LaTeX reader: fix bugs in raw LaTeX parsing.

Fix `rawTeXParser`.  Make macro expansion in raw LaTeX depend on
the setting of the `latex_macros` extension.  Previously macros
were always expanded, even in raw TeX in markdown. In addition,
there was previously a bug that caused content to be garbled
in certain cases.

Closes #11253.

Handle `ifstrequal` at a lower level, like the other `if` commands.
See #11253.

3 files changed, 55 insertions, 29 deletions

diff --git a/src/Text/Pandoc/Readers/LaTeX.hs b/src/Text/Pandoc/Readers/LaTeX.hs
index 68714954c..c9d2d62d3 100644
--- a/src/Text/Pandoc/Readers/LaTeX.hs
+++ b/src/Text/Pandoc/Readers/LaTeX.hs
@@ -177,8 +177,7 @@ rawLaTeXInline = do
           (   rawLaTeXParser toks
               (mempty <$ (controlSeq "input" >> skipMany rawopt >> braced))
               inlines
-          <|> rawLaTeXParser toks (inlineEnvironment <|> inlineCommand')
-              inlines
+          <|> rawLaTeXParser toks inline inlines
           )
   finalbraces <- mconcat <$> many (try (string "{}")) -- see #5439
   return $ raw <> T.pack finalbraces
@@ -426,7 +425,6 @@ inlineCommands = M.unions
     , ("textcolor", coloredInline "color")
     , ("colorbox", coloredInline "background-color")
     -- etoolbox
-    , ("ifstrequal", ifstrequal)
     , ("newtoggle", braced >>= newToggle)
     , ("toggletrue", braced >>= setToggle True)
     , ("togglefalse", braced >>= setToggle False)
@@ -566,18 +564,6 @@ ifToggle = do
                   report $ UndefinedToggle name' pos
   return ()
 
-ifstrequal :: (PandocMonad m, Monoid a) => LP m a
-ifstrequal = do
-  str1 <- tok
-  str2 <- tok
-  ifequal <- withVerbatimMode braced
-  ifnotequal <- withVerbatimMode braced
-  TokStream _ ts <- getInput
-  if str1 == str2
-     then setInput $ TokStream False (ifequal ++ ts)
-     else setInput $ TokStream False (ifnotequal ++ ts)
-  return mempty
-
 coloredInline :: PandocMonad m => Text -> LP m Inlines
 coloredInline stylename = do
   skipopts
@@ -1026,7 +1012,6 @@ blockCommands = M.fromList
    -- alignment
    , ("raggedright", pure mempty)
    -- etoolbox
-   , ("ifstrequal", ifstrequal)
    , ("newtoggle", braced >>= newToggle)
    , ("toggletrue", braced >>= setToggle True)
    , ("togglefalse", braced >>= setToggle False)
diff --git a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
index f4d363380..bb76f6e18 100644
--- a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
+++ b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
@@ -301,14 +301,14 @@ rawLaTeXParser toks parser valParser = do
               Left _    -> mzero
               Right ((val, raw), st) -> do
                 updateState (updateMacros ((NonEmpty.head (sMacros st)) <>))
-                let skipTilPos stopPos = do
-                      anyChar
+                let rawChar = do
                       pos <- getPosition
-                      if pos >= stopPos
-                         then return ()
-                         else skipTilPos stopPos
-                skipTilPos endpos
-                let result = untokenize raw
+                      if pos >= endpos
+                         then mzero
+                         else anyChar
+                result <- (guardEnabled Ext_latex_macros
+                             >> (untokenize raw <$ skipMany rawChar))
+                          <|> T.pack <$> many rawChar
                 -- ensure we end with space if input did, see #4442
                 let result' =
                       case reverse toks' of
@@ -650,16 +650,30 @@ trySpecialMacro "xspace" ts = do
     Tok pos Word t : _
       | startsWithAlphaNum t -> return $ Tok pos Spaces " " : ts'
     _ -> return ts'
-trySpecialMacro "iftrue" ts = handleIf True ts
-trySpecialMacro "iffalse" ts = handleIf False ts
+trySpecialMacro "iftrue" ts = handleIf (ifParser True) ts
+trySpecialMacro "iffalse" ts = handleIf (ifParser False) ts
 trySpecialMacro "ifmmode" ts = do
   mathMode <- sMathMode <$> getState
-  handleIf mathMode ts
+  handleIf (ifParser mathMode) ts
+trySpecialMacro "ifstrequal" ts = do
+  handleIf ifStrequalParser ts
 trySpecialMacro _ _ = mzero
 
-handleIf :: PandocMonad m => Bool -> [Tok] -> LP m [Tok]
-handleIf b ts = do
-  res' <- lift $ runParserT (ifParser b) defaultLaTeXState "tokens"
+ifStrequalParser :: PandocMonad m => LP m [Tok]
+ifStrequalParser = do
+  str1 <- braced <|> count 1 anyTok
+  str2 <- braced <|> count 1 anyTok
+  ifequal <- withVerbatimMode (braced <|> count 1 anyTok)
+  ifnotequal <- withVerbatimMode (braced <|> count 1 anyTok)
+  TokStream _ ts <- getInput
+  return $
+    if untokenize str1 == untokenize str2
+       then ifequal ++ ts
+       else ifnotequal ++ ts
+
+handleIf :: PandocMonad m => LP m [Tok] -> [Tok] -> LP m [Tok]
+handleIf parser ts = do
+  res' <- lift $ runParserT parser defaultLaTeXState "tokens"
                $ TokStream False ts
   case res' of
     Left _ -> Prelude.fail "Could not parse conditional"
diff --git a/test/command/11253.md b/test/command/11253.md
new file mode 100644
index 000000000..cc10d8bc0
--- /dev/null
+++ b/test/command/11253.md
@@ -0,0 +1,27 @@
+```
+% pandoc -f markdown -t native
+\ifstrequal{hello}{hello}{TRUE}{FALSE}
+\ifstrequal{hello}{world}{TRUE}{FALSE}
+^D
+[ Para
+    [ RawInline (Format "tex") "TRUE"
+    , SoftBreak
+    , RawInline (Format "tex") "FALSE"
+    ]
+]
+```
+
+```
+% pandoc -f markdown-latex_macros -t native
+\ifstrequal{hello}{hello}{TRUE}{FALSE}
+\ifstrequal{hello}{world}{TRUE}{FALSE}
+^D
+[ Para
+    [ RawInline
+        (Format "tex") "\\ifstrequal{hello}{hello}{TRUE}{FALSE}"
+    , SoftBreak
+    , RawInline
+        (Format "tex") "\\ifstrequal{hello}{world}{TRUE}{FALSE}"
+    ]
+]
+```