LaTeX writer: properly handle boolean value for csquotes variable.

Closes #10403.

src/Text/Pandoc/Writers/LaTeX.hs

@@ -39,7 +39,7 @@ import Data.Monoid (Any (..))
 import Data.Text (Text)
 import qualified Data.Text as T
 import Network.URI (unEscapeString)
-import Text.DocTemplates (FromContext(lookupContext), renderTemplate)
+import Text.DocTemplates (FromContext(lookupContext), Val(..), renderTemplate)
 import Text.Collate.Lang (renderLang, Lang(langLanguage))
 import Text.Pandoc.Class.PandocMonad (PandocMonad, report, toLang)
 import Text.Pandoc.Definition
@@ -157,11 +157,15 @@ pandocToLaTeX options (Pandoc meta blocks) = do
                                           _               -> "article"
   when (documentClass `elem` chaptersClasses) $
      modify $ \s -> s{ stHasChapters = True }
-  case lookupContext "csquotes" (writerVariables options) `mplus`
-       (stringify <$> lookupMeta "csquotes" meta) of
-     Nothing      -> return ()
-     Just "false" -> return ()
-     Just _       -> modify $ \s -> s{stCsquotes = True}
+  let csquotes =
+        case lookupContext "csquotes" (writerVariables options) of
+          Just (BoolVal v) -> v
+          Just (SimpleVal (Text _ t)) -> t /= ("false" :: Text)
+          _ -> case stringify <$> lookupMeta "csquotes" meta of
+                  Nothing -> False
+                  Just "false" -> False
+                  Just _ -> True
+  when csquotes $ modify $ \s -> s{stCsquotes = True}
   let (blocks'', lastHeader) = if writerCiteMethod options == Citeproc then
                                  (blocks', [])
                                else case reverse blocks' of