    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Text.PrettyPrint.Annotated.WL
    -- Copyright   :  Google, Inc. (c) 2013,
    --                Edward Kmett (c) 2011,
    --                Daan Leijen  (c) 2000
    --
    -- License     :  BSD-style (see the file LICENSE)
    --
    -- Maintainer  :  mail@daniel-mendler.de
    -- Stability   :  experimental
    -- Portability :  portable
    --
    -- Pretty print module based on Daan Leijen's implementation of Philip Wadler's
    -- \"prettier printer\"
    --
    -- @
    --      \"A prettier printer\"
    --      Draft paper, April 1997, revised March 1998.
    --      <http://homepages.inf.ed.ac.uk/wadler/papers/prettier/prettier.pdf>
    -- @
    --
    -- This is an implementation of the pretty printing combinators
    -- described by Philip Wadler (1997). In their bare essence, the
    -- combinators of Wadler are not expressive enough to describe some
    -- commonly occurring layouts. The PPrint library adds new primitives
    -- to describe these layouts and works well in practice.
    --
    -- The library is based on a single way to concatenate documents,
    -- which is associative and has both a left and right unit.  This
    -- simple design leads to an efficient and short implementation. The
    -- simplicity is reflected in the predictable behaviour of the
    -- combinators which make them easy to use in practice.
    --
    -- A thorough description of the primitive combinators and their
    -- implementation can be found in Philip Wadler's paper
    -- (1997). Additions and the main differences with his original paper
    -- are:
    --
    -- * The nil document is called 'mempty'. We cannot use 'empty'
    -- for compatibility with base.
    --
    -- * The operator '</>' is used
    -- for soft line breaks.
    --
    -- * There are three new primitives: 'align', 'fill' and
    -- 'fillBreak'. These are very useful in practice.
    --
    -- * Lots of other useful combinators, like 'fillSep' and 'list'.
    --
    -- * There are three renderers, 'renderPretty/renderPrettyDefault' and 'renderSmart'
    -- for pretty printing and 'renderCompact' for compact output. The pretty printing algorithm
    -- also uses a ribbon-width now for even prettier output.
    --
    -- * There are display routines 'displayS' and 'display' for strings,
    -- 'displayT' for lazy text, 'displayIO' for file based output.
    -- Generalized display routines for display with annotations
    -- are provided, i.e., 'displayDecoratedA' and 'displayDecorated'.
    -- Furthermore 'displaySpans' exists which creates a monoid and a SpanList
    -- of the annotations.
    --
    -- * There is a 'Pretty' class which creates documents without annotations.
    --
    -- * The implementation uses optimised representations and strictness
    -- annotations.
    --
    -- * There is the wl-pprint-console package, based on this package,
    -- which provides additional display routines, e.g., colorful output using
    -- ANSI escape sequences.
    --
    -----------------------------------------------------------
    module Text.PrettyPrint.Annotated.WL (
      -- * Documents
      Doc(..), putDoc, hPutDoc

      -- * Basic combinators
      , char, text, nest, line, linebreak, group, softline
      , softbreak, hardline, flatAlt, flatten

      -- * Annotations
      , annotate, noAnnotate, docMapAnn
      , simpleDocMapAnn, simpleDocScanAnn

      -- * Alignment
      --
      -- The combinators in this section can not be described by Wadler's
      -- original combinators. They align their output relative to the
      -- current output position - in contrast to @nest@ which always
      -- aligns to the current nesting level. This deprives these
      -- combinators from being \`optimal\'. In practice however they
      -- prove to be very useful. The combinators in this section should
      -- be used with care, since they are more expensive than the other
      -- combinators. For example, @align@ shouldn't be used to pretty
      -- print all top-level declarations of a language, but using @hang@
      -- for let expressions is fine.
      , align, hang, indent, encloseSep, list, tupled, semiBraces

      -- * Operators
      , (<+>), (</>), (<//>), (<#>), (<##>)

      -- * List combinators
      , hsep, vsep, fillSep, sep, hcat, vcat, fillCat, cat, punctuate

      -- * Fillers
      , fill, fillBreak

      -- * Bracketing combinators
      , enclose, squotes, dquotes, parens, angles, braces, brackets

      -- * Character documents
      , lparen, rparen, langle, rangle, lbrace, rbrace, lbracket, rbracket
      , squote, dquote, semi, colon, comma, space, dot, backslash, equals

      -- * Pretty class
      , Pretty(..)

      -- * Rendering
      , SimpleDoc(..), renderPrettyDefault, renderPretty, renderCompact, renderSmart
      , display, displayS, displayT, displayIO, displayDecoratedA, displayDecorated
      , SpanList, displaySpans

      -- * Undocumented

      , column, nesting, width, columns, ribbon

      -- * Re-exported standard functions
      , mempty, (<>)
      ) where

    import Data.Foldable hiding (fold)
    import Data.Traversable
    import Data.Int
    import Data.Word
    import Data.Bifunctor
    import Data.Functor.Identity
    import qualified Data.Text as T
    import qualified Data.Text.Lazy as TL
    import qualified Data.Text.Lazy.Builder as TL
    import Data.List.NonEmpty (NonEmpty)
    import Numeric.Natural (Natural)
    import Control.Applicative
    import Data.Sequence (Seq)
    import Data.Semigroup
    import System.IO (Handle,hPutStr,stdout)
    import Control.DeepSeq (NFData)
    import GHC.Generics (Generic)
    import Data.String (IsString(..))

    infixr 5 </>, <//>, <#>, <##>
    infixr 6 <+>

    -----------------------------------------------------------
    -- list, tupled and semiBraces pretty print a list of
    -- documents either horizontally or vertically aligned.
    -----------------------------------------------------------

    -- | The document @(list xs)@ comma separates the documents @xs@ and
    -- encloses them in square brackets. The documents are rendered
    -- horizontally if that fits the page. Otherwise they are aligned
    -- vertically. All comma separators are put in front of the elements.
    list :: Foldable f => f (Doc a) -> Doc a
    list :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    list = Doc a -> Doc a -> Doc a -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    Doc a -> Doc a -> Doc a -> f (Doc a) -> Doc a
    encloseSep Doc a
    forall a. Doc a
    lbracket Doc a
    forall a. Doc a
    rbracket Doc a
    forall a. Doc a
    comma

    -- | The document @(tupled xs)@ comma separates the documents @xs@ and
    -- encloses them in parenthesis. The documents are rendered
    -- horizontally if that fits the page. Otherwise they are aligned
    -- vertically. All comma separators are put in front of the elements.
    tupled :: Foldable f => f (Doc a) -> Doc a
    tupled :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    tupled = Doc a -> Doc a -> Doc a -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    Doc a -> Doc a -> Doc a -> f (Doc a) -> Doc a
    encloseSep Doc a
    forall a. Doc a
    lparen Doc a
    forall a. Doc a
    rparen Doc a
    forall a. Doc a
    comma

    (<+>) :: Doc a -> Doc a -> Doc a
    Doc a
    x <+> :: forall a. Doc a -> Doc a -> Doc a
    <+> Doc a
    y = Doc a
    x Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    forall a. Doc a
    space Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    y

    -- | The document @(semiBraces xs)@ separates the documents @xs@ with
    -- semi colons and encloses them in braces. The documents are rendered
    -- horizontally if that fits the page. Otherwise they are aligned
    -- vertically. All semi colons are put in front of the elements.
    semiBraces :: Foldable f => f (Doc a) -> Doc a
    semiBraces :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    semiBraces = Doc a -> Doc a -> Doc a -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    Doc a -> Doc a -> Doc a -> f (Doc a) -> Doc a
    encloseSep Doc a
    forall a. Doc a
    lbrace Doc a
    forall a. Doc a
    rbrace Doc a
    forall a. Doc a
    semi

    -- | The document @(encloseSep l r sep xs)@ concatenates the documents
    -- @xs@ separated by @sep@ and encloses the resulting document by @l@
    -- and @r@. The documents are rendered horizontally if that fits the
    -- page. Otherwise they are aligned vertically. All separators are put
    -- in front of the elements. For example, the combinator 'list' can be
    -- defined with @encloseSep@:
    --
    -- > list xs = encloseSep lbracket rbracket comma xs
    -- > test    = text "list" <+> (list (map int [10,200,3000]))
    --
    -- Which is layed out with a page width of 20 as:
    --
    -- @
    -- list [10, 200, 3000]
    -- @
    --
    -- But when the page width is 15, it is layed out as:
    --
    -- @
    -- list [ 10
    --      , 200
    --      , 3000 ]
    -- @
    encloseSep :: Foldable f => Doc a -> Doc a -> Doc a -> f (Doc a) -> Doc a
    encloseSep :: forall (f :: * -> *) a.
    Foldable f =>
    Doc a -> Doc a -> Doc a -> f (Doc a) -> Doc a
    encloseSep Doc a
    left Doc a
    right Doc a
    sp f (Doc a)
    ds0
        = case f (Doc a) -> [Doc a]
    forall a. f a -> [a]
    forall (t :: * -> *) a. Foldable t => t a -> [a]
    toList f (Doc a)
    ds0 of
            []  -> Doc a
    left Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    right
            [Doc a
    d] -> Doc a
    left Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    d Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    right
            [Doc a]
    ds  -> Doc a -> Doc a
    forall a. Doc a -> Doc a
    group (Doc a -> Doc a) -> Doc a -> Doc a
    forall a b. (a -> b) -> a -> b
    $ Doc a -> Doc a
    forall a. Doc a -> Doc a
    align (Doc a -> Doc a) -> Doc a -> Doc a
    forall a b. (a -> b) -> a -> b
    $ Doc a
    left'
                     Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> [Doc a] -> Doc a
    forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    vcat ((Doc a -> Doc a -> Doc a) -> [Doc a] -> [Doc a] -> [Doc a]
    forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
    zipWith Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    (<>) (Doc a
    forall a. Monoid a => a
    mempty Doc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    : Doc a -> [Doc a]
    forall a. a -> [a]
    repeat (Doc a
    sp Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    forall a. Doc a
    space)) [Doc a]
    ds)
                     Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    right'
              where left' :: Doc a
    left'  = Doc a
    left Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    flatAlt Doc a
    forall a. Doc a
    space Doc a
    forall a. Monoid a => a
    mempty
                    right' :: Doc a
    right' = Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    flatAlt Doc a
    forall a. Doc a
    space Doc a
    forall a. Monoid a => a
    mempty Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    right

    -----------------------------------------------------------
    -- punctuate p [d1,d2,...,dn] => [d1 <> p,d2 <> p, ... ,dn]
    -----------------------------------------------------------

    -- | @(punctuate p xs)@ concatenates all documents in @xs@ with
    -- document @p@ except for the last document.
    --
    -- > someText = map text ["words","in","a","tuple"]
    -- > test     = parens (align (cat (punctuate comma someText)))
    --
    -- This is layed out on a page width of 20 as:
    --
    -- @
    -- (words,in,a,tuple)
    -- @
    --
    -- But when the page width is 15, it is layed out as:
    --
    -- @
    -- (words,
    --  in,
    --  a,
    --  tuple)
    -- @
    --
    -- (If you want put the commas in front of their elements instead of
    -- at the end, you should use 'tupled' or, in general, 'encloseSep'.)
    punctuate :: Traversable f => Doc a -> f (Doc a) -> f (Doc a)
    punctuate :: forall (f :: * -> *) a.
    Traversable f =>
    Doc a -> f (Doc a) -> f (Doc a)
    punctuate Doc a
    p f (Doc a)
    xs = ([Doc a], f (Doc a)) -> f (Doc a)
    forall a b. (a, b) -> b
    snd (([Doc a], f (Doc a)) -> f (Doc a))
    -> ([Doc a], f (Doc a)) -> f (Doc a)
    forall a b. (a -> b) -> a -> b
    $ ([Doc a] -> Doc a -> ([Doc a], Doc a))
    -> [Doc a] -> f (Doc a) -> ([Doc a], f (Doc a))
    forall (t :: * -> *) s a b.
    Traversable t =>
    (s -> a -> (s, b)) -> s -> t a -> (s, t b)
    mapAccumL (\(Doc a
    d:[Doc a]
    ds) Doc a
    _ -> ([Doc a]
    ds, if [Doc a] -> Bool
    forall a. [a] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Doc a]
    ds then Doc a
    d else Doc a
    d Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    p)) (f (Doc a) -> [Doc a]
    forall a. f a -> [a]
    forall (t :: * -> *) a. Foldable t => t a -> [a]
    toList f (Doc a)
    xs) f (Doc a)
    xs

    -----------------------------------------------------------
    -- high-level combinators
    -----------------------------------------------------------

    -- | The document @(sep xs)@ concatenates all documents @xs@ either
    -- horizontally with @(\<+\>)@, if it fits the page, or vertically with
    -- @(\<\#\>)@.
    --
    -- > sep xs  = group (vsep xs)
    sep :: Foldable f => f (Doc a) -> Doc a
    sep :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    sep = Doc a -> Doc a
    forall a. Doc a -> Doc a
    group (Doc a -> Doc a) -> (f (Doc a) -> Doc a) -> f (Doc a) -> Doc a
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . f (Doc a) -> Doc a
    forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    vsep

    -- | The document @(fillSep xs)@ concatenates documents @xs@
    -- horizontally with @(\<+\>)@ as long as its fits the page, then
    -- inserts a @line@ and continues doing that for all documents in
    -- @xs@.
    --
    -- > fillSep xs  = foldr (</>) mempty xs
    fillSep :: Foldable f => f (Doc a) -> Doc a
    fillSep :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    fillSep = (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    fold Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    (</>)

    -- | The document @(hsep xs)@ concatenates all documents @xs@
    -- horizontally with @(\<+\>)@.
    hsep :: Foldable f => f (Doc a) -> Doc a
    hsep :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    hsep = (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    fold Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    (<+>)

    -- | The document @(vsep xs)@ concatenates all documents @xs@
    -- vertically with @(\<\#\>)@. If a 'group' undoes the line breaks
    -- inserted by @vsep@, all documents are separated with a space.
    --
    -- > someText = map text (words ("text to lay out"))
    -- >
    -- > test     = text "some" <+> vsep someText
    --
    -- This is layed out as:
    --
    -- @
    -- some text
    -- to
    -- lay
    -- out
    -- @
    --
    -- The 'align' combinator can be used to align the documents under
    -- their first element
    --
    -- > test = text "some" <+> align (vsep someText)
    --
    -- Which is printed as:
    --
    -- @
    -- some text
    --      to
    --      lay
    --      out
    -- @
    vsep :: Foldable f => f (Doc a) -> Doc a
    vsep :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    vsep = (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    fold Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    (<#>)

    -- | The document @(cat xs)@ concatenates all documents @xs@ either
    -- horizontally with @(\<\>)@, if it fits the page, or vertically with
    -- @(\<\#\#\>)@.
    --
    -- > cat xs  = group (vcat xs)
    cat :: Foldable f => f (Doc a) -> Doc a
    cat :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    cat = Doc a -> Doc a
    forall a. Doc a -> Doc a
    group (Doc a -> Doc a) -> (f (Doc a) -> Doc a) -> f (Doc a) -> Doc a
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . f (Doc a) -> Doc a
    forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    vcat

    -- | The document @(fillCat xs)@ concatenates documents @xs@
    -- horizontally with @(\<\>)@ as long as its fits the page, then inserts
    -- a @linebreak@ and continues doing that for all documents in @xs@.
    --
    -- > fillCat xs  = foldr (<//>) mempty xs
    fillCat :: Foldable f => f (Doc a) -> Doc a
    fillCat :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    fillCat = (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    fold Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    (<//>)

    -- | The document @(hcat xs)@ concatenates all documents @xs@
    -- horizontally with @(\<\>)@.
    hcat :: Foldable f => f (Doc a) -> Doc a
    hcat :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    hcat = (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    fold Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    (<>)

    -- | The document @(vcat xs)@ concatenates all documents @xs@
    -- vertically with @(\<\#\#\>)@. If a 'group' undoes the line breaks
    -- inserted by @vcat@, all documents are directly concatenated.
    vcat :: Foldable f => f (Doc a) -> Doc a
    vcat :: forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    vcat = (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    forall (f :: * -> *) a.
    Foldable f =>
    (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    fold Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    (<##>)

    fold :: Foldable f => (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    fold :: forall (f :: * -> *) a.
    Foldable f =>
    (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    fold Doc a -> Doc a -> Doc a
    f f (Doc a)
    xs | f (Doc a) -> Bool
    forall a. f a -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null f (Doc a)
    xs = Doc a
    forall a. Monoid a => a
    mempty
              | Bool
    otherwise = (Doc a -> Doc a -> Doc a) -> f (Doc a) -> Doc a
    forall a. (a -> a -> a) -> f a -> a
    forall (t :: * -> *) a. Foldable t => (a -> a -> a) -> t a -> a
    foldr1 Doc a -> Doc a -> Doc a
    f f (Doc a)
    xs

    instance Semigroup (Doc a) where
      -- | The document @(x \<\> y)@ concatenates document @x@ and document
      -- @y@. It is an associative operation having 'mempty' as a left and
      -- right unit.  (infixl 6)
      <> :: Doc a -> Doc a -> Doc a
    (<>) = Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    Cat

    instance Monoid (Doc a) where
      mappend :: Doc a -> Doc a -> Doc a
    mappend = Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    Cat
      mempty :: Doc a
    mempty = Doc a
    forall a. Doc a
    Empty
      mconcat :: [Doc a] -> Doc a
    mconcat = [Doc a] -> Doc a
    forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    hcat

    -- | The document @(x \<\/\> y)@ concatenates document @x@ and @y@ with a
    -- 'softline' in between. This effectively puts @x@ and @y@ either
    -- next to each other (with a @space@ in between) or underneath each
    -- other. (infixr 5)
    (</>) :: Doc a -> Doc a -> Doc a
    Doc a
    x </> :: forall a. Doc a -> Doc a -> Doc a
    </> Doc a
    y = Doc a
    x Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    forall a. Doc a
    softline Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    y

    -- | The document @(x \<\/\/\> y)@ concatenates document @x@ and @y@ with
    -- a 'softbreak' in between. This effectively puts @x@ and @y@ either
    -- right next to each other or underneath each other. (infixr 5)
    (<//>) :: Doc a -> Doc a -> Doc a
    Doc a
    x <//> :: forall a. Doc a -> Doc a -> Doc a
    <//> Doc a
    y = Doc a
    x Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    forall a. Doc a
    softbreak Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    y

    -- | The document @(x \<\#\> y)@ concatenates document @x@ and @y@ with a
    -- 'line' in between. (infixr 5)
    (<#>) :: Doc a -> Doc a -> Doc a
    Doc a
    x <#> :: forall a. Doc a -> Doc a -> Doc a
    <#> Doc a
    y = Doc a
    x Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    forall a. Doc a
    line Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    y

    -- | The document @(x \<\#\#\> y)@ concatenates document @x@ and @y@ with
    -- a @linebreak@ in between. (infixr 5)
    (<##>) :: Doc a -> Doc a -> Doc a
    Doc a
    x <##> :: forall a. Doc a -> Doc a -> Doc a
    <##> Doc a
    y = Doc a
    x Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    forall a. Doc a
    linebreak Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    y

    -- | The document @softline@ behaves like 'space' if the resulting
    -- output fits the page, otherwise it behaves like 'line'.
    --
    -- > softline = group line
    softline :: Doc a
    softline :: forall a. Doc a
    softline = Doc a -> Doc a
    forall a. Doc a -> Doc a
    group Doc a
    forall a. Doc a
    line

    -- | The document @softbreak@ behaves like 'mempty' if the resulting
    -- output fits the page, otherwise it behaves like 'line'.
    --
    -- > softbreak  = group linebreak
    softbreak :: Doc a
    softbreak :: forall a. Doc a
    softbreak = Doc a -> Doc a
    forall a. Doc a -> Doc a
    group Doc a
    forall a. Doc a
    linebreak

    -- | Document @(squotes x)@ encloses document @x@ with single quotes
    -- \"'\".
    squotes :: Doc a -> Doc a
    squotes :: forall a. Doc a -> Doc a
    squotes = Doc a -> Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a -> Doc a
    enclose Doc a
    forall a. Doc a
    squote Doc a
    forall a. Doc a
    squote

    -- | Document @(dquotes x)@ encloses document @x@ with double quotes
    -- '\"'.
    dquotes :: Doc a -> Doc a
    dquotes :: forall a. Doc a -> Doc a
    dquotes = Doc a -> Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a -> Doc a
    enclose Doc a
    forall a. Doc a
    dquote Doc a
    forall a. Doc a
    dquote

    -- | Document @(braces x)@ encloses document @x@ in braces, \"{\" and
    -- \"}\".
    braces :: Doc a -> Doc a
    braces :: forall a. Doc a -> Doc a
    braces = Doc a -> Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a -> Doc a
    enclose Doc a
    forall a. Doc a
    lbrace Doc a
    forall a. Doc a
    rbrace

    -- | Document @(parens x)@ encloses document @x@ in parenthesis, \"(\"
    -- and \")\".
    parens :: Doc a -> Doc a
    parens :: forall a. Doc a -> Doc a
    parens = Doc a -> Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a -> Doc a
    enclose Doc a
    forall a. Doc a
    lparen Doc a
    forall a. Doc a
    rparen

    -- | Document @(angles x)@ encloses document @x@ in angles, \"\<\" and
    -- \"\>\".
    angles :: Doc a -> Doc a
    angles :: forall a. Doc a -> Doc a
    angles = Doc a -> Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a -> Doc a
    enclose Doc a
    forall a. Doc a
    langle Doc a
    forall a. Doc a
    rangle

    -- | Document @(brackets x)@ encloses document @x@ in square brackets,
    -- \"[\" and \"]\".
    brackets :: Doc a -> Doc a
    brackets :: forall a. Doc a -> Doc a
    brackets = Doc a -> Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a -> Doc a
    enclose Doc a
    forall a. Doc a
    lbracket Doc a
    forall a. Doc a
    rbracket

    -- | The document @(enclose l r x)@ encloses document @x@ between
    -- documents @l@ and @r@ using @(\<\>)@.
    --
    -- > enclose l r x   = l <> x <> r
    enclose :: Doc a -> Doc a -> Doc a -> Doc a
    enclose :: forall a. Doc a -> Doc a -> Doc a -> Doc a
    enclose Doc a
    l Doc a
    r Doc a
    x = Doc a
    l Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    x Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    r

    -- | The document @lparen@ contains a left parenthesis, \"(\".
    lparen :: Doc a
    lparen :: forall a. Doc a
    lparen = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '('

    -- | The document @rparen@ contains a right parenthesis, \")\".
    rparen :: Doc a
    rparen :: forall a. Doc a
    rparen = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    ')'

    -- | The document @langle@ contains a left angle, \"\<\".
    langle :: Doc a
    langle :: forall a. Doc a
    langle = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '<'

    -- | The document @rangle@ contains a right angle, \">\".
    rangle :: Doc a
    rangle :: forall a. Doc a
    rangle = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '>'

    -- | The document @lbrace@ contains a left brace, \"{\".
    lbrace :: Doc a
    lbrace :: forall a. Doc a
    lbrace = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '{'

    -- | The document @rbrace@ contains a right brace, \"}\".
    rbrace :: Doc a
    rbrace :: forall a. Doc a
    rbrace = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '}'

    -- | The document @lbracket@ contains a left square bracket, \"[\".
    lbracket :: Doc a
    lbracket :: forall a. Doc a
    lbracket = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '['

    -- | The document @rbracket@ contains a right square bracket, \"]\".
    rbracket :: Doc a
    rbracket :: forall a. Doc a
    rbracket = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    ']'

    -- | The document @squote@ contains a single quote, \"'\".
    squote :: Doc a
    squote :: forall a. Doc a
    squote = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '\''

    -- | The document @dquote@ contains a double quote, '\"'.
    dquote :: Doc a
    dquote :: forall a. Doc a
    dquote = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '"'

    -- | The document @semi@ contains a semi colon, \";\".
    semi :: Doc a
    semi :: forall a. Doc a
    semi = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    ';'

    -- | The document @colon@ contains a colon, \":\".
    colon :: Doc a
    colon :: forall a. Doc a
    colon = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    ':'

    -- | The document @comma@ contains a comma, \",\".
    comma :: Doc a
    comma :: forall a. Doc a
    comma = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    ','

    -- | The document @space@ contains a single space, \" \".
    --
    -- > x <+> y   = x <> space <> y
    space :: Doc a
    space :: forall a. Doc a
    space = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    ' '

    -- | The document @dot@ contains a single dot, \".\".
    dot :: Doc a
    dot :: forall a. Doc a
    dot = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '.'

    -- | The document @backslash@ contains a back slash, \"\\\".
    backslash :: Doc a
    backslash :: forall a. Doc a
    backslash = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '\\'

    -- | The document @equals@ contains an equal sign, \"=\".
    equals :: Doc a
    equals :: forall a. Doc a
    equals = Char -> Doc a
    forall a. Char -> Doc a
    char Char
    '='

    docMapAnn :: (a -> Doc a' -> Doc a') -> Doc a -> Doc a'
    docMapAnn :: forall a a'. (a -> Doc a' -> Doc a') -> Doc a -> Doc a'
    docMapAnn a -> Doc a' -> Doc a'
    an = Doc a -> Doc a'
    go
     where
      go :: Doc a -> Doc a'
    go Doc a
    Empty          = Doc a'
    forall a. Doc a
    Empty
      go (Char Char
    x)       = Char -> Doc a'
    forall a. Char -> Doc a
    Char Char
    x
      go (Text Int
    i String
    s)     = Int -> String -> Doc a'
    forall a. Int -> String -> Doc a
    Text Int
    i String
    s
      go Doc a
    Line           = Doc a'
    forall a. Doc a
    Line
      go (FlatAlt Doc a
    l Doc a
    r)  = Doc a' -> Doc a' -> Doc a'
    forall a. Doc a -> Doc a -> Doc a
    FlatAlt (Doc a -> Doc a'
    go Doc a
    l) (Doc a -> Doc a'
    go Doc a
    r)
      go (Cat Doc a
    l Doc a
    r)      = Doc a' -> Doc a' -> Doc a'
    forall a. Doc a -> Doc a -> Doc a
    Cat (Doc a -> Doc a'
    go Doc a
    l) (Doc a -> Doc a'
    go Doc a
    r)
      go (Nest Int
    i Doc a
    d)     = Int -> Doc a' -> Doc a'
    forall a. Int -> Doc a -> Doc a
    Nest Int
    i (Doc a -> Doc a'
    go Doc a
    d)
      go (Union Doc a
    l Doc a
    r)    = Doc a' -> Doc a' -> Doc a'
    forall a. Doc a -> Doc a -> Doc a
    Union (Doc a -> Doc a'
    go Doc a
    l) (Doc a -> Doc a'
    go Doc a
    r)
      go (Annotate a
    a Doc a
    d) = a -> Doc a' -> Doc a'
    an a
    a (Doc a -> Doc a'
    go Doc a
    d)
      go (Column Int -> Doc a
    f)     = (Int -> Doc a') -> Doc a'
    forall a. (Int -> Doc a) -> Doc a
    Column (Doc a -> Doc a'
    go (Doc a -> Doc a') -> (Int -> Doc a) -> Int -> Doc a'
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Int -> Doc a
    f)
      go (Nesting Int -> Doc a
    k)    = (Int -> Doc a') -> Doc a'
    forall a. (Int -> Doc a) -> Doc a
    Nesting (Doc a -> Doc a'
    go (Doc a -> Doc a') -> (Int -> Doc a) -> Int -> Doc a'
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Int -> Doc a
    k)
      go (Columns Maybe Int -> Doc a
    k)    = (Maybe Int -> Doc a') -> Doc a'
    forall a. (Maybe Int -> Doc a) -> Doc a
    Columns (Doc a -> Doc a'
    go (Doc a -> Doc a') -> (Maybe Int -> Doc a) -> Maybe Int -> Doc a'
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Maybe Int -> Doc a
    k)
      go (Ribbon Maybe Int -> Doc a
    k)     = (Maybe Int -> Doc a') -> Doc a'
    forall a. (Maybe Int -> Doc a) -> Doc a
    Ribbon (Doc a -> Doc a'
    go (Doc a -> Doc a') -> (Maybe Int -> Doc a) -> Maybe Int -> Doc a'
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Maybe Int -> Doc a
    k)

    instance IsString (Doc a) where
      fromString :: String -> Doc a
    fromString = String -> Doc a
    forall a. String -> Doc a
    forall a b. Pretty a => a -> Doc b
    pretty

    -----------------------------------------------------------
    -- overloading "pretty"
    -----------------------------------------------------------

    -- | The member @prettyList@ is only used to define the @instance Pretty
    -- a => Pretty [a]@. In normal circumstances only the @pretty@ function
    -- is used.
    class Pretty a where
      pretty     :: a   -> Doc b
      prettyList :: [a] -> Doc b
      prettyList = [Doc b] -> Doc b
    forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    list ([Doc b] -> Doc b) -> ([a] -> [Doc b]) -> [a] -> Doc b
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (a -> Doc b) -> [a] -> [Doc b]
    forall a b. (a -> b) -> [a] -> [b]
    map a -> Doc b
    forall b. a -> Doc b
    forall a b. Pretty a => a -> Doc b
    pretty

      default pretty :: Show a => a -> Doc b
      pretty = String -> Doc b
    forall a. String -> Doc a
    text (String -> Doc b) -> (a -> String) -> a -> Doc b
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . a -> String
    forall a. Show a => a -> String
    show

    instance Pretty (Doc a) where
      pretty :: forall b. Doc a -> Doc b
    pretty = Doc a -> Doc b
    forall a b. Doc a -> Doc b
    noAnnotate

    instance Pretty a => Pretty [a] where
      pretty :: forall b. [a] -> Doc b
    pretty = [a] -> Doc b
    forall b. [a] -> Doc b
    forall a b. Pretty a => [a] -> Doc b
    prettyList

    instance Pretty T.Text where
      pretty :: forall b. Text -> Doc b
    pretty = String -> Doc b
    forall a. String -> Doc a
    forall a b. Pretty a => a -> Doc b
    pretty (String -> Doc b) -> (Text -> String) -> Text -> Doc b
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Text -> String
    T.unpack

    instance Pretty TL.Text where
      pretty :: forall b. Text -> Doc b
    pretty = String -> Doc b
    forall a. String -> Doc a
    forall a b. Pretty a => a -> Doc b
    pretty (String -> Doc b) -> (Text -> String) -> Text -> Doc b
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Text -> String
    TL.unpack

    instance Pretty () where
      pretty :: forall b. () -> Doc b
    pretty () = String -> Doc b
    forall a. String -> Doc a
    text String
    "()"

    instance Pretty Char where
      pretty :: forall a. Char -> Doc a
    pretty = Char -> Doc b
    forall a. Char -> Doc a
    char
      prettyList :: forall a. String -> Doc a
    prettyList String
    "" = Doc b
    forall a. Monoid a => a
    mempty
      prettyList (Char
    '\n':String
    s) = Doc b
    forall a. Doc a
    line Doc b -> Doc b -> Doc b
    forall a. Semigroup a => a -> a -> a
    <> String -> Doc b
    forall a. String -> Doc a
    forall a b. Pretty a => [a] -> Doc b
    prettyList String
    s
      prettyList String
    s = let (String
    xs,String
    ys) = (Char -> Bool) -> String -> (String, String)
    forall a. (a -> Bool) -> [a] -> ([a], [a])
    span (Char -> Char -> Bool
    forall a. Eq a => a -> a -> Bool
    /=Char
    '\n') String
    s in String -> Doc b
    forall a. String -> Doc a
    text String
    xs Doc b -> Doc b -> Doc b
    forall a. Semigroup a => a -> a -> a
    <> String -> Doc b
    forall a. String -> Doc a
    forall a b. Pretty a => [a] -> Doc b
    prettyList String
    ys

    instance Pretty a => Pretty (Seq a) where
      pretty :: forall b. Seq a -> Doc b
    pretty = [a] -> Doc b
    forall b. [a] -> Doc b
    forall a b. Pretty a => [a] -> Doc b
    prettyList ([a] -> Doc b) -> (Seq a -> [a]) -> Seq a -> Doc b
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Seq a -> [a]
    forall a. Seq a -> [a]
    forall (t :: * -> *) a. Foldable t => t a -> [a]
    toList

    instance Pretty a => Pretty (NonEmpty a) where
      pretty :: forall b. NonEmpty a -> Doc b
    pretty = [a] -> Doc b
    forall b. [a] -> Doc b
    forall a b. Pretty a => [a] -> Doc b
    prettyList ([a] -> Doc b) -> (NonEmpty a -> [a]) -> NonEmpty a -> Doc b
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . NonEmpty a -> [a]
    forall a. NonEmpty a -> [a]
    forall (t :: * -> *) a. Foldable t => t a -> [a]
    toList

    instance (Pretty a, Pretty b) => Pretty (a,b) where
      pretty :: forall b. (a, b) -> Doc b
    pretty (a
    x, b
    y) = [Doc b] -> Doc b
    forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    tupled [a -> Doc b
    forall b. a -> Doc b
    forall a b. Pretty a => a -> Doc b
    pretty a
    x, b -> Doc b
    forall b. b -> Doc b
    forall a b. Pretty a => a -> Doc b
    pretty b
    y]

    instance (Pretty a, Pretty b, Pretty c) => Pretty (a,b,c) where
      pretty :: forall b. (a, b, c) -> Doc b
    pretty (a
    x, b
    y, c
    z) = [Doc b] -> Doc b
    forall (f :: * -> *) a. Foldable f => f (Doc a) -> Doc a
    tupled [a -> Doc b
    forall b. a -> Doc b
    forall a b. Pretty a => a -> Doc b
    pretty a
    x, b -> Doc b
    forall b. b -> Doc b
    forall a b. Pretty a => a -> Doc b
    pretty b
    y, c -> Doc b
    forall b. c -> Doc b
    forall a b. Pretty a => a -> Doc b
    pretty c
    z]

    instance Pretty a => Pretty (Maybe a) where
      pretty :: forall b. Maybe a -> Doc b
    pretty = Doc b -> (a -> Doc b) -> Maybe a -> Doc b
    forall b a. b -> (a -> b) -> Maybe a -> b
    maybe Doc b
    forall a. Monoid a => a
    mempty a -> Doc b
    forall b. a -> Doc b
    forall a b. Pretty a => a -> Doc b
    pretty

    instance Pretty Bool
    instance Pretty Int
    instance Pretty Int8
    instance Pretty Int16
    instance Pretty Int32
    instance Pretty Int64
    instance Pretty Word
    instance Pretty Word8
    instance Pretty Word16
    instance Pretty Word32
    instance Pretty Word64
    instance Pretty Integer
    instance Pretty Natural
    instance Pretty Float
    instance Pretty Double
    instance Pretty Rational

    -----------------------------------------------------------
    -- semi primitive: fill and fillBreak
    -----------------------------------------------------------

    -- | The document @(fillBreak i x)@ first renders document @x@. It
    -- then appends @space@s until the width is equal to @i@. If the
    -- width of @x@ is already larger than @i@, the nesting level is
    -- increased by @i@ and a @line@ is appended. When we redefine @ptype@
    -- in the previous example to use @fillBreak@, we get a useful
    -- variation of the previous output:
    --
    -- > ptype (name,tp)
    -- >        = fillBreak 6 (text name) <+> text "::" <+> text tp
    --
    -- The output will now be:
    --
    -- @
    -- let mempty  :: Doc a
    --     nest   :: Int -> Doc a -> Doc a
    --     linebreak
    --            :: Doc a
    -- @
    fillBreak :: Int -> Doc a -> Doc a
    fillBreak :: forall a. Int -> Doc a -> Doc a
    fillBreak Int
    f Doc a
    x = Doc a -> (Int -> Doc a) -> Doc a
    forall a. Doc a -> (Int -> Doc a) -> Doc a
    width Doc a
    x ((Int -> Doc a) -> Doc a) -> (Int -> Doc a) -> Doc a
    forall a b. (a -> b) -> a -> b
    $ \Int
    w ->
                      if Int
    w Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    > Int
    f then Int -> Doc a -> Doc a
    forall a. Int -> Doc a -> Doc a
    nest Int
    f Doc a
    forall a. Doc a
    linebreak
                               else String -> Doc a
    forall a. String -> Doc a
    text (Int -> String
    spaces (Int
    f Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    w))

    -- | The document @(fill i x)@ renders document @x@. It then appends
    -- @space@s until the width is equal to @i@. If the width of @x@ is
    -- already larger, nothing is appended. This combinator is quite
    -- useful in practice to output a list of bindings. The following
    -- example demonstrates this.
    --
    -- > types  = [("mempty","Doc a")
    -- >          ,("nest","Int -> Doc a -> Doc a")
    -- >          ,("linebreak","Doc a")]
    -- >
    -- > ptype (name,tp)
    -- >        = fill 6 (text name) <+> text "::" <+> text tp
    -- >
    -- > test   = text "let" <+> align (vcat (map ptype types))
    --
    -- Which is layed out as:
    --
    -- @
    -- let mempty  :: Doc a
    --     nest   :: Int -> Doc a -> Doc a
    --     linebreak :: Doc a
    -- @
    fill :: Int -> Doc a -> Doc a
    fill :: forall a. Int -> Doc a -> Doc a
    fill Int
    f Doc a
    d = Doc a -> (Int -> Doc a) -> Doc a
    forall a. Doc a -> (Int -> Doc a) -> Doc a
    width Doc a
    d ((Int -> Doc a) -> Doc a) -> (Int -> Doc a) -> Doc a
    forall a b. (a -> b) -> a -> b
    $ \Int
    w ->
                         if Int
    w Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    >= Int
    f
                         then Doc a
    forall a. Monoid a => a
    mempty
                         else String -> Doc a
    forall a. String -> Doc a
    text (Int -> String
    spaces (Int
    f Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    w))

    width :: Doc a -> (Int -> Doc a) -> Doc a
    width :: forall a. Doc a -> (Int -> Doc a) -> Doc a
    width Doc a
    d Int -> Doc a
    f = (Int -> Doc a) -> Doc a
    forall a. (Int -> Doc a) -> Doc a
    column (\Int
    k1 -> Doc a
    d Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> (Int -> Doc a) -> Doc a
    forall a. (Int -> Doc a) -> Doc a
    column (\Int
    k2 -> Int -> Doc a
    f (Int
    k2 Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    k1)))

    -----------------------------------------------------------
    -- semi primitive: Alignment and indentation
    -----------------------------------------------------------

    -- | The document @(indent i x)@ indents document @x@ with @i@ spaces.
    --
    -- > test  = indent 4 (fillSep (map text
    -- >         (words "the indent combinator indents these words !")))
    --
    -- Which lays out with a page width of 20 as:
    --
    -- @
    --     the indent
    --     combinator
    --     indents these
    --     words !
    -- @
    indent :: Int -> Doc a -> Doc a
    indent :: forall a. Int -> Doc a -> Doc a
    indent Int
    i Doc a
    d = Int -> Doc a -> Doc a
    forall a. Int -> Doc a -> Doc a
    hang Int
    i (String -> Doc a
    forall a. String -> Doc a
    text (Int -> String
    spaces Int
    i) Doc a -> Doc a -> Doc a
    forall a. Semigroup a => a -> a -> a
    <> Doc a
    d)

    -- | The hang combinator implements hanging indentation. The document
    -- @(hang i x)@ renders document @x@ with a nesting level set to the
    -- current column plus @i@. The following example uses hanging
    -- indentation for some text:
    --
    -- > test  = hang 4 (fillSep (map text
    -- >         (words "the hang combinator indents these words !")))
    --
    -- Which lays out on a page with a width of 20 characters as:
    --
    -- @
    -- the hang combinator
    --     indents these
    --     words !
    -- @
    --
    -- The @hang@ combinator is implemented as:
    --
    -- > hang i x  = align (nest i x)
    hang :: Int -> Doc a -> Doc a
    hang :: forall a. Int -> Doc a -> Doc a
    hang Int
    i Doc a
    d = Doc a -> Doc a
    forall a. Doc a -> Doc a
    align (Int -> Doc a -> Doc a
    forall a. Int -> Doc a -> Doc a
    nest Int
    i Doc a
    d)

    -- | The document @(align x)@ renders document @x@ with the nesting
    -- level set to the current column. It is used for example to
    -- implement 'hang'.
    --
    -- As an example, we will put a document right above another one,
    -- regardless of the current nesting level:
    --
    -- > x $$ y = align (x <#> y)
    --
    -- > test = text "hi" <+> (text "nice" $$ text "world")
    --
    -- which will be layed out as:
    --
    -- @
    -- hi nice
    --    world
    -- @
    align :: Doc a -> Doc a
    align :: forall a. Doc a -> Doc a
    align Doc a
    d = (Int -> Doc a) -> Doc a
    forall a. (Int -> Doc a) -> Doc a
    column ((Int -> Doc a) -> Doc a) -> (Int -> Doc a) -> Doc a
    forall a b. (a -> b) -> a -> b
    $ \Int
    k ->
             (Int -> Doc a) -> Doc a
    forall a. (Int -> Doc a) -> Doc a
    nesting ((Int -> Doc a) -> Doc a) -> (Int -> Doc a) -> Doc a
    forall a b. (a -> b) -> a -> b
    $ \Int
    i -> Int -> Doc a -> Doc a
    forall a. Int -> Doc a -> Doc a
    nest (Int
    k Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    i) Doc a
    d   --nesting might be negative :-)

    -----------------------------------------------------------
    -- Primitives
    -----------------------------------------------------------

    -- | The data type @Doc@ represents pretty documents.
    --
    -- @Doc@ is an instance of the 'Show' class. @(show doc)@ pretty
    -- prints document @doc@ with a page width of 100 characters and a
    -- ribbon width of 40 characters.
    --
    -- > show (text "hello" <#> text "world")
    --
    -- Which would return the string \"hello\\nworld\", i.e.
    --
    -- @
    -- hello
    -- world
    -- @
    data Doc a
      = Empty
      | Char {-# UNPACK #-} !Char       -- invariant: char is not '\n'
      | Text {-# UNPACK #-} !Int String -- invariant: text doesn't contain '\n'
      | Line
      | FlatAlt (Doc a) (Doc a)         -- Render the first doc, but when flattened, render the second.
      | Cat (Doc a) (Doc a)
      | Nest {-# UNPACK #-} !Int (Doc a)
      | Union (Doc a) (Doc a) -- invariant: first lines of first doc longer than the first lines of the second doc
      | Annotate a (Doc a)
      | Column  (Int -> Doc a)
      | Nesting (Int -> Doc a)
      | Columns (Maybe Int -> Doc a)
      | Ribbon  (Maybe Int -> Doc a)
      deriving ((forall x. Doc a -> Rep (Doc a) x)
    -> (forall x. Rep (Doc a) x -> Doc a) -> Generic (Doc a)
    forall x. Rep (Doc a) x -> Doc a
    forall x. Doc a -> Rep (Doc a) x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    forall a x. Rep (Doc a) x -> Doc a
    forall a x. Doc a -> Rep (Doc a) x
    $cfrom :: forall a x. Doc a -> Rep (Doc a) x
    from :: forall x. Doc a -> Rep (Doc a) x
    $cto :: forall a x. Rep (Doc a) x -> Doc a
    to :: forall x. Rep (Doc a) x -> Doc a
    Generic, (forall a b. (a -> b) -> Doc a -> Doc b)
    -> (forall a b. a -> Doc b -> Doc a) -> Functor Doc
    forall a b. a -> Doc b -> Doc a
    forall a b. (a -> b) -> Doc a -> Doc b
    forall (f :: * -> *).
    (forall a b. (a -> b) -> f a -> f b)
    -> (forall a b. a -> f b -> f a) -> Functor f
    $cfmap :: forall a b. (a -> b) -> Doc a -> Doc b
    fmap :: forall a b. (a -> b) -> Doc a -> Doc b
    $c<$ :: forall a b. a -> Doc b -> Doc a
    <$ :: forall a b. a -> Doc b -> Doc a
    Functor)

    instance NFData a => NFData (Doc a)

    -- | Annotate a document.
    annotate :: a -> Doc a -> Doc a
    annotate :: forall a. a -> Doc a -> Doc a
    annotate = a -> Doc a -> Doc a
    forall a. a -> Doc a -> Doc a
    Annotate

    -- | Remove the annotations from a document.
    noAnnotate :: Doc a -> Doc a'
    noAnnotate :: forall a b. Doc a -> Doc b
    noAnnotate = (a -> Doc a' -> Doc a') -> Doc a -> Doc a'
    forall a a'. (a -> Doc a' -> Doc a') -> Doc a -> Doc a'
    docMapAnn ((a -> Doc a' -> Doc a') -> Doc a -> Doc a')
    -> (a -> Doc a' -> Doc a') -> Doc a -> Doc a'
    forall a b. (a -> b) -> a -> b
    $ (Doc a' -> Doc a') -> a -> Doc a' -> Doc a'
    forall a b. a -> b -> a
    const Doc a' -> Doc a'
    forall a. a -> a
    id

    -- | The data type @SimpleDoc@ represents rendered documents and is
    -- used by the display functions.
    --
    -- The @Int@ in @SText@ contains the length of the string. The @Int@
    -- in @SLine@ contains the indentation for that line. The library
    -- provides two default display functions 'displayS' and
    -- 'displayIO'. You can provide your own display function by writing a
    -- function from a @SimpleDoc@ to your own output format.
    data SimpleDoc a
      = SEmpty
      | SChar {-# UNPACK #-} !Char (SimpleDoc a)
      | SText {-# UNPACK #-} !Int String (SimpleDoc a)
      | SLine {-# UNPACK #-} !Int (SimpleDoc a)
      | SPushAnn a (SimpleDoc a)
      | SPopAnn  a (SimpleDoc a)
      deriving ((forall x. SimpleDoc a -> Rep (SimpleDoc a) x)
    -> (forall x. Rep (SimpleDoc a) x -> SimpleDoc a)
    -> Generic (SimpleDoc a)
    forall x. Rep (SimpleDoc a) x -> SimpleDoc a
    forall x. SimpleDoc a -> Rep (SimpleDoc a) x
    forall a.
    (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
    forall a x. Rep (SimpleDoc a) x -> SimpleDoc a
    forall a x. SimpleDoc a -> Rep (SimpleDoc a) x
    $cfrom :: forall a x. SimpleDoc a -> Rep (SimpleDoc a) x
    from :: forall x. SimpleDoc a -> Rep (SimpleDoc a) x
    $cto :: forall a x. Rep (SimpleDoc a) x -> SimpleDoc a
    to :: forall x. Rep (SimpleDoc a) x -> SimpleDoc a
    Generic, (forall a b. (a -> b) -> SimpleDoc a -> SimpleDoc b)
    -> (forall a b. a -> SimpleDoc b -> SimpleDoc a)
    -> Functor SimpleDoc
    forall a b. a -> SimpleDoc b -> SimpleDoc a
    forall a b. (a -> b) -> SimpleDoc a -> SimpleDoc b
    forall (f :: * -> *).
    (forall a b. (a -> b) -> f a -> f b)
    -> (forall a b. a -> f b -> f a) -> Functor f
    $cfmap :: forall a b. (a -> b) -> SimpleDoc a -> SimpleDoc b
    fmap :: forall a b. (a -> b) -> SimpleDoc a -> SimpleDoc b
    $c<$ :: forall a b. a -> SimpleDoc b -> SimpleDoc a
    <$ :: forall a b. a -> SimpleDoc b -> SimpleDoc a
    Functor, (forall m. Monoid m => SimpleDoc m -> m)
    -> (forall m a. Monoid m => (a -> m) -> SimpleDoc a -> m)
    -> (forall m a. Monoid m => (a -> m) -> SimpleDoc a -> m)
    -> (forall a b. (a -> b -> b) -> b -> SimpleDoc a -> b)
    -> (forall a b. (a -> b -> b) -> b -> SimpleDoc a -> b)
    -> (forall b a. (b -> a -> b) -> b -> SimpleDoc a -> b)
    -> (forall b a. (b -> a -> b) -> b -> SimpleDoc a -> b)
    -> (forall a. (a -> a -> a) -> SimpleDoc a -> a)
    -> (forall a. (a -> a -> a) -> SimpleDoc a -> a)
    -> (forall a. SimpleDoc a -> [a])
    -> (forall a. SimpleDoc a -> Bool)
    -> (forall a. SimpleDoc a -> Int)
    -> (forall a. Eq a => a -> SimpleDoc a -> Bool)
    -> (forall a. Ord a => SimpleDoc a -> a)
    -> (forall a. Ord a => SimpleDoc a -> a)
    -> (forall a. Num a => SimpleDoc a -> a)
    -> (forall a. Num a => SimpleDoc a -> a)
    -> Foldable SimpleDoc
    forall a. Eq a => a -> SimpleDoc a -> Bool
    forall a. Num a => SimpleDoc a -> a
    forall a. Ord a => SimpleDoc a -> a
    forall m. Monoid m => SimpleDoc m -> m
    forall a. SimpleDoc a -> Bool
    forall a. SimpleDoc a -> Int
    forall a. SimpleDoc a -> [a]
    forall a. (a -> a -> a) -> SimpleDoc a -> a
    forall m a. Monoid m => (a -> m) -> SimpleDoc a -> m
    forall b a. (b -> a -> b) -> b -> SimpleDoc a -> b
    forall a b. (a -> b -> b) -> b -> SimpleDoc a -> b
    forall (t :: * -> *).
    (forall m. Monoid m => t m -> m)
    -> (forall m a. Monoid m => (a -> m) -> t a -> m)
    -> (forall m a. Monoid m => (a -> m) -> t a -> m)
    -> (forall a b. (a -> b -> b) -> b -> t a -> b)
    -> (forall a b. (a -> b -> b) -> b -> t a -> b)
    -> (forall b a. (b -> a -> b) -> b -> t a -> b)
    -> (forall b a. (b -> a -> b) -> b -> t a -> b)
    -> (forall a. (a -> a -> a) -> t a -> a)
    -> (forall a. (a -> a -> a) -> t a -> a)
    -> (forall a. t a -> [a])
    -> (forall a. t a -> Bool)
    -> (forall a. t a -> Int)
    -> (forall a. Eq a => a -> t a -> Bool)
    -> (forall a. Ord a => t a -> a)
    -> (forall a. Ord a => t a -> a)
    -> (forall a. Num a => t a -> a)
    -> (forall a. Num a => t a -> a)
    -> Foldable t
    $cfold :: forall m. Monoid m => SimpleDoc m -> m
    fold :: forall m. Monoid m => SimpleDoc m -> m
    $cfoldMap :: forall m a. Monoid m => (a -> m) -> SimpleDoc a -> m
    foldMap :: forall m a. Monoid m => (a -> m) -> SimpleDoc a -> m
    $cfoldMap' :: forall m a. Monoid m => (a -> m) -> SimpleDoc a -> m
    foldMap' :: forall m a. Monoid m => (a -> m) -> SimpleDoc a -> m
    $cfoldr :: forall a b. (a -> b -> b) -> b -> SimpleDoc a -> b
    foldr :: forall a b. (a -> b -> b) -> b -> SimpleDoc a -> b
    $cfoldr' :: forall a b. (a -> b -> b) -> b -> SimpleDoc a -> b
    foldr' :: forall a b. (a -> b -> b) -> b -> SimpleDoc a -> b
    $cfoldl :: forall b a. (b -> a -> b) -> b -> SimpleDoc a -> b
    foldl :: forall b a. (b -> a -> b) -> b -> SimpleDoc a -> b
    $cfoldl' :: forall b a. (b -> a -> b) -> b -> SimpleDoc a -> b
    foldl' :: forall b a. (b -> a -> b) -> b -> SimpleDoc a -> b
    $cfoldr1 :: forall a. (a -> a -> a) -> SimpleDoc a -> a
    foldr1 :: forall a. (a -> a -> a) -> SimpleDoc a -> a
    $cfoldl1 :: forall a. (a -> a -> a) -> SimpleDoc a -> a
    foldl1 :: forall a. (a -> a -> a) -> SimpleDoc a -> a
    $ctoList :: forall a. SimpleDoc a -> [a]
    toList :: forall a. SimpleDoc a -> [a]
    $cnull :: forall a. SimpleDoc a -> Bool
    null :: forall a. SimpleDoc a -> Bool
    $clength :: forall a. SimpleDoc a -> Int
    length :: forall a. SimpleDoc a -> Int
    $celem :: forall a. Eq a => a -> SimpleDoc a -> Bool
    elem :: forall a. Eq a => a -> SimpleDoc a -> Bool
    $cmaximum :: forall a. Ord a => SimpleDoc a -> a
    maximum :: forall a. Ord a => SimpleDoc a -> a
    $cminimum :: forall a. Ord a => SimpleDoc a -> a
    minimum :: forall a. Ord a => SimpleDoc a -> a
    $csum :: forall a. Num a => SimpleDoc a -> a
    sum :: forall a. Num a => SimpleDoc a -> a
    $cproduct :: forall a. Num a => SimpleDoc a -> a
    product :: forall a. Num a => SimpleDoc a -> a
    Foldable, Functor SimpleDoc
    Foldable SimpleDoc
    (Functor SimpleDoc, Foldable SimpleDoc) =>
    (forall (f :: * -> *) a b.
     Applicative f =>
     (a -> f b) -> SimpleDoc a -> f (SimpleDoc b))
    -> (forall (f :: * -> *) a.
        Applicative f =>
        SimpleDoc (f a) -> f (SimpleDoc a))
    -> (forall (m :: * -> *) a b.
        Monad m =>
        (a -> m b) -> SimpleDoc a -> m (SimpleDoc b))
    -> (forall (m :: * -> *) a.
        Monad m =>
        SimpleDoc (m a) -> m (SimpleDoc a))
    -> Traversable SimpleDoc
    forall (t :: * -> *).
    (Functor t, Foldable t) =>
    (forall (f :: * -> *) a b.
     Applicative f =>
     (a -> f b) -> t a -> f (t b))
    -> (forall (f :: * -> *) a. Applicative f => t (f a) -> f (t a))
    -> (forall (m :: * -> *) a b.
        Monad m =>
        (a -> m b) -> t a -> m (t b))
    -> (forall (m :: * -> *) a. Monad m => t (m a) -> m (t a))
    -> Traversable t
    forall (m :: * -> *) a.
    Monad m =>
    SimpleDoc (m a) -> m (SimpleDoc a)
    forall (f :: * -> *) a.
    Applicative f =>
    SimpleDoc (f a) -> f (SimpleDoc a)
    forall (m :: * -> *) a b.
    Monad m =>
    (a -> m b) -> SimpleDoc a -> m (SimpleDoc b)
    forall (f :: * -> *) a b.
    Applicative f =>
    (a -> f b) -> SimpleDoc a -> f (SimpleDoc b)
    $ctraverse :: forall (f :: * -> *) a b.
    Applicative f =>
    (a -> f b) -> SimpleDoc a -> f (SimpleDoc b)
    traverse :: forall (f :: * -> *) a b.
    Applicative f =>
    (a -> f b) -> SimpleDoc a -> f (SimpleDoc b)
    $csequenceA :: forall (f :: * -> *) a.
    Applicative f =>
    SimpleDoc (f a) -> f (SimpleDoc a)
    sequenceA :: forall (f :: * -> *) a.
    Applicative f =>
    SimpleDoc (f a) -> f (SimpleDoc a)
    $cmapM :: forall (m :: * -> *) a b.
    Monad m =>
    (a -> m b) -> SimpleDoc a -> m (SimpleDoc b)
    mapM :: forall (m :: * -> *) a b.
    Monad m =>
    (a -> m b) -> SimpleDoc a -> m (SimpleDoc b)
    $csequence :: forall (m :: * -> *) a.
    Monad m =>
    SimpleDoc (m a) -> m (SimpleDoc a)
    sequence :: forall (m :: * -> *) a.
    Monad m =>
    SimpleDoc (m a) -> m (SimpleDoc a)
    Traversable)

    instance NFData a => NFData (SimpleDoc a)

    -- | The document @(char c)@ contains the literal character @c@. The
    -- character shouldn't be a newline (@'\n'@), the function 'line'
    -- should be used for line breaks.
    char :: Char -> Doc a
    char :: forall a. Char -> Doc a
    char Char
    '\n' = Doc a
    forall a. Doc a
    line
    char Char
    c = Char -> Doc a
    forall a. Char -> Doc a
    Char Char
    c

    -- | The document @(text s)@ contains the literal string @s@. The
    -- string shouldn't contain any newline (@'\n'@) characters. If the
    -- string contains newline characters, the function 'pretty' should be
    -- used.
    text :: String -> Doc a
    text :: forall a. String -> Doc a
    text String
    "" = Doc a
    forall a. Doc a
    Empty
    text String
    s  = Int -> String -> Doc a
    forall a. Int -> String -> Doc a
    Text (String -> Int
    forall a. [a] -> Int
    forall (t :: * -> *) a. Foldable t => t a -> Int
    length String
    s) String
    s

    -- | The @line@ document advances to the next line and indents to the
    -- current nesting level. Document @line@ behaves like @(text \" \")@
    -- if the line break is undone by 'group'.
    line :: Doc a
    line :: forall a. Doc a
    line = Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    FlatAlt Doc a
    forall a. Doc a
    Line Doc a
    forall a. Doc a
    space

    -- | The @linebreak@ document advances to the next line and indents to
    -- the current nesting level. Document @linebreak@ behaves like
    -- 'mempty' if the line break is undone by 'group'.
    linebreak :: Doc a
    linebreak :: forall a. Doc a
    linebreak = Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    FlatAlt Doc a
    forall a. Doc a
    Line Doc a
    forall a. Monoid a => a
    mempty

    -- | A linebreak that can not be flattened; it is guaranteed to be
    -- rendered as a newline.
    hardline :: Doc a
    hardline :: forall a. Doc a
    hardline = Doc a
    forall a. Doc a
    Line

    -- | The document @(nest i x)@ renders document @x@ with the current
    -- indentation level increased by i (See also 'hang', 'align' and
    -- 'indent').
    --
    -- > nest 2 (text "hello" <#> text "world") <#> text "!"
    --
    -- outputs as:
    --
    -- @
    -- hello
    --   world
    -- !
    -- @
    nest :: Int -> Doc a -> Doc a
    nest :: forall a. Int -> Doc a -> Doc a
    nest = Int -> Doc a -> Doc a
    forall a. Int -> Doc a -> Doc a
    Nest

    column, nesting :: (Int -> Doc a) -> Doc a
    column :: forall a. (Int -> Doc a) -> Doc a
    column = (Int -> Doc a) -> Doc a
    forall a. (Int -> Doc a) -> Doc a
    Column
    nesting :: forall a. (Int -> Doc a) -> Doc a
    nesting = (Int -> Doc a) -> Doc a
    forall a. (Int -> Doc a) -> Doc a
    Nesting

    columns :: (Maybe Int -> Doc a) -> Doc a
    columns :: forall a. (Maybe Int -> Doc a) -> Doc a
    columns = (Maybe Int -> Doc a) -> Doc a
    forall a. (Maybe Int -> Doc a) -> Doc a
    Columns

    ribbon :: (Maybe Int -> Doc a) -> Doc a
    ribbon :: forall a. (Maybe Int -> Doc a) -> Doc a
    ribbon = (Maybe Int -> Doc a) -> Doc a
    forall a. (Maybe Int -> Doc a) -> Doc a
    Ribbon

    -- | The @group@ combinator is used to specify alternative
    -- layouts. The document @(group x)@ undoes all line breaks in
    -- document @x@. The resulting line is added to the current line if
    -- that fits the page. Otherwise, the document @x@ is rendered without
    -- any changes.
    group :: Doc a -> Doc a
    group :: forall a. Doc a -> Doc a
    group Doc a
    x = Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    Union (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten Doc a
    x) Doc a
    x

    -- | @flatAlt@ creates a document that changes when flattened; normally
    -- it is rendered as the first argument, but when flattened is rendered
    -- as the second.
    flatAlt :: Doc a -> Doc a -> Doc a
    flatAlt :: forall a. Doc a -> Doc a -> Doc a
    flatAlt = Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    FlatAlt

    flatten :: Doc a -> Doc a
    flatten :: forall a. Doc a -> Doc a
    flatten (FlatAlt Doc a
    _ Doc a
    y)   = Doc a
    y
    flatten (Cat Doc a
    x Doc a
    y)       = Doc a -> Doc a -> Doc a
    forall a. Doc a -> Doc a -> Doc a
    Cat (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten Doc a
    x) (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten Doc a
    y)
    flatten (Nest Int
    i Doc a
    x)      = Int -> Doc a -> Doc a
    forall a. Int -> Doc a -> Doc a
    Nest Int
    i (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten Doc a
    x)
    flatten (Union Doc a
    x Doc a
    _)     = Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten Doc a
    x
    flatten (Annotate a
    a Doc a
    x)  = a -> Doc a -> Doc a
    forall a. a -> Doc a -> Doc a
    Annotate a
    a (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten Doc a
    x)
    flatten (Column Int -> Doc a
    f)      = (Int -> Doc a) -> Doc a
    forall a. (Int -> Doc a) -> Doc a
    Column (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten (Doc a -> Doc a) -> (Int -> Doc a) -> Int -> Doc a
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Int -> Doc a
    f)
    flatten (Nesting Int -> Doc a
    f)     = (Int -> Doc a) -> Doc a
    forall a. (Int -> Doc a) -> Doc a
    Nesting (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten (Doc a -> Doc a) -> (Int -> Doc a) -> Int -> Doc a
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Int -> Doc a
    f)
    flatten (Columns Maybe Int -> Doc a
    f)     = (Maybe Int -> Doc a) -> Doc a
    forall a. (Maybe Int -> Doc a) -> Doc a
    Columns (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten (Doc a -> Doc a) -> (Maybe Int -> Doc a) -> Maybe Int -> Doc a
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Maybe Int -> Doc a
    f)
    flatten (Ribbon Maybe Int -> Doc a
    f)      = (Maybe Int -> Doc a) -> Doc a
    forall a. (Maybe Int -> Doc a) -> Doc a
    Ribbon (Doc a -> Doc a
    forall a. Doc a -> Doc a
    flatten (Doc a -> Doc a) -> (Maybe Int -> Doc a) -> Maybe Int -> Doc a
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Maybe Int -> Doc a
    f)
    flatten a :: Doc a
    a@Empty{}       = Doc a
    a
    flatten a :: Doc a
    a@Char{}        = Doc a
    a
    flatten a :: Doc a
    a@Text{}        = Doc a
    a
    flatten a :: Doc a
    a@Line{}        = Doc a
    a

    -----------------------------------------------------------
    -- Renderers
    -----------------------------------------------------------

    -----------------------------------------------------------
    -- renderPretty: the default pretty printing algorithm
    -----------------------------------------------------------

    -- list of indentation/document pairs; saves an indirection over [(Int,Doc)]
    data Docs a e
      = Nil
      | Cons {-# UNPACK #-} !Int (Doc a) (Docs a e)

    -- | This is the default pretty printer which is used by 'show',
    -- 'putDoc' and 'hPutDoc'. @(renderPretty ribbonfrac width x)@ renders
    -- document @x@ with a page width of @width@ and a ribbon width of
    -- @(ribbonfrac * width)@ characters. The ribbon width is the maximal
    -- amount of non-indentation characters on a line. The parameter
    -- @ribbonfrac@ should be between @0.0@ and @1.0@. If it is lower or
    -- higher, the ribbon width will be 0 or @width@ respectively.
    renderPretty :: Float -> Int -> Doc a -> SimpleDoc a
    renderPretty :: forall a. Float -> Int -> Doc a -> SimpleDoc a
    renderPretty = (Int
     -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a)
    -> Float -> Int -> Doc a -> SimpleDoc a
    forall a.
    (Int
     -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a)
    -> Float -> Int -> Doc a -> SimpleDoc a
    renderFits Int
    -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    forall a.
    Int
    -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    nicest1

    -- | This is the default pretty printer which is used by 'show',
    -- 'putDoc' and 'hPutDoc'. This routine uses a page width of 100 characters
    -- and a ribbon width of 40 characters.
    renderPrettyDefault :: Doc a -> SimpleDoc a
    renderPrettyDefault :: forall a. Doc a -> SimpleDoc a
    renderPrettyDefault = Float -> Int -> Doc a -> SimpleDoc a
    forall a. Float -> Int -> Doc a -> SimpleDoc a
    renderPretty Float
    0.4 Int
    100

    -- | A slightly smarter rendering algorithm with more lookahead. It provides
    -- provide earlier breaking on deeply nested structures.
    -- For example, consider this python-ish pseudocode:
    -- @fun(fun(fun(fun(fun([abcdefg, abcdefg])))))@
    -- If we put a softbreak (+ nesting 2) after each open parenthesis, and align
    -- the elements of the list to match the opening brackets, this will render with
    -- @renderPretty@ and a page width of 20c as:
    -- @
    -- fun(fun(fun(fun(fun([
    --                     | abcdef,
    --                     | abcdef,
    --                     ]
    --   )))))             |
    -- @
    -- Where the 20c. boundary has been marked with |. Because @renderPretty@ only
    -- uses one-line lookahead, it sees that the first line fits, and is stuck
    -- putting the second and third lines after the 20c mark. In contrast,
    -- @renderSmart@ will continue to check the potential document up to the end of
    -- the indentation level. Thus, it will format the document as:
    --
    -- @
    -- fun(                |
    --   fun(              |
    --     fun(            |
    --       fun(          |
    --         fun([       |
    --               abcdef,
    --               abcdef,
    --             ]       |
    --   )))))             |
    -- @
    -- Which fits within the 20c. mark.
    -- In addition, @renderSmart@ uses this lookahead to minimize the number of
    -- lines printed, leading to more compact and visually appealing output.
    -- Consider this example using the same syntax as above:
    -- @aaaaaaaaaaa([abc, def, ghi])@
    -- When rendered with @renderPretty@ and a page width of 20c, we get:
    -- @
    -- aaaaaaaaaaa([ abc
    --             , def
    --             , ghi ])
    -- @
    -- Whereas when rendered with @renderSmart@ and a page width of 20c, we get:
    -- @
    -- aaaaaaaaaaa(
    --   [abc, def, ghi])
    -- @
    renderSmart :: Int -> Doc a -> SimpleDoc a
    renderSmart :: forall a. Int -> Doc a -> SimpleDoc a
    renderSmart = (Int
     -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a)
    -> Float -> Int -> Doc a -> SimpleDoc a
    forall a.
    (Int
     -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a)
    -> Float -> Int -> Doc a -> SimpleDoc a
    renderFits Int
    -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    forall a.
    Int
    -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    nicestR Float
    1.0

    renderFits :: (Int -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a
                   -> SimpleDoc a)
                  -> Float -> Int -> Doc a -> SimpleDoc a
    renderFits :: forall a.
    (Int
     -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a)
    -> Float -> Int -> Doc a -> SimpleDoc a
    renderFits Int
    -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    nicest Float
    rfrac Int
    w Doc a
    x
        = Int
    -> Int
    -> (Int -> Int -> SimpleDoc a)
    -> Docs a (ZonkAny 0)
    -> SimpleDoc a
    forall {e}.
    Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    0 Int
    0 (\Int
    _ Int
    _ -> SimpleDoc a
    forall a. SimpleDoc a
    SEmpty) (Int -> Doc a -> Docs a (ZonkAny 0) -> Docs a (ZonkAny 0)
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    0 Doc a
    x Docs a (ZonkAny 0)
    forall a e. Docs a e
    Nil)
        where
          -- r :: the ribbon width in characters
          r :: Int
    r  = Int -> Int -> Int
    forall a. Ord a => a -> a -> a
    max Int
    0 (Int -> Int -> Int
    forall a. Ord a => a -> a -> a
    min Int
    w (Float -> Int
    forall b. Integral b => Float -> b
    forall a b. (RealFrac a, Integral b) => a -> b
    round (Int -> Float
    forall a b. (Integral a, Num b) => a -> b
    fromIntegral Int
    w Float -> Float -> Float
    forall a. Num a => a -> a -> a
    * Float
    rfrac)))

          -- best :: n = indentation of current line
          --         k = current column
          --        (ie. (k >= n) && (k - n == count of inserted characters)
          best :: Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z Docs a e
    Nil           = Int -> Int -> SimpleDoc a
    z Int
    n Int
    k
          best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Cons Int
    i Doc a
    d Docs a e
    ds) =
            case Doc a
    d of
              Doc a
    Empty         -> Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z Docs a e
    ds
              Char Char
    c        -> let k' :: Int
    k' = Int
    kInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    1 in Int -> SimpleDoc a -> SimpleDoc a
    forall a b. a -> b -> b
    seq Int
    k' (Char -> SimpleDoc a -> SimpleDoc a
    forall a. Char -> SimpleDoc a -> SimpleDoc a
    SChar Char
    c (Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k' Int -> Int -> SimpleDoc a
    z Docs a e
    ds))
              Text Int
    l String
    s      -> let k' :: Int
    k' = Int
    kInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    l in Int -> SimpleDoc a -> SimpleDoc a
    forall a b. a -> b -> b
    seq Int
    k' (Int -> String -> SimpleDoc a -> SimpleDoc a
    forall a. Int -> String -> SimpleDoc a -> SimpleDoc a
    SText Int
    l String
    s (Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k' Int -> Int -> SimpleDoc a
    z Docs a e
    ds))
              Doc a
    Line          -> Int -> SimpleDoc a -> SimpleDoc a
    forall a. Int -> SimpleDoc a -> SimpleDoc a
    SLine Int
    i (Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    i Int
    i Int -> Int -> SimpleDoc a
    z Docs a e
    ds)
              FlatAlt Doc a
    l Doc a
    _   -> Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i Doc a
    l Docs a e
    ds)
              Cat Doc a
    x' Doc a
    y      -> Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i Doc a
    x' (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i Doc a
    y Docs a e
    ds))
              Nest Int
    j Doc a
    x'     -> let i' :: Int
    i' = Int
    iInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    j in Int -> SimpleDoc a -> SimpleDoc a
    forall a b. a -> b -> b
    seq Int
    i' (Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i' Doc a
    x' Docs a e
    ds))
              Annotate a
    a Doc a
    d' -> let z' :: Int -> Int -> SimpleDoc a
    z' Int
    n' Int
    k' = a -> SimpleDoc a -> SimpleDoc a
    forall a. a -> SimpleDoc a -> SimpleDoc a
    SPopAnn a
    a (SimpleDoc a -> SimpleDoc a) -> SimpleDoc a -> SimpleDoc a
    forall a b. (a -> b) -> a -> b
    $ Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n' Int
    k' Int -> Int -> SimpleDoc a
    z Docs a e
    ds
                               in a -> SimpleDoc a -> SimpleDoc a
    forall a. a -> SimpleDoc a -> SimpleDoc a
    SPushAnn a
    a (Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z' (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i Doc a
    d' Docs a e
    forall a e. Docs a e
    Nil))
              Union Doc a
    p Doc a
    q     -> Int
    -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    nicest Int
    n Int
    k Int
    w Int
    r (Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i Doc a
    p Docs a e
    ds))
                                              (Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i Doc a
    q Docs a e
    ds))
              Column Int -> Doc a
    f      -> Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i (Int -> Doc a
    f Int
    k) Docs a e
    ds)
              Nesting Int -> Doc a
    f     -> Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i (Int -> Doc a
    f Int
    i) Docs a e
    ds)
              Columns Maybe Int -> Doc a
    f     -> Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i (Maybe Int -> Doc a
    f (Maybe Int -> Doc a) -> Maybe Int -> Doc a
    forall a b. (a -> b) -> a -> b
    $ Int -> Maybe Int
    forall a. a -> Maybe a
    Just Int
    w) Docs a e
    ds)
              Ribbon Maybe Int -> Doc a
    f      -> Int
    -> Int -> (Int -> Int -> SimpleDoc a) -> Docs a e -> SimpleDoc a
    best Int
    n Int
    k Int -> Int -> SimpleDoc a
    z (Int -> Doc a -> Docs a e -> Docs a e
    forall a e. Int -> Doc a -> Docs a e -> Docs a e
    Cons Int
    i (Maybe Int -> Doc a
    f (Maybe Int -> Doc a) -> Maybe Int -> Doc a
    forall a b. (a -> b) -> a -> b
    $ Int -> Maybe Int
    forall a. a -> Maybe a
    Just Int
    r) Docs a e
    ds)

    -- @nicest1@ compares the first lines of the two documents.
    -- n = nesting, k = column, p = pagewidth
    nicest1 :: Int -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    nicest1 :: forall a.
    Int
    -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    nicest1 Int
    n Int
    k Int
    p Int
    r SimpleDoc a
    x' SimpleDoc a
    y | Int -> Int -> SimpleDoc a -> Bool
    forall {t} {a}. t -> Int -> SimpleDoc a -> Bool
    fits (Int -> Int -> Int
    forall a. Ord a => a -> a -> a
    min Int
    n Int
    k) Int
    wid SimpleDoc a
    x' = SimpleDoc a
    x'
                         | Bool
    otherwise = SimpleDoc a
    y
      where wid :: Int
    wid = Int -> Int -> Int
    forall a. Ord a => a -> a -> a
    min (Int
    p Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    k) (Int
    r Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    k Int -> Int -> Int
    forall a. Num a => a -> a -> a
    + Int
    n)
            fits :: t -> Int -> SimpleDoc a -> Bool
    fits t
    _ Int
    w SimpleDoc a
    _        | Int
    w Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < Int
    0 = Bool
    False
            fits t
    _ Int
    _ SimpleDoc a
    SEmpty           = Bool
    True
            fits t
    m Int
    w (SChar Char
    _ SimpleDoc a
    x)      = t -> Int -> SimpleDoc a -> Bool
    fits t
    m (Int
    w Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    1) SimpleDoc a
    x
            fits t
    m Int
    w (SText Int
    l String
    _ SimpleDoc a
    x)    = t -> Int -> SimpleDoc a -> Bool
    fits t
    m (Int
    w Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    l) SimpleDoc a
    x
            fits t
    _ Int
    _ (SLine Int
    _ SimpleDoc a
    _)      = Bool
    True
            fits t
    m Int
    w (SPushAnn a
    _ SimpleDoc a
    x)   = t -> Int -> SimpleDoc a -> Bool
    fits t
    m Int
    w SimpleDoc a
    x
            fits t
    m Int
    w (SPopAnn  a
    _ SimpleDoc a
    x)   = t -> Int -> SimpleDoc a -> Bool
    fits t
    m Int
    w SimpleDoc a
    x

    -- @nicestR@ compares the initial lines of the two documents that are nested at
    -- least as deep as the current nesting level. If the initial lines of both
    -- documents fit within the page width, the document that takes fewer lines is
    -- prefered, with preference toward the first.
    nicestR :: Int -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    nicestR :: forall a.
    Int
    -> Int -> Int -> Int -> SimpleDoc a -> SimpleDoc a -> SimpleDoc a
    nicestR Int
    n Int
    k Int
    p Int
    r SimpleDoc a
    x' SimpleDoc a
    y =
      if Int -> Int -> SimpleDoc a -> Double
    forall {a}. Int -> Int -> SimpleDoc a -> Double
    fits (Int -> Int -> Int
    forall a. Ord a => a -> a -> a
    min Int
    n Int
    k) Int
    wid SimpleDoc a
    x' Double -> Double -> Bool
    forall a. Ord a => a -> a -> Bool
    <= Int -> Int -> SimpleDoc a -> Double
    forall {a}. Int -> Int -> SimpleDoc a -> Double
    fits (Int -> Int -> Int
    forall a. Ord a => a -> a -> a
    min Int
    n Int
    k) Int
    wid SimpleDoc a
    y then SimpleDoc a
    x' else SimpleDoc a
    y
      where wid :: Int
    wid = Int -> Int -> Int
    forall a. Ord a => a -> a -> a
    min (Int
    p Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    k) (Int
    r Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    k Int -> Int -> Int
    forall a. Num a => a -> a -> a
    + Int
    n)
            inf :: Double
    inf = Double
    1.0Double -> Double -> Double
    forall a. Fractional a => a -> a -> a
    /Double
    0 :: Double
            -- @fits@ has a little more lookahead: assuming that nesting roughly
            -- corresponds to syntactic depth, @fitsR@ checks that not only the
            -- current line fits, but the entire syntactic structure being formatted
            -- at this level of indentation fits. If we were to remove the second
            -- case for @SLine@, we would check that not only the current structure
            -- fits, but also the rest of the document, which would be slightly more
            -- intelligent but would have exponential runtime (and is prohibitively
            -- expensive in practice).
            -- m = minimum nesting level to fit in
            -- w = the width in which to fit the first line
            fits :: Int -> Int -> SimpleDoc a -> Double
    fits Int
    _ Int
    w SimpleDoc a
    _           | Int
    w Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < Int
    0     = Double
    inf
            fits Int
    _ Int
    _ SimpleDoc a
    SEmpty                  = Double
    0
            fits Int
    m Int
    w (SChar Char
    _ SimpleDoc a
    x)             = Int -> Int -> SimpleDoc a -> Double
    fits Int
    m (Int
    w Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    1) SimpleDoc a
    x
            fits Int
    m Int
    w (SText Int
    l String
    _ SimpleDoc a
    x)           = Int -> Int -> SimpleDoc a -> Double
    fits Int
    m (Int
    w Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    l) SimpleDoc a
    x
            fits Int
    m Int
    _ (SLine Int
    i SimpleDoc a
    x) | Int
    m Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < Int
    i     = Double
    1 Double -> Double -> Double
    forall a. Num a => a -> a -> a
    + Int -> Int -> SimpleDoc a -> Double
    fits Int
    m (Int
    p Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    i) SimpleDoc a
    x
                                 | Bool
    otherwise = Double
    0
            fits Int
    m Int
    w (SPushAnn a
    _ SimpleDoc a
    x)          = Int -> Int -> SimpleDoc a -> Double
    fits Int
    m Int
    w SimpleDoc a
    x
            fits Int
    m Int
    w (SPopAnn  a
    _ SimpleDoc a
    x)          = Int -> Int -> SimpleDoc a -> Double
    fits Int
    m Int
    w SimpleDoc a
    x

    -----------------------------------------------------------
    -- renderCompact: renders documents without indentation
    --  fast and fewer characters output, good for machines
    -----------------------------------------------------------

    -- | @(renderCompact x)@ renders document @x@ without adding any
    -- indentation. Since no \'pretty\' printing is involved, this
    -- renderer is very fast. The resulting output contains fewer
    -- characters than a pretty printed version and can be used for output
    -- that is read by other programs.
    renderCompact :: Doc a -> SimpleDoc a
    renderCompact :: forall a. Doc a -> SimpleDoc a
    renderCompact Doc a
    x
        = SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    forall {a}. SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    forall a. SimpleDoc a
    SEmpty Int
    0 [Doc a
    x]
        where
          scan :: SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    _ []     = SimpleDoc a
    z
          scan SimpleDoc a
    z Int
    k (Doc a
    d:[Doc a]
    ds) =
            case Doc a
    d of
              Doc a
    Empty         -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k [Doc a]
    ds
              Char Char
    c        -> let k' :: Int
    k' = Int
    kInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    1 in Int -> SimpleDoc a -> SimpleDoc a
    forall a b. a -> b -> b
    seq Int
    k' (Char -> SimpleDoc a -> SimpleDoc a
    forall a. Char -> SimpleDoc a -> SimpleDoc a
    SChar Char
    c (SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k' [Doc a]
    ds))
              Text Int
    l String
    s      -> let k' :: Int
    k' = Int
    kInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    l in Int -> SimpleDoc a -> SimpleDoc a
    forall a b. a -> b -> b
    seq Int
    k' (Int -> String -> SimpleDoc a -> SimpleDoc a
    forall a. Int -> String -> SimpleDoc a -> SimpleDoc a
    SText Int
    l String
    s (SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k' [Doc a]
    ds))
              Annotate a
    a Doc a
    d' -> a -> SimpleDoc a -> SimpleDoc a
    forall a. a -> SimpleDoc a -> SimpleDoc a
    SPushAnn a
    a (SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan (a -> SimpleDoc a -> SimpleDoc a
    forall a. a -> SimpleDoc a -> SimpleDoc a
    SPopAnn a
    a (SimpleDoc a -> SimpleDoc a) -> SimpleDoc a -> SimpleDoc a
    forall a b. (a -> b) -> a -> b
    $ SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k [Doc a]
    ds) Int
    k [Doc a
    d'])
              Doc a
    Line          -> Int -> SimpleDoc a -> SimpleDoc a
    forall a. Int -> SimpleDoc a -> SimpleDoc a
    SLine Int
    0 (SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    0 [Doc a]
    ds)
              FlatAlt Doc a
    y Doc a
    _   -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k (Doc a
    yDoc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :[Doc a]
    ds)
              Cat Doc a
    y Doc a
    z'      -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k (Doc a
    yDoc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :Doc a
    z'Doc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :[Doc a]
    ds)
              Nest Int
    _ Doc a
    y      -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k (Doc a
    yDoc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :[Doc a]
    ds)
              Union Doc a
    _ Doc a
    y     -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k (Doc a
    yDoc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :[Doc a]
    ds)
              Column Int -> Doc a
    f      -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k (Int -> Doc a
    f Int
    kDoc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :[Doc a]
    ds)
              Nesting Int -> Doc a
    f     -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k (Int -> Doc a
    f Int
    0Doc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :[Doc a]
    ds)
              Columns Maybe Int -> Doc a
    f     -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k (Maybe Int -> Doc a
    f Maybe Int
    forall a. Maybe a
    NothingDoc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :[Doc a]
    ds)
              Ribbon  Maybe Int -> Doc a
    f     -> SimpleDoc a -> Int -> [Doc a] -> SimpleDoc a
    scan SimpleDoc a
    z Int
    k (Maybe Int -> Doc a
    f Maybe Int
    forall a. Maybe a
    NothingDoc a -> [Doc a] -> [Doc a]
    forall a. a -> [a] -> [a]
    :[Doc a]
    ds)

    -----------------------------------------------------------
    -- Displayers:  displayS and displayIO
    -----------------------------------------------------------

    simpleDocMapAnn :: (r -> a -> r)                            -- ^ SPushAnn state update
                    -> (r -> a -> r)                            -- ^ SPopAnn state update
                    -> (r -> SimpleDoc a' -> SimpleDoc a')      -- ^ SPushAnn processor
                    -> (r -> SimpleDoc a' -> SimpleDoc a')      -- ^ SPopAnn processor
                    -> r                                        -- ^ Initial state
                    -> SimpleDoc a -> SimpleDoc a'
    simpleDocMapAnn :: forall r a a'.
    (r -> a -> r)
    -> (r -> a -> r)
    -> (r -> SimpleDoc a' -> SimpleDoc a')
    -> (r -> SimpleDoc a' -> SimpleDoc a')
    -> r
    -> SimpleDoc a
    -> SimpleDoc a'
    simpleDocMapAnn r -> a -> r
    upPush r -> a -> r
    upPop r -> SimpleDoc a' -> SimpleDoc a'
    push r -> SimpleDoc a' -> SimpleDoc a'
    pop = r -> SimpleDoc a -> SimpleDoc a'
    go
     where
      go :: r -> SimpleDoc a -> SimpleDoc a'
    go r
    _ SimpleDoc a
    SEmpty         = SimpleDoc a'
    forall a. SimpleDoc a
    SEmpty
      go r
    r (SChar Char
    c SimpleDoc a
    x)    = Char -> SimpleDoc a' -> SimpleDoc a'
    forall a. Char -> SimpleDoc a -> SimpleDoc a
    SChar Char
    c   (r -> SimpleDoc a -> SimpleDoc a'
    go r
    r SimpleDoc a
    x)
      go r
    r (SText Int
    l String
    s SimpleDoc a
    x)  = Int -> String -> SimpleDoc a' -> SimpleDoc a'
    forall a. Int -> String -> SimpleDoc a -> SimpleDoc a
    SText Int
    l String
    s (r -> SimpleDoc a -> SimpleDoc a'
    go r
    r SimpleDoc a
    x)
      go r
    r (SLine Int
    i SimpleDoc a
    x)    = Int -> SimpleDoc a' -> SimpleDoc a'
    forall a. Int -> SimpleDoc a -> SimpleDoc a
    SLine Int
    i   (r -> SimpleDoc a -> SimpleDoc a'
    go r
    r SimpleDoc a
    x)
      go r
    r (SPushAnn a
    a SimpleDoc a
    x) = let r' :: r
    r' = r -> a -> r
    upPush r
    r a
    a in r -> SimpleDoc a' -> SimpleDoc a'
    push r
    r' (SimpleDoc a' -> SimpleDoc a') -> SimpleDoc a' -> SimpleDoc a'
    forall a b. (a -> b) -> a -> b
    $ r -> SimpleDoc a -> SimpleDoc a'
    go r
    r' SimpleDoc a
    x
      go r
    r (SPopAnn  a
    a SimpleDoc a
    x) = let r' :: r
    r' = r -> a -> r
    upPop  r
    r a
    a in r -> SimpleDoc a' -> SimpleDoc a'
    pop  r
    r' (SimpleDoc a' -> SimpleDoc a') -> SimpleDoc a' -> SimpleDoc a'
    forall a b. (a -> b) -> a -> b
    $ r -> SimpleDoc a -> SimpleDoc a'
    go r
    r' SimpleDoc a
    x

    simpleDocScanAnn :: (r -> a -> r) -- ^ SPushAnn state merge
                     -> r             -- ^ Initial state
                     -> SimpleDoc a
                     -> SimpleDoc r
    simpleDocScanAnn :: forall r a. (r -> a -> r) -> r -> SimpleDoc a -> SimpleDoc r
    simpleDocScanAnn r -> a -> r
    f r
    r0 = ([r] -> a -> [r])
    -> ([r] -> a -> [r])
    -> ([r] -> SimpleDoc r -> SimpleDoc r)
    -> ([r] -> SimpleDoc r -> SimpleDoc r)
    -> [r]
    -> SimpleDoc a
    -> SimpleDoc r
    forall r a a'.
    (r -> a -> r)
    -> (r -> a -> r)
    -> (r -> SimpleDoc a' -> SimpleDoc a')
    -> (r -> SimpleDoc a' -> SimpleDoc a')
    -> r
    -> SimpleDoc a
    -> SimpleDoc a'
    simpleDocMapAnn [r] -> a -> [r]
    merge [r] -> a -> [r]
    forall {a} {p}. [a] -> p -> [a]
    pop (r -> SimpleDoc r -> SimpleDoc r
    forall a. a -> SimpleDoc a -> SimpleDoc a
    SPushAnn (r -> SimpleDoc r -> SimpleDoc r)
    -> ([r] -> r) -> [r] -> SimpleDoc r -> SimpleDoc r
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . [r] -> r
    forall a. HasCallStack => [a] -> a
    head) (r -> SimpleDoc r -> SimpleDoc r
    forall a. a -> SimpleDoc a -> SimpleDoc a
    SPopAnn (r -> SimpleDoc r -> SimpleDoc r)
    -> ([r] -> r) -> [r] -> SimpleDoc r -> SimpleDoc r
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . [r] -> r
    forall a. HasCallStack => [a] -> a
    head) [r
    r0]
      where merge :: [r] -> a -> [r]
    merge rs :: [r]
    rs@(r
    r:[r]
    _) a
    x = r -> a -> r
    f r
    r a
    x r -> [r] -> [r]
    forall a. a -> [a] -> [a]
    : [r]
    rs
            merge []     a
    _ = String -> [r]
    forall a. HasCallStack => String -> a
    error String
    "Stack underflow"
            pop :: [a] -> p -> [a]
    pop   (a
    _:[a]
    rs) p
    _ = [a]
    rs
            pop   []     p
    _ = String -> [a]
    forall a. HasCallStack => String -> a
    error String
    "Stack underflow"

    -- | Display a rendered document.
    --
    -- This function takes a means of pushing an annotated region, a means of ending it,
    -- and a means of displaying a string, with effects @f@ to display or compute the output @o@.
    displayDecoratedA :: (Applicative f, Monoid o)
                      => (a -> f o)        -- ^ How to push an annotated region
                      -> (a -> f o)        -- ^ How to end an annotated region
                      -> (String -> f o)   -- ^ How to display a string (from document or whitespace)
                      -> SimpleDoc a
                      -> f o
    displayDecoratedA :: forall (f :: * -> *) o a.
    (Applicative f, Monoid o) =>
    (a -> f o) -> (a -> f o) -> (String -> f o) -> SimpleDoc a -> f o
    displayDecoratedA a -> f o
    push a -> f o
    pop String -> f o
    str = SimpleDoc a -> f o
    go
     where
      go :: SimpleDoc a -> f o
    go SimpleDoc a
    SEmpty         = o -> f o
    forall a. a -> f a
    forall (f :: * -> *) a. Applicative f => a -> f a
    pure o
    forall a. Monoid a => a
    mempty
      go (SChar Char
    c SimpleDoc a
    x)    = String -> f o
    str (Char -> String
    forall a. a -> [a]
    forall (f :: * -> *) a. Applicative f => a -> f a
    pure Char
    c) f o -> f o -> f o
    <++> SimpleDoc a -> f o
    go SimpleDoc a
    x
      go (SText Int
    _ String
    s SimpleDoc a
    x)  = String -> f o
    str String
    s f o -> f o -> f o
    <++> SimpleDoc a -> f o
    go SimpleDoc a
    x
      go (SLine Int
    i SimpleDoc a
    x)    = String -> f o
    str (Char
    '\n'Char -> String -> String
    forall a. a -> [a] -> [a]
    :Int -> String
    spaces Int
    i) f o -> f o -> f o
    <++> SimpleDoc a -> f o
    go SimpleDoc a
    x
      go (SPushAnn a
    a SimpleDoc a
    x) = a -> f o
    push a
    a f o -> f o -> f o
    <++> SimpleDoc a -> f o
    go SimpleDoc a
    x
      go (SPopAnn  a
    a SimpleDoc a
    x) = a -> f o
    pop  a
    a f o -> f o -> f o
    <++> SimpleDoc a -> f o
    go SimpleDoc a
    x
      <++> :: f o -> f o -> f o
    (<++>) = (o -> o -> o) -> f o -> f o -> f o
    forall a b c. (a -> b -> c) -> f a -> f b -> f c
    forall (f :: * -> *) a b c.
    Applicative f =>
    (a -> b -> c) -> f a -> f b -> f c
    liftA2 o -> o -> o
    forall a. Monoid a => a -> a -> a
    mappend
    {-# SPECIALIZE displayDecoratedA :: Monoid o => (a -> Identity o) -> (a -> Identity o) -> (String -> Identity o) -> SimpleDoc a -> Identity o #-}
    {-# SPECIALIZE displayDecoratedA :: Monoid o => (a -> (o -> o)) -> (a -> (o -> o)) -> (String -> (o -> o)) -> SimpleDoc a -> (o -> o) #-}

    -- | Display a rendered document.
    --
    -- This function takes a means of pushing an annotated region, a means of ending it,
    -- and a means of displaying a string to compute the output @o@.
    displayDecorated :: Monoid o
                     => (a -> o)        -- ^ How to push an annotated region
                     -> (a -> o)        -- ^ How to end an annotated region
                     -> (String -> o)   -- ^ How to display a string (from document or whitespace)
                     -> SimpleDoc a
                     -> o
    displayDecorated :: forall o a.
    Monoid o =>
    (a -> o) -> (a -> o) -> (String -> o) -> SimpleDoc a -> o
    displayDecorated a -> o
    push a -> o
    pop String -> o
    str = Identity o -> o
    forall a. Identity a -> a
    runIdentity (Identity o -> o)
    -> (SimpleDoc a -> Identity o) -> SimpleDoc a -> o
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    .
      (a -> Identity o)
    -> (a -> Identity o)
    -> (String -> Identity o)
    -> SimpleDoc a
    -> Identity o
    forall (f :: * -> *) o a.
    (Applicative f, Monoid o) =>
    (a -> f o) -> (a -> f o) -> (String -> f o) -> SimpleDoc a -> f o
    displayDecoratedA (o -> Identity o
    forall a. a -> Identity a
    forall (f :: * -> *) a. Applicative f => a -> f a
    pure (o -> Identity o) -> (a -> o) -> a -> Identity o
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . a -> o
    push) (o -> Identity o
    forall a. a -> Identity a
    forall (f :: * -> *) a. Applicative f => a -> f a
    pure (o -> Identity o) -> (a -> o) -> a -> Identity o
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . a -> o
    pop) (o -> Identity o
    forall a. a -> Identity a
    forall (f :: * -> *) a. Applicative f => a -> f a
    pure (o -> Identity o) -> (String -> o) -> String -> Identity o
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . String -> o
    str)

    -- | @(displayIO handle simpleDoc)@ writes @simpleDoc@ to the file
    -- handle @handle@, discarding all annotations. This function
    -- is used for example by 'hPutDoc':
    --
    -- > hPutDoc handle doc = displayIO handle (renderPrettyDefault doc)
    displayIO :: Handle -> SimpleDoc a -> IO ()
    displayIO :: forall a. Handle -> SimpleDoc a -> IO ()
    displayIO Handle
    handle = (a -> IO ())
    -> (a -> IO ()) -> (String -> IO ()) -> SimpleDoc a -> IO ()
    forall (f :: * -> *) o a.
    (Applicative f, Monoid o) =>
    (a -> f o) -> (a -> f o) -> (String -> f o) -> SimpleDoc a -> f o
    displayDecoratedA a -> IO ()
    forall {b}. b -> IO ()
    cpu a -> IO ()
    forall {b}. b -> IO ()
    cpu (Handle -> String -> IO ()
    hPutStr Handle
    handle)
     where cpu :: b -> IO ()
    cpu = IO () -> b -> IO ()
    forall a b. a -> b -> a
    const (IO () -> b -> IO ()) -> IO () -> b -> IO ()
    forall a b. (a -> b) -> a -> b
    $ () -> IO ()
    forall a. a -> IO a
    forall (f :: * -> *) a. Applicative f => a -> f a
    pure ()

    -- | @(displayS simpleDoc)@ takes the output @simpleDoc@ from a
    -- rendering function and transforms it to a 'ShowS' type (for use in
    -- the 'Show' class). Along the way, all annotations are
    -- discarded.
    displayS :: SimpleDoc a -> ShowS
    displayS :: forall a. SimpleDoc a -> String -> String
    displayS = (a -> String -> String)
    -> (a -> String -> String)
    -> (String -> String -> String)
    -> SimpleDoc a
    -> String
    -> String
    forall (f :: * -> *) o a.
    (Applicative f, Monoid o) =>
    (a -> f o) -> (a -> f o) -> (String -> f o) -> SimpleDoc a -> f o
    displayDecoratedA a -> String -> String
    forall {b} {a}. b -> a -> a
    ci a -> String -> String
    forall {b} {a}. b -> a -> a
    ci String -> String -> String
    forall a. [a] -> [a] -> [a]
    (++)
     where ci :: b -> a -> a
    ci = (a -> a) -> b -> a -> a
    forall a b. a -> b -> a
    const a -> a
    forall a. a -> a
    id

    -- | @(display simpleDoc)@ takes the output @simpleDoc@ from a
    -- rendering function and outputs a 'String'. Along the way, all annotations are
    -- discarded.
    display :: SimpleDoc a -> String
    display :: forall a. SimpleDoc a -> String
    display = (SimpleDoc a -> String -> String)
    -> String -> SimpleDoc a -> String
    forall a b c. (a -> b -> c) -> b -> a -> c
    flip SimpleDoc a -> String -> String
    forall a. SimpleDoc a -> String -> String
    displayS String
    ""

    -- | @(display simpleDoc)@ takes the output @simpleDoc@ from a
    -- rendering function and outputs a 'Text'. Along the way, all annotations are
    -- discarded.
    displayT :: SimpleDoc a -> TL.Text
    displayT :: forall a. SimpleDoc a -> Text
    displayT = Builder -> Text
    TL.toLazyText (Builder -> Text)
    -> (SimpleDoc a -> Builder) -> SimpleDoc a -> Text
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (a -> Builder)
    -> (a -> Builder) -> (String -> Builder) -> SimpleDoc a -> Builder
    forall o a.
    Monoid o =>
    (a -> o) -> (a -> o) -> (String -> o) -> SimpleDoc a -> o
    displayDecorated a -> Builder
    forall {b}. b -> Builder
    cm a -> Builder
    forall {b}. b -> Builder
    cm String -> Builder
    TL.fromString
     where cm :: b -> Builder
    cm = Builder -> b -> Builder
    forall a b. a -> b -> a
    const Builder
    forall a. Monoid a => a
    mempty

    -- | The type alias @SpanList@ is used by @displaySpan@
    --
    -- First element is the starting position, second the length
    -- and third the annotation at the given range.
    type SpanList a = [(Int, Int, a)]

    -- | Generate a pair of a string and a list of source span/annotation pairs
    displaySpans :: Monoid o => (String -> o) -> SimpleDoc a -> (o, SpanList a)
    displaySpans :: forall o a.
    Monoid o =>
    (String -> o) -> SimpleDoc a -> (o, SpanList a)
    displaySpans String -> o
    str = Int -> [Int] -> SimpleDoc a -> (o, [(Int, Int, a)])
    forall {c}. Int -> [Int] -> SimpleDoc c -> (o, [(Int, Int, c)])
    go Int
    0 []
     where
      go :: Int -> [Int] -> SimpleDoc c -> (o, [(Int, Int, c)])
    go Int
    _ []          SimpleDoc c
    SEmpty          = (o
    forall a. Monoid a => a
    mempty, [])
      go Int
    i [Int]
    stk         (SChar Char
    c SimpleDoc c
    x)     = (o -> o) -> (o, [(Int, Int, c)]) -> (o, [(Int, Int, c)])
    forall a b c. (a -> b) -> (a, c) -> (b, c)
    forall (p :: * -> * -> *) a b c.
    Bifunctor p =>
    (a -> b) -> p a c -> p b c
    first (o -> o -> o
    forall a. Monoid a => a -> a -> a
    mappend (o -> o -> o) -> o -> o -> o
    forall a b. (a -> b) -> a -> b
    $ String -> o
    str (String -> o) -> String -> o
    forall a b. (a -> b) -> a -> b
    $ Char -> String
    forall a. a -> [a]
    forall (f :: * -> *) a. Applicative f => a -> f a
    pure Char
    c) ((o, [(Int, Int, c)]) -> (o, [(Int, Int, c)]))
    -> (o, [(Int, Int, c)]) -> (o, [(Int, Int, c)])
    forall a b. (a -> b) -> a -> b
    $ Int -> [Int] -> SimpleDoc c -> (o, [(Int, Int, c)])
    go (Int
    iInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    1) [Int]
    stk SimpleDoc c
    x
      go Int
    i [Int]
    stk         (SText Int
    l String
    s SimpleDoc c
    x)   = (o -> o) -> (o, [(Int, Int, c)]) -> (o, [(Int, Int, c)])
    forall a b c. (a -> b) -> (a, c) -> (b, c)
    forall (p :: * -> * -> *) a b c.
    Bifunctor p =>
    (a -> b) -> p a c -> p b c
    first (o -> o -> o
    forall a. Monoid a => a -> a -> a
    mappend (o -> o -> o) -> o -> o -> o
    forall a b. (a -> b) -> a -> b
    $ String -> o
    str String
    s) ((o, [(Int, Int, c)]) -> (o, [(Int, Int, c)]))
    -> (o, [(Int, Int, c)]) -> (o, [(Int, Int, c)])
    forall a b. (a -> b) -> a -> b
    $ Int -> [Int] -> SimpleDoc c -> (o, [(Int, Int, c)])
    go (Int
    i Int -> Int -> Int
    forall a. Num a => a -> a -> a
    + Int
    l) [Int]
    stk SimpleDoc c
    x
      go Int
    i [Int]
    stk         (SLine Int
    ind SimpleDoc c
    x)   = (o -> o) -> (o, [(Int, Int, c)]) -> (o, [(Int, Int, c)])
    forall a b c. (a -> b) -> (a, c) -> (b, c)
    forall (p :: * -> * -> *) a b c.
    Bifunctor p =>
    (a -> b) -> p a c -> p b c
    first (o -> o -> o
    forall a. Monoid a => a -> a -> a
    mappend (o -> o -> o) -> o -> o -> o
    forall a b. (a -> b) -> a -> b
    $ String -> o
    str (String -> o) -> String -> o
    forall a b. (a -> b) -> a -> b
    $ Char
    '\n'Char -> String -> String
    forall a. a -> [a] -> [a]
    :Int -> String
    spaces Int
    ind) ((o, [(Int, Int, c)]) -> (o, [(Int, Int, c)]))
    -> (o, [(Int, Int, c)]) -> (o, [(Int, Int, c)])
    forall a b. (a -> b) -> a -> b
    $ Int -> [Int] -> SimpleDoc c -> (o, [(Int, Int, c)])
    go (Int
    1Int -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    iInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    ind) [Int]
    stk SimpleDoc c
    x
      go Int
    i [Int]
    stk         (SPushAnn c
    _ SimpleDoc c
    x)  = Int -> [Int] -> SimpleDoc c -> (o, [(Int, Int, c)])
    go Int
    i (Int
    iInt -> [Int] -> [Int]
    forall a. a -> [a] -> [a]
    :[Int]
    stk) SimpleDoc c
    x
      go Int
    i (Int
    start:[Int]
    stk) (SPopAnn c
    ann SimpleDoc c
    x) = ([(Int, Int, c)] -> [(Int, Int, c)])
    -> (o, [(Int, Int, c)]) -> (o, [(Int, Int, c)])
    forall b c a. (b -> c) -> (a, b) -> (a, c)
    forall (p :: * -> * -> *) b c a.
    Bifunctor p =>
    (b -> c) -> p a b -> p a c
    second ((Int
    start, Int
    iInt -> Int -> Int
    forall a. Num a => a -> a -> a
    -Int
    start, c
    ann)(Int, Int, c) -> [(Int, Int, c)] -> [(Int, Int, c)]
    forall a. a -> [a] -> [a]
    :) ((o, [(Int, Int, c)]) -> (o, [(Int, Int, c)]))
    -> (o, [(Int, Int, c)]) -> (o, [(Int, Int, c)])
    forall a b. (a -> b) -> a -> b
    $ Int -> [Int] -> SimpleDoc c -> (o, [(Int, Int, c)])
    go Int
    i [Int]
    stk SimpleDoc c
    x
      go Int
    _ [Int]
    _           SimpleDoc c
    SEmpty          = String -> (o, [(Int, Int, c)])
    forall a. HasCallStack => String -> a
    error String
    "Stack not empty"
      go Int
    _ []          (SPopAnn c
    _ SimpleDoc c
    _)   = String -> (o, [(Int, Int, c)])
    forall a. HasCallStack => String -> a
    error String
    "Stack underflow"

    -----------------------------------------------------------
    -- default pretty printers: show, putDoc and hPutDoc
    -----------------------------------------------------------
    instance Show (Doc a) where
      showsPrec :: Int -> Doc a -> String -> String
    showsPrec Int
    _ = SimpleDoc a -> String -> String
    forall a. SimpleDoc a -> String -> String
    displayS (SimpleDoc a -> String -> String)
    -> (Doc a -> SimpleDoc a) -> Doc a -> String -> String
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Doc a -> SimpleDoc a
    forall a. Doc a -> SimpleDoc a
    renderPrettyDefault

    -- | The action @(putDoc doc)@ pretty prints document @doc@ to the
    -- standard output, with a page width of 100 characters and a ribbon
    -- width of 40 characters.
    --
    -- > main :: IO ()
    -- > main = do{ putDoc (text "hello" <+> text "world") }
    --
    -- Which would output
    --
    -- @
    -- hello world
    -- @
    putDoc :: Doc a -> IO ()
    putDoc :: forall a. Doc a -> IO ()
    putDoc = Handle -> Doc a -> IO ()
    forall a. Handle -> Doc a -> IO ()
    hPutDoc Handle
    stdout

    -- | @(hPutDoc handle doc)@ pretty prints document @doc@ to the file
    -- handle @handle@ with a page width of 100 characters and a ribbon
    -- width of 40 characters.
    --
    -- > main = do{ handle <- openFile "MyFile" WriteMode
    -- >          ; hPutDoc handle (vcat (map text
    -- >                            ["vertical","text"]))
    -- >          ; hClose handle
    -- >          }
    hPutDoc :: Handle -> Doc a -> IO ()
    hPutDoc :: forall a. Handle -> Doc a -> IO ()
    hPutDoc Handle
    handle = Handle -> SimpleDoc a -> IO ()
    forall a. Handle -> SimpleDoc a -> IO ()
    displayIO Handle
    handle (SimpleDoc a -> IO ()) -> (Doc a -> SimpleDoc a) -> Doc a -> IO ()
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Doc a -> SimpleDoc a
    forall a. Doc a -> SimpleDoc a
    renderPrettyDefault

    -----------------------------------------------------------
    -- insert spaces
    -----------------------------------------------------------
    spaces :: Int -> String
    spaces :: Int -> String
    spaces Int
    n | Int
    n Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    <= Int
    0    = String
    ""
             | Bool
    otherwise = Int -> Char -> String
    forall a. Int -> a -> [a]
    replicate Int
    n Char
    ' '