diff --git a/COPYING b/COPYING
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+++ b/COPYING
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+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
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+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.
diff --git a/Language/Symantic/Document.hs b/Language/Symantic/Document.hs
new file mode 100644
--- /dev/null
+++ b/Language/Symantic/Document.hs
@@ -0,0 +1,13 @@
+module Language.Symantic.Document
+ ( module Language.Symantic.Document.Sym
+ , module Language.Symantic.Document.ANSI
+ , module Language.Symantic.Document.Dim
+ , module Language.Symantic.Document.Plain
+ , module Language.Symantic.Document.Valid
+ ) where
+
+import Language.Symantic.Document.Sym
+import Language.Symantic.Document.ANSI
+import Language.Symantic.Document.Dim
+import Language.Symantic.Document.Plain
+import Language.Symantic.Document.Valid
diff --git a/Language/Symantic/Document/ANSI.hs b/Language/Symantic/Document/ANSI.hs
new file mode 100644
--- /dev/null
+++ b/Language/Symantic/Document/ANSI.hs
@@ -0,0 +1,162 @@
+module Language.Symantic.Document.ANSI where
+
+import Control.Monad (Monad(..), replicateM_)
+import Data.Bool (Bool(..))
+import Data.Function (($), (.), const)
+import Data.Monoid (Monoid(..))
+import Data.Semigroup (Semigroup(..))
+import Data.String (IsString(..))
+import System.Console.ANSI
+import System.IO (IO)
+import Text.Show (Show(..))
+import qualified Data.List as L
+import qualified Data.Text.IO as T
+import qualified Data.Text.Lazy as TL
+import qualified Data.Text.Lazy.Builder as TLB
+import qualified Data.Text.Lazy.IO as TL
+import qualified System.IO as IO
+
+import Language.Symantic.Document.Sym
+
+-- * Type 'ANSI'
+newtype ANSI = ANSI { unANSI :: [SGR] -> TLB.Builder }
+instance IsString ANSI where
+	fromString s = ANSI $ const t
+		where t = fromString s
+
+ansi :: ANSI -> TLB.Builder
+ansi (ANSI d) = d []
+
+pushSGR :: SGR -> ANSI -> ANSI
+pushSGR c (ANSI d) = ANSI $ \cs ->
+	fromString (setSGRCode [c]) <>
+	d (c:cs) <>
+	fromString (setSGRCode $ Reset:L.reverse cs)
+
+instance Semigroup ANSI where
+	ANSI x <> ANSI y = ANSI $ \c -> x c <> y c
+instance Monoid ANSI where
+	mempty  = empty
+	mappend = (<>)
+instance Doc_Text ANSI where
+	replicate i d = ANSI $ TLB.fromLazyText . TL.replicate (int64OfInt i) . TLB.toLazyText . unANSI d
+	int     = ANSI . const . fromString . show
+	integer = ANSI . const . fromString . show
+	char    = ANSI . const . TLB.singleton
+	string  = ANSI . const . fromString
+	text    = ANSI . const . TLB.fromText
+	ltext   = ANSI . const . TLB.fromLazyText
+	charH   = char
+	stringH = string
+	textH   = text
+	ltextH  = ltext
+instance Doc_Color ANSI where
+	reverse     = pushSGR $ SetSwapForegroundBackground True
+	black       = pushSGR $ SetColor Foreground Dull  Black
+	red         = pushSGR $ SetColor Foreground Dull  Red
+	green       = pushSGR $ SetColor Foreground Dull  Green
+	yellow      = pushSGR $ SetColor Foreground Dull  Yellow
+	blue        = pushSGR $ SetColor Foreground Dull  Blue
+	magenta     = pushSGR $ SetColor Foreground Dull  Magenta
+	cyan        = pushSGR $ SetColor Foreground Dull  Cyan
+	white       = pushSGR $ SetColor Foreground Dull  White
+	blacker     = pushSGR $ SetColor Foreground Vivid Black
+	redder      = pushSGR $ SetColor Foreground Vivid Red
+	greener     = pushSGR $ SetColor Foreground Vivid Green
+	yellower    = pushSGR $ SetColor Foreground Vivid Yellow
+	bluer       = pushSGR $ SetColor Foreground Vivid Blue
+	magentaer   = pushSGR $ SetColor Foreground Vivid Magenta
+	cyaner      = pushSGR $ SetColor Foreground Vivid Cyan
+	whiter      = pushSGR $ SetColor Foreground Vivid White
+	onBlack     = pushSGR $ SetColor Background Dull  Black
+	onRed       = pushSGR $ SetColor Background Dull  Red
+	onGreen     = pushSGR $ SetColor Background Dull  Green
+	onYellow    = pushSGR $ SetColor Background Dull  Yellow
+	onBlue      = pushSGR $ SetColor Background Dull  Blue
+	onMagenta   = pushSGR $ SetColor Background Dull  Magenta
+	onCyan      = pushSGR $ SetColor Background Dull  Cyan
+	onWhite     = pushSGR $ SetColor Background Dull  White
+	onBlacker   = pushSGR $ SetColor Background Vivid Black
+	onRedder    = pushSGR $ SetColor Background Vivid Red
+	onGreener   = pushSGR $ SetColor Background Vivid Green
+	onYellower  = pushSGR $ SetColor Background Vivid Yellow
+	onBluer     = pushSGR $ SetColor Background Vivid Blue
+	onMagentaer = pushSGR $ SetColor Background Vivid Magenta
+	onCyaner    = pushSGR $ SetColor Background Vivid Cyan
+	onWhiter    = pushSGR $ SetColor Background Vivid White
+instance Doc_Decoration ANSI where
+	bold        = pushSGR $ SetConsoleIntensity BoldIntensity
+	underline   = pushSGR $ SetUnderlining SingleUnderline
+	italic      = pushSGR $ SetItalicized True
+
+-- * Type 'ANSI_IO'
+newtype ANSI_IO = ANSI_IO { unANSI_IO :: [SGR] -> IO.Handle -> IO () }
+instance IsString ANSI_IO where
+	fromString s = ANSI_IO $ \_c h -> IO.hPutStr h t
+		where t = fromString s
+
+ansiIO :: ANSI_IO -> IO.Handle -> IO ()
+ansiIO (ANSI_IO d) = d []
+
+pushSGR_IO :: SGR -> ANSI_IO -> ANSI_IO
+pushSGR_IO c (ANSI_IO d) = ANSI_IO $ \cs h -> do
+	hSetSGR h [c]
+	d (c:cs) h
+	hSetSGR h $ Reset:L.reverse cs
+
+instance Semigroup ANSI_IO where
+	ANSI_IO x <> ANSI_IO y = ANSI_IO $ \c h -> do {x c h; y c h}
+instance Monoid ANSI_IO where
+	mempty  = empty
+	mappend = (<>)
+instance Doc_Text ANSI_IO where
+	empty         = ANSI_IO $ \_ _ -> return ()
+	replicate i d = ANSI_IO $ \c   -> replicateM_ i . unANSI_IO d c
+	int       i   = ANSI_IO $ \_ h -> IO.hPutStr  h (show i)
+	integer   i   = ANSI_IO $ \_ h -> IO.hPutStr  h (show i)
+	char      x   = ANSI_IO $ \_ h -> IO.hPutChar h x
+	string    x   = ANSI_IO $ \_ h -> IO.hPutStr  h x
+	text      x   = ANSI_IO $ \_ h -> T.hPutStr   h x
+	ltext     x   = ANSI_IO $ \_ h -> TL.hPutStr  h x
+	charH         = char
+	stringH       = string
+	textH         = text
+	ltextH        = ltext
+instance Doc_Color ANSI_IO where
+	reverse     = pushSGR_IO $ SetSwapForegroundBackground True
+	black       = pushSGR_IO $ SetColor Foreground Dull  Black
+	red         = pushSGR_IO $ SetColor Foreground Dull  Red
+	green       = pushSGR_IO $ SetColor Foreground Dull  Green
+	yellow      = pushSGR_IO $ SetColor Foreground Dull  Yellow
+	blue        = pushSGR_IO $ SetColor Foreground Dull  Blue
+	magenta     = pushSGR_IO $ SetColor Foreground Dull  Magenta
+	cyan        = pushSGR_IO $ SetColor Foreground Dull  Cyan
+	white       = pushSGR_IO $ SetColor Foreground Dull  White
+	blacker     = pushSGR_IO $ SetColor Foreground Vivid Black
+	redder      = pushSGR_IO $ SetColor Foreground Vivid Red
+	greener     = pushSGR_IO $ SetColor Foreground Vivid Green
+	yellower    = pushSGR_IO $ SetColor Foreground Vivid Yellow
+	bluer       = pushSGR_IO $ SetColor Foreground Vivid Blue
+	magentaer   = pushSGR_IO $ SetColor Foreground Vivid Magenta
+	cyaner      = pushSGR_IO $ SetColor Foreground Vivid Cyan
+	whiter      = pushSGR_IO $ SetColor Foreground Vivid White
+	onBlack     = pushSGR_IO $ SetColor Background Dull  Black
+	onRed       = pushSGR_IO $ SetColor Background Dull  Red
+	onGreen     = pushSGR_IO $ SetColor Background Dull  Green
+	onYellow    = pushSGR_IO $ SetColor Background Dull  Yellow
+	onBlue      = pushSGR_IO $ SetColor Background Dull  Blue
+	onMagenta   = pushSGR_IO $ SetColor Background Dull  Magenta
+	onCyan      = pushSGR_IO $ SetColor Background Dull  Cyan
+	onWhite     = pushSGR_IO $ SetColor Background Dull  White
+	onBlacker   = pushSGR_IO $ SetColor Background Vivid Black
+	onRedder    = pushSGR_IO $ SetColor Background Vivid Red
+	onGreener   = pushSGR_IO $ SetColor Background Vivid Green
+	onYellower  = pushSGR_IO $ SetColor Background Vivid Yellow
+	onBluer     = pushSGR_IO $ SetColor Background Vivid Blue
+	onMagentaer = pushSGR_IO $ SetColor Background Vivid Magenta
+	onCyaner    = pushSGR_IO $ SetColor Background Vivid Cyan
+	onWhiter    = pushSGR_IO $ SetColor Background Vivid White
+instance Doc_Decoration ANSI_IO where
+	bold        = pushSGR_IO $ SetConsoleIntensity BoldIntensity
+	underline   = pushSGR_IO $ SetUnderlining SingleUnderline
+	italic      = pushSGR_IO $ SetItalicized True
diff --git a/Language/Symantic/Document/Dim.hs b/Language/Symantic/Document/Dim.hs
new file mode 100644
--- /dev/null
+++ b/Language/Symantic/Document/Dim.hs
@@ -0,0 +1,102 @@
+module Language.Symantic.Document.Dim where
+
+import Data.Eq (Eq)
+import Data.Foldable (Foldable(..))
+import Data.Function (($), id)
+import Data.Functor ((<$>))
+import Data.Int (Int)
+import Data.Monoid (Monoid(..))
+import Data.Ord (Ord(..))
+import Data.Semigroup (Semigroup(..))
+import Data.String (IsString(..))
+import Prelude (max, Num(..), toInteger)
+import Text.Show (Show(..))
+import qualified Data.List as L
+import qualified Data.Text as T
+import qualified Data.Text.Lazy as TL
+
+import Language.Symantic.Document.Sym
+
+-- * Type 'Dim'
+data Dim
+ =   Dim
+ { width       :: Int -- ^ Maximun line length.
+ , height      :: Int -- ^ Number of newlines.
+ , width_first :: Int -- ^ Length of the first line.
+ , width_last  :: Int -- ^ Length of the last line.
+ } deriving (Eq, Show)
+instance IsString Dim where
+	fromString [] = Dim 0 0 0 0
+	fromString s =
+		Dim
+		 { width       = maximum ws
+		 , height      = length ls
+		 , width_first = if null ws then 0 else L.head ws
+		 , width_last  = if null ws then 0 else L.last ws
+		 }
+		where
+		ls = L.lines s
+		ws = length <$> ls
+
+dim :: Dim -> Dim
+dim = id
+
+instance Semigroup Dim where
+	Dim wx hx wfx wlx <> Dim wy hy wfy wly =
+		let h = hx + hy in
+		case (hx, hy) of
+		 (0, 0) -> let w = wx  + wy  in Dim w h w w
+		 (0, _) -> let v = wfx + wfy in Dim (max v (wx + wy)) h v wly
+		 (_, 0) -> let v = wlx + wfy in Dim (max v (wx + wy)) h wfx v
+		 _      -> Dim (max wx wy) h wfx wly
+instance Monoid Dim where
+	mempty  = empty
+	mappend = (<>)
+instance Doc_Text Dim where
+	spaces    i   = Dim i 0 i i
+	replicate i d = if i <= 0 then empty else d <> replicate (i - 1) d
+	int       i   = fromString $ show i
+	integer   i   = fromString $ show i
+	charH     _c  = Dim 1 0 1 1
+	stringH   t   = Dim l 0 l l where l = length t
+	textH     t   = Dim l 0 l l where l = T.length t
+	ltextH    t   = Dim l 0 l l where l = fromInteger $ toInteger $ TL.length t
+	                                    -- XXX: conversion may overflow
+instance Doc_Color Dim where
+	reverse     = id
+	black       = id
+	red         = id
+	green       = id
+	yellow      = id
+	blue        = id
+	magenta     = id
+	cyan        = id
+	white       = id
+	blacker     = id
+	redder      = id
+	greener     = id
+	yellower    = id
+	bluer       = id
+	magentaer   = id
+	cyaner      = id
+	whiter      = id
+	onBlack     = id
+	onRed       = id
+	onGreen     = id
+	onYellow    = id
+	onBlue      = id
+	onMagenta   = id
+	onCyan      = id
+	onWhite     = id
+	onBlacker   = id
+	onRedder    = id
+	onGreener   = id
+	onYellower  = id
+	onBluer     = id
+	onMagentaer = id
+	onCyaner    = id
+	onWhiter    = id
+instance Doc_Decoration Dim where
+	bold        = id
+	underline   = id
+	italic      = id
diff --git a/Language/Symantic/Document/Plain.hs b/Language/Symantic/Document/Plain.hs
new file mode 100644
--- /dev/null
+++ b/Language/Symantic/Document/Plain.hs
@@ -0,0 +1,150 @@
+module Language.Symantic.Document.Plain where
+
+import Control.Monad (Monad(..), replicateM_)
+import Data.Function (($), (.), id)
+import Data.Monoid (Monoid(..))
+import Data.Semigroup (Semigroup(..))
+import Data.String (IsString(..))
+import System.IO (IO)
+import Text.Show (Show(..))
+import qualified Data.Text.IO as T
+import qualified Data.Text.Lazy as TL
+import qualified Data.Text.Lazy.IO as TL
+import qualified Data.Text.Lazy.Builder as TLB
+import qualified System.IO as IO
+
+import Language.Symantic.Document.Sym
+
+-- * Type 'Plain'
+newtype Plain
+ =      Plain TLB.Builder
+ deriving (Show)
+instance IsString Plain where
+	fromString = Plain . fromString
+
+plain :: Plain -> TLB.Builder
+plain (Plain d) = d
+
+
+instance Semigroup Plain where
+	Plain x <> Plain y = Plain (x <> y)
+instance Monoid Plain where
+	mempty  = empty
+	mappend = (<>)
+instance Doc_Text Plain where
+	int         = Plain . fromString . show
+	integer     = Plain . fromString . show
+	replicate i = Plain . TLB.fromLazyText . TL.replicate (int64OfInt i) . TLB.toLazyText . plain
+	char        = Plain . TLB.singleton
+	string      = Plain . fromString
+	text        = Plain . TLB.fromText
+	ltext       = Plain . TLB.fromLazyText
+	charH       = char
+	stringH     = string
+	textH       = text
+	ltextH      = ltext
+instance Doc_Color Plain where
+	reverse     = id
+	black       = id
+	red         = id
+	green       = id
+	yellow      = id
+	blue        = id
+	magenta     = id
+	cyan        = id
+	white       = id
+	blacker     = id
+	redder      = id
+	greener     = id
+	yellower    = id
+	bluer       = id
+	magentaer   = id
+	cyaner      = id
+	whiter      = id
+	onBlack     = id
+	onRed       = id
+	onGreen     = id
+	onYellow    = id
+	onBlue      = id
+	onMagenta   = id
+	onCyan      = id
+	onWhite     = id
+	onBlacker   = id
+	onRedder    = id
+	onGreener   = id
+	onYellower  = id
+	onBluer     = id
+	onMagentaer = id
+	onCyaner    = id
+	onWhiter    = id
+instance Doc_Decoration Plain where
+	bold        = id
+	underline   = id
+	italic      = id
+
+-- * Type 'PlainIO'
+newtype PlainIO
+ =      PlainIO { unPlainH :: IO.Handle -> IO () }
+instance IsString PlainIO where
+	fromString s = PlainIO $ \h -> IO.hPutStr h t
+		where t = fromString s
+
+plainIO :: PlainIO -> IO.Handle -> IO ()
+plainIO (PlainIO d) = d
+
+instance Semigroup PlainIO where
+	PlainIO x <> PlainIO y = PlainIO $ \h -> do {x h; y h}
+instance Monoid PlainIO where
+	mempty  = empty
+	mappend = (<>)
+instance Doc_Text PlainIO where
+	empty         = PlainIO $ \_ -> return ()
+	int     i     = PlainIO $ \h -> IO.hPutStr  h (show i)
+	integer i     = PlainIO $ \h -> IO.hPutStr  h (show i)
+	replicate i d = PlainIO $ replicateM_ i . plainIO d
+	char    x     = PlainIO $ \h -> IO.hPutChar h x
+	string  x     = PlainIO $ \h -> IO.hPutStr  h x
+	text    x     = PlainIO $ \h -> T.hPutStr   h x
+	ltext   x     = PlainIO $ \h -> TL.hPutStr  h x
+	charH         = char
+	stringH       = string
+	textH         = text
+	ltextH        = ltext
+instance Doc_Color PlainIO where
+	reverse       = id
+	black         = id
+	red           = id
+	green         = id
+	yellow        = id
+	blue          = id
+	magenta       = id
+	cyan          = id
+	white         = id
+	blacker       = id
+	redder        = id
+	greener       = id
+	yellower      = id
+	bluer         = id
+	magentaer     = id
+	cyaner        = id
+	whiter        = id
+	onBlack       = id
+	onRed         = id
+	onGreen       = id
+	onYellow      = id
+	onBlue        = id
+	onMagenta     = id
+	onCyan        = id
+	onWhite       = id
+	onBlacker     = id
+	onRedder      = id
+	onGreener     = id
+	onYellower    = id
+	onBluer       = id
+	onMagentaer   = id
+	onCyaner      = id
+	onWhiter      = id
+instance Doc_Decoration PlainIO where
+	bold          = id
+	underline     = id
+	italic        = id
diff --git a/Language/Symantic/Document/Sym.hs b/Language/Symantic/Document/Sym.hs
new file mode 100644
--- /dev/null
+++ b/Language/Symantic/Document/Sym.hs
@@ -0,0 +1,287 @@
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE ViewPatterns #-}
+module Language.Symantic.Document.Sym where
+
+import Data.Char (Char)
+import Data.Eq (Eq(..))
+import Data.Foldable (Foldable(..))
+import Data.Function ((.))
+import Data.Functor (Functor(..))
+import Data.Int (Int, Int64)
+import Data.Maybe (Maybe(..))
+import Data.Semigroup (Semigroup(..))
+import Data.String (String, IsString)
+import Data.Text (Text)
+import Prelude (Integer, fromInteger, toInteger)
+import qualified Data.List as L
+import qualified Data.Text as T
+import qualified Data.Text.Lazy as TL
+
+-- * Class 'Doc_Text'
+class (IsString d, Semigroup d) => Doc_Text d where
+	charH     :: Char    -> d -- ^ XXX: MUST NOT be '\n'
+	stringH   :: String  -> d -- ^ XXX: MUST NOT contain '\n'
+	textH     :: Text    -> d -- ^ XXX: MUST NOT contain '\n'
+	ltextH    :: TL.Text -> d -- ^ XXX: MUST NOT contain '\n'
+	replicate :: Int -> d -> d
+	integer   :: Integer -> d
+	default charH     :: Doc_Text (ReprOf d) => Trans d => Char -> d
+	default stringH   :: Doc_Text (ReprOf d) => Trans d => String -> d
+	default textH     :: Doc_Text (ReprOf d) => Trans d => Text -> d
+	default ltextH    :: Doc_Text (ReprOf d) => Trans d => TL.Text -> d
+	default replicate :: Doc_Text (ReprOf d) => Trans d => Int -> d -> d
+	default integer   :: Doc_Text (ReprOf d) => Trans d => Integer -> d
+	charH     = trans . charH
+	stringH   = trans . stringH
+	textH     = trans . textH
+	ltextH    = trans . ltextH
+	replicate = trans1 . replicate
+	integer   = trans . integer
+	
+	empty     :: d
+	eol       :: d
+	space     :: d
+	spaces    :: Int -> d
+	int       :: Int -> d
+	char      :: Char    -> d
+	string    :: String  -> d
+	text      :: Text    -> d
+	ltext     :: TL.Text -> d
+	catH      :: Foldable f => f d -> d
+	catV      :: Foldable f => f d -> d
+	paren     :: d -> d
+	brace     :: d -> d
+	bracket   :: d -> d
+	bquote    :: d -> d
+	dquote    :: d -> d
+	fquote    :: d -> d
+	squote    :: d -> d
+	
+	empty     = ""
+	eol       = "\n"
+	space     = char ' '
+	spaces i  = replicate i space
+	int       = integer . toInteger
+	char      = \case '\n' -> eol; c -> charH c
+	string    = catV . fmap stringH . lines
+	text      = catV . fmap textH   . lines
+	ltext     = catV . fmap ltextH  . lines
+	catH      = foldr (<>) empty
+	catV l    = if null l then empty else foldr1 (\a acc -> a <> eol <> acc) l
+	paren   d = charH '('   <> d <> charH ')'
+	brace   d = charH '{'   <> d <> charH '}'
+	bracket d = charH '['   <> d <> charH ']'
+	bquote  d = charH '`'   <> d <> charH '`'
+	dquote  d = charH '\"'  <> d <> charH '\"'
+	fquote  d =       "« "  <> d <>       " »"
+	squote  d = charH '\''  <> d <> charH '\''
+	-- default catH :: Doc_Text (ReprOf d) => Trans d => Foldable f => Functor f => f d -> d
+	-- default catV :: Doc_Text (ReprOf d) => Trans d => Foldable f => Functor f => f d -> d
+	-- catH  l = trans (catH (fmap unTrans l))
+	-- catV  l = trans (catV (fmap unTrans l))
+
+-- * Class 'Doc_Color'
+class Doc_Color d where
+	reverse :: d -> d
+	
+	-- Foreground colors
+	-- Dull
+	black   :: d -> d
+	red     :: d -> d
+	green   :: d -> d
+	yellow  :: d -> d
+	blue    :: d -> d
+	magenta :: d -> d
+	cyan    :: d -> d
+	white   :: d -> d
+	
+	-- Vivid
+	blacker   :: d -> d
+	redder    :: d -> d
+	greener   :: d -> d
+	yellower  :: d -> d
+	bluer     :: d -> d
+	magentaer :: d -> d
+	cyaner    :: d -> d
+	whiter    :: d -> d
+	
+	-- Background colors
+	-- Dull
+	onBlack   :: d -> d
+	onRed     :: d -> d
+	onGreen   :: d -> d
+	onYellow  :: d -> d
+	onBlue    :: d -> d
+	onMagenta :: d -> d
+	onCyan    :: d -> d
+	onWhite   :: d -> d
+	
+	-- Vivid
+	onBlacker   :: d -> d
+	onRedder    :: d -> d
+	onGreener   :: d -> d
+	onYellower  :: d -> d
+	onBluer     :: d -> d
+	onMagentaer :: d -> d
+	onCyaner    :: d -> d
+	onWhiter    :: d -> d
+	
+	default reverse     :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default black       :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default red         :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default green       :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default yellow      :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default blue        :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default magenta     :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default cyan        :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default white       :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default blacker     :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default redder      :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default greener     :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default yellower    :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default bluer       :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default magentaer   :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default cyaner      :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default whiter      :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onBlack     :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onRed       :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onGreen     :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onYellow    :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onBlue      :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onMagenta   :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onCyan      :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onWhite     :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onBlacker   :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onRedder    :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onGreener   :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onYellower  :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onBluer     :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onMagentaer :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onCyaner    :: Doc_Color (ReprOf d) => Trans d => d -> d
+	default onWhiter    :: Doc_Color (ReprOf d) => Trans d => d -> d
+	
+	reverse     = trans1 reverse
+	black       = trans1 black
+	red         = trans1 red
+	green       = trans1 green
+	yellow      = trans1 yellow
+	blue        = trans1 blue
+	magenta     = trans1 magenta
+	cyan        = trans1 cyan
+	white       = trans1 white
+	blacker     = trans1 blacker
+	redder      = trans1 redder
+	greener     = trans1 greener
+	yellower    = trans1 yellower
+	bluer       = trans1 bluer
+	magentaer   = trans1 magentaer
+	cyaner      = trans1 cyaner
+	whiter      = trans1 whiter
+	onBlack     = trans1 onBlack
+	onRed       = trans1 onRed
+	onGreen     = trans1 onGreen
+	onYellow    = trans1 onYellow
+	onBlue      = trans1 onBlue
+	onMagenta   = trans1 onMagenta
+	onCyan      = trans1 onCyan
+	onWhite     = trans1 onWhite
+	onBlacker   = trans1 onBlacker
+	onRedder    = trans1 onRedder
+	onGreener   = trans1 onGreener
+	onYellower  = trans1 onYellower
+	onBluer     = trans1 onBluer
+	onMagentaer = trans1 onMagentaer
+	onCyaner    = trans1 onCyaner
+	onWhiter    = trans1 onWhiter
+
+-- * Class 'Doc_Decoration'
+class Doc_Decoration d where
+	bold      :: d -> d
+	underline :: d -> d
+	italic    :: d -> d
+	default bold      :: Doc_Decoration (ReprOf d) => Trans d => d -> d
+	default underline :: Doc_Decoration (ReprOf d) => Trans d => d -> d
+	default italic    :: Doc_Decoration (ReprOf d) => Trans d => d -> d
+	bold      = trans1 bold
+	underline = trans1 underline
+	italic    = trans1 italic
+
+-- * Class 'Trans'
+class Trans tr where
+	-- | Return the underlying @tr@ of the transformer.
+	type ReprOf tr :: *
+	
+	-- | Lift a tr to the transformer's.
+	trans :: ReprOf tr -> tr
+	-- | Unlift a tr from the transformer's.
+	unTrans :: tr -> ReprOf tr
+	
+	-- | Identity transformation for a unary symantic method.
+	trans1 :: (ReprOf tr -> ReprOf tr) -> (tr -> tr)
+	trans1 f = trans . f . unTrans
+	
+	-- | Identity transformation for a binary symantic method.
+	trans2
+	 :: (ReprOf tr -> ReprOf tr -> ReprOf tr)
+	 -> (tr -> tr -> tr)
+	trans2 f t1 t2 = trans (f (unTrans t1) (unTrans t2))
+	
+	-- | Identity transformation for a ternary symantic method.
+	trans3
+	 :: (ReprOf tr -> ReprOf tr -> ReprOf tr -> ReprOf tr)
+	 -> (tr -> tr -> tr -> tr)
+	trans3 f t1 t2 t3 = trans (f (unTrans t1) (unTrans t2) (unTrans t3))
+
+
+-- * Class 'SplitOnCharWithEmpty'
+class SplitOnCharWithEmpty t where
+	splitOnCharWithEmpty :: Char -> t -> [t]
+instance SplitOnCharWithEmpty Text where
+	splitOnCharWithEmpty sep t =
+		case T.break (== sep) t of
+		 (chunk, T.uncons -> Just (_, rest)) -> chunk : splitOnCharWithEmpty sep rest
+		 (chunk, _) -> [chunk]
+instance SplitOnCharWithEmpty TL.Text where
+	splitOnCharWithEmpty sep t =
+		case TL.break (== sep) t of
+		 (chunk, TL.uncons -> Just (_, rest)) -> chunk : splitOnCharWithEmpty sep rest
+		 (chunk, _) -> [chunk]
+instance SplitOnCharWithEmpty String where
+	splitOnCharWithEmpty sep t =
+		case L.break (== sep) t of
+		 (chunk, _:rest) -> chunk : splitOnCharWithEmpty sep rest
+		 (chunk, []) -> [chunk]
+
+lines :: SplitOnCharWithEmpty t => t -> [t]
+lines = splitOnCharWithEmpty '\n'
+
+int64OfInt :: Int -> Int64
+int64OfInt = fromInteger . toInteger
+
+
+{-
+-- * Class 'SplitOnChar'
+
+class SplitOnChar t where
+	splitOnChar :: Char -> t -> [t]
+instance SplitOnChar Text where
+	splitOnChar sep t =
+		case Text.uncons t of
+		 Nothing -> []
+		 Just (x, xs) ->
+			if x == sep
+			then splitOnChar sep xs
+			else
+				let (chunk, rest) = Text.break (== sep) t in
+				chunk:splitOnChar sep rest
+instance SplitOnChar String where
+	splitOnChar sep t =
+		case t of
+		 [] -> []
+		 x:xs ->
+			if x == sep
+			then splitOnChar sep xs
+			else
+				let (chunk, rest) = List.break (== sep) t in
+				chunk:splitOnChar sep rest
+-}
diff --git a/Language/Symantic/Document/Valid.hs b/Language/Symantic/Document/Valid.hs
new file mode 100644
--- /dev/null
+++ b/Language/Symantic/Document/Valid.hs
@@ -0,0 +1,112 @@
+module Language.Symantic.Document.Valid where
+
+import Control.Applicative (Applicative(..))
+import Control.Monad (Monad(..))
+import Data.Eq (Eq(..))
+import Data.Foldable (elem)
+import Data.Function (($), (.), id)
+import Data.Functor (Functor(..))
+import Data.Int (Int)
+import Data.Monoid (Monoid(..))
+import Data.Ord (Ord(..))
+import Data.Semigroup (Semigroup(..))
+import Data.String (IsString(..))
+import Text.Show (Show)
+import qualified Data.Text as T
+import qualified Data.Text.Lazy as TL
+
+import Language.Symantic.Document.Sym
+
+-- * Type 'Valid'
+data Valid repr
+ =   KO [Error_Valid]
+ |   Ok repr
+ deriving (Eq, Show)
+instance IsString repr => IsString (Valid repr) where
+	fromString = Ok . fromString
+
+valid :: Valid repr -> Valid repr
+valid = id
+
+-- ** Type 'Error_Valid'
+data Error_Valid
+ =   Error_Valid_not_horizontal TL.Text
+ |   Error_Valid_negative_replicate Int
+ deriving (Eq, Show)
+
+instance Semigroup repr => Semigroup (Valid repr) where
+	Ok x <> Ok y = Ok $ x <> y
+	KO x <> Ok _ = KO x
+	Ok _ <> KO y = KO y
+	KO x <> KO y = KO $ x <> y
+instance (Doc_Text repr, Semigroup repr) => Monoid (Valid repr) where
+	mempty  = empty
+	mappend = (<>)
+instance Functor Valid where
+	fmap _ (KO e) = KO e
+	fmap f (Ok a) = Ok $ f a
+instance Applicative Valid where
+	pure = Ok
+	Ok f  <*> Ok a  = Ok $ f a
+	KO e  <*> KO e' = KO $ e <> e'
+	Ok _f <*> KO e  = KO e
+	KO e  <*> Ok _a = KO e
+instance Monad Valid where
+	return = Ok
+	Ok a >>= f = f a
+	KO e >>= _ = KO e
+instance (Doc_Text repr, Semigroup repr) => Doc_Text (Valid repr) where
+	replicate i _ | i < 0 = KO [Error_Valid_negative_replicate i]
+	replicate i d         = d >>= Ok . replicate i
+	int       = pure . int
+	integer   = pure . integer
+	char      = pure . char
+	string    = pure . string
+	text      = pure . text
+	ltext     = pure . ltext
+	charH '\n'= KO [Error_Valid_not_horizontal $ TL.singleton '\n']
+	charH c   = Ok $ charH c
+	stringH t | '\n' `elem` t = KO [Error_Valid_not_horizontal $ fromString t]
+	stringH t = Ok $ stringH t
+	textH   t | T.any (== '\n') t = KO [Error_Valid_not_horizontal $ TL.fromStrict t]
+	textH   t = Ok $ textH t
+	ltextH  t | TL.any (== '\n') t = KO [Error_Valid_not_horizontal t]
+	ltextH  t = Ok $ ltextH t
+instance Doc_Color repr => Doc_Color (Valid repr) where
+	reverse     = fmap reverse
+	black       = fmap black
+	red         = fmap red
+	green       = fmap green
+	yellow      = fmap yellow
+	blue        = fmap blue
+	magenta     = fmap magenta
+	cyan        = fmap cyan
+	white       = fmap white
+	blacker     = fmap blacker
+	redder      = fmap redder
+	greener     = fmap greener
+	yellower    = fmap yellower
+	bluer       = fmap bluer
+	magentaer   = fmap magentaer
+	cyaner      = fmap cyaner
+	whiter      = fmap whiter
+	onBlack     = fmap onBlack
+	onRed       = fmap onRed
+	onGreen     = fmap onGreen
+	onYellow    = fmap onYellow
+	onBlue      = fmap onBlue
+	onMagenta   = fmap onMagenta
+	onCyan      = fmap onCyan
+	onWhite     = fmap onWhite
+	onBlacker   = fmap onBlacker
+	onRedder    = fmap onRedder
+	onGreener   = fmap onGreener
+	onYellower  = fmap onYellower
+	onBluer     = fmap onBluer
+	onMagentaer = fmap onMagentaer
+	onCyaner    = fmap onCyaner
+	onWhiter    = fmap onWhiter
+instance Doc_Decoration repr => Doc_Decoration (Valid repr) where
+	bold      = fmap bold
+	italic    = fmap italic
+	underline = fmap underline
diff --git a/stack.yaml b/stack.yaml
new file mode 100644
--- /dev/null
+++ b/stack.yaml
@@ -0,0 +1,3 @@
+resolver: nightly-2017-02-03
+packages:
+- '.'
diff --git a/symantic-document.cabal b/symantic-document.cabal
new file mode 100644
--- /dev/null
+++ b/symantic-document.cabal
@@ -0,0 +1,57 @@
+author: Julien Moutinho <julm+symantic@autogeree.net>
+-- bug-reports: http://bug.autogeree.net/symantic
+build-type: Simple
+cabal-version: >= 1.8
+category: Text
+-- data-dir: data
+-- data-files: 
+description: Symantics for generating documents.
+extra-source-files:
+  stack.yaml
+extra-tmp-files:
+-- homepage: http://pad.autogeree.net/informatique/symantic
+license: GPL-3
+license-file: COPYING
+maintainer: Julien Moutinho <julm+symantic@autogeree.net>
+name: symantic-document
+stability: experimental
+synopsis: Document symantics.
+tested-with: GHC==8.0.2
+-- PVP:  +-+------- breaking API changes
+--       | | +----- non-breaking API additions
+--       | | | +--- code changes with no API change
+version: 0.0.0.20170623
+
+source-repository head
+  location: git://git.autogeree.net/symantic
+  type:     git
+
+Library
+  extensions:
+    NoImplicitPrelude
+    DataKinds
+    DefaultSignatures
+    FlexibleContexts
+    FlexibleInstances
+    LambdaCase
+    MultiParamTypeClasses
+    NamedFieldPuns
+    OverloadedStrings
+    ScopedTypeVariables
+    StandaloneDeriving
+    TupleSections
+    TypeFamilies
+    TypeOperators
+  ghc-options: -Wall -fno-warn-tabs
+  exposed-modules:
+    Language.Symantic.Document
+    Language.Symantic.Document.ANSI
+    Language.Symantic.Document.Dim
+    Language.Symantic.Document.Plain
+    Language.Symantic.Document.Sym
+    Language.Symantic.Document.Valid
+  build-depends:
+    ansi-terminal
+    , base >= 4.6 && < 5
+    , text
+    -- , transformers >= 0.4 && < 0.5
