Adjusted others, labeled link

src/Lexer.hs

@@ -7,12 +7,11 @@ module Lexer (
 ) where
 
 import Control.Monad (mfilter, void)
-import Data.Char (isAlphaNum, isPrint)
 import Data.Functor (($>))
 import Data.Text (Text)
 import Data.Text qualified as Text
-import Debug.Trace (traceM)
 import GHC.Stack (HasCallStack)
+import GHC.Unicode (isControl, isPrint, isSpace)
 import ParserMonad (Parser, initialParserState)
 import Text.Parsec
 import Text.Parsec qualified as Parsec
@@ -22,20 +21,34 @@ type LocatedToken = (SourcePos, Token)
 
 type Lexer = Parser [LocatedToken]
 
+data Level
+  = One
+  | Two
+  | Three
+  | Four
+  | Five
+  | Six
+  deriving (Eq, Show)
+
 data Token
   = Token Text
   | Anchor
-  | AngleOpen
-  | AngleClose
   | BirdTrack
   | BoldOpen
   | BoldClose
+  | Escape
   | EmphasisOpen
   | EmphasisClose
+  | Header Level
   | MonospaceOpen
   | MonospaceClose
   | Newline
-  | Escape
+  | LabeledLinkOpen
+  | LabeledLinkClose
+  | ParenOpen
+  | ParenClose
+  | BracketOpen
+  | BracketClose
   | MathsParenOpen
   | MathsParenClose
   | MathsBracketOpen
@@ -62,25 +75,18 @@ lexText = go
               <$> [ mathsBracket
                   , mathsParens
                   , escape -- maths go before escape to avoid mismatch
+                  , headers
                   , newlineToken
                   , spaceToken
+                  , labeledLink
                   , quotes
                   , textElement
-                  , identifier
                   , birdTrack
                   , other
                   ]
         rest <- go
         pure (toks <> rest)
 
-match :: Parser a -> Parser (Text, a)
-match p = do
-  input <- getInput
-  result <- p
-  input' <- getInput
-  let !consumed = Text.take (Text.length input - Text.length input') input
-  pure (consumed, result)
-
 -- Tokens
 
 textElement :: Parser [LocatedToken]
@@ -90,26 +96,39 @@ textElement =
       <$> [ emphasis
           , bold
           , monospace
-          , angles
+          ]
+
+headers :: Parser [LocatedToken]
+headers =
+  choice $
+    Parsec.try
+      <$> [ header1
+          , header2
+          , header3
+          , header4
+          , header5
+          , header6
           ]
 
 delimitedMaybe :: Parser a -> Parser a -> Token -> Maybe Token -> Parser [LocatedToken]
-delimitedMaybe op cl ot ct = do
+delimitedMaybe openMark closeMark openToken closeToken = do
   openPos <- getPosition
-  void op -- opening
+  void openMark
   tokenPos <- getPosition
-  content <- any'
+  content <- anyUntil closeMark
   closePos <- getPosition
-  void cl
-  let openTok :: LocatedToken = (openPos, ot)
+  void closeMark
+
+  let openTok :: LocatedToken = (openPos, openToken)
       res :: LocatedToken = (tokenPos, Token content)
-      closeToks :: [LocatedToken] = case ct of
+      closeToks :: [LocatedToken] = case closeToken of
         Just close -> [(closePos, close)]
         Nothing -> []
 
   pure $ [openTok, res] <> closeToks
- where
-  any' = Text.pack <$> manyTill anyChar (lookAhead cl)
+
+anyUntil :: Parser a -> Parser Text
+anyUntil p = Text.pack <$> manyTill anyChar (lookAhead p)
 
 delimited :: Parser a -> Parser a -> Token -> Token -> Parser [LocatedToken]
 delimited a b c d = delimitedMaybe a b c (Just d)
@@ -120,6 +139,51 @@ delimitedSymmetric s t1 t2 = delimited s s t1 t2
 eol :: Parser ()
 eol = void "\n" <|> Parsec.eof
 
+header1 :: Lexer
+header1 = delimitedMaybe (void $ "= ") eol (Header One) Nothing
+
+header2 :: Lexer
+header2 = delimitedMaybe (void $ "== ") eol (Header Two) Nothing
+
+header3 :: Lexer
+header3 = delimitedMaybe (void $ "=== ") eol (Header Three) Nothing
+
+header4 :: Lexer
+header4 = delimitedMaybe (void $ "==== ") eol (Header Four) Nothing
+
+header5 :: Lexer
+header5 = delimitedMaybe (void $ "===== ") eol (Header Five) Nothing
+
+header6 :: Lexer
+header6 = delimitedMaybe (void $ "====== ") eol (Header Six) Nothing
+
+labeledLink :: Lexer
+labeledLink = do
+  pos <- getPosition
+  void $ string "<"
+  pos1 <- getPosition
+  void $ string "["
+  pos2 <- getPosition
+  text <- anyUntil $ Text.pack <$> string "]"
+  pos3 <- getPosition
+  void $ "]"
+  pos4 <- getPosition
+  void $ "("
+  pos5 <- getPosition
+  link <- anyUntil $ Text.pack <$> string ")"
+  pos6 <- getPosition
+  void $ ")"
+
+  pure $
+    [ (pos, LabeledLinkOpen)
+    , (pos1, BracketOpen)
+    , (pos2, Token text)
+    , (pos3, BracketClose)
+    , (pos4, ParenOpen)
+    , (pos5, Token link)
+    , (pos6, ParenClose)
+    ]
+
 mathsBracket :: Lexer
 mathsBracket = delimited (void $ "\\[") (void "\\]") MathsBracketOpen MathsBracketClose
 
@@ -144,20 +208,13 @@ bold = delimitedSymmetric "__" BoldOpen BoldClose
 monospace :: Lexer
 monospace = delimitedSymmetric "@" MonospaceOpen MonospaceClose
 
--- parens :: Parser [LocatedToken]
--- parens = delimited "(" ")" ParenOpen ParenClose
-
--- brackets :: Lexer
--- brackets = delimited "[" "]" ParenOpen ParenClose
-
-angles :: Parser [LocatedToken]
-angles = delimited "<" ">" AngleOpen AngleClose
-
 other :: Lexer
 other = do
   pos <- getPosition
-  c <- takeWhile1_ isPrint
+  c <- takeWhile1_ isAlphaNum
   pure . pure $ (pos, Token c)
+ where
+  isAlphaNum c = isPrint c && not (isControl c) && not (isSpace c)
 
 spaceToken :: Lexer
 spaceToken = do
@@ -171,12 +228,6 @@ newlineToken = do
   _ <- newline
   pure . pure $ (pos, Newline)
 
-identifier :: Lexer
-identifier = do
-  pos <- getPosition
-  txt <- takeWhile1_ isAlphaNum
-  pure . pure $ (pos, Token txt)
-
 -------
 -- Helpers
 -------

test/Spec.hs

@@ -23,6 +23,7 @@ main = hspec $ do
       it "bare string" someString
       it "emphasis" emphatic
       it "monospace" monospace
+      it "labeled link" labeledLink
       it "bird tracks" birdTracks
       it "quotes" quotes
       it "ignores nesting" ignoreNesting
@@ -37,6 +38,20 @@ main = hspec $ do
 -- Tests
 ------------
 
+labeledLink :: Expectation
+labeledLink =
+  "<[link here](http://to.here) label>"
+    `shouldLexTo` [ (1, 1, LabeledLinkOpen)
+                  , (1, 2, BracketOpen)
+                  , (1, 3, Token "link here")
+                  , (1, 12, BracketClose)
+                  , (1, 13, ParenOpen)
+                  , (1, 14, Token "http://to.here")
+                  , (1, 28, ParenClose)
+                  , (1, 29, Space)
+                  , (1, 30, Token "label>")
+                  ]
+
 maths :: IO ()
 maths = do
   "\\[some math\\]"
@@ -60,8 +75,7 @@ escaping =
 unicode :: Expectation
 unicode =
   "ドラゴンクエストの冒険者🐉"
-    `shouldLexTo` [ (1, 1, Token "ドラゴンクエストの冒険者")
-                  , (1, 13, Token "🐉")
+    `shouldLexTo` [ (1, 1, Token "ドラゴンクエストの冒険者🐉")
                   ]
 
 ignoreNesting :: Expectation