aboutsummaryrefslogtreecommitdiff
path: root/src/Text/Pandoc/Lua/Module/Utils.hs
blob: 11a0bda842fa17535426cff5211aaee1ccecce01 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
{- |
   Module      : Text.Pandoc.Lua.Module.Utils
   Copyright   : Copyright © 2017-2020 Albert Krewinkel
   License     : GNU GPL, version 2 or above

   Maintainer  : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
   Stability   : alpha

Utility module for lua, exposing internal helper functions.
-}
module Text.Pandoc.Lua.Module.Utils
  ( pushModule
  ) where

import Control.Applicative ((<|>))
import Data.Default (def)
import Data.Version (Version)
import Foreign.Lua (Peekable, Lua, NumResults)
import Text.Pandoc.Class.PandocIO (runIO)
import Text.Pandoc.Class.PandocMonad (setUserDataDir)
import Text.Pandoc.Definition ( Pandoc, Meta, MetaValue (..), Block, Inline
                              , Citation, Attr, ListAttributes)
import Text.Pandoc.Lua.Marshaling ()
import Text.Pandoc.Lua.Util (addFunction)

import qualified Data.Digest.Pure.SHA as SHA
import qualified Data.ByteString.Lazy as BSL
import qualified Data.Text as T
import qualified Foreign.Lua as Lua
import qualified Text.Pandoc.Builder as B
import qualified Text.Pandoc.Filter.JSON as JSONFilter
import qualified Text.Pandoc.Shared as Shared

-- | Push the "pandoc.utils" module to the lua stack.
pushModule :: Maybe FilePath -> Lua NumResults
pushModule mbDatadir = do
  Lua.newtable
  addFunction "blocks_to_inlines" blocksToInlines
  addFunction "equals" equals
  addFunction "make_sections" makeSections
  addFunction "normalize_date" normalizeDate
  addFunction "run_json_filter" (runJSONFilter mbDatadir)
  addFunction "sha1" sha1
  addFunction "stringify" stringify
  addFunction "to_roman_numeral" toRomanNumeral
  addFunction "Version" (return :: Version -> Lua Version)
  return 1

-- | Squashes a list of blocks into inlines.
blocksToInlines :: [Block] -> Lua.Optional [Inline] -> Lua [Inline]
blocksToInlines blks optSep = do
  let sep = case Lua.fromOptional optSep of
              Just x -> B.fromList x
              Nothing -> Shared.defaultBlocksSeparator
  return $ B.toList (Shared.blocksToInlinesWithSep sep blks)

-- | Convert list of Pandoc blocks into sections using Divs.
makeSections :: Bool -> Lua.Optional Int -> [Block] -> Lua [Block]
makeSections number baselevel =
  return . Shared.makeSections number (Lua.fromOptional baselevel)

-- | Parse a date and convert (if possible) to "YYYY-MM-DD" format. We
-- limit years to the range 1601-9999 (ISO 8601 accepts greater than
-- or equal to 1583, but MS Word only accepts dates starting 1601).
-- Returns nil instead of a string if the conversion failed.
normalizeDate :: T.Text -> Lua (Lua.Optional T.Text)
normalizeDate = return . Lua.Optional . Shared.normalizeDate

-- | Run a JSON filter on the given document.
runJSONFilter :: Maybe FilePath
              -> Pandoc
              -> FilePath
              -> Lua.Optional [String]
              -> Lua NumResults
runJSONFilter mbDatadir doc filterFile optArgs = do
  args <- case Lua.fromOptional optArgs of
            Just x -> return x
            Nothing -> do
              Lua.getglobal "FORMAT"
              (:[]) <$> Lua.popValue
  filterRes <- Lua.liftIO . runIO $ do
    setUserDataDir mbDatadir
    JSONFilter.apply def args filterFile doc
  case filterRes of
    Left err -> Lua.raiseError (show err)
    Right d -> (1 :: NumResults) <$ Lua.push d

-- | Calculate the hash of the given contents.
sha1 :: BSL.ByteString
     -> Lua T.Text
sha1 = return . T.pack . SHA.showDigest . SHA.sha1

-- | Convert pandoc structure to a string with formatting removed.
-- Footnotes are skipped (since we don't want their contents in link
-- labels).
stringify :: AstElement -> Lua T.Text
stringify el = return $ case el of
  PandocElement pd -> Shared.stringify pd
  InlineElement i  -> Shared.stringify i
  BlockElement b   -> Shared.stringify b
  MetaElement m    -> Shared.stringify m
  CitationElement c  -> Shared.stringify c
  MetaValueElement m -> stringifyMetaValue m
  _                  -> mempty

stringifyMetaValue :: MetaValue -> T.Text
stringifyMetaValue mv = case mv of
  MetaBool b   -> T.toLower $ T.pack (show b)
  MetaString s -> s
  _            -> Shared.stringify mv

equals :: AstElement -> AstElement -> Lua Bool
equals e1 e2 = return (e1 == e2)

data AstElement
  = PandocElement Pandoc
  | MetaElement Meta
  | BlockElement Block
  | InlineElement Inline
  | MetaValueElement MetaValue
  | AttrElement Attr
  | ListAttributesElement ListAttributes
  | CitationElement Citation
  deriving (Eq, Show)

instance Peekable AstElement where
  peek idx  = do
    res <- Lua.try $  (PandocElement <$> Lua.peek idx)
                  <|> (InlineElement <$> Lua.peek idx)
                  <|> (BlockElement <$> Lua.peek idx)
                  <|> (AttrElement <$> Lua.peek idx)
                  <|> (ListAttributesElement <$> Lua.peek idx)
                  <|> (MetaElement <$> Lua.peek idx)
                  <|> (MetaValueElement <$> Lua.peek idx)
    case res of
      Right x -> return x
      Left _ -> Lua.throwException
        "Expected an AST element, but could not parse value as such."

-- | Convert a number < 4000 to uppercase roman numeral.
toRomanNumeral :: Lua.Integer -> Lua T.Text
toRomanNumeral = return . Shared.toRomanNumeral . fromIntegral