Jira writer: use Span identifiers as anchors

Closes: tarleb/jira-wiki-markup#3.

src/Text/Pandoc/Writers/Jira.hs

@@ -292,7 +292,9 @@ quotedToJira qtype xs = do
 spanToJira :: PandocMonad m
            => Attr -> [Inline]
            -> JiraConverter m [Jira.Inline]
-spanToJira (_, _classes, _) = toJiraInlines
+spanToJira (ident, _classes, _attribs) inls = case ident of
+  "" -> toJiraInlines inls
+  _  -> (Jira.Anchor ident :) <$> toJiraInlines inls
 
 registerNotes :: PandocMonad m => [Block] -> JiraConverter m [Jira.Inline]
 registerNotes contents = do

test/Tests/Writers/Jira.hs

@@ -3,6 +3,7 @@ module Tests.Writers.Jira (tests) where
 
 import Data.Text (unpack)
 import Test.Tasty
+import Test.Tasty.HUnit (HasCallStack)
 import Tests.Helpers
 import Text.Pandoc
 import Text.Pandoc.Arbitrary ()
@@ -12,7 +13,7 @@ jira :: (ToPandoc a) => a -> String
 jira = unpack . purely (writeJira def) . toPandoc
 
 infix 4 =:
-(=:) :: (ToString a, ToPandoc a)
+(=:) :: (ToString a, ToPandoc a, HasCallStack)
      => String -> (a, String) -> TestTree
 (=:) = test jira
 
@@ -61,5 +62,11 @@ tests =
         linkWith ("", ["user-account"], []) "~johndoe" "" "~johndoe" =?>
         "[~johndoe]"
       ]
+
+    , testGroup "spans"
+      [ "id is used as anchor" =:
+        spanWith ("unicorn", [], []) (str "Unicorn") =?>
+        "{anchor:unicorn}Unicorn"
+      ]
     ]
   ]