Parse bold, italic and strikethrough in-order, instead of trying to find

the end, then parsing everything in the middle.

The current approach parses the opening bold (or italic), some text,
then the closing bold (or italic), instead of parsing the opening,
closing, then everything in between.

src/MdToHTML.hs

@@ -166,32 +166,31 @@ parseHeader = do
 
 -- Parse bold text
 parseBold :: ReadP MdToken
-parseBold = do
-  text <-
-    choice
-      [ between (string "__") (string "__") (many1 (lookaheadParse (/= "__"))),
-        between (string "**") (string "**") (many1 (lookaheadParse (/= "**")))
-      ]
-  let parsedText = fst $ leftmostLongestParse parseLine text
-  return (Bold parsedText)
+parseBold = parseBoldWith "**" <|> parseBoldWith "__"
+  where
+    parseBoldWith delim = do
+      string delim
+      inside <- greedyParse1 parseLineToken
+      string delim
+      return (Bold (Line inside))
 
 -- Parse italic text
 parseItalic :: ReadP MdToken
-parseItalic = do
-  text <-
-    choice
-      [ between (string "_") (string "_") (munch1 (/= '_')),
-        between (string "*") (string "*") (munch1 (/= '*'))
-      ]
-  let parsedText = fst $ leftmostLongestParse parseLine text
-  return (Italic parsedText)
+parseItalic = parseBoldWith "*" <|> parseBoldWith "_"
+  where
+    parseBoldWith delim = do
+      string delim
+      inside <- greedyParse1 parseLineToken
+      string delim
+      return (Italic (Line inside))
 
 -- Parse strikethrough text
 parseStrikethrough :: ReadP MdToken
 parseStrikethrough = do
-  text <- between (string "~~") (string "~~") (many1 (lookaheadParse (/= "~~")))
-  let parsedText = fst $ leftmostLongestParse parseLine text
-  return (Strikethrough parsedText)
+  string "~~"
+  inside <- many1 parseLineToken
+  string "~~"
+  return (Strikethrough (Line inside))
 
 -- Parse a link
 parseLink :: ReadP MdToken