From ea479bf28a4031f408af12ea92d3e19f9a838820 Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Mon, 4 Jan 2021 14:05:03 -0800
Subject: [PATCH] LaTeX reader: handle filecontents environment.

Closes #7003.
---
 src/Text/Pandoc/Readers/LaTeX.hs         | 32 ++++++++++++++++----
 src/Text/Pandoc/Readers/LaTeX/Parsing.hs |  2 ++
 test/command/7003.md                     | 37 ++++++++++++++++++++++++
 3 files changed, 65 insertions(+), 6 deletions(-)
 create mode 100644 test/command/7003.md

diff --git a/src/Text/Pandoc/Readers/LaTeX.hs b/src/Text/Pandoc/Readers/LaTeX.hs
index d9fe0f502..14a41a911 100644
--- a/src/Text/Pandoc/Readers/LaTeX.hs
+++ b/src/Text/Pandoc/Readers/LaTeX.hs
@@ -1219,6 +1219,7 @@ preamble :: PandocMonad m => LP m Blocks
 preamble = mconcat <$> many preambleBlock
   where preambleBlock =  (mempty <$ spaces1)
                      <|> macroDef (rawBlock "latex")
+                     <|> filecontents
                      <|> (mempty <$ blockCommand)
                      <|> (mempty <$ braced)
                      <|> (do notFollowedBy (begin_ "document")
@@ -1272,6 +1273,16 @@ include name = do
   mapM_ (insertIncluded defaultExt) fs
   return mempty
 
+readFileFromTexinputs :: PandocMonad m => FilePath -> LP m (Maybe Text)
+readFileFromTexinputs fp = do
+  fileContentsMap <- sFileContents <$> getState
+  case M.lookup (T.pack fp) fileContentsMap of
+    Just t -> return (Just t)
+    Nothing -> do
+      dirs <- map T.unpack . splitTextBy (==':') . fromMaybe "."
+               <$> lookupEnv "TEXINPUTS"
+      readFileFromDirs dirs fp
+
 insertIncluded :: PandocMonad m
                => FilePath
                -> FilePath
@@ -1281,13 +1292,12 @@ insertIncluded defaultExtension f' = do
                 ".tex" -> f'
                 ".sty" -> f'
                 _      -> addExtension f' defaultExtension
-  dirs <- map T.unpack . splitTextBy (==':') . fromMaybe "." <$> lookupEnv "TEXINPUTS"
   pos <- getPosition
   containers <- getIncludeFiles <$> getState
   when (T.pack f `elem` containers) $
     throwError $ PandocParseError $ T.pack $ "Include file loop at " ++ show pos
   updateState $ addIncludeFile $ T.pack f
-  mbcontents <- readFileFromDirs dirs f
+  mbcontents <- readFileFromTexinputs f
   contents <- case mbcontents of
                    Just s -> return s
                    Nothing -> do
@@ -1695,6 +1705,18 @@ environments = M.fromList
    , ("iftoggle", try $ ifToggle >> block)
    ]
 
+filecontents :: PandocMonad m => LP m Blocks
+filecontents = try $ do
+  controlSeq "begin"
+  name <- untokenize <$> braced
+  guard $ name == "filecontents" || name == "filecontents*"
+  skipopts
+  fp <- untokenize <$> braced
+  txt <- verbEnv name
+  updateState $ \st ->
+    st{ sFileContents = M.insert fp txt (sFileContents st) }
+  return mempty
+
 theoremstyle :: PandocMonad m => LP m Blocks
 theoremstyle = do
   stylename <- untokenize <$> braced
@@ -1894,8 +1916,7 @@ inputMinted = do
   pos <- getPosition
   attr <- mintedAttr
   f <- T.filter (/='"') . untokenize <$> braced
-  dirs <- map T.unpack . splitTextBy (==':') . fromMaybe "." <$> lookupEnv "TEXINPUTS"
-  mbCode <- readFileFromDirs dirs (T.unpack f)
+  mbCode <- readFileFromTexinputs (T.unpack f)
   rawcode <- case mbCode of
                   Just s -> return s
                   Nothing -> do
@@ -1981,8 +2002,7 @@ inputListing = do
   pos <- getPosition
   options <- option [] keyvals
   f <- T.filter (/='"') . untokenize <$> braced
-  dirs <- map T.unpack . splitTextBy (==':') . fromMaybe "." <$> lookupEnv "TEXINPUTS"
-  mbCode <- readFileFromDirs dirs (T.unpack f)
+  mbCode <- readFileFromTexinputs (T.unpack f)
   codeLines <- case mbCode of
                       Just s -> return $ T.lines s
                       Nothing -> do
diff --git a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
index 563d32883..e92ed387c 100644
--- a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
+++ b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
@@ -152,6 +152,7 @@ data LaTeXState = LaTeXState{ sOptions       :: ReaderOptions
                             , sHasChapters   :: Bool
                             , sToggles       :: M.Map Text Bool
                             , sExpanded      :: Bool
+                            , sFileContents  :: M.Map Text Text
                             }
      deriving Show
 
@@ -177,6 +178,7 @@ defaultLaTeXState = LaTeXState{ sOptions       = def
                               , sHasChapters   = False
                               , sToggles       = M.empty
                               , sExpanded      = False
+                              , sFileContents  = M.empty
                               }
 
 instance PandocMonad m => HasQuoteContext LaTeXState m where
diff --git a/test/command/7003.md b/test/command/7003.md
new file mode 100644
index 000000000..1f6275943
--- /dev/null
+++ b/test/command/7003.md
@@ -0,0 +1,37 @@
+```
+% pandoc -f latex -t native
+\documentclass{article}
+\usepackage{listings}
+
+\lstset{basicstyle=\ttfamily}
+
+\begin{filecontents*}[overwrite]{example.tex}
+\documentclass{article}
+\begin{document}
+\section{Bar}
+This a Bar section
+\end{document}
+\end{filecontents*}
+
+\begin{document}
+
+\section{With lstlisting environment}
+
+\begin{lstlisting}
+\documentclass{article}
+\begin{document}
+\section{Foo}
+This a Foo section
+\end{document}
+\end{lstlisting}
+
+\section{With lstinputlisting command}
+
+\lstinputlisting{example.tex}
+\end{document}
+^D
+[Header 1 ("with-lstlisting-environment",[],[]) [Str "With",Space,Str "lstlisting",Space,Str "environment"]
+,CodeBlock ("",[],[]) "\\documentclass{article}\n\\begin{document}\n\\section{Foo}\nThis a Foo section\n\\end{document}"
+,Header 1 ("with-lstinputlisting-command",[],[]) [Str "With",Space,Str "lstinputlisting",Space,Str "command"]
+,CodeBlock ("",["latex"],[]) "\\documentclass{article}\n\\begin{document}\n\\section{Bar}\nThis a Bar section\n\\end{document}"]
+```