LaTeX reader: handle includes without surrounding blanklines.

In addition, `\input` can now be used in an inline context,
e.g. to provide part of a paragraph, as it can in LaTeX.

Closes #4553.

pandoc.cabal

@@ -192,6 +192,7 @@ extra-source-files:
                  test/command/inkscape-cube.svg
                  test/command/sub-file-chapter-1.tex
                  test/command/sub-file-chapter-2.tex
+                 test/command/bar.tex
                  test/command/3510-subdoc.org
                  test/command/3510-export.latex
                  test/command/3510-src.hs

src/Text/Pandoc/Readers/LaTeX.hs

@@ -1642,6 +1642,8 @@ inlineCommands = M.union inlineLanguageCommands $ M.fromList
   , ("Rn", romanNumeralLower)
   -- babel
   , ("foreignlanguage", foreignlanguage)
+  -- include
+  , ("input", include "input")
   ]
 
 makeUppercase :: Inlines -> Inlines
@@ -1917,7 +1919,6 @@ end_ t = try (do
 preamble :: PandocMonad m => LP m Blocks
 preamble = mempty <$ many preambleBlock
   where preambleBlock =  spaces1
-                     <|> void include
                      <|> void macroDef
                      <|> void blockCommand
                      <|> void braced
@@ -1930,11 +1931,8 @@ paragraph = do
      then return mempty
      else return $ para x
 
-include :: PandocMonad m => LP m Blocks
-include = do
-  (Tok _ (CtrlSeq name) _) <-
-                    controlSeq "include" <|> controlSeq "input" <|>
-                    controlSeq "subfile" <|> controlSeq "usepackage"
+include :: (PandocMonad m, Monoid a) => Text -> LP m a
+include name = do
   skipMany opt
   fs <- (map (T.unpack . removeDoubleQuotes . T.strip) . T.splitOn "," .
          untokenize) <$> braced
@@ -2251,6 +2249,11 @@ blockCommands = M.fromList
    -- LaTeX colors
    , ("textcolor", coloredBlock "color")
    , ("colorbox", coloredBlock "background-color")
+   -- include
+   , ("include", include "include")
+   , ("input", include "input")
+   , ("subfile", include "subfile")
+   , ("usepackage", include "usepackage")
    ]
 
 
@@ -2689,7 +2692,6 @@ block :: PandocMonad m => LP m Blocks
 block = do
   res <- (mempty <$ spaces1)
     <|> environment
-    <|> include
     <|> macroDef
     <|> blockCommand
     <|> paragraph

test/command/4553.md

@@ -0,0 +1,15 @@
+```
+pandoc -f latex -t native
+foo \include{command/bar}
+^D
+[Para [Str "foo"]
+,Para [Emph [Str "hi",Space,Str "there"]]]
+```
+
+```
+pandoc -f latex -t native
+foo \input{command/bar}
+^D
+[Para [Str "foo",Space,Emph [Str "hi",Space,Str "there"]]]
+```
+

test/command/bar.tex

@@ -0,0 +1 @@
+\emph{hi there}