internal/Printer.hs
--- a/src/Text/Pretty/Simple/Internal/Printer.hs
+++ b/src/Text/Pretty/Simple/Internal/Printer.hs
@@ -32,14 +32,14 @@
 import Control.Monad.IO.Class (MonadIO, liftIO)
 import Control.Monad (join)
 import Control.Monad.State (MonadState, evalState, modify, gets)
-import Data.Char (isPrint, isSpace, ord)
-import Data.List (dropWhileEnd)
+import Data.Char (isPrint, ord)
 import Data.List.NonEmpty (NonEmpty, nonEmpty)
 import Data.Maybe (fromMaybe)
 import Prettyprinter
-  (indent, line', PageWidth(AvailablePerLine), layoutPageWidth, nest, hsep,
+  (indent, line', PageWidth(AvailablePerLine), layoutPageWidth, nest,
     concatWith, space, Doc, SimpleDocStream, annotate, defaultLayoutOptions,
-    enclose, hcat, layoutSmart, line, unAnnotateS, pretty, group)
+    enclose, hcat, layoutSmart, line, unAnnotateS, pretty, group,
+    removeTrailingWhitespace)
 import Data.Typeable (Typeable)
 import GHC.Generics (Generic)
 import Numeric (showHex)
@@ -197,11 +197,11 @@
 layoutString :: OutputOptions -> String -> SimpleDocStream Style
 layoutString opts =
   annotateStyle opts
+    . removeTrailingWhitespace
     . layoutSmart defaultLayoutOptions
       {layoutPageWidth = AvailablePerLine (outputOptionsPageWidth opts) 1}
     . indent (outputOptionsInitialIndent opts)
     . prettyExprs' opts
-    . preprocess opts
     . expressionParse
 
 -- | Slight adjustment of 'prettyExprs' for the outermost level,
@@ -220,10 +220,10 @@
       in
         if isSimple x then
           -- keep the expression on the current line
-          nest 2 $ space <> doc
+          nest 2 doc
         else
           -- put the expression on a new line, indented (unless grouped)
-          nest (outputOptionsIndentAmount opts) $ line <> doc
+          nest (outputOptionsIndentAmount opts) $ line' <> doc
 
 -- | Construct a 'Doc' from a single 'Expr'.
 prettyExpr :: OutputOptions -> Expr -> Doc Annotation
@@ -231,20 +231,30 @@
   Brackets xss -> list "[" "]" xss
   Braces xss -> list "{" "}" xss
   Parens xss -> list "(" ")" xss
-  StringLit s -> join enclose (annotate Quote "\"") $ annotate String $ pretty s
+  StringLit s -> join enclose (annotate Quote "\"") $ annotate String $ pretty $
+    case outputOptionsStringStyle opts of
+      Literal -> s
+      EscapeNonPrintable -> escapeNonPrintable $ readStr s
+      DoNotEscapeNonPrintable -> readStr s
   CharLit s -> join enclose (annotate Quote "'") $ annotate String $ pretty s
   Other s -> pretty s
   NumberLit n -> annotate Num $ pretty n
   where
+    readStr :: String -> String
+    readStr s = fromMaybe s . readMaybe $ '"' : s ++ "\""
     list :: Doc Annotation -> Doc Annotation -> CommaSeparated [Expr]
       -> Doc Annotation
     list open close (CommaSeparated xss) =
       enclose (annotate Open open) (annotate Close close) $ case xss of
         [] -> mempty
         [xs] | all isSimple xs ->
-          space <> hsep (map (prettyExpr opts) xs) <> space
-        _ -> concatWith lineAndCommaSep (map (prettyExprs opts) xss)
+          space <> hcat (map (prettyExpr opts) xs) <> space
+        _ -> concatWith lineAndCommaSep (map (\xs -> spaceIfNeeded xs <> prettyExprs opts xs) xss)
           <> if outputOptionsCompactParens opts then space else line
+          where
+            spaceIfNeeded = \case
+              Other (' ' : _) : _ -> mempty
+              _ -> space
     lineAndCommaSep x y = x <> line' <> annotate Comma "," <> y
 
 -- | Determine whether this expression should be displayed on a single line.
@@ -292,33 +302,6 @@
   | String
   | Num
 
--- | Apply various transformations to clean up the 'Expr's.
-preprocess :: OutputOptions -> [Expr] -> [Expr]
-preprocess opts = map processExpr . removeEmptyOthers
-  where
-    processExpr = \case
-      Brackets xss -> Brackets $ cs xss
-      Braces xss -> Braces $ cs xss
-      Parens xss -> Parens $ cs xss
-      StringLit s -> StringLit $
-        case outputOptionsStringStyle opts of
-          Literal -> s
-          EscapeNonPrintable -> escapeNonPrintable $ readStr s
-          DoNotEscapeNonPrintable -> readStr s
-      CharLit s -> CharLit s
-      Other s -> Other $ shrinkWhitespace $ strip s
-      NumberLit n -> NumberLit n
-    cs (CommaSeparated ess) = CommaSeparated $ map (preprocess opts) ess
-    readStr :: String -> String
-    readStr s = fromMaybe s . readMaybe $ '"': s ++ "\""
-
--- | Remove any 'Other' 'Expr's which contain only spaces.
--- These provide no value, but mess up formatting if left in.
-removeEmptyOthers :: [Expr] -> [Expr]
-removeEmptyOthers = filter $ \case
-  Other s -> not $ all isSpace s
-  _ -> True
-
 -- | Replace non-printable characters with hex escape sequences.
 --
 -- >>> escapeNonPrintable "\x1\x2"
@@ -334,7 +317,7 @@
 -- >>> escapeNonPrintable "h\101llo"
 -- "hello"
 escapeNonPrintable :: String -> String
-escapeNonPrintable input = foldr escape "" input
+escapeNonPrintable = foldr escape ""
 
 -- | Replace an unprintable character except a newline
 -- with a hex escape sequence.
@@ -342,22 +325,6 @@
 escape c
   | isPrint c || c == '\n' = (c:)
   | otherwise = ('\\':) . ('x':) . showHex (ord c)
-
--- | Compress multiple whitespaces to just one whitespace.
---
--- >>> shrinkWhitespace "  hello    there  "
--- " hello there "
-shrinkWhitespace :: String -> String
-shrinkWhitespace (' ':' ':t) = shrinkWhitespace (' ':t)
-shrinkWhitespace (h:t) = h : shrinkWhitespace t
-shrinkWhitespace "" = ""
-
--- | Remove trailing and leading whitespace (see 'Data.Text.strip').
---
--- >>> strip "  hello    there  "
--- "hello    there"
-strip :: String -> String
-strip = dropWhile isSpace . dropWhileEnd isSpace
 
 -- | A bidirectional Turing-machine tape:
 -- infinite in both directions, with a head pointing to one element.