HTML reader/writer: Better handling of <q> with cite attribute (#5837)

* HTML reader: Handle cite attribute for quotes.  If a `<q>` tag has a `cite` attribute, we interpret it as a Quoted element with an inner Span.  Closes #5798

* Refactor url canonicalization into a helper function

* Modify HTML writer to handle quote with cite.

[0]: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/q

5 files changed, 69 insertions, 25 deletions

diff --git a/src/Text/Pandoc/Readers/HTML.hs b/src/Text/Pandoc/Readers/HTML.hs
index b6f88d3a9..1ed61591b 100644
--- a/src/Text/Pandoc/Readers/HTML.hs
+++ b/src/Text/Pandoc/Readers/HTML.hs
@@ -684,19 +684,27 @@ pSelfClosing f g = do
   return open
 
 pQ :: PandocMonad m => TagParser m Inlines
-pQ = do
-  context <- asks quoteContext
-  let quoteType = case context of
-                       InDoubleQuote -> SingleQuote
-                       _             -> DoubleQuote
-  let innerQuoteContext = if quoteType == SingleQuote
-                             then InSingleQuote
-                             else InDoubleQuote
-  let constructor = case quoteType of
-                            SingleQuote -> B.singleQuoted
-                            DoubleQuote -> B.doubleQuoted
-  withQuoteContext innerQuoteContext $
-    pInlinesInTags "q" constructor
+pQ = choice $ map try [citedQuote, normalQuote]
+  where citedQuote = do
+          tag <- pSatisfy $ tagOpenLit "q" (any ((=="cite") . fst))
+
+          url <- canonicalizeUrl $ T.unpack $ fromAttrib "cite" tag
+          let uid = fromMaybe (T.unpack $ fromAttrib "name" tag) $
+                       maybeFromAttrib "id" tag
+          let cls = words $ T.unpack $ fromAttrib "class" tag
+
+          makeQuote $ B.spanWith (uid, cls, [("cite", escapeURI url)])
+        normalQuote = do
+          pSatisfy $ tagOpenLit "q" (const True)
+          makeQuote id
+        makeQuote wrapper = do
+          ctx <- asks quoteContext
+          let (constructor, innerContext) = case ctx of
+                        InDoubleQuote -> (B.singleQuoted, InSingleQuote)
+                        _             -> (B.doubleQuoted, InDoubleQuote)
+
+          content <- withQuoteContext innerContext (mconcat <$> manyTill inline (pCloses "q"))
+          return $ extractSpaces (constructor . wrapper) content
 
 pEmph :: PandocMonad m => TagParser m Inlines
 pEmph = pInlinesInTags "em" B.emph <|> pInlinesInTags "i" B.emph
@@ -757,21 +765,13 @@ pLink = try $ do
        Nothing   ->
          return $ extractSpaces (B.spanWith (uid, cls, [])) lab
        Just url' -> do
-         mbBaseHref <- baseHref <$> getState
-         let url = case (parseURIReference url', mbBaseHref) of
-                        (Just rel, Just bs) ->
-                          show (rel `nonStrictRelativeTo` bs)
-                        _                   -> url'
+         url <- canonicalizeUrl url'
          return $ extractSpaces (B.linkWith (uid, cls, []) (escapeURI url) title) lab
 
 pImage :: PandocMonad m => TagParser m Inlines
 pImage = do
   tag <- pSelfClosing (=="img") (isJust . lookup "src")
-  mbBaseHref <- baseHref <$> getState
-  let url' = T.unpack $ fromAttrib "src" tag
-  let url = case (parseURIReference url', mbBaseHref) of
-                 (Just rel, Just bs) -> show (rel `nonStrictRelativeTo` bs)
-                 _                   -> url'
+  url <- canonicalizeUrl $ T.unpack $ fromAttrib "src" tag
   let title = T.unpack $ fromAttrib "title" tag
   let alt = T.unpack $ fromAttrib "alt" tag
   let uid = T.unpack $ fromAttrib "id" tag
@@ -1292,6 +1292,17 @@ isSpace '\n' = True
 isSpace '\r' = True
 isSpace _    = False
 
+-- Utilities
+
+-- | Adjusts a url according to the document's base URL.
+canonicalizeUrl :: PandocMonad m => String -> TagParser m String
+canonicalizeUrl url = do
+  mbBaseHref <- baseHref <$> getState
+  return $ case (parseURIReference url, mbBaseHref) of
+                (Just rel, Just bs) -> show (rel `nonStrictRelativeTo` bs)
+                _                   -> url
+
+
 -- Instances
 
 instance HasMacros HTMLState where
diff --git a/src/Text/Pandoc/Writers/HTML.hs b/src/Text/Pandoc/Writers/HTML.hs
index a1a617829..08d8345b0 100644
--- a/src/Text/Pandoc/Writers/HTML.hs
+++ b/src/Text/Pandoc/Writers/HTML.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE CPP                 #-}
+{-# LANGUAGE LambdaCase          #-}
 {-# LANGUAGE MultiWayIf          #-}
 {-# LANGUAGE NoImplicitPrelude   #-}
 {-# LANGUAGE OverloadedStrings   #-}
@@ -1047,10 +1048,17 @@ inlineToHtml opts inline = do
                                               strToHtml "’")
                               DoubleQuote -> (strToHtml "“",
                                               strToHtml "”")
-                        in  if writerHtmlQTags opts
+
+                        in if writerHtmlQTags opts
                                then do
                                  modify $ \st -> st{ stQuotes = True }
-                                 H.q `fmap` inlineListToHtml opts lst
+                                 let (maybeAttr, lst') = case lst of
+                                      [Span attr@(_, _, kvs) cs]
+                                        | any ((=="cite") . fst) kvs
+                                          -> (Just attr, cs)
+                                      cs -> (Nothing, cs)
+                                 H.q `fmap` inlineListToHtml opts lst'
+                                   >>= maybe return (addAttrs opts) maybeAttr
                                else (\x -> leftQuote >> x >> rightQuote)
                                     `fmap` inlineListToHtml opts lst
     (Math t str) -> do
diff --git a/test/Tests/Writers/HTML.hs b/test/Tests/Writers/HTML.hs
index de8b1ef17..94549e0d8 100644
--- a/test/Tests/Writers/HTML.hs
+++ b/test/Tests/Writers/HTML.hs
@@ -13,6 +13,11 @@ import Text.Pandoc.Builder
 html :: (ToPandoc a) => a -> String
 html = unpack . purely (writeHtml4String def{ writerWrapText = WrapNone }) . toPandoc
 
+htmlQTags :: (ToPandoc a) => a -> String
+htmlQTags = unpack
+  . purely (writeHtml4String def{ writerWrapText = WrapNone, writerHtmlQTags = True })
+  . toPandoc
+
 {-
   "my test" =: X =?> Y
 
@@ -48,4 +53,16 @@ tests = [ testGroup "inline code"
             definitionList [(mempty, [para $ text "foo bar"])]
             =?> "<dl><dt></dt><dd><p>foo bar</p></dd></dl>"
           ]
+        , testGroup "quotes"
+          [ "quote with cite attribute (without q-tags)" =:
+            doubleQuoted (spanWith ("", [], [("cite", "http://example.org")]) (str "examples"))
+            =?> "“<span cite=\"http://example.org\">examples</span>”"
+          , tQ "quote with cite attribute (with q-tags)" $
+            doubleQuoted (spanWith ("", [], [("cite", "http://example.org")]) (str "examples"))
+            =?> "<q cite=\"http://example.org\">examples</q>"
+          ]
         ]
+        where
+          tQ :: (ToString a, ToPandoc a)
+               => String -> (a, String) -> TestTree
+          tQ = test htmlQTags
diff --git a/test/html-reader.html b/test/html-reader.html
index a2bca5d2c..ae937af82 100644
--- a/test/html-reader.html
+++ b/test/html-reader.html
@@ -81,6 +81,10 @@ span.pandocNoteMarker { }
 </blockquote>
 <p>And a following paragraph.</p>
 <hr />
+<h1>Inline quotes</h1>
+<p>Normal text but then a <q cite="https://www.imdb.com/title/tt0062622/quotes/qt0396921">inline quote</q>.</p>
+<p><q>Missing a cite attribute means its just normal text</q></p>
+<hr />
 <h1>Code Blocks</h1>
 <p>Code:</p>
 <pre><code>---- (should be four hyphens)
diff --git a/test/html-reader.native b/test/html-reader.native
index acd0087ef..5643fb73f 100644
--- a/test/html-reader.native
+++ b/test/html-reader.native
@@ -51,6 +51,10 @@ Pandoc (Meta {unMeta = fromList [("generator",MetaInlines [Str "pandoc"]),("titl
   [Para [Str "Don't",Space,Str "quote",Space,Str "me."]]]
 ,Para [Str "And",Space,Str "a",Space,Str "following",Space,Str "paragraph."]
 ,HorizontalRule
+,Header 1 ("inline-quotes",[],[]) [Str "Inline",Space,Str "quotes"]
+,Para [Str "Normal",Space,Str "text",Space,Str "but",Space,Str "then",Space,Str "a",Space,Quoted DoubleQuote [Span ("",[],[("cite","https://www.imdb.com/title/tt0062622/quotes/qt0396921")]) [Str "inline",Space,Str "quote"]],Str "."]
+,Para [Quoted DoubleQuote [Str "Missing",Space,Str "a",Space,Str "cite",Space,Str "attribute",Space,Str "means",Space,Str "its",Space,Str "just",Space,Str "normal",Space,Str "text"]]
+,HorizontalRule
 ,Header 1 ("code-blocks",[],[]) [Str "Code",Space,Str "Blocks"]
 ,Para [Str "Code:"]
 ,CodeBlock ("",[],[]) "---- (should be four hyphens)\n\nsub status {\n    print \"working\";\n}\n\nthis code block is indented by one tab"