From ee160d7c4cc912554fe0a1c7ff9fb802e9e72b64 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Tue, 25 Apr 2017 15:00:27 +0200
Subject: [PATCH] LaTeX writer: fix error with line breaks after empty
content.
LaTeX requires something before a line break, so we insert a
`~` if no printable content has yet been emitted.
Closes #2874.
---
src/Text/Pandoc/Writers/LaTeX.hs | 47 +++++++++++++++++++-------------
test/command/2874.md | 14 ++++++++++
2 files changed, 42 insertions(+), 19 deletions(-)
create mode 100644 test/command/2874.md
diff --git a/src/Text/Pandoc/Writers/LaTeX.hs b/src/Text/Pandoc/Writers/LaTeX.hs
index 70539a4a6..59d6030cf 100644
--- a/src/Text/Pandoc/Writers/LaTeX.hs
+++ b/src/Text/Pandoc/Writers/LaTeX.hs
@@ -81,6 +81,7 @@ data WriterState =
, stInternalLinks :: [String] -- list of internal link targets
, stUsesEuro :: Bool -- true if euro symbol used
, stBeamer :: Bool -- produce beamer
+ , stEmptyLine :: Bool -- true if no content on line
}
startingState :: WriterOptions -> WriterState
@@ -107,7 +108,8 @@ startingState options = WriterState {
, stIncremental = writerIncremental options
, stInternalLinks = []
, stUsesEuro = False
- , stBeamer = False }
+ , stBeamer = False
+ , stEmptyLine = True }
-- | Convert Pandoc to LaTeX.
writeLaTeX :: PandocMonad m => WriterOptions -> Pandoc -> m String
@@ -680,7 +682,8 @@ toColDescriptor align =
AlignDefault -> "l"
blockListToLaTeX :: PandocMonad m => [Block] -> LW m Doc
-blockListToLaTeX lst = vsep `fmap` mapM blockToLaTeX lst
+blockListToLaTeX lst =
+ vsep `fmap` mapM (\b -> setEmptyLine True >> blockToLaTeX b) lst
tableRowToLaTeX :: PandocMonad m
=> Bool
@@ -882,7 +885,7 @@ inlineListToLaTeX :: PandocMonad m
=> [Inline] -- ^ Inlines to convert
-> LW m Doc
inlineListToLaTeX lst =
- mapM inlineToLaTeX (fixBreaks $ fixLineInitialSpaces lst)
+ mapM inlineToLaTeX (fixLineInitialSpaces lst)
>>= return . hcat
-- nonbreaking spaces (~) in LaTeX don't work after line breaks,
-- so we turn nbsps after hard breaks to \hspace commands.
@@ -894,14 +897,6 @@ inlineListToLaTeX lst =
fixNbsps s = let (ys,zs) = span (=='\160') s
in replicate (length ys) hspace ++ [Str zs]
hspace = RawInline "latex" "\\hspace*{0.333em}"
- -- linebreaks after blank lines cause problems:
- fixBreaks [] = []
- fixBreaks ys@(LineBreak : LineBreak : _) =
- case span (== LineBreak) ys of
- (lbs, rest) -> RawInline "latex"
- ("\\\\[" ++ show (length lbs) ++
- "\\baselineskip]") : fixBreaks rest
- fixBreaks (y:ys) = y : fixBreaks ys
isQuoted :: Inline -> Bool
isQuoted (Quoted _ _) = True
@@ -927,9 +922,9 @@ inlineToLaTeX (Span (id',classes,kvs) ils) = do
return $ (if null id'
then empty
else "\\protect" <> linkAnchor) <>
- if null cmds
- then braces contents
- else foldr inCmd contents cmds
+ (if null cmds
+ then braces contents
+ else foldr inCmd contents cmds)
inlineToLaTeX (Emph lst) =
inlineListToLaTeX lst >>= return . inCmd "emph"
inlineToLaTeX (Strong lst) =
@@ -1007,18 +1002,27 @@ inlineToLaTeX (Quoted qt lst) = do
if isEnabled Ext_smart opts
then char '`' <> inner <> char '\''
else char '\x2018' <> inner <> char '\x2019'
-inlineToLaTeX (Str str) = liftM text $ stringToLaTeX TextString str
-inlineToLaTeX (Math InlineMath str) =
+inlineToLaTeX (Str str) = do
+ setEmptyLine False
+ liftM text $ stringToLaTeX TextString str
+inlineToLaTeX (Math InlineMath str) = do
+ setEmptyLine False
return $ "\\(" <> text str <> "\\)"
-inlineToLaTeX (Math DisplayMath str) =
+inlineToLaTeX (Math DisplayMath str) = do
+ setEmptyLine False
return $ "\\[" <> text str <> "\\]"
inlineToLaTeX il@(RawInline f str)
| f == Format "latex" || f == Format "tex"
- = return $ text str
+ = do
+ setEmptyLine False
+ return $ text str
| otherwise = do
report $ InlineNotRendered il
return empty
-inlineToLaTeX (LineBreak) = return $ "\\\\" <> cr
+inlineToLaTeX (LineBreak) = do
+ emptyLine <- gets stEmptyLine
+ setEmptyLine True
+ return $ (if emptyLine then "~" else "") <> "\\\\" <> cr
inlineToLaTeX SoftBreak = do
wrapText <- gets (writerWrapText . stOptions)
case wrapText of
@@ -1048,6 +1052,7 @@ inlineToLaTeX (Link _ txt (src, _)) =
return $ text ("\\href{" ++ src' ++ "}{") <>
contents <> char '}'
inlineToLaTeX (Image attr _ (source, _)) = do
+ setEmptyLine False
modify $ \s -> s{ stGraphics = True }
opts <- gets stOptions
let showDim dir = let d = text (show dir) <> "="
@@ -1073,6 +1078,7 @@ inlineToLaTeX (Image attr _ (source, _)) = do
(if inHeading then "\\protect\\includegraphics" else "\\includegraphics") <>
dims <> braces (text source'')
inlineToLaTeX (Note contents) = do
+ setEmptyLine False
inMinipage <- gets stInMinipage
modify (\s -> s{stInNote = True})
contents' <- blockListToLaTeX contents
@@ -1100,6 +1106,9 @@ protectCode (x@(Code _ _) : xs) = ltx "\\mbox{" : x : ltx "}" : xs
where ltx = RawInline (Format "latex")
protectCode (x : xs) = x : protectCode xs
+setEmptyLine :: PandocMonad m => Bool -> LW m ()
+setEmptyLine b = modify $ \st -> st{ stEmptyLine = b }
+
citationsToNatbib :: PandocMonad m => [Citation] -> LW m Doc
citationsToNatbib (one:[])
= citeCommand c p s k
diff --git a/test/command/2874.md b/test/command/2874.md
new file mode 100644
index 000000000..1fb530dc1
--- /dev/null
+++ b/test/command/2874.md
@@ -0,0 +1,14 @@
+```
+% pandoc -f html -t latex
+<a></a>
+<br/>
+^D
+{}~\\
+```
+
+```
+% pandoc -f html -t latex
+<a name="foo"></a><br/>
+^D
+\protect\hypertarget{foo}{}{}~\\
+```