From 58a5683d1ce759f80ca7eb3b35663b717ae2abd5 Mon Sep 17 00:00:00 2001
From: Simon Hengel <sol@typeful.net>
Date: Sun, 2 Nov 2014 12:07:24 +0800
Subject: Allow markdown links at the beginning of a paragraph

---
 .../src/Documentation/Haddock/Parser.hs            | 20 ++++++++++++++--
 .../test/Documentation/Haddock/ParserSpec.hs       | 28 +++++++++++++++++++---
 2 files changed, 43 insertions(+), 5 deletions(-)

(limited to 'haddock-library')

diff --git a/haddock-library/src/Documentation/Haddock/Parser.hs b/haddock-library/src/Documentation/Haddock/Parser.hs
index e53597eb..f1fd5dda 100644
--- a/haddock-library/src/Documentation/Haddock/Parser.hs
+++ b/haddock-library/src/Documentation/Haddock/Parser.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ViewPatterns #-}
 -- |
 -- Module      :  Documentation.Haddock.Parser
 -- Copyright   :  (c) Mateusz Kowalczyk 2013-2014,
@@ -217,8 +218,9 @@ paragraph = examples <|> skipSpace *> (
   <|> codeblock
   <|> property
   <|> header
+  <|> textParagraphThatStartsWithMarkdownLink
   <|> definitionList
-  <|> textParagraph
+  <|> docParagraph <$> textParagraph
   )
 
 -- | Headers inside the comment denoted with @=@ signs, up to 6 levels
@@ -238,7 +240,21 @@ header = do
   return $ DocHeader (Header (length delim) line) `docAppend` rest
 
 textParagraph :: Parser (DocH mod Identifier)
-textParagraph = docParagraph . parseString . intercalate "\n" <$> many1 nonEmptyLine
+textParagraph = parseString . intercalate "\n" <$> many1 nonEmptyLine
+
+textParagraphThatStartsWithMarkdownLink :: Parser (DocH mod Identifier)
+textParagraphThatStartsWithMarkdownLink = docParagraph <$> (docAppend <$> markdownLink <*> optionalTextParagraph)
+  where
+    optionalTextParagraph :: Parser (DocH mod Identifier)
+    optionalTextParagraph = (docAppend <$> whitespace <*> textParagraph) <|> pure DocEmpty
+
+    whitespace :: Parser (DocH mod a)
+    whitespace = DocString <$> (f <$> takeHorizontalSpace <*> optional "\n")
+      where
+        f :: BS.ByteString -> Maybe BS.ByteString -> String
+        f xs (fromMaybe "" -> x)
+          | BS.null (xs <> x) = ""
+          | otherwise = " "
 
 -- | Parses unordered (bullet) lists.
 unorderedList :: Parser (DocH mod Identifier)
diff --git a/haddock-library/test/Documentation/Haddock/ParserSpec.hs b/haddock-library/test/Documentation/Haddock/ParserSpec.hs
index cb417cf6..6d152ee2 100644
--- a/haddock-library/test/Documentation/Haddock/ParserSpec.hs
+++ b/haddock-library/test/Documentation/Haddock/ParserSpec.hs
@@ -28,6 +28,9 @@ parseParas = Parse.toRegular . Parse.parseParas
 parseString :: String -> Doc String
 parseString = Parse.toRegular . Parse.parseString
 
+hyperlink :: String -> Maybe String -> Doc String
+hyperlink url = DocHyperlink . Hyperlink url
+
 main :: IO ()
 main = hspec spec
 
@@ -83,9 +86,6 @@ spec = do
           "don't use apostrophe's in the wrong place's"
 
     context "when parsing URLs" $ do
-      let hyperlink :: String -> Maybe String -> Doc String
-          hyperlink url = DocHyperlink . Hyperlink url
-
       it "parses a URL" $ do
         "<http://example.com/>" `shouldParseTo` hyperlink "http://example.com/" Nothing
 
@@ -387,6 +387,28 @@ spec = do
         it "turns it into a code block" $ do
           "@foo@" `shouldParseTo` DocCodeBlock "foo"
 
+      context "when a paragraph starts with a markdown link" $ do
+        it "correctly parses it as a text paragraph (not a definition list)" $ do
+          "[label](url)" `shouldParseTo`
+            DocParagraph (hyperlink "url" "label")
+
+        it "can be followed by an other paragraph" $ do
+          "[label](url)\n\nfoobar" `shouldParseTo`
+            DocParagraph (hyperlink "url" "label") <> DocParagraph "foobar"
+
+        context "when paragraph contains additional text" $ do
+          it "accepts more text after the link" $ do
+            "[label](url) foo bar baz" `shouldParseTo`
+              DocParagraph (hyperlink "url" "label" <> " foo bar baz")
+
+          it "accepts a newline right after the markdown link" $ do
+            "[label](url)\nfoo bar baz" `shouldParseTo`
+              DocParagraph (hyperlink "url" "label" <> " foo bar baz")
+
+          it "can be followed by an other paragraph" $ do
+            "[label](url)foo\n\nbar" `shouldParseTo`
+              DocParagraph (hyperlink "url" "label" <> "foo") <> DocParagraph "bar"
+
     context "when parsing birdtracks" $ do
       it "parses them as a code block" $ do
         unlines [
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