RST writer: fix figure handling.

This fixes a number of regressions from pandoc 2.x.

Properly handle caption, alt attribute in figures.

No longer treat a paragraph with a single image in it as a figure
(we have a dedicated Figure element now).

Closes #8930, closes #8871.

src/Text/Pandoc/Writers/RST.hs

@@ -262,21 +262,6 @@ blockToRST (Div (ident,classes,_kvs) bs) = do
            nest 3 contents $$
            blankline
 blockToRST (Plain inlines) = inlineListToRST inlines
-blockToRST (Para [Image attr txt (src, _)]) = do
-  description <- inlineListToRST txt
-  dims <- imageDimsToRST attr
-  let fig = "image:: " <> literal src
-      alt | null txt = empty
-          | otherwise = ":alt: " <> description
-      capt = empty
-      (_,cls,_) = attr
-      classes = case cls of
-                   []               -> empty
-                   ["align-right"]  -> ":align: right"
-                   ["align-left"]   -> ":align: left"
-                   ["align-center"] -> ":align: center"
-                   _ -> ":class: " <> literal (T.unwords cls)
-  return $ hang 3 ".. " (fig $$ alt $$ classes $$ dims $+$ capt) $$ blankline
 blockToRST (Para inlines)
   | LineBreak `elem` inlines =
       linesToLineBlock $ splitBy (==LineBreak) inlines
@@ -394,13 +379,21 @@ blockToRST (DefinitionList items) = do
   -- ensure that sublists have preceding blank line
   return $ blankline $$ vcat contents $$ blankline
 
-blockToRST (Figure (ident, classes, _) _ body) = do
+blockToRST (Figure (ident, classes, _kvs)
+             (Caption _ longCapt) body) = do
   let figure attr txt (src, tit) = do
         description <- inlineListToRST txt
+        capt <- blockListToRST longCapt
         dims <- imageDimsToRST attr
-        let fig = "figure:: " <> literal src
-            alt = ":alt: " <> if T.null tit then description else literal tit
-            capt = description
+        let fig = "figure::" <+> literal src
+            alt = if null txt
+                     then if T.null tit
+                              then empty
+                              else ":alt:" <+> literal tit
+                     else ":alt:" <+> description
+            name = if T.null ident
+                      then empty
+                      else "name:" <+> literal ident
             (_,cls,_) = attr
             align = case cls of
                       []               -> empty
@@ -408,7 +401,7 @@ blockToRST (Figure (ident, classes, _) _ body) = do
                       ["align-left"]   -> ":align: left"
                       ["align-center"] -> ":align: center"
                       _ -> ":figclass: " <> literal (T.unwords cls)
-        return $ hang 3 ".. " (fig $$ alt $$ align $$ dims $+$ capt)
+        return $ hang 3 ".. " (fig $$ name $$ alt $$ align $$ dims $+$ capt)
               $$ blankline
   case body of
     [Para  [Image attr txt tgt]] -> figure attr txt tgt

test/command/4420.md

@@ -2,8 +2,8 @@
 % pandoc -f native -t rst
 [Para [Image ("",["align-right"],[("width","100px")]) [Str "image"] ("foo.png","fig:test")]]
 ^D
-.. image:: foo.png
-   :alt: image
-   :align: right
+|image|
+
+.. |image| image:: foo.png
    :width: 100px
 ```

test/command/6948.md

@@ -4,9 +4,9 @@ as an independent image:
 % pandoc -f native -t rst
 [Para [Image ("",["align-center"],[]) [Str "https://pandoc.org/diagram.jpg"] ("https://pandoc.org/diagram.jpg","")]]
 ^D
-.. image:: https://pandoc.org/diagram.jpg
-   :alt: https://pandoc.org/diagram.jpg
-   :align: center
+|https://pandoc.org/diagram.jpg|
+
+.. |https://pandoc.org/diagram.jpg| image:: https://pandoc.org/diagram.jpg
 ```
 
 Here we just omit the center attribute as it's not valid:

test/command/figures-rst.md

@@ -6,5 +6,8 @@ Figure float with caption at the figure level.
 
 ^D
 .. figure:: foo.png
+   name: fig-id
    :alt: fig:
+
+   Caption
 ```

test/writer.rst

@@ -784,7 +784,7 @@ Images
 From “Voyage dans la Lune” by Georges Melies (1902):
 
 .. figure:: lalune.jpg
-   :alt: Voyage dans la Lune
+   :alt: lalune
 
    lalune