LaTeX writer: Protect VERB in caption (#11139)

Also apply hlint suggestions for fewer imports and
moving brackets to avoid $.

3 files changed, 16 insertions, 5 deletions

diff --git a/src/Text/Pandoc/Writers/LaTeX.hs b/src/Text/Pandoc/Writers/LaTeX.hs
index eb4671c18..24ed4bebc 100644
--- a/src/Text/Pandoc/Writers/LaTeX.hs
+++ b/src/Text/Pandoc/Writers/LaTeX.hs
@@ -32,7 +32,7 @@ import Control.Monad
       unless )
 import Crypto.Hash (hashWith, MD5(MD5))
 import Data.Containers.ListUtils (nubOrd)
-import Data.Char (isDigit, isAscii)
+import Data.Char (isDigit, isAscii, isLetter)
 import Data.List (intersperse, (\\))
 import Data.Maybe (catMaybes, fromMaybe, isJust, mapMaybe, isNothing)
 import Data.Monoid (Any (..))
@@ -68,7 +68,6 @@ import Text.Pandoc.Writers.Shared
 import qualified Data.Attoparsec.Text as A
 import qualified Text.Pandoc.UTF8 as UTF8
 import qualified Text.Pandoc.Writers.AnnotatedTable as Ann
-import Data.Char (isLetter)
 import Control.Applicative ((<|>))
 
 -- Work around problems with notes inside emphasis (see #8982)
@@ -677,7 +676,7 @@ blockToLaTeX (Figure (ident, _, kvs) captnode body) = do
       , stSubfigure = stSubfigure st || isSubfigure
       }
 
-  let containsTable = getAny . (query $ \case
+  let containsTable = getAny . query (\case
         Table {}  -> Any True
         _         -> Any False)
   st <- get
@@ -948,6 +947,7 @@ inlineToLaTeX (Code (_,classes,kvs) str) = do
   inHeading <- gets stInHeading
   inItem <- gets stInItem
   inSoul <- gets stInSoulCommand
+  inCaption <- gets stInCaption
   let listingsCode = do
         let listingsopts = (case getListingsLanguage classes of
                                 Just l  -> (("language", mbBraced l):)
@@ -1000,7 +1000,14 @@ inlineToLaTeX (Code (_,classes,kvs) str) = do
   -- (see #1294). with regular texttt we don't get an error, but we get
   -- incorrect results if there is a space (see #5529).
   let inMbox x = "\\mbox" <> braces x
-  (if inSoul then inMbox else id) <$>
+
+  -- for captions we need to protect VERB with \protect (see #6821)
+  let protect x = "\\protect" <> x
+
+  let optionalProtect = case () of _ | inSoul -> inMbox
+                                     | inCaption -> protect
+                                     | otherwise -> id
+  optionalProtect <$>
    case writerHighlightMethod opts of
      _ | inHeading || inItem  -> rawCode  -- see #5574
      IdiomaticHighlighting    -> listingsCode
diff --git a/src/Text/Pandoc/Writers/LaTeX/Caption.hs b/src/Text/Pandoc/Writers/LaTeX/Caption.hs
index 2efbfa86e..9a63fee3c 100644
--- a/src/Text/Pandoc/Writers/LaTeX/Caption.hs
+++ b/src/Text/Pandoc/Writers/LaTeX/Caption.hs
@@ -23,7 +23,7 @@ import Text.Pandoc.Shared
 import Text.Pandoc.Walk
 import Text.Pandoc.Writers.LaTeX.Notes (notesToLaTeX)
 import Text.Pandoc.Writers.LaTeX.Types
-  ( LW, WriterState (stExternalNotes, stNotes) )
+  ( LW, WriterState (stExternalNotes, stNotes, stInCaption) )
 
 
 -- | Produces the components of a LaTeX 'caption' command. Returns a triple
@@ -35,6 +35,7 @@ getCaption :: PandocMonad m
            -> Caption
            -> LW m (Doc Text, Doc Text, Doc Text)
 getCaption inlineListToLaTeX externalNotes (Caption maybeShort long) = do
+  modify $ \st -> st{ stInCaption = True }
   let long' = blocksToInlines long
   oldExternalNotes <- gets stExternalNotes
   modify $ \st -> st{ stExternalNotes = externalNotes, stNotes = [] }
@@ -53,4 +54,5 @@ getCaption inlineListToLaTeX externalNotes (Caption maybeShort long) = do
                              then toShortCapt long'
                              else return empty
                   Just short -> toShortCapt short
+  modify $ \st -> st{ stInCaption = False }
   return (capt, captForLof, footnotes)
diff --git a/src/Text/Pandoc/Writers/LaTeX/Types.hs b/src/Text/Pandoc/Writers/LaTeX/Types.hs
index 1295d2d01..4906026ed 100644
--- a/src/Text/Pandoc/Writers/LaTeX/Types.hs
+++ b/src/Text/Pandoc/Writers/LaTeX/Types.hs
@@ -54,6 +54,7 @@ data WriterState =
   , stLang          :: Maybe Lang    -- ^ lang specified in metadata
   , stInSoulCommand :: Bool          -- ^ in a soul command like ul
   , stCancel        :: Bool          -- ^ true if document uses \cancel
+  , stInCaption     :: Bool          -- ^ true if in a caption
   }
 
 startingState :: WriterOptions -> WriterState
@@ -95,4 +96,5 @@ startingState options =
   , stLang = Nothing
   , stInSoulCommand = False
   , stCancel = False
+  , stInCaption = False
   }