Allow URI as cite key.uri-cite-key

This affects Markdown and Org with `+citations`.

Note that we had to constrain the type of the `citeKey` parser
in `Text.Pandoc.Parsing` to accept `[Char]` instead of arbitrary
streams.

3 files changed, 25 insertions, 10 deletions

diff --git a/MANUAL.txt b/MANUAL.txt
index 934556c8a..53bab3265 100644
--- a/MANUAL.txt
+++ b/MANUAL.txt
@@ -3558,7 +3558,8 @@ Each citation must have a key, composed of '@' + the citation
 identifier from the database, and may optionally have a prefix,
 a locator, and a suffix.  The citation key must begin with a letter, digit,
 or `_`, and may contain alphanumerics, `_`, and internal punctuation
-characters (`:.#$%&-+?<>~/`).  Here are some examples:
+characters (`:.#$%&-+?<>~/`).  Alternatively, a URI may be used.
+Here are some examples:
 
     Blah blah [see @doe99, pp. 33-35; also @smith04, chap. 1].
 
@@ -3566,6 +3567,8 @@ characters (`:.#$%&-+?<>~/`).  Here are some examples:
 
     Blah blah [@smith04; @doe99].
 
+    Blah blah [@https://example.com/refs?number=30553, chap. 1].
+
 `pandoc-citeproc` detects locator terms in the [CSL locale files].
 Either abbreviated or unabbreviated forms are accepted. In the `en-US`
 locale, locator terms can be written in either singular or plural forms,
diff --git a/src/Text/Pandoc/Parsing.hs b/src/Text/Pandoc/Parsing.hs
index c86f6718a..9475081c4 100644
--- a/src/Text/Pandoc/Parsing.hs
+++ b/src/Text/Pandoc/Parsing.hs
@@ -548,7 +548,7 @@ emailAddress = try $ toResult <$> mailbox <*> (char '@' *> domain)
        sepby1 p sep      = (:) <$> p <*> many (try $ sep >> p)
 
 
-uriScheme :: Stream s m Char => ParserT s st m String
+uriScheme :: (Monad m, Stream s m Char) => ParserT s st m String
 uriScheme = oneOfStringsCI (Set.toList schemes)
 
 -- | Parses a URI. Returns pair of original and URI-escaped version.
@@ -1388,18 +1388,20 @@ nested p = do
   updateState $ \st -> st{ stateMaxNestingLevel = nestlevel }
   return res
 
-citeKey :: (Stream s m Char, HasLastStrPosition st)
-        => ParserT s st m (Bool, String)
+citeKey :: (Monad m, HasLastStrPosition st)
+        => ParserT [Char] st m (Bool, String)
 citeKey = try $ do
   guard =<< notAfterString
   suppress_author <- option False (char '-' *> return True)
   char '@'
-  firstChar <- alphaNum <|> char '_' <|> char '*' -- @* for wildcard in nocite
-  let regchar = satisfy (\c -> isAlphaNum c || c == '_')
-  let internal p = try $ p <* lookAhead regchar
-  rest <- many $ regchar <|> internal (oneOf ":.#$%&-+?<>~/") <|>
-                 try (oneOf ":/" <* lookAhead (char '/'))
-  let key = firstChar:rest
+  key <- (fst <$> uri) <|>
+          do firstChar <- alphaNum <|> char '_' <|> char '*'
+             -- @* for wildcard in nocite
+             let regchar = satisfy (\c -> isAlphaNum c || c == '_')
+             let internal p = try $ p <* lookAhead regchar
+             rest <- many $ regchar <|> internal (oneOf ":.#$%&-+?<>~/") <|>
+                            try (oneOf ":/" <* lookAhead (char '/'))
+             return (firstChar:rest)
   return (suppress_author, key)
 
 
diff --git a/test/Tests/Readers/Markdown.hs b/test/Tests/Readers/Markdown.hs
index 1cd32b87d..393b0baa4 100644
--- a/test/Tests/Readers/Markdown.hs
+++ b/test/Tests/Readers/Markdown.hs
@@ -417,6 +417,16 @@ tests = [ testGroup "inline code"
                         , citationHash    = 0
                         }
                 ] "@1657:huyghens")
+          , "key is URI" =:
+            "@https://example.com/cgi-bin/ubb/forumdisplay.cgi?action=topics&number=527" =?> para (cite [
+                Citation{ citationId      = "https://example.com/cgi-bin/ubb/forumdisplay.cgi?action=topics&number=527"
+                        , citationPrefix  = []
+                        , citationSuffix  = []
+                        , citationMode    = AuthorInText
+                        , citationNoteNum = 0
+                        , citationHash    = 0
+                        }
+                ] "@https://example.com/cgi-bin/ubb/forumdisplay.cgi?action=topics&number=527")
           ]
         , let citation = cite [Citation "cita" [] [] AuthorInText 0 0] (str "@cita")
           in testGroup "footnote/link following citation" -- issue #2083