Table.hs

{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
   Module      : Text.Pandoc.Writers.LaTeX.Table
   Copyright   : Copyright (C) 2006-2021 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>
   Stability   : alpha
   Portability : portable

Output LaTeX formatted tables.
-}
module Text.Pandoc.Writers.LaTeX.Table
  ( tableToLaTeX
  ) where
import Control.Monad.State.Strict
import Data.List (intersperse)
import Data.List.NonEmpty (NonEmpty ((:|)))
import Data.Text (Text)
import qualified Data.Text as T
import Text.Pandoc.Class.PandocMonad (PandocMonad)
import Text.Pandoc.Definition
import Text.DocLayout
  ( Doc, braces, cr, empty, hcat, hsep, isEmpty, literal, nest
  , text, vcat, ($$) )
import Text.Pandoc.Shared (blocksToInlines, splitBy, tshow)
import Text.Pandoc.Walk (walk)
import Text.Pandoc.Writers.LaTeX.Caption (getCaption)
import Text.Pandoc.Writers.LaTeX.Notes (notesToLaTeX)
import Text.Pandoc.Writers.LaTeX.Types
  ( LW, WriterState (stBeamer, stExternalNotes, stInMinipage, stMultiRow
                    , stNotes, stTable) )
import Text.Printf (printf)
import qualified Text.Pandoc.Builder as B
import qualified Text.Pandoc.Writers.AnnotatedTable as Ann

tableToLaTeX :: PandocMonad m
             => ([Inline] -> LW m (Doc Text))
             -> ([Block]  -> LW m (Doc Text))
             -> Ann.Table
             -> LW m (Doc Text)
tableToLaTeX inlnsToLaTeX blksToLaTeX tbl = do
  let (Ann.Table _attr caption _specs thead tbodies tfoot) = tbl
  CaptionDocs capt captNotes <- captionToLaTeX inlnsToLaTeX caption
  let removeNote (Note _) = Span ("", [], []) []
      removeNote x        = x
  firsthead <- if isEmpty capt || isEmptyHead thead
               then return empty
               else ($$ text "\\endfirsthead") <$>
                    headToLaTeX blksToLaTeX thead
  head' <- if isEmptyHead thead
           then return "\\toprule"
           -- avoid duplicate notes in head and firsthead:
           else headToLaTeX blksToLaTeX
                (if isEmpty firsthead
                 then thead
                 else walk removeNote thead)
  rows' <- mapM (rowToLaTeX blksToLaTeX BodyCell) $
                mconcat (map bodyRows tbodies) <> footRows tfoot
  modify $ \s -> s{ stTable = True }
  notes <- notesToLaTeX <$> gets stNotes
  return
    $  "\\begin{longtable}[]" <>
          braces ("@{}" <> colDescriptors tbl <> "@{}")
          -- the @{} removes extra space at beginning and end
    $$ capt
    $$ firsthead
    $$ head'
    $$ "\\endhead"
    $$ vcat rows'
    $$ "\\bottomrule"
    $$ "\\end{longtable}"
    $$ captNotes
    $$ notes

-- | Creates column descriptors for the table.
colDescriptors :: Ann.Table -> Doc Text
colDescriptors (Ann.Table _attr _caption specs thead tbodies tfoot) =
  let (aligns, widths) = unzip specs

      defaultWidthsOnly = all (== ColWidthDefault) widths
      isSimpleTable = all (all isSimpleCell) $ mconcat
                      [ headRows thead
                      , concatMap bodyRows tbodies
                      , footRows tfoot
                      ]

      relativeWidths = if defaultWidthsOnly
                       then replicate (length specs)
                            (1 / fromIntegral (length specs))
                       else map toRelWidth widths
  in if defaultWidthsOnly && isSimpleTable
     then hcat $ map (literal . colAlign) aligns
     else (cr <>) . nest 2 . vcat . map literal $
          zipWith (toColDescriptor (length specs))
                  aligns
                  relativeWidths
  where
    toColDescriptor :: Int -> Alignment -> Double -> Text
    toColDescriptor numcols align width =
      T.pack $ printf
      ">{%s\\arraybackslash}p{(\\columnwidth - %d\\tabcolsep) * \\real{%0.2f}}"
      (T.unpack (alignCommand align))
      ((numcols - 1) * 2)
      width

    isSimpleCell (Ann.Cell _ _ (Cell _attr _align _rowspan _colspan blocks)) =
      case blocks of
        [Para _]  -> True
        [Plain _] -> True
        []        -> True
        _         -> False

    toRelWidth ColWidthDefault = 0
    toRelWidth (ColWidth w)    = w

alignCommand :: Alignment -> Text
alignCommand = \case
  AlignLeft    -> "\\raggedright"
  AlignRight   -> "\\raggedleft"
  AlignCenter  -> "\\centering"
  AlignDefault -> "\\raggedright"

colAlign :: Alignment -> Text
colAlign = \case
  AlignLeft    -> "l"
  AlignRight   -> "r"
  AlignCenter  -> "c"
  AlignDefault -> "l"

data CaptionDocs =
  CaptionDocs
  { captionCommand :: Doc Text
  , captionNotes :: Doc Text
  }

captionToLaTeX :: PandocMonad m
               => ([Inline] -> LW m (Doc Text))
               -> Caption
               -> LW m CaptionDocs
captionToLaTeX inlnsToLaTeX (Caption _maybeShort longCaption) = do
  let caption = blocksToInlines longCaption
  (captionText, captForLof, captNotes) <- getCaption inlnsToLaTeX False caption
  return $ CaptionDocs
    { captionNotes = captNotes
    , captionCommand = if isEmpty captionText
                       then empty
                       else "\\caption" <> captForLof <>
                            braces captionText <> "\\tabularnewline"
    }

type BlocksWriter m = [Block] -> LW m (Doc Text)

headToLaTeX :: PandocMonad m
            => BlocksWriter m
            -> Ann.TableHead
            -> LW m (Doc Text)
headToLaTeX blocksWriter (Ann.TableHead _attr headerRows) = do
  rowsContents <- mapM (rowToLaTeX blocksWriter HeaderCell . headerRowCells)
                       headerRows
  return ("\\toprule" $$ vcat rowsContents $$ "\\midrule")

-- | Converts a row of table cells into a LaTeX row.
rowToLaTeX :: PandocMonad m
           => BlocksWriter m
           -> CellType
           -> [Ann.Cell]
           -> LW m (Doc Text)
rowToLaTeX blocksWriter celltype row = do
  cellsDocs <- mapM (cellToLaTeX blocksWriter celltype) (fillRow row)
  return $ hsep (intersperse "&" cellsDocs) <> " \\\\"

-- | Pads row with empty cells to adjust for rowspans above this row.
fillRow :: [Ann.Cell] -> [Ann.Cell]
fillRow = go 0
  where
    go _ [] = []
    go n (acell@(Ann.Cell _spec (Ann.ColNumber colnum) cell):cells) =
      let (Cell _ _ _ (ColSpan colspan) _) = cell
      in map mkEmptyCell [n .. colnum - 1] ++
         acell : go (colnum + colspan) cells

    mkEmptyCell :: Int -> Ann.Cell
    mkEmptyCell colnum =
      Ann.Cell ((AlignDefault, ColWidthDefault):|[])
               (Ann.ColNumber colnum)
               B.emptyCell

isEmptyHead :: Ann.TableHead -> Bool
isEmptyHead (Ann.TableHead _attr []) = True
isEmptyHead (Ann.TableHead _attr rows) = all (null . headerRowCells) rows

-- | Gets all cells in a header row.
headerRowCells :: Ann.HeaderRow -> [Ann.Cell]
headerRowCells (Ann.HeaderRow _attr _rownum cells) = cells

-- | Gets all cells in a body row.
bodyRowCells :: Ann.BodyRow -> [Ann.Cell]
bodyRowCells (Ann.BodyRow _attr _rownum rowhead cells) = rowhead <> cells

-- | Gets a list of rows of the table body, where a row is a simple
-- list of cells.
bodyRows :: Ann.TableBody -> [[Ann.Cell]]
bodyRows (Ann.TableBody _attr _rowheads headerRows rows) =
  map headerRowCells headerRows <> map bodyRowCells rows

-- | Gets a list of rows of the table head, where a row is a simple
-- list of cells.
headRows :: Ann.TableHead -> [[Ann.Cell]]
headRows (Ann.TableHead _attr rows) = map headerRowCells rows

-- | Gets a list of rows from the foot, where a row is a simple list
-- of cells.
footRows :: Ann.TableFoot -> [[Ann.Cell]]
footRows (Ann.TableFoot _attr rows) = map headerRowCells rows

-- For simple latex tables (without minipages or parboxes),
-- we need to go to some lengths to get line breaks working:
-- as LineBreak bs = \vtop{\hbox{\strut as}\hbox{\strut bs}}.
fixLineBreaks :: Block -> Block
fixLineBreaks (Para ils)  = Para $ fixLineBreaks' ils
fixLineBreaks (Plain ils) = Plain $ fixLineBreaks' ils
fixLineBreaks x           = x

fixLineBreaks' :: [Inline] -> [Inline]
fixLineBreaks' ils = case splitBy (== LineBreak) ils of
                       []     -> []
                       [xs]   -> xs
                       chunks -> RawInline "tex" "\\vtop{" :
                                 concatMap tohbox chunks <>
                                 [RawInline "tex" "}"]
  where tohbox ys = RawInline "tex" "\\hbox{\\strut " : ys <>
                    [RawInline "tex" "}"]

-- We also change display math to inline math, since display
-- math breaks in simple tables.
displayMathToInline :: Inline -> Inline
displayMathToInline (Math DisplayMath x) = Math InlineMath x
displayMathToInline x                    = x

cellToLaTeX :: PandocMonad m
            => BlocksWriter m
            -> CellType
            -> Ann.Cell
            -> LW m (Doc Text)
cellToLaTeX blockListToLaTeX celltype annotatedCell = do
  let (Ann.Cell _specs _colnum cell) = annotatedCell
  let (Cell _attr align rowspan colspan blocks) = cell
  beamer <- gets stBeamer
  externalNotes <- gets stExternalNotes
  inMinipage <- gets stInMinipage
  -- See #5367 -- footnotehyper/footnote don't work in beamer,
  -- so we need to produce the notes outside the table...
  modify $ \st -> st{ stExternalNotes = beamer }
  let isPlainOrPara = \case
        Para{}  -> True
        Plain{} -> True
        _       -> False
  result <-
    if all isPlainOrPara blocks
       then
         blockListToLaTeX $ walk fixLineBreaks $ walk displayMathToInline blocks
       else do
         modify $ \st -> st{ stInMinipage = True }
         cellContents <- blockListToLaTeX blocks
         modify $ \st -> st{ stInMinipage = inMinipage }
         let valign = text $ case celltype of
                               HeaderCell -> "[b]"
                               BodyCell   -> "[t]"
         let halign = literal $ alignCommand align
         return $ "\\begin{minipage}" <> valign <>
                  braces "\\linewidth" <> halign <> cr <>
                  cellContents <> cr <>
                  "\\end{minipage}"
  modify $ \st -> st{ stExternalNotes = externalNotes }
  when (rowspan /= RowSpan 1) $
    modify (\st -> st{ stMultiRow = True })
  let inMultiColumn x = case colspan of
                          (ColSpan 1) -> x
                          (ColSpan n) -> "\\multicolumn"
                                         <> braces (literal (tshow n))
                                         <> braces (literal $ colAlign align)
                                         <> braces x
  let inMultiRow x = case rowspan of
                       (RowSpan 1) -> x
                       (RowSpan n) -> let nrows = literal (tshow n)
                                      in "\\multirow" <> braces nrows
                                         <> braces "*" <> braces x
  return . inMultiColumn . inMultiRow $ result

data CellType
  = HeaderCell
  | BodyCell