Language/Symantic/XML/Write.hs

   1 {-# LANGUAGE BangPatterns #-}
   2 {-# LANGUAGE OverloadedStrings #-}
   3 {-# LANGUAGE StrictData #-}
   4 module Language.Symantic.XML.Write where
   5
   6 import Control.Applicative (Applicative(..), liftA2)
   7 import Control.Monad (Monad(..))
   8 import Data.Bool
   9 import Data.Default.Class (Default(..))
  10 import Data.Eq (Eq(..))
  11 import Data.Foldable (Foldable(..), all)
  12 import Data.Function (($), (.), const)
  13 import Data.Maybe (Maybe(..))
  14 import Data.Monoid (Monoid(..))
  15 import Data.Semigroup (Semigroup(..))
  16 import Data.String (String, IsString(..))
  17 import Data.Traversable (Traversable(..))
  18 import System.IO (IO, FilePath)
  19 import Text.Show (Show(..))
  20 import qualified Control.Monad.Trans.Reader as R
  21 import qualified Control.Monad.Trans.State as S
  22 import qualified Data.ByteString.Lazy as BSL
  23 import qualified Data.Char as Char
  24 import qualified Data.HashMap.Strict as HM
  25 import qualified Data.HashSet as HS
  26 import qualified Data.Sequence as Seq
  27 import qualified Data.Text.Lazy as TL
  28 import qualified Data.Text.Lazy.Builder as TLB
  29 import qualified Data.Text.Lazy.Encoding as TL
  30
  31 import Language.Symantic.XML.Document as XML
  32
  33 writeXML :: XMLs -> TL.Text
  34 writeXML xs = TLB.toLazyText $ write xs `R.runReader` def
  35
  36 writeXMLIndented :: TL.Text -> XMLs -> TL.Text
  37 writeXMLIndented ind xs =
  38         TLB.toLazyText $
  39         write xs `R.runReader` def
  40          { reader_indent       = if TL.null ind then mempty else "\n"
  41          , reader_indent_delta = ind
  42          }
  43
  44 writeFile :: FilePath -> TL.Text -> IO ()
  45 writeFile fp t = BSL.writeFile fp $ TL.encodeUtf8 t
  46
  47 -- * Type 'Write'
  48 type Write = R.Reader Reader TLB.Builder
  49 instance Semigroup Write where
  50         (<>) = liftA2 (<>)
  51 instance Monoid Write where
  52         mempty = return ""
  53         mappend = (<>)
  54 instance IsString Write where
  55         fromString = return . fromString
  56
  57 -- ** Type 'Reader'
  58 data Reader = Reader
  59  { reader_ns_scope     :: Namespaces NCName
  60  , reader_indent       :: TLB.Builder
  61  , reader_indent_delta :: TL.Text
  62  , reader_no_text      :: Bool
  63  }
  64 instance Default Reader where
  65         def = Reader
  66          { reader_ns_scope     = def
  67          , reader_indent       = ""
  68          , reader_indent_delta = ""
  69          , reader_no_text      = False
  70          }
  71
  72 -- * Class 'Buildable'
  73 class Buildable a where
  74         build :: a -> TLB.Builder
  75 instance Buildable Char.Char where
  76         build = TLB.singleton
  77 instance Buildable String where
  78         build = TLB.fromString
  79 instance Buildable TL.Text where
  80         build = TLB.fromLazyText
  81 instance Buildable NCName where
  82         build = build . unNCName
  83 instance Buildable Name where
  84         build = build . unName
  85 instance Buildable PName where
  86         build PName{..} =
  87                 case pNameSpace of
  88                  Nothing -> build pNameLocal
  89                  Just p -> build p<>":"<> build pNameLocal
  90 instance Buildable Namespace where
  91         build = build . unNamespace
  92 instance Buildable EntityRef where
  93         build EntityRef{..} = "&"<>build entityRef_name<>";"
  94 instance Buildable CharRef where
  95         build (CharRef c) = "&#"<>build (show (Char.ord c))<>";"
  96 instance Buildable EscapedText where
  97         build = foldMap $ \case
  98          EscapedPlain     t -> build t
  99          EscapedEntityRef r -> build r
 100          EscapedCharRef   r -> build r
 101
 102 -- * Class 'Writable'
 103 class Writeable a where
 104         write :: a -> Write
 105 instance Writeable NCName where
 106         write = return . TLB.fromLazyText . unNCName
 107 instance Writeable XMLs where
 108         write xs = do
 109                 ro <- R.ask
 110                 if TL.null (reader_indent_delta ro)
 111                  then foldMap write xs
 112                  else
 113                         R.local (const ro{reader_no_text}) $
 114                                 foldMap write xs
 115                         where reader_no_text =
 116                                 (`all` xs) $ \case
 117                                  Tree (Sourced _ (NodeText txt)) _ts ->
 118                                         all (\case
 119                                          EscapedPlain t -> TL.all Char.isSpace t
 120                                          _ -> False) txt
 121                                  _ -> True
 122 instance Writeable XML where
 123         write (Tree (Sourced _src nod) xs) = do
 124                 ro <- R.ask
 125                 case nod of
 126                         NodeAttr an
 127                          | [Tree (Sourced _ (NodeText av)) _] <- toList xs -> do
 128                                 return $ " "<>buildAttr (prefixifyQName (reader_ns_scope ro) an) av
 129                          | otherwise -> mempty
 130                         NodeCDATA t ->
 131                                 return $
 132                                         reader_indent ro <>
 133                                         "<[CDATA[["<>build t<>"]]>"
 134                         NodeComment t ->
 135                                 return $
 136                                         reader_indent ro <>
 137                                         "<!--"<>build t<>"-->"
 138                         NodeElem elemQName -> do
 139                                 let (elemAttrs, elemChilds) =
 140                                         (`Seq.spanl` xs) $ \case
 141                                                  Tree (Sourced _ NodeAttr{}) _ -> True
 142                                                  _ -> False
 143                                 let (usedNS, declNS) ::
 144                                         ( HS.HashSet Namespace
 145                                         , Namespaces NCName
 146                                         ) =
 147                                         foldl' go (initUsedNS, initDeclNS) elemAttrs
 148                                         where
 149                                         initUsedNS
 150                                          | qNameSpace elemQName == xmlns_empty = mempty
 151                                          | otherwise                           = HS.singleton $ qNameSpace elemQName
 152                                         initDeclNS = def{namespaces_default = namespaces_default $ reader_ns_scope ro}
 153                                         go (!uNS, !dNS) = \case
 154                                                 Tree (Sourced _ (NodeAttr QName{..})) vs
 155                                                  -- xmlns:prefix="namespace"
 156                                                  | qNameSpace == xmlns_xmlns
 157                                                  , [Tree (Sourced _ (NodeText t)) _] <- toList vs ->
 158                                                         let n = unescapeText t in
 159                                                         (uNS,) dNS
 160                                                          { namespaces_prefixes =
 161                                                                 (if TL.null n
 162                                                                 then HM.delete
 163                                                                 -- NOTE: empty namespace means removal of the prefix from scope.
 164                                                                 else (`HM.insert` qNameLocal))
 165                                                                  (Namespace n)
 166                                                                  (namespaces_prefixes dNS)
 167                                                          }
 168                                                  -- xmlns="namespace"
 169                                                  | qNameSpace == xmlns_empty
 170                                                  , qNameLocal == NCName "xmlns"
 171                                                  , [Tree (Sourced _ (NodeText t)) _] <- toList vs ->
 172                                                         (uNS,)
 173                                                         dNS{namespaces_default = Namespace $ unescapeText t}
 174                                                  -- name="value"
 175                                                  | qNameSpace == xmlns_empty -> (uNS, dNS)
 176                                                  -- {namespace}name="value"
 177                                                  | otherwise -> (HS.insert qNameSpace uNS, dNS)
 178                                                 _ -> (uNS, dNS)
 179                                 let inhNS =
 180                                         -- NOTE: the inherited namespaces,
 181                                         -- including those declared at this element.
 182                                         HM.union
 183                                          (namespaces_prefixes declNS)
 184                                          (namespaces_prefixes (reader_ns_scope ro))
 185                                 let autoNS =
 186                                         -- NOTE: the namespaces used but not declared nor default,
 187                                         -- with fresh prefixes.
 188                                         HM.delete (namespaces_default declNS) $
 189                                         (`S.evalState` HS.empty) $
 190                                         traverse
 191                                          (\() -> S.gets freshNCName)
 192                                          (HS.toMap usedNS `HM.difference` inhNS)
 193                                 let autoAttrs =
 194                                         -- NOTE: XMLify autoNS
 195                                         HM.foldlWithKey'
 196                                          (\acc (Namespace v) p ->
 197                                                 (acc Seq.|>) $
 198                                                         Tree (notSourced $ NodeAttr QName{qNameSpace=xmlns_xmlns, qNameLocal=p}) $
 199                                                                 pure $ tree0 $ notSourced $ NodeText $ pure $ EscapedPlain v
 200                                          ) mempty autoNS
 201                                 let scopeNS = declNS { namespaces_prefixes = autoNS <> inhNS }
 202                                 return $
 203                                         let build_elemPName = build $ prefixifyQName scopeNS elemQName in
 204                                         let build_elemAttrs =
 205                                                 (`foldMap` (autoAttrs <> elemAttrs)) $ \case
 206                                                  Tree (Sourced _ (NodeAttr an)) vs
 207                                                   | [Tree (Sourced _ (NodeText av)) _] <- toList vs ->
 208                                                         " "<>buildAttr (prefixifyQName scopeNS{namespaces_default=""} an) av
 209                                                  _ -> mempty in
 210                                         reader_indent ro
 211                                          <> "<"<>build_elemPName
 212                                          <> build_elemAttrs <>
 213                                         let build_elemChilds = write elemChilds
 214                                                 `R.runReader` ro
 215                                                  { reader_ns_scope = scopeNS
 216                                                  , reader_indent   = reader_indent ro <> build (reader_indent_delta ro)
 217                                                  } in
 218                                         if null elemChilds
 219                                         then "/>"
 220                                         else ">"
 221                                                  <> build_elemChilds
 222                                                  <> (
 223                                                         if TL.null (reader_indent_delta ro)
 224                                                         || noIndent elemChilds
 225                                                         then mempty
 226                                                         else reader_indent ro
 227                                                  )
 228                                                  <> "</"<>build_elemPName<>">"
 229                                         where
 230                                         noIndent =
 231                                                 all $ \case
 232                                                  Tree (Sourced _ (NodeText _txt)) _ts -> True
 233                                                  _ -> False
 234                         NodePI pn pv
 235                          | pn == "xml" -> do
 236                                 write_xs <- write xs
 237                                 return $
 238                                         "<?"<>build pn<>s<>write_xs<>"?>"
 239                          | otherwise ->
 240                                 return $
 241                                         reader_indent ro <>
 242                                         "<?"<>build pn<>s<>build pv<>"?>"
 243                                 where s | TL.null pv = ""
 244                                         | otherwise  = " "
 245                         NodeText t -> do
 246                                 return $
 247                                         if reader_no_text ro
 248                                          then mempty
 249                                          else build t
 250
 251 buildAttr :: PName -> EscapedText -> TLB.Builder
 252 buildAttr n v = build n<>"=\""<>buildAttrValue v<>"\""
 253
 254 buildAttrValue :: EscapedText -> TLB.Builder
 255 buildAttrValue = foldMap $ \case
 256  EscapedPlain p -> build p
 257  EscapedEntityRef EntityRef{..} ->
 258         build $ TL.replace "\"" "&quot;" entityRef_value
 259  EscapedCharRef (CharRef c)
 260         | c == '\"' -> "&quot;"
 261         | otherwise -> build c
 262
 263 removeSpaces :: XMLs -> XMLs
 264 removeSpaces xs =
 265         if (`all` xs) $ \case
 266          Tree (Sourced _ (NodeText txt)) _ts ->
 267                 all (\case
 268                  EscapedPlain t -> TL.all Char.isSpace t
 269                  _ -> False) txt
 270          _ -> True
 271         then (`Seq.filter` xs) $ \case
 272                  Tree (Sourced _ NodeText{}) _ts -> False
 273                  _ -> True
 274         else xs