LaTeX reader: support column specs like `*{2}{r}`.

This is equivalent to `rr`.  We now expand it like a macro.

Closes #4056.

2 files changed, 27 insertions, 4 deletions

diff --git a/src/Text/Pandoc/Readers/LaTeX.hs b/src/Text/Pandoc/Readers/LaTeX.hs
index 708980f1d..28c8fd736 100644
--- a/src/Text/Pandoc/Readers/LaTeX.hs
+++ b/src/Text/Pandoc/Readers/LaTeX.hs
@@ -2406,8 +2406,7 @@ parseAligns = try $ do
         case safeRead ds of
               Just w  -> return w
               Nothing -> return 0.0
-  let alignSpec = try $ do
-        spaces
+  let alignSpec = do
         pref <- option [] alignPrefix
         spaces
         al <- alignChar
@@ -2418,10 +2417,21 @@ parseAligns = try $ do
         spaces
         suff <- option [] alignSuffix
         return (al, width, (pref, suff))
+  let starAlign = do -- *{2}{r} == rr, we just expand like a macro
+        symbol '*'
+        spaces
+        ds <- trim . toksToString <$> braced
+        spaces
+        spec <- braced
+        case safeRead ds of
+             Just n  -> do
+               getInput >>= setInput . (mconcat (replicate n spec) ++)
+             Nothing -> fail $ "Could not parse " ++ ds ++ " as number"
   bgroup
   spaces
   maybeBar
-  aligns' <- many (alignSpec <* maybeBar)
+  aligns' <- many $ try $ spaces >> optional starAlign >>
+                            (alignSpec <* maybeBar)
   spaces
   egroup
   spaces
diff --git a/test/command/4056.md b/test/command/4056.md
index be245a30d..eed4f6d6a 100644
--- a/test/command/4056.md
+++ b/test/command/4056.md
@@ -8,4 +8,17 @@
 [RawBlock (Format "latex") "\\parbox[t]{0.4\\textwidth}{\n\\begin{shaded}\n\\end{shaded}\n}"]
 ```
 
-
+```
+% pandoc -f latex -t native
+\begin{tabular}{l*{2}{r}}
+Blah & Foo & Bar \\
+\end{tabular}
+^D
+[Table [] [AlignLeft,AlignRight,AlignRight] [0.0,0.0,0.0]
+ [[]
+ ,[]
+ ,[]]
+ [[[Plain [Str "Blah"]]
+  ,[Plain [Str "Foo"]]
+  ,[Plain [Str "Bar"]]]]]
+```