Adding org backend.

2 files changed, 1253 insertions, 0 deletions

diff --git a/haddock-api/src/Haddock/Backends/Org.hs b/haddock-api/src/Haddock/Backends/Org.hs
new file mode 100644
index 00000000..cdd95d42
--- /dev/null
+++ b/haddock-api/src/Haddock/Backends/Org.hs
@@ -0,0 +1,1016 @@
+{-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE TupleSections #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Haddock.Backends.Org
+  ( ppOrg
+  , cleanPkgStr
+  ) where
+import           Control.Monad.State.Strict     ( State
+                                                , evalState
+                                                , get
+                                                , put
+                                                )
+import           Data.List                      ( intercalate
+                                                , intersperse
+                                                , isSuffixOf
+                                                , singleton
+                                                , sortOn
+                                                )
+import           Data.Map                       ( (!?)
+                                                , toList
+                                                )
+import qualified Data.Map                      as M
+                                                ( empty
+                                                , map
+                                                , null
+                                                )
+import           Data.Maybe                     ( fromMaybe )
+import           Documentation.Haddock.Markup   ( markup
+                                                , plainMarkup
+                                                )
+import           GHC                            ( ConDecl(..)
+                                                , ConDeclField(..)
+                                                , FamEqn(..)
+                                                , FamilyDecl(..)
+                                                , FamilyInfo(..)
+                                                , FamilyResultSig(..)
+                                                , FieldOcc(..)
+                                                , ForeignDecl(..)
+                                                , GenLocated(..)
+                                                , HsArg(..)
+                                                , HsConDeclGADTDetails(..)
+                                                , HsConDeclH98Details
+                                                , HsConDetails(..)
+                                                , HsDataDefn(..)
+                                                , HsDecl(..)
+                                                , HsForAllTelescope(..)
+                                                , HsOuterSigTyVarBndrs
+                                                , HsOuterTyVarBndrs(..)
+                                                , HsScaled(..)
+                                                , HsSigType(..)
+                                                , HsTupleSort(..)
+                                                , HsTyLit(..)
+                                                , HsTyVarBndr(..)
+                                                , HsType(..)
+                                                , InjectivityAnn(..)
+                                                , LHsContext
+                                                , LHsKind
+                                                , LHsQTyVars(..)
+                                                , LHsTyVarBndr
+                                                , LHsType
+                                                , LInjectivityAnn
+                                                , LTyFamInstEqn
+                                                , ModuleName
+                                                , Name
+                                                , NewOrData(..)
+                                                , RdrName
+                                                , Sig(..)
+                                                , TyClDecl(..)
+                                                , dropWildCards
+                                                , getName
+                                                , hsIPNameFS
+                                                , hsQTvExplicit
+                                                , moduleNameString
+                                                , unLoc
+                                                )
+import           GHC.Data.FastString            ( unpackFS )
+import           GHC.Types.Basic                ( PromotionFlag(..)
+                                                , TopLevelFlag(..)
+                                                )
+import           GHC.Types.Name                 ( isDataConName
+                                                , nameModule_maybe
+                                                , nameOccName
+                                                )
+import           GHC.Types.Name.Occurrence      ( OccName
+                                                , occNameString
+                                                )
+import           GHC.Unit.Types                 ( GenModule(..)
+                                                , Module
+                                                , unitString
+                                                )
+import           GHC.Utils.Outputable           ( showPprUnsafe )
+import qualified GHC.Utils.Ppr                 as Pretty
+import           GHC.Utils.Ppr                  ( (<+>)
+                                                , (<>)
+                                                , comma
+                                                , hsep
+                                                , punctuate
+                                                , text
+                                                )
+import           Haddock.Backends.Org.Types
+import           Haddock.GhcUtils               ( Precedence(..)
+                                                , hsLTyVarNameI
+                                                , moduleString
+                                                , reparenTypePrec
+                                                )
+import           Haddock.Types                  ( Doc
+                                                , DocForDecl
+                                                , DocH(..)
+                                                , DocInstance
+                                                , DocName(..)
+                                                , DocNameI
+                                                , Documentation(..)
+                                                , ExportItem(..)
+                                                , FnArgsDoc
+                                                , Header(..)
+                                                , Hyperlink(..)
+                                                , InstHead(..)
+                                                , InstType(..)
+                                                , Interface(..)
+                                                , MDoc
+                                                , MetaDoc(..)
+                                                , ModLink(..)
+                                                , Picture(..)
+                                                , TableCell(..)
+                                                , TableRow(..)
+                                                , Wrap(..)
+                                                , showWrapped
+                                                )
+import qualified Haddock.Types                 as HT
+                                                ( Example(..)
+                                                , Table(..)
+                                                )
+import           Prelude                 hiding ( (<>) )
+
+
+type PDoc = Pretty.Doc
+type ModPath = (String, String) -- (package, module)
+type SubDocs = [(DocName, DocForDecl DocName)]
+
+packageLevel, modLevel :: Int
+packageLevel = 1
+modLevel = 2
+
+-- prefix for unimplemented and error
+unimp, docError :: String -> String
+unimp = ("UNIMP$" ++)
+docError = ("ERROR$" ++)
+
+unimpHeading :: String -> Int -> OrgBlock
+unimpHeading thing level = headingPlainText (unimp thing) level
+
+emptyDoc :: DocForDecl DocName
+emptyDoc = (Documentation Nothing Nothing, M.empty)
+
+-- The main function
+ppOrg :: String -> Maybe (Doc RdrName) -> String -> [Interface] -> String
+ppOrg title mbPrologue pkgId = orgToString . fromOrgDocument . toOrgDocument
+  title
+  mbPrologue
+  (cleanPkgStr pkgId)
+
+toOrgDocument
+  :: String -> Maybe (Doc RdrName) -> String -> [Interface] -> OrgDocument
+toOrgDocument title mbPrologue pkgId ifaces =
+  OrgDocument M.empty (processPackage title mbPrologue pkgId ifaces)
+
+processPackage
+  :: String -> Maybe (Doc RdrName) -> String -> [Interface] -> [OrgBlock]
+processPackage title mbPrologue pkgId ifaces =
+  headingPlainTextCId title pkgId packageLevel
+    : Paragraph [plaintext $ maybe [] removeMarkup' mbPrologue]
+    : concatMap processModule (sortOn ifaceMod ifaces)
+
+processModule :: Interface -> [OrgBlock]
+processModule iface =
+  let
+    mdl         = moduleString $ ifaceMod iface
+    pkg         = cleanPkgStr $ unitString $ moduleUnit $ ifaceMod iface
+    path        = (pkg, mdl)
+    heading     = headingPlainTextCId mdl (pkg ++ "." ++ mdl) modLevel
+    description = ppDocumentation (ifaceRnDoc iface) (Just modLevel)
+    exported =
+      evalState (mapM (processExport path) (ifaceRnExportItems iface)) modLevel
+        ++ [ ppDocInsts
+               (ifaceRnOrphanInstances iface)
+               "Orphan Instances"
+               (modLevel + 1)
+           ]
+  in
+    heading : description ++ concat exported
+
+processExport :: ModPath -> ExportItem DocNameI -> State Int [OrgBlock]
+-- TODO: handle bundled patterns, fixities and splice
+processExport path (ExportDecl (L _ decl) _pats docs subdocs insts _fixities _splice)
+  = do
+    baseLevel <- get
+    return $ ppHsDecl decl insts docs subdocs path (baseLevel + 1)
+processExport _ (ExportNoDecl _ _          ) = error "ExportNoDecl"
+processExport _ (ExportGroup offset _ label) = do
+  put $ modLevel + offset
+  return $ ppDocBlock (DocHeader (Header (modLevel + offset) label)) (Just 0)
+processExport _ (ExportDoc    mDoc) = return $ ppMDoc mDoc (Just modLevel)
+processExport _ (ExportModule mdl ) = do
+  baseLevel <- get
+  return
+    [ Heading
+        (baseLevel + 1)
+        [plaintext "module", Whitespace, Link (text (moduleString mdl)) []]
+        []
+    ]
+
+-- * To Org elements
+-- ** Documentation to Org elements
+
+ppFnArgsDoc :: FnArgsDoc DocName -> [OrgBlock]
+ppFnArgsDoc aDoc = if M.null aDoc
+  then []
+  else ((`ppDoc` Nothing) . DocParagraph . DocString) "Arguments (in order):"
+    ++ ((`ppDoc` Nothing) . DocOrderedList . toList . M.map _doc) aDoc
+
+ppDocumentation :: Documentation DocName -> Maybe Int -> [OrgBlock]
+ppDocumentation (Documentation (Just mdoc) _) minLevel = ppMDoc mdoc minLevel
+ppDocumentation _                             _        = []
+
+ppMDoc :: MDoc DocName -> Maybe Int -> [OrgBlock]
+ppMDoc (MetaDoc _ doc) = ppDoc doc
+
+ppDoc :: Doc DocName -> Maybe Int -> [OrgBlock]
+ppDoc x l = if isBlock x then ppDocBlock x l else [Paragraph $ ppDocInline x]
+
+ppDocBlock :: Doc DocName -> Maybe Int -> [OrgBlock]
+ppDocBlock x _ | not (isBlock x) = ppDocBlock (DocParagraph x) Nothing
+ppDocBlock DocEmpty         _    = []
+ppDocBlock (DocAppend x y ) l    = ppDocBlock x l ++ ppDocBlock y l
+ppDocBlock (DocParagraph x) _    = [Paragraph (ppDocInline x)]
+ppDocBlock (DocUnorderedList docs) _ =
+  [PlainList Unordered $ (`ppDocBlock` Nothing) <$> docs]
+ppDocBlock (DocOrderedList items) _ =
+  [PlainList Ordered (map ((`ppDocBlock` Nothing) . snd) items)]
+ppDocBlock (DocDefList pairs) _ =
+  [ DefList
+      $   (\(term, def) -> (ppDocInline term, ppDocBlock def Nothing))
+      <$> pairs
+  ]
+ppDocBlock (DocCodeBlock doc) _ =
+  [SrcBlock $ text $ fixLeadingStar $ removeMarkup doc]
+ppDocBlock (DocMathDisplay x) _ = [MathDisplay (text x)]
+ppDocBlock (DocExamples examples) _ =
+  (\(HT.Example expr res) -> Example
+      (text (fixLeadingStar expr))
+      (text $ fixLeadingStar $ intercalate "\n" res)
+    )
+    <$> examples
+ppDocBlock (DocHeader (Header level label)) (Just l) =
+  [Heading (level + l) (ppDocInline label) []]
+ppDocBlock (DocTable (HT.Table hRows bRows)) _ = ppTable hRows bRows
+ppDocBlock doc _ = [Paragraph [plaintext $ unimp "ppDocBlock: " ++ show doc]]
+
+ppDocInline :: Doc DocName -> [OrgInline]
+ppDocInline x | isBlock x = [plaintext $ docError "BLOCK_IN_INLINE" ++ show x]
+ppDocInline (DocAppend x y           ) = ppDocInline x ++ ppDocInline y
+ppDocInline (DocString              x) = [plaintext x]
+ppDocInline (DocIdentifier          x) = ppWrapped ppDocName x
+ppDocInline (DocIdentifierUnchecked x) = ppWrapped ppMO x
+ppDocInline (DocModule (ModLink modName mbModLabel)) =
+  [Link (text modName) (maybe [] ppDocInline mbModLabel)]
+ppDocInline (DocWarning    x) = [plaintext $ unimp $ "DocWarning: " ++ show x]
+ppDocInline (DocEmphasis   x) = [Italic $ ppDocInline x]
+ppDocInline (DocMonospaced x) = [Code $ text $ removeMarkup x]
+ppDocInline (DocBold       x) = [Bold $ ppDocInline x]
+ppDocInline (DocHyperlink (Hyperlink url label)) =
+  [Link (text url) (maybe [] ppDocInline label)]
+ppDocInline (DocPic (Picture url mbTitle)) =
+  [Link (text url) (maybe [] (singleton . plaintext) mbTitle)]
+ppDocInline (DocAName      x) = [Anchor (text x)]
+ppDocInline (DocMathInline x) = [MathInline (text x)]
+ppDocInline (DocProperty   x) = [plaintext x]
+ppDocInline doc               = [plaintext $ unimp "ppDocInline: " ++ show doc]
+
+-- *** Handling tables
+-- current coordinates, colspan and rowspan coordinates
+type SpanState = ((Int, Int), [(Int, Int)], [(Int, Int)])
+
+emptySpanState :: SpanState
+emptySpanState = ((0, 0), [], [])
+
+-- marks for cells connected with colspan and rowspan
+leftSym, upSym :: Bool -> String
+leftSym True  = "<"
+leftSym False = ""
+upSym True  = "^"
+upSym False = ""
+
+ppTable :: [TableRow (Doc DocName)] -> [TableRow (Doc DocName)] -> [OrgBlock]
+ppTable header body =
+  [ Table (evalState (ppTable' header) emptySpanState)
+          (evalState (ppTable' body) emptySpanState)
+  ]
+
+ppTable' :: [TableRow (Doc DocName)] -> State SpanState [[[OrgInline]]]
+ppTable' []                      = return []
+ppTable' (TableRow cells : rest) = do
+  cur   <- ppTableRow' cells
+  rest' <- ppTable' rest
+  return $ cur : rest'
+
+-- handle a table row, tracking colspans and rowspans
+ppTableRow' :: [TableCell (Doc DocName)] -> State SpanState [[OrgInline]]
+ppTableRow' [] = return []
+ppTableRow' (TableCell colspan rowspan doc : rest) = do
+  ((x, y), colspans, rowspans) <- get
+  let
+    left    = (not . null) colspans && (x, y) `elem` colspans
+    up      = (not . null) rowspans && (x, y) `elem` rowspans
+    content = if left || up
+      then [plaintext (leftSym left ++ upSym up)]
+      else ppDocInline doc
+    newColspans = if left
+      then colspans
+      else colspans ++ map (\i -> (x, y + i)) [1 .. colspan - 1]
+    newRowspans = if up
+      then rowspans
+      else rowspans ++ map (\i -> (x + i, y)) [1 .. rowspan - 1]
+    extraLeft = if null rest
+      then length (takeWhile (`elem` newColspans) (map (x, ) [y + 1 ..]))
+      else 0
+    extraUp = if null rest
+      then length (takeWhile (`elem` newRowspans) (map (x, ) [y + 1 ..]))
+      else 0
+    n        = max extraLeft extraUp
+    lefts    = replicate extraLeft True ++ replicate (n - extraLeft) False
+    ups      = replicate extraUp True ++ replicate (n - extraUp) False
+    extra    = zipWith (\l u -> [plaintext (leftSym l ++ upSym u)]) lefts ups
+    newCoord = if null rest then (x + 1, 0) else (x, y + 1)
+  put (newCoord, newColspans, newRowspans)
+  rest' <- ppTableRow' rest
+  return $ content : extra ++ rest'
+
+-- ** AST to Org elements
+
+ppHsDecl
+  :: HsDecl DocNameI
+  -> [DocInstance DocNameI]
+  -> DocForDecl DocName
+  -> SubDocs
+  -> ModPath
+  -> Int
+  -> [OrgBlock]
+ppHsDecl (TyClD _ decl) insts docs subdocs path level =
+  ppTyClDecl decl docs subdocs path level
+    ++ ppDocInsts insts "Instances:" (level + 1)
+ppHsDecl (SigD _ sig) _ docs subdocs path level =
+  ppSig sig docs subdocs path level
+ppHsDecl (ForD _ for) _ docs _ path level = ppForeignDecl for docs path level
+ppHsDecl _ _ docs _ _ level =
+  unimpHeading "HsDecl" level : ppDocForDecl docs (Just level)
+
+ppForeignDecl
+  :: ForeignDecl DocNameI -> DocForDecl DocName -> ModPath -> Int -> [OrgBlock]
+ppForeignDecl (ForeignImport _ (L _ name) (L _ sigType) _) docs path level =
+  Heading level
+          (Plain (docNameToDoc name) : plaintext " :: " : ppHsSigType sigType)
+          (cIdPaths path name)
+    : ppDocForDecl docs (Just level)
+ppForeignDecl _ docs _ level =
+  unimpHeading "ForeignDecl" level : ppDocForDecl docs (Just level)
+
+ppDocInsts :: [DocInstance DocNameI] -> String -> Int -> [OrgBlock]
+ppDocInsts [] _ _ = []
+ppDocInsts insts heading level =
+  [headingPlainText heading level, PlainList Unordered (map ppDocInst insts)]
+
+ppDocInst :: DocInstance DocNameI -> [OrgBlock]
+ppDocInst (InstHead clsName types (ClassInst {..}), mbMdoc, _docName, _mbMod) =
+  prependInlinesToBlocks
+    (  interNotNull
+        [Whitespace]
+        [ ppContext clsiCtx
+        , ppDocName clsName
+        , intercalate [Whitespace]
+                      (map (ppHsType . reparenTypePrec PREC_CON) types)
+        ]
+    ++ if mbMDocHasDoc mbMdoc
+       then
+         [Whitespace, plaintext "::", Whitespace]
+       else
+         []
+    )
+    (maybe [] (`ppMDoc` Nothing) mbMdoc)
+ppDocInst (InstHead clsName types (TypeInst mbRhs), mbMdoc, _docName, _mbMod) =
+  prependInlinesToBlocks
+    (  plaintext "type "
+    :  ppDocName clsName
+    ++ [Whitespace]
+    ++ intercalate [Whitespace]
+                   (map (ppHsType . reparenTypePrec PREC_CON) types)
+    ++ maybe
+         []
+         (\ty -> plaintext " = " : ppHsType (reparenTypePrec PREC_TOP ty))
+         mbRhs
+    ++ if mbMDocHasDoc mbMdoc
+         then [Whitespace, plaintext "::", Whitespace]
+         else []
+    )
+    (maybe [] (`ppMDoc` Nothing) mbMdoc)
+-- TODO: add decl    
+ppDocInst (InstHead clsName types (DataInst _decl), mbMdoc, _docName, _mbMod) =
+  prependInlinesToBlocks
+    (  plaintext "data "
+    :  ppDocName clsName
+    ++ [Whitespace]
+    ++ intercalate [Whitespace]
+                   (map (ppHsType . reparenTypePrec PREC_CON) types)
+    ++ if mbMDocHasDoc mbMdoc
+         then [Whitespace, plaintext "::", Whitespace]
+         else []
+    )
+    (maybe [] (`ppMDoc` Nothing) mbMdoc)
+
+mbMDocHasDoc :: Maybe (MDoc DocName) -> Bool
+mbMDocHasDoc Nothing                     = False
+mbMDocHasDoc (Just (MetaDoc _ DocEmpty)) = False
+mbMDocHasDoc _                           = True
+
+parensIfMany :: [a] -> [OrgInline] -> [OrgInline]
+parensIfMany xs org = if length xs > 1 then orgParens org else org
+
+dcSuffix :: DocName -> String
+dcSuffix name = if isDataConName (getName name) then ":dc" else ""
+
+idPath :: ModPath -> DocName -> String
+idPath (pkg, mdl) name =
+  pkg ++ "." ++ mdl ++ "." ++ docNameToString name ++ dcSuffix name
+
+idPath' :: Module -> DocName -> String
+idPath' mdl name =
+  idPath (cleanPkgStr $ unitString $ moduleUnit mdl, moduleString mdl) name
+
+idPathNoPkg :: String -> DocName -> String
+idPathNoPkg mdl name = mdl ++ "." ++ docNameToString name ++ dcSuffix name
+
+cIdPaths :: ModPath -> DocName -> Properties
+cIdPaths path@(_, mdl) name = cIdsProp [idPath path name, idPathNoPkg mdl name]
+
+ppTyClDecl
+  :: TyClDecl DocNameI
+  -> DocForDecl DocName
+  -> SubDocs
+  -> ModPath
+  -> Int
+  -> [OrgBlock]
+-- data T a b
+-- newtype T a b
+-- TODO: handle fixity
+ppTyClDecl (DataDecl _ (L _ name) tcdTyVars _ defn@(HsDataDefn { dd_ND = nd, dd_cons = cons })) docs subdocs path level
+  = [ Heading
+        level
+        ( Plain
+            ((ppNewOrData nd) <+> (docNameToDoc name) <+> hsep
+              (ppName <$> tyvarNames tcdTyVars)
+            )
+        : if gadt then [plaintext " where"] else []
+        )
+        (cIdPaths path name)
+    ]
+    ++ ppDocForDecl docs (Just level)
+    ++ ppDataDefn defn subdocs path (level + 1)
+ where
+  gadt = case cons of
+    []                    -> False
+    L _ ConDeclGADT{} : _ -> True
+    _                     -> False
+ppTyClDecl (DataDecl{}) docs _ _ level =
+  unimpHeading "DataDecl" level : ppDocForDecl docs (Just level)
+-- type T a b    
+ppTyClDecl (SynDecl _ (L _ name) tcdTyVars _fixity (L _ rhs)) docs _ path level
+  = [ Heading
+        level
+        (  intersperse
+            Whitespace
+            (  [plaintext "type", Plain $ docNameToDoc name]
+            ++ map (Plain . ppName) (tyvarNames tcdTyVars)
+            ++ [Plain $ text "= "]
+            )
+        ++ ppHsType rhs
+        )
+        (cIdPaths path name)
+    ]
+    ++ ppDocForDecl docs (Just level)
+-- class
+ppTyClDecl (ClassDecl {..}) docs subdocs path level =
+  [ Heading
+      level
+      (interNotNull
+        [Whitespace]
+        [ [plaintext "class"]
+        , ppMbLHsContext tcdCtxt
+        , (singleton . Plain . docNameToDoc . unLoc) tcdLName
+        , intersperse Whitespace (map (Plain . ppName) (tyvarNames tcdTyVars))
+        ]
+      )
+      (cIdPaths path (unLoc tcdLName))
+    ]
+    ++ ppDocForDecl docs (Just level)
+    -- TODO: do we need an aDoc here instead of M.empty?
+    -- TODO: handle default sigs
+    ++ concatMap
+         ((\sig -> ppSig sig emptyDoc subdocs path (level + 1)) . unLoc)
+         tcdSigs
+-- type family ... where
+-- TODO: handle infix
+ppTyClDecl (FamDecl _ (FamilyDecl _ (ClosedTypeFamily mbEqns) TopLevel (L _ name) tyvars _fixity (L _ resSig) mbInj)) docs subdocs path level
+  = Heading
+      level
+      (  [plaintext "type family ", Plain $ docNameToDoc name, Whitespace]
+      ++ ppLHsQTyVars tyvars
+      ++ ppFamilyResultSig resSig "="
+      ++ maybe [] ppLInjectivityAnn mbInj
+      ++ [plaintext " where"]
+      )
+      (cIdPaths path name)
+    :  ppDocForDecl docs (Just level)
+    ++ concatMap (\x -> ppLTyFamInstEqn x subdocs path (level + 1))
+                 (fromMaybe [] mbEqns)
+-- data family
+-- type family
+-- DataFamily or OpenTypeFamily
+ppTyClDecl (FamDecl _ (FamilyDecl _ info TopLevel (L _ name) tyvars _fixity (L _ resSig) mbInj)) docs _ path level
+  = Heading
+      level
+      (  [pre, Plain $ docNameToDoc name, Whitespace]
+      ++ ppLHsQTyVars tyvars
+      ++ ppFamilyResultSig resSig op
+      ++ maybe [] ppLInjectivityAnn mbInj
+      )
+      (cIdPaths path name)
+    : ppDocForDecl docs (Just level)
+ where
+  pre = case info of
+    DataFamily     -> plaintext "data family "
+    OpenTypeFamily -> plaintext "type family "
+  op = case info of
+    DataFamily -> "::"
+    _          -> "="
+ppTyClDecl (FamDecl{}) docs _ _ level =
+  unimpHeading "FamDecl" level : ppDocForDecl docs (Just level)
+
+ppLTyFamInstEqn
+  :: LTyFamInstEqn DocNameI -> SubDocs -> ModPath -> Int -> [OrgBlock]
+ppLTyFamInstEqn (L _ (FamEqn _ (L _ name) _ tyPats _fixity rhs)) subdocs _ level
+  = Heading
+      level
+      (interNotNull
+        [Whitespace]
+        [ ppDocName name
+        , intercalate [Whitespace] (map ppHsArg tyPats)
+        , [plaintext "="]
+        , ppLHsType (reparenTypePrec PREC_TOP <$> rhs)
+        ]
+      )
+      []
+    : maybe [] (`ppDocForDecl` (Just level)) (lookup name subdocs)
+
+ppHsArg :: HsArg (LHsType DocNameI) (LHsKind DocNameI) -> [OrgInline]
+ppHsArg (HsValArg ty) = ppLHsType (reparenTypePrec PREC_CON <$> ty)
+ppHsArg _             = [plaintext $ unimp "HsArg"]
+
+ppLInjectivityAnn :: LInjectivityAnn DocNameI -> [OrgInline]
+ppLInjectivityAnn (L _ (InjectivityAnn _ (L _ l) rs)) =
+  [ plaintext " | "
+  , Plain $ docNameToDoc l
+  , plaintext " -> "
+  , Plain $ hsep $ map (docNameToDoc . unLoc) rs
+  ]
+ppLInjectivityAnn _ = [plaintext $ unimp "LInjectivityAnn"]
+
+ppFamilyResultSig :: FamilyResultSig DocNameI -> String -> [OrgInline]
+ppFamilyResultSig (KindSig _ (L _ x)) op =
+  [Whitespace, plaintext op, Whitespace] ++ ppHsType x
+ppFamilyResultSig (NoSig{}) _ = []
+ppFamilyResultSig (TyVarSig _ x) op =
+  [Whitespace, plaintext op, Whitespace] ++ ppLHsTyVarBndr x
+
+ppDataDefn :: HsDataDefn DocNameI -> SubDocs -> ModPath -> Int -> [OrgBlock]
+ppDataDefn (HsDataDefn _ _ _ _ _ cons _derivs) subdocs path level =
+  concatMap ((\con -> ppConDecl con subdocs path level) . unLoc) cons
+ppDataDefn _ _ _ level = [unimpHeading "DataDecl" level]
+
+ppConDecl :: ConDecl DocNameI -> SubDocs -> ModPath -> Int -> [OrgBlock]
+-- T1 a Int
+-- TODO: handle infix
+ppConDecl (ConDeclH98 _ (L _ docName) _forall exTvs mbCtxt args _) subdocs path level
+  = Heading
+      level
+      (interNotNull
+        [Whitespace]
+        [ ppForAll exTvs
+        , ppMbLHsContext mbCtxt
+        , [Plain (docNameToDoc docName)]
+        , prefixOnly
+        ]
+      )
+      (cIdPaths path docName)
+    :  case lookup docName subdocs of
+         Just (doc, aDoc) ->
+           prefixWithDocs aDoc ++ ppDocumentation doc (Just level)
+         Nothing -> []
+    ++ ppConDeclRecCon args subdocs path (level + 1)
+ where
+  prefixOnly = case args of
+    PrefixCon _ args' -> interNotNull [Whitespace] (map ppHsScaled args')
+    RecCon _          -> [plaintext "{"]
+    _                 -> []
+  prefixWithDocs :: FnArgsDoc DocName -> [OrgBlock]
+  prefixWithDocs aDoc = if M.null aDoc
+    then []
+    else case args of
+      PrefixCon _ args' ->
+        [ Paragraph [plaintext "Arguments:"]
+        , DefList
+          (map (\(i, arg) -> (ppHsScaled arg, ppADoc aDoc i)) (zip [1 ..] args')
+          )
+        ]
+      _ -> ppFnArgsDoc aDoc
+-- TODO: handle con_bndrs and con_mb_cxt
+ppConDecl (ConDeclGADT _ names _ _ args resTy _) subdocs path level =
+  [ Heading
+      level
+      (  interNotNull
+          [Whitespace]
+          [ intersperse (Plain $ text ", ")
+                        (map (Plain . docNameToDoc . unLoc) names)
+          , [plaintext "::"]
+          ]
+      ++ [Whitespace]
+      ++ ppConDeclGADTDetailsPrefix args resTy
+      )
+      (concatMap (cIdPaths path . unLoc) names)
+    ]
+    ++ maybe []
+             (`ppDocForDecl` (Just level))
+             (lookup (unLoc $ head names) subdocs)
+    ++ ppConDeclGADTDetailsRec args resTy subdocs path (level + 1)
+
+
+ppForAll :: [LHsTyVarBndr a DocNameI] -> [OrgInline]
+ppForAll [] = []
+ppForAll xs =
+  intercalate [Whitespace] ([plaintext "forall"] : map ppLHsTyVarBndr xs)
+    ++ [plaintext "."]
+
+ppConDeclGADTDetailsPrefix
+  :: HsConDeclGADTDetails DocNameI -> LHsType DocNameI -> [OrgInline]
+ppConDeclGADTDetailsPrefix (PrefixConGADT args) resTy =
+  intercalate [plaintext " -> "] (map ppHsScaled args ++ [ppLHsType resTy])
+ppConDeclGADTDetailsPrefix (RecConGADT{}) _ = [plaintext "{"]
+
+ppConDeclGADTDetailsRec
+  :: HsConDeclGADTDetails DocNameI
+  -> LHsType DocNameI
+  -> SubDocs
+  -> ModPath
+  -> Int
+  -> [OrgBlock]
+ppConDeclGADTDetailsRec (RecConGADT (L _ args)) resTy subdocs path level =
+  concatMap (\arg -> ppConDeclField (unLoc arg) subdocs path level) args
+    ++ [Heading level (plaintext "} -> " : ppLHsType resTy) []]
+ppConDeclGADTDetailsRec _ _ _ _ _ = []
+
+ppConDeclRecCon
+  :: HsConDeclH98Details DocNameI -> SubDocs -> ModPath -> Int -> [OrgBlock]
+ppConDeclRecCon (RecCon (L _ args)) subdocs path level =
+  concatMap (\arg -> ppConDeclField (unLoc arg) subdocs path level) args
+ppConDeclRecCon _ _ _ _ = []
+
+ppConDeclField
+  :: ConDeclField DocNameI -> SubDocs -> ModPath -> Int -> [OrgBlock]
+ppConDeclField (ConDeclField _ names (L _ ty) _) subdocs path level =
+  [ Heading
+      level
+      (interNotNull
+        [Whitespace]
+        [ intersperse
+          (Plain $ text ", ")
+          (map (Plain . docNameToDoc . fieldOccDocName . unLoc) names)
+        , [plaintext "::"]
+        , ppHsType ty
+        ]
+      )
+      (concatMap (cIdPaths path . fieldOccDocName . unLoc) names)
+    ]
+    ++ maybe [] (`ppDocForDecl` (Just level)) (lookup docName subdocs)
+  where docName = (fieldOccDocName . unLoc . head) names
+
+fieldOccDocName :: FieldOcc DocNameI -> DocName
+fieldOccDocName (FieldOcc docName _) = docName
+
+-- TODO: handle linear types
+ppHsScaled :: HsScaled DocNameI (LHsType DocNameI) -> [OrgInline]
+ppHsScaled (HsScaled _ (L _ ty)) = ppHsType ty
+
+ppSig
+  :: Sig DocNameI
+  -> DocForDecl DocName
+  -> SubDocs
+  -> ModPath
+  -> Int
+  -> [OrgBlock]
+-- toplevel decl e.g. f :: Int -> String
+ppSig (TypeSig _ lhs rhs) (doc, aDoc) _ path level =
+  Heading
+      level
+      (  [ Plain (hsep $ punctuate comma $ docNameToDoc . unLoc <$> lhs)
+         , Whitespace
+         , plaintext "::"
+         , Whitespace
+         ]
+      ++ (ppHsSigType hsSig)
+      )
+      (concatMap (cIdPaths path . unLoc) lhs)
+    :  (if M.null aDoc then [] else ppHsSigTypeDoc hsSig aDoc)
+    ++ ppDocumentation doc (Just level)
+  where hsSig = unLoc (dropWildCards rhs)
+-- class method decl
+ppSig (ClassOpSig _ _ names (L _ sigType)) _ subdocs path level =
+  [ Heading
+      level
+      (  [ Plain (hsep $ punctuate comma $ docNameToDoc . unLoc <$> names)
+         , Whitespace
+         , plaintext "::"
+         , Whitespace
+         ]
+      ++ ppHsSigType sigType
+      )
+      (concatMap (cIdPaths path . unLoc) names)
+    ]
+    ++ case lookup (unLoc (head names)) subdocs of
+         Just (doc, aDoc) ->
+           (if M.null aDoc then [] else ppHsSigTypeDoc sigType aDoc)
+             ++ ppDocumentation doc (Just level)
+         Nothing -> []
+ppSig (PatSynSig _ names (L _ hsSig)) (doc, aDoc) _ path level =
+  Heading
+      level
+      (  [ plaintext "pattern "
+         , Plain (hsep $ punctuate comma $ docNameToDoc . unLoc <$> names)
+         , Whitespace
+         , plaintext "::"
+         , Whitespace
+         ]
+      ++ (ppHsSigType hsSig)
+      )
+      (concatMap (cIdPaths path . unLoc) names)
+    :  (if M.null aDoc then [] else ppHsSigTypeDoc hsSig aDoc)
+    ++ ppDocumentation doc (Just level)
+
+-- TODO: every class's sigs start with a MinimalSig
+ppSig (MinimalSig{}) _ _ _ _     = []
+ppSig _              _ _ _ level = [headingPlainText (unimp "Sig") level]
+
+ppNewOrData :: NewOrData -> PDoc
+ppNewOrData NewType  = text "newtype"
+ppNewOrData DataType = text "data"
+
+ppHsSigType :: HsSigType DocNameI -> [OrgInline]
+ppHsSigType (HsSig _ bndrs (L _ ty)) = interNotNull
+  [Whitespace]
+  [ppHsOuterSigTyVarBndrs bndrs, ppHsType (reparenTypePrec PREC_TOP ty)]
+
+ppHsOuterSigTyVarBndrs :: HsOuterSigTyVarBndrs DocNameI -> [OrgInline]
+ppHsOuterSigTyVarBndrs bndrs = case bndrs of
+  HsOuterExplicit _ tyVarBndrs -> ppForAll tyVarBndrs
+  _                            -> []
+
+ppHsSigTypeDoc :: HsSigType DocNameI -> FnArgsDoc DocName -> [OrgBlock]
+ppHsSigTypeDoc (HsSig _ bndrs (L _ ty)) adoc =
+  [Paragraph [plaintext "Arguments:"], DefList (forall ++ ppHsTypeDoc ty 0)]
+ where
+  ppHsTypeDoc :: HsType DocNameI -> Int -> [DefListItem]
+  ppHsTypeDoc (HsFunTy _ _ (L _ lTy) (L _ rTy)) i =
+    ppHsTypeDoc lTy i ++ ppHsTypeDoc rTy (i + 1)
+  ppHsTypeDoc (HsQualTy _ mbCtxt (L _ body)) i =
+    (ppMbLHsContext mbCtxt, []) : ppHsTypeDoc body i
+  ppHsTypeDoc (HsForAllTy _ tele (L _ body)) i =
+    (ppHsForAllTelescope tele ++ [plaintext "."], []) : ppHsTypeDoc body i
+  ppHsTypeDoc typ i = [(ppHsType typ, ppADoc adoc i)]
+  forall = case ppHsOuterSigTyVarBndrs bndrs of
+    [] -> []
+    is -> [(is, [])]
+
+ppDocForDecl :: DocForDecl DocName -> Maybe Int -> [OrgBlock]
+ppDocForDecl (doc, adoc) l = ppFnArgsDoc adoc ++ ppDocumentation doc l
+
+ppADoc :: FnArgsDoc DocName -> Int -> [OrgBlock]
+ppADoc adoc i = case adoc !? i of
+  Nothing   -> []
+  Just mdoc -> ppMDoc mdoc Nothing
+
+ppHsType :: HsType DocNameI -> [OrgInline]
+-- e.g. -> forall d. d
+ppHsType (HsForAllTy _ tele (L _ body)) =
+  ppHsForAllTelescope tele ++ [plaintext ".", Whitespace] ++ ppHsType body
+-- e.g. forall a. Ord a => a
+ppHsType (HsQualTy _ mbCtxt (L _ body)) =
+  interNotNull [Whitespace] [ppMbLHsContext mbCtxt, ppHsType body]
+-- e.g. Bool
+ppHsType (HsTyVar _ promo (L _ docName)) =
+  ppPromoted promo ++ ppDocName docName
+-- e.g. IO ()
+ppHsType (HsAppTy _ (L _ lTy) (L _ rTy)) =
+  ppHsType lTy ++ [Whitespace] ++ ppHsType rTy
+ppHsType (HsAppKindTy _ _ _) = [plaintext $ unimp "HsAppKindTy"]
+ppHsType (HsFunTy _ _ (L _ lTy) (L _ rTy)) =
+  ppHsType lTy ++ [Whitespace, plaintext "->", Whitespace] ++ ppHsType rTy
+-- e.g. [a]
+ppHsType (HsListTy _ (L _ ty) ) = orgBrackets $ ppHsType ty
+-- e.g. ()
+-- e.g. (a, b)
+ppHsType (HsTupleTy _ sort tys) = orgParens $ maybeUnbox $ intercalate
+  [plaintext ",", Whitespace]
+  (ppHsType . unLoc <$> tys)
+ where
+  maybeUnbox = case sort of
+    HsUnboxedTuple           -> orgUnbox
+    HsBoxedOrConstraintTuple -> id
+-- e.g. (# a | b #)    
+ppHsType (HsSumTy _ tys) =
+  orgParens . orgUnbox $ intercalate [plaintext " | "] (map ppLHsType tys)
+ppHsType (HsOpTy _ (L _ lTy) (L _ docName) (L _ rTy)) =
+  intercalate [Whitespace] [ppHsType lTy, ppDocName docName, ppHsType rTy]
+-- e.g. (a -> a)
+ppHsType (HsParTy _ (L _ t)) = orgParens $ ppHsType t
+-- e.g. ?callStack :: CallStack
+ppHsType (HsIParamTy _ (L _ name) ty) =
+  (plaintext $ '?' : unpackFS (hsIPNameFS name))
+    : plaintext " :: "
+    : ppLHsType ty
+ppHsType (HsStarTy _ _) = [plaintext "*"]
+-- e.g. (a :: k)
+ppHsType (HsKindSig _ (L _ t) (L _ k)) =
+  ppHsType t ++ [plaintext " :: "] ++ ppHsType k
+ppHsType (HsSpliceTy _ _              ) = [plaintext $ unimp "HsSpliceTy"]
+-- e.g.   -> a            -- ^ Second argument
+-- The third arg in docty is HsDocString
+ppHsType (HsDocTy  _ (L _ t) _        ) = ppHsType t
+ppHsType (HsBangTy _ _       (L _ ty) ) = plaintext "!" : ppHsType ty
+ppHsType (HsRecTy _ _                 ) = [plaintext $ unimp "HsRecTy"]
+-- TODO: is it possible that promo is NotPromoted?  If so what is the difference
+-- from a vanilla list (cf ExplicitTuple does not have a promo flag)?
+ppHsType (HsExplicitListTy _ promo tys) = ppPromoted promo
+  ++ orgBrackets (intercalate [plaintext ", "] (map ppLHsType tys))
+ppHsType (HsExplicitTupleTy _ tys) =
+  plaintext "'" : orgParens (intercalate [plaintext ", "] (map ppLHsType tys))
+ppHsType (HsTyLit _ lit) = [plaintext $ shown]
+ where
+  shown = case lit of
+    HsNumTy  _ x -> show x
+    HsStrTy  _ x -> show x
+    HsCharTy _ x -> show x
+ppHsType (HsWildCardTy _) = [plaintext "_"]
+ppHsType _                = [plaintext $ unimp "HsType"]
+
+ppLHsType :: LHsType DocNameI -> [OrgInline]
+ppLHsType (L _ x) = ppHsType x
+
+ppMbLHsContext :: Maybe (LHsContext DocNameI) -> [OrgInline]
+ppMbLHsContext = maybe [] (ppContext . map unLoc . unLoc)
+
+ppContext :: [HsType DocNameI] -> [OrgInline]
+ppContext [] = []
+ppContext ctx =
+  parensIfMany ctx (intercalate [plaintext ",", Whitespace] (map ppHsType ctx))
+    ++ [Whitespace, plaintext "=>"]
+
+ppPromoted :: PromotionFlag -> [OrgInline]
+ppPromoted flag = case flag of
+  NotPromoted -> []
+  IsPromoted  -> [plaintext "'"]
+
+ppDocName :: DocName -> [OrgInline]
+ppDocName docName@(Documented _ mdl) =
+  [Link (text "#" <> text (idPath' mdl docName)) [Plain $ docNameToDoc docName]]
+ppDocName docName@(Undocumented name) = case nameModule_maybe name of
+  Nothing  -> [Plain $ docNameToDoc docName]
+  Just mdl -> ppDocName (Documented name mdl)
+
+-- TODO: determine whether it's a subordinate based on NameSpace
+ppMO :: (ModuleName, OccName) -> [OrgInline]
+ppMO (mdl, occ) =
+  [ Link (text $ "#" ++ moToString (mdl, occ))
+         [plaintext $ moToString (mdl, occ)]
+  ]
+
+ppHsForAllTelescope :: HsForAllTelescope DocNameI -> [OrgInline]
+ppHsForAllTelescope (HsForAllInvis _ bndrs) =
+  intercalate [Whitespace] ([plaintext "forall"] : map ppLHsTyVarBndr bndrs)
+ppHsForAllTelescope _ = [plaintext $ unimp "HsForAllTelescope"]
+
+ppLHsTyVarBndr :: LHsTyVarBndr a DocNameI -> [OrgInline]
+ppLHsTyVarBndr (L _ x) = ppHsTyVarBndr x
+
+ppHsTyVarBndr :: HsTyVarBndr a DocNameI -> [OrgInline]
+ppHsTyVarBndr (UserTyVar _ _ (L _ docName)) = [Plain $ docNameToDoc docName]
+ppHsTyVarBndr (KindedTyVar _ _ (L _ docName) (L _ ty)) =
+  orgParens $ Plain (docNameToDoc docName) : plaintext " :: " : ppHsType ty
+
+ppOccName :: OccName -> PDoc
+ppOccName = text . occNameString
+
+ppName :: Name -> PDoc
+ppName = ppOccName . nameOccName
+
+docNameToDoc :: DocName -> PDoc
+docNameToDoc = ppName . getName
+
+docNameToString :: DocName -> String
+docNameToString = occNameString . nameOccName . getName
+
+ppWrapped :: (a -> [OrgInline]) -> Wrap a -> [OrgInline]
+ppWrapped p (Unadorned     n) = p n
+ppWrapped p (Parenthesized n) = orgParens $ p n
+ppWrapped p (Backticked    n) = plaintext "`" : p n ++ [plaintext "`"]
+
+wrapDocNameToString :: Wrap DocName -> String
+wrapDocNameToString = showWrapped docNameToString
+
+wrapMOToString :: Wrap (ModuleName, OccName) -> String
+wrapMOToString = showWrapped moToString
+
+moToString :: (ModuleName, OccName) -> String
+moToString (mdl, occ) = moduleNameString mdl ++ "." ++ occNameString occ
+
+removeMarkup :: Doc DocName -> String
+removeMarkup = markup (plainMarkup wrapMOToString wrapDocNameToString)
+
+removeMarkup' :: Doc RdrName -> String
+removeMarkup' = markup (plainMarkup wrapMOToString (showWrapped showPprUnsafe))
+
+orgUnbox :: [OrgInline] -> [OrgInline]
+orgUnbox xs = interNotNull [Whitespace] [[plaintext "#"], xs, [plaintext "#"]]
+
+-- * Utilities
+
+interNotNull :: [a] -> [[a]] -> [a]
+interNotNull xs = intercalate xs . filter (not . null)
+
+tyvarNames :: LHsQTyVars DocNameI -> [Name]
+tyvarNames = map (getName . hsLTyVarNameI) . hsQTvExplicit
+
+ppLHsQTyVars :: LHsQTyVars DocNameI -> [OrgInline]
+ppLHsQTyVars (HsQTvs _ bndrs) =
+  intercalate [Whitespace] (map ppLHsTyVarBndr bndrs)
+ppLHsQTyVars _ = [plaintext $ unimp "LHsQTyVars"]
+
+isBlock :: DocH mod id -> Bool
+isBlock DocEmpty                   = True
+isBlock (DocAppend x y           ) = isBlock x || isBlock y
+isBlock (DocString              _) = False
+isBlock (DocParagraph           _) = True
+isBlock (DocIdentifier          _) = False
+isBlock (DocIdentifierUnchecked _) = False
+isBlock (DocModule              _) = False
+isBlock (DocWarning             _) = False
+isBlock (DocEmphasis            _) = False
+isBlock (DocMonospaced          _) = False
+isBlock (DocBold                _) = False
+isBlock (DocUnorderedList       _) = True
+isBlock (DocOrderedList         _) = True
+isBlock (DocDefList             _) = True
+isBlock (DocCodeBlock           _) = True
+isBlock (DocHyperlink           _) = False
+isBlock (DocPic                 _) = False
+isBlock (DocMathInline          _) = False
+isBlock (DocMathDisplay         _) = True
+isBlock (DocAName               _) = False
+isBlock (DocProperty            _) = False
+isBlock (DocExamples            _) = True
+isBlock (DocHeader              _) = True
+isBlock (DocTable               _) = True
+
+cleanPkgStr :: String -> String
+cleanPkgStr = removeHash . removeInplace
+
+removeInplace :: String -> String
+removeInplace s | isSuffixOf "-inplace" s = take (length s - 8) s
+removeInplace s                           = s
+
+-- A silly heuristic that removes the last 65 chars if the string is longer than 65 chars
+-- useful for removing hash from a unit id string like
+-- sqlite-simple-0.4.18.2-fe5243655374e8f6ef336683926e98123d2de2f3265d2b935e0897c09586970b
+removeHash :: String -> String
+removeHash s | length s > 65 = take (length s - 65) s
+removeHash s                 = s
+
+hackageUrl :: String -> String -> String -> Bool -> String
+-- module should be of the form GHC-Hs-Decls instead of GHC.Hs.Decls
+hackageUrl pkg mdl id isSub =
+  "https://hackage.haskell.org/package/"
+    ++ pkg
+    ++ "/docs/"
+    ++ mdl
+    ++ ".html#"
+    ++ if isSub then "v" else "t" ++ ":" ++ id
+
+-- * Orphan instances for show
+
+instance Show DocName where
+  show = showPprUnsafe
+
+instance Show OccName where
+  show = showPprUnsafe
diff --git a/haddock-api/src/Haddock/Backends/Org/Types.hs b/haddock-api/src/Haddock/Backends/Org/Types.hs
new file mode 100644
index 00000000..81f2add5
--- /dev/null
+++ b/haddock-api/src/Haddock/Backends/Org/Types.hs
@@ -0,0 +1,237 @@
+{-# LANGUAGE DeriveDataTypeable, DeriveGeneric, FlexibleContexts #-}
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Haddock.Backends.Org.Types where
+
+import           Data.Char                      ( isSpace )
+import           Data.List                      ( dropWhileEnd
+                                                , intercalate
+                                                )
+import           Data.Map                       ( Map )
+import           GHC.Utils.Ppr                  ( ($$)
+                                                , (<+>)
+                                                , (<>)
+                                                , Doc
+                                                , Mode(..)
+                                                , brackets
+                                                , empty
+                                                , fullRender
+                                                , hang
+                                                , hcat
+                                                , hsep
+                                                , punctuate
+                                                , text
+                                                , txtPrinter
+                                                , vcat
+                                                )
+import           Prelude                 hiding ( (<>) )
+
+-- * Some consts
+defListSep :: Doc
+defListSep = text "::"
+
+unorderedBullet, orderedBullet :: String
+unorderedBullet = "-"
+orderedBullet = "."
+
+colons :: Doc -> Doc
+colons doc = text ":" <> doc <> text ":"
+
+-- * Document, Sections and Headings
+
+data OrgDocument = OrgDocument
+  { oDKeywords :: Map String Doc
+  , oDBlocks   :: [OrgBlock]
+  }
+  deriving Show
+
+-- todo: handle keywords
+
+type Properties = [(String, String)]
+
+-- * Blocks
+
+-- | Org block. Like a Pandoc Block.
+data OrgBlock
+  = Heading Int [OrgInline] Properties
+  | PlainList ListType [[OrgBlock]]
+  | DefList [DefListItem]
+  | Paragraph [OrgInline]
+  | Table [[[OrgInline]]] [[[OrgInline]]]
+  | SrcBlock Doc
+  | MathDisplay Doc
+  | Example Doc Doc -- expression and result
+  deriving (Show)
+
+-- Lists
+
+data ListType = Ordered | Unordered
+  deriving (Show)
+
+type DefListItem = ([OrgInline], [OrgBlock])
+
+-- * Inlines
+
+-- | Objects (inline elements). Derived from Pandoc's Inline.
+data OrgInline
+  = Plain Doc
+  | Italic [OrgInline]
+  | Bold [OrgInline]
+  | Code Doc
+  | Link Doc [OrgInline]
+  | Anchor Doc
+  | Whitespace
+  | MathInline Doc
+  deriving (Show)
+
+-- * From Org elements to Doc
+
+fromOrgDocument :: OrgDocument -> Doc
+fromOrgDocument (OrgDocument _ blocks) = fromOrgBlocks blocks <> text "\n"
+
+fromOrgBlock :: OrgBlock -> Doc
+fromOrgBlock (Heading level inlines props) = hang
+  (text (replicate level '*') <+> fromOrgInlines inlines)
+  (level + 1)
+  (fromOrgProperties props)
+fromOrgBlock (Paragraph inlines) = fromOrgInlines inlines
+fromOrgBlock (SrcBlock code) =
+  -- The \n followed by <> code makes indentation work, given the code has no indent
+  vcat [text "#+begin_src haskell\n" <> code, text "#+end_src"]
+fromOrgBlock (DefList defs) = vcat $ map
+  (\(term, def) -> fromOrgListItem
+    unorderedBullet
+    (prependInlinesToBlocks (term ++ [Whitespace, plaintext "::", Whitespace])
+                            def
+    )
+  )
+  defs
+fromOrgBlock (PlainList Unordered items) =
+  vcat $ map (uncurry fromOrgListItem) (zip (repeat unorderedBullet) items)
+fromOrgBlock (PlainList Ordered items) = vcat $ map
+  (uncurry fromOrgListItem)
+  (zip (map ((++ orderedBullet) . show) [1 ..]) items)
+fromOrgBlock (Example expr res) =
+  (fromOrgBlock (SrcBlock expr)) $$ (text "#+RESULTS:") $$ res
+fromOrgBlock (MathDisplay doc) = doc
+fromOrgBlock (Table header body) =
+  vcat (map fromOrgTableRow header) $$ tableRule len $$ vcat
+    (map fromOrgTableRow body)
+ where
+  len = case header of
+    [] -> case body of
+      []    -> 0
+      h : _ -> length h
+    h : _ -> length h
+
+tableRule :: Int -> Doc
+tableRule n =
+  text "|" <> hcat (punctuate (text "|") (replicate n (text "-"))) <> text "|"
+
+fromOrgTableRow :: [[OrgInline]] -> Doc
+fromOrgTableRow row =
+  text "|" <+> hsep (punctuate (text "|") (map fromOrgInlines row)) <+> text "|"
+
+prependInlinesToBlock :: [OrgInline] -> OrgBlock -> [OrgBlock]
+prependInlinesToBlock [] block = [block]
+prependInlinesToBlock _ (Heading _ _ _) =
+  error "Prepending inlines to a heading!"
+prependInlinesToBlock is (Paragraph is') = [Paragraph (is ++ is')]
+prependInlinesToBlock is block           = [Paragraph is, block]
+
+prependInlinesToBlocks :: [OrgInline] -> [OrgBlock] -> [OrgBlock]
+prependInlinesToBlocks is []      = [Paragraph is]
+prependInlinesToBlocks is (h : t) = prependInlinesToBlock is h ++ t
+
+fromOrgProperties :: Properties -> Doc
+fromOrgProperties props | null props = empty
+fromOrgProperties props =
+  colons (text "PROPERTIES")
+    $$ vcat (map (\(prop, value) -> colons (text prop) <+> text value) props)
+    $$ colons (text "END")
+
+fromOrgBlocks :: [OrgBlock] -> Doc
+fromOrgBlocks = vcat . punctuate (text "\n") . map fromOrgBlock
+
+fromOrgBlocksTight :: [OrgBlock] -> Doc
+fromOrgBlocksTight = vcat . map fromOrgBlock
+
+fromOrgListItem :: String -> [OrgBlock] -> Doc
+fromOrgListItem _      []          = empty
+fromOrgListItem bullet (hd : rest) = hang (text bullet <+> fromOrgBlock hd)
+                                          (length bullet + 1)
+                                          (fromOrgBlocksTight rest)
+
+fromOrgInline :: OrgInline -> Doc
+fromOrgInline (Plain doc        ) = doc
+fromOrgInline (Code  doc        ) = text "~" <> doc <> text "~"
+fromOrgInline (Link target label) = brackets $ brackets target <> if null label
+  then empty
+  else brackets (fromOrgInlines label)
+fromOrgInline (Bold   inlines) = text "*" <> fromOrgInlines inlines <> text "*"
+fromOrgInline (Italic inlines) = text "/" <> fromOrgInlines inlines <> text "/"
+fromOrgInline (Anchor doc    ) = text "<<" <> doc <> text ">>"
+fromOrgInline Whitespace       = text " "
+fromOrgInline (MathInline doc) = text "\\(" <+> doc <+> text "\\)"
+
+fromOrgInlines :: [OrgInline] -> Doc
+fromOrgInlines = hcat . map fromOrgInline
+
+-- * To string
+
+orgToString :: Doc -> String
+orgToString = fullRender (PageMode True) 0 1 txtPrinter ""
+
+-- * Utilities for creating org elements
+
+cIdProp :: String -> Properties
+cIdProp cid = [("CUSTOM_ID", cid)]
+
+cIdsProp :: [String] -> Properties
+cIdsProp cids = map (\cid -> ("CUSTOM_ID", cid)) cids
+
+plaintext :: String -> OrgInline
+plaintext = Plain . text . unfill
+
+unfill :: String -> String
+unfill "" = ""
+unfill s =
+  let
+    xs          = lines s
+    preStripped = head xs : map (dropWhile isSpace) (tail xs)
+    stripped =
+      map (dropWhileEnd isSpace) (init preStripped) ++ [last preStripped]
+  in
+    unwords stripped
+
+fixLeadingStar :: String -> String
+fixLeadingStar =
+  intercalate "\n"
+    . map
+        (\line ->
+          if not (null line) && head line == '*' then ' ' : line else line
+        )
+    . lines
+
+headingPlainText :: String -> Int -> OrgBlock
+headingPlainText title level = Heading level [plaintext title] []
+
+headingPlainTextCId :: String -> String -> Int -> OrgBlock
+headingPlainTextCId title cid level =
+  Heading level [plaintext title] (cIdProp cid)
+
+singleHeadingPlainText :: String -> Int -> [OrgBlock]
+singleHeadingPlainText title level = [headingPlainText title level]
+
+singleHeadingPlain :: Doc -> Int -> [OrgBlock]
+singleHeadingPlain title level = [Heading level [Plain title] []]
+
+singleHeadingPlainCId :: Doc -> String -> Int -> [OrgBlock]
+singleHeadingPlainCId title cid level =
+  [Heading level [Plain title] (cIdProp cid)]
+
+orgParens :: [OrgInline] -> [OrgInline]
+orgParens xs = plaintext "(" : xs ++ [plaintext ")"]
+
+orgBrackets :: [OrgInline] -> [OrgInline]
+orgBrackets xs = plaintext "[" : xs ++ [plaintext "]"]