Made some changes

src/MdToHTML.hs

@@ -33,7 +33,7 @@ data MdToken
   | Blockquote [MdToken]
   | UnordList [MdToken]
   | OrdList [MdToken]
-  | Code String
+  | Code MdToken
   | Codeblock String
   | Link MdToken URL
   | Image MdToken ImgPath
@@ -51,11 +51,11 @@ instance Show MdToken where
   show (Line tokens) = concatMap show tokens
   show Linebreak = "<br>"
   show SingleNewline = " "
-  show HorizontalRule = "---------"
+  show HorizontalRule = "<hr>"
   show (Blockquote tokens) = "<blockquote>" ++ concatMap show tokens ++ "</blockquote>"
   show (UnordList tokens) = "<ul>" ++ concatMap (prepend "<li>" . append "</li>" . show) tokens ++ "</ul>"
   show (OrdList tokens) = "<ol>" ++ concatMap (prepend "<li>" . append "</li>" . show) tokens ++ "</ol>"
-  show (Code code) = show code
+  show (Code code) = "<code>" ++ show code ++ "</code>"
   show (Codeblock code) = show code
   show (Link txt url) = "<a href=\"" ++ getUrl url ++ "\">" ++ show txt ++ "</a>"
   show (Image txt imgPath) = "<img src=" ++ getPath imgPath ++ ">" ++ show txt ++ "</img>"
@@ -88,7 +88,9 @@ leftmostLongestParse parser input =
         Nothing -> (mempty, mempty)
         Just x -> x
 
-specialChars = "\\#*_[\n"
+specialChars = "\\#*_[\n`"
+
+escapableChars = '~' : specialChars
 
 -- Makes a parser greedy. Instead of returning all possible parses, only the longest one is returned.
 greedyParse :: ReadP a -> ReadP [a]
@@ -118,6 +120,16 @@ fallthroughParser :: [ReadP a] -> ReadP a
 fallthroughParser [x] = x
 fallthroughParser (x : xs) = x <++ fallthroughParser xs
 
+myMany :: (Monoid a) => ReadP a -> ReadP [a]
+myMany p = do
+  remaining <- look
+  case remaining of
+    [] -> return []
+    _ -> return [] +++ myMany1 p
+
+myMany1 :: (Monoid a) => ReadP a -> ReadP [a]
+myMany1 p = liftM2 (:) p (myMany p)
+
 -- ---------------
 
 -- Parse a markdown header, denoted by 1-6 #'s followed by some text, followed by EOL.
@@ -141,19 +153,25 @@ parseBold = parseBoldWith "**" <|> parseBoldWith "__"
   where
     parseBoldWith delim = do
       string delim
-      inside <- greedyParse1 parseLineToken
+      inside <- myMany1 parseLineToken
       string delim
       return (Bold (Line inside))
 
 -- Parse italic text
 parseItalic :: ReadP MdToken
-parseItalic = parseItalicWith "*" <|> parseItalicWith "_"
+parseItalic = parseItalicWith '*' <|> parseItalicWith '_'
   where
     parseItalicWith delim = do
-      string delim
+      exactlyOnce delim
-      inside <- greedyParse1 parseLineToken
+      inside <- myMany1 parseLineToken
-      string delim
+      exactlyOnce delim
       return (Italic (Line inside))
+    exactlyOnce ch = do
+      char ch
+      remaining <- look
+      case remaining of
+        [] -> return ch
+        x : xs -> if x == ch then pfail else return ch
 
 -- Parse strikethrough text
 parseStrikethrough :: ReadP MdToken
@@ -163,6 +181,14 @@ parseStrikethrough = do
   string "~~"
   return (Strikethrough (Line inside))
 
+-- Parse code
+parseCode :: ReadP MdToken
+parseCode = do
+  string "`"
+  inside <- many1 get
+  string "`"
+  return (Code (Unit inside))
+
 -- Parse a link
 parseLink :: ReadP MdToken
 parseLink = do
@@ -188,27 +214,22 @@ parseSingleNewline = do
 parseEscapedChar :: ReadP MdToken
 parseEscapedChar = do
   char '\\'
-  escapedChar <- choice (map char specialChars) -- Parse any of the special chars.
+  escapedChar <- choice (map char escapableChars) -- Parse any of the special chars.
   return (Unit [escapedChar])
 
 -- Parse a character as a Unit.
 parseUnit :: ReadP MdToken
 parseUnit = do
-  text <- satisfy (`notElem` specialChars)
+  -- text <- satisfy (`notElem` specialChars)
+  text <- get
   return (Unit [text])
 
--- Parse a regular string as a Unit.
-parseString :: ReadP MdToken
-parseString = do
-  firstChar <- satisfy (/= '\n') -- Must parse at least one non-newline character here
-  text <- munch (`notElem` specialChars)
-  return (Unit (firstChar : text))
-
 lineParsers :: [ReadP MdToken]
 lineParsers =
   [ parseLinebreak,
     parseSingleNewline,
     parseEscapedChar,
+    parseCode,
     parseBold,
     parseItalic,
     parseStrikethrough,
@@ -220,6 +241,7 @@ listLineParsers :: [ReadP MdToken]
 listLineParsers =
   [ parseLinebreak,
     parseEscapedChar,
+    parseCode,
     parseBold,
     parseItalic,
     parseStrikethrough,
@@ -244,7 +266,7 @@ parseLine :: ReadP MdToken
 parseLine = do
   skipSpaces
   -- Fail if we have reached the end of the document.
-  parsed <- manyTill parseLineToken eof
+  parsed <- myMany1 parseLineToken
   return (Line parsed)
 
 -- Parse a paragraph, which is a 'Line' (can span multiple actual lines), separated by double-newlines.

src/MdToHtmlTest.hs

@@ -22,6 +22,7 @@ headerTests =
 boldTests =
   TestList
     [ check_equal "Should convert bold" "<p><b>Hello</b></p>" (convert "__Hello__"),
+      check_equal " Should not convert incomplete bold" "<p>**Hello</p>" (convert "**Hello"),
       check_equal "Should convert italic" "<p><i>Hello</i></p>" (convert "_Hello_"),
       check_equal "Should convert bold and italic in a sentence" "<p>It <i>is</i> a <b>wonderful</b> day</p>" (convert "It _is_ a __wonderful__ day"),
       check_equal "Should convert nested bold and italic" "<p><b>Bold then <i>Italic</i></b></p>" (convert "**Bold then *Italic***"),
@@ -93,6 +94,13 @@ orderedListTests =
       check_equal "Unordered list in ordered list" "<ol><li>Item 1</li><li>Item 2<ul><li>Item 1</li><li>Item 2</li></ul></li><li>Item 3</li></ol>" (convert "1. Item 1\n2. Item 2\n    - Item 1\n    * Item 2\n4. Item 3")
     ]
 
+codeTests =
+  TestList
+    [ check_equal "Code by itself" "<p><code>Hello world!</code></p>" (convert "`Hello world!`"),
+      check_equal "Code in a paragraph" "<p>The following <code>text</code> is code</p>" (convert "The following `text` is code"),
+      check_equal "Code across paragraphs (shouldn't work" "<p>`Incomplete</p><p>Code`</p>" (convert "`Incomplete\n\nCode`")
+    ]
+
 integrationTests =
   TestList
     [ check_equal "Integration 1" "<h1>Sample Markdown</h1><p>This is some basic, sample markdown.</p><h2><b>Second</b> <i>Heading</i></h2>" (convert "# Sample Markdown\n\n This is some basic, sample markdown.\n\n  ## __Second__ _Heading_"),
@@ -127,6 +135,7 @@ tests =
       blockquoteTests,
       unorderedListTests,
       orderedListTests,
+      codeTests,
       integrationTests
     ]