Added expression eval; adjusted birdtrack, added sol combinator.

sp

@@ -0,0 +1,48 @@
+2025-09-28T19:31:53.102437Z | Info | haskell-language-server version: 2.11.0.0 (GHC: 9.10.2) (PATH: /Users/igor/.ghcup/hls/2.11.0.0/lib/haskell-language-server-2.11.0.0/bin/haskell-language-server-9.10.2)
+2025-09-28T19:31:53.103002Z | Info | Directory: /Users/igor/dev/haddock2
+2025-09-28T19:31:53.103169Z | Info | Logging heap statistics every 60.00s
+2025-09-28T19:31:53.107534Z | Info | Cradle path: src/Parser.hs
+2025-09-28T19:31:53.107609Z | Warning | No [cradle](https://github.com/mpickering/hie-bios#hie-bios) found for src/Parser.hs.
+Proceeding with [implicit cradle](https://hackage.haskell.org/package/implicit-hie).
+You should ignore this message, unless you see a 'Multi Cradle: No prefixes matched' error.
+2025-09-28T19:31:53.107865Z | Info | invoking build tool to determine build flags (this may take some time depending on the cache)
+2025-09-28T19:31:53.217226Z | Info | Load cabal cradle using single file
+2025-09-28T19:31:53.306920Z | Info | cabal --builddir=/Users/igor/.cache/hie-bios/dist-haddock2-46ec6b456aa9d4df12c3c8dec8c82e6e v2-repl --with-compiler /Users/igor/.cache/hie-bios/wrapper-b54f81dea4c0e6d1626911c526bc4e36 /Users/igor/dev/haddock2/src/Parser.hs
+  Environment Variables
+    HIE_BIOS_OUTPUT: /private/var/folders/9h/3j3xz6k52s95nrz7fkscvxph0000gs/T/HIE_BIOS_OUTPUT74985-0
+    HIE_BIOS_GHC: /Users/igor/.ghcup/bin/ghc
+    HIE_BIOS_GHC_ARGS: -B/Users/igor/.ghcup/ghc/9.10.2/lib/ghc-9.10.2/lib
+2025-09-28T19:31:54.614435Z | Info | Interface files cache directory: /Users/igor/.cache/ghcide/haddock2-0.1.0.0-inplace-haddock2-lib-94626af6e87fa2a1c5fe808fee1ff90470339b17
+2025-09-28T19:31:54.616421Z | Info | Making new HscEnv. In-place unit ids: [haddock2-0.1.0.0-inplace-haddock2-lib]
+2025-09-28T19:31:54.624755Z | Info | Cradle path: app/Main.hs
+2025-09-28T19:31:54.625170Z | Warning | No [cradle](https://github.com/mpickering/hie-bios#hie-bios) found for app/Main.hs.
+Proceeding with [implicit cradle](https://hackage.haskell.org/package/implicit-hie).
+You should ignore this message, unless you see a 'Multi Cradle: No prefixes matched' error.
+2025-09-28T19:31:54.625483Z | Info | invoking build tool to determine build flags (this may take some time depending on the cache)
+2025-09-28T19:31:54.738862Z | Info | Load cabal cradle using single file
+2025-09-28T19:31:54.831553Z | Info | cabal --builddir=/Users/igor/.cache/hie-bios/dist-haddock2-46ec6b456aa9d4df12c3c8dec8c82e6e v2-repl --with-compiler /Users/igor/.cache/hie-bios/wrapper-b54f81dea4c0e6d1626911c526bc4e36 /Users/igor/dev/haddock2/app/Main.hs
+  Environment Variables
+    HIE_BIOS_OUTPUT: /private/var/folders/9h/3j3xz6k52s95nrz7fkscvxph0000gs/T/HIE_BIOS_OUTPUT74985-1
+    HIE_BIOS_GHC: /Users/igor/.ghcup/bin/ghc
+    HIE_BIOS_GHC_ARGS: -B/Users/igor/.ghcup/ghc/9.10.2/lib/ghc-9.10.2/lib
+2025-09-28T19:31:55.143536Z | Info | Interface files cache directory: /Users/igor/.cache/ghcide/haddock2-0.1.0.0-inplace-haddock2-9922c59f82c27147a754c9396574cd2314aa3d19
+2025-09-28T19:31:55.143714Z | Info | Interface files cache directory: /Users/igor/.cache/ghcide/haddock2-0.1.0.0-inplace-haddock2-lib-9922c59f82c27147a754c9396574cd2314aa3d19
+2025-09-28T19:31:55.145930Z | Info | Making new HscEnv. In-place unit ids: [ haddock2-0.1.0.0-inplace-haddock2
+                                      , haddock2-0.1.0.0-inplace-haddock2-lib ]
+2025-09-28T19:31:55.158809Z | Info | Cradle path: test/Spec.hs
+2025-09-28T19:31:55.158933Z | Warning | No [cradle](https://github.com/mpickering/hie-bios#hie-bios) found for test/Spec.hs.
+Proceeding with [implicit cradle](https://hackage.haskell.org/package/implicit-hie).
+You should ignore this message, unless you see a 'Multi Cradle: No prefixes matched' error.
+2025-09-28T19:31:55.159193Z | Info | invoking build tool to determine build flags (this may take some time depending on the cache)
+2025-09-28T19:31:55.275847Z | Info | Load cabal cradle using single file
+2025-09-28T19:31:55.368454Z | Info | cabal --builddir=/Users/igor/.cache/hie-bios/dist-haddock2-46ec6b456aa9d4df12c3c8dec8c82e6e v2-repl --with-compiler /Users/igor/.cache/hie-bios/wrapper-b54f81dea4c0e6d1626911c526bc4e36 /Users/igor/dev/haddock2/test/Spec.hs
+  Environment Variables
+    HIE_BIOS_OUTPUT: /private/var/folders/9h/3j3xz6k52s95nrz7fkscvxph0000gs/T/HIE_BIOS_OUTPUT74985-2
+    HIE_BIOS_GHC: /Users/igor/.ghcup/bin/ghc
+    HIE_BIOS_GHC_ARGS: -B/Users/igor/.ghcup/ghc/9.10.2/lib/ghc-9.10.2/lib
+2025-09-28T19:31:57.159162Z | Info | Interface files cache directory: /Users/igor/.cache/ghcide/haddock2-0.1.0.0-inplace-haddock2-test-c33b0758a00798820f56b5dde448009132dfd22d
+2025-09-28T19:31:57.159344Z | Info | Interface files cache directory: /Users/igor/.cache/ghcide/haddock2-0.1.0.0-inplace-haddock2-c33b0758a00798820f56b5dde448009132dfd22d
+2025-09-28T19:31:57.159444Z | Info | Interface files cache directory: /Users/igor/.cache/ghcide/haddock2-0.1.0.0-inplace-haddock2-lib-c33b0758a00798820f56b5dde448009132dfd22d
+2025-09-28T19:31:57.171150Z | Info | Making new HscEnv. In-place unit ids: [ haddock2-0.1.0.0-inplace-haddock2
+                                      , haddock2-0.1.0.0-inplace-haddock2-lib
+                                      , haddock2-0.1.0.0-inplace-haddock2-test ]

src/Lexer.hs

@@ -42,6 +42,7 @@ data Token
   | Escape
   | EmphasisOpen
   | EmphasisClose
+  | Expression
   | Header Level
   | MonospaceOpen
   | MonospaceClose
@@ -101,6 +102,7 @@ lexText = go
 
           , try module_
           , quotes
+          , try expression
           , birdTrack
 
             -- starts with "\"
@@ -158,16 +160,26 @@ delimited openP closeP openTok closeTok = asList <$> delimitedAsTuple (openTok <
   asList (a, tok, b) = [a, tok, b]
 
 delimitedNoTrailing :: Parser open -> Parser close -> Token -> Parser [LocatedToken]
-delimitedNoTrailing openP closeP openTok = asList <$> delimitedAsTuple (openTok <$ openP) (void closeP)
+delimitedNoTrailing openP closeP openTok =
+  asList <$> delimitedAsTuple (openTok <$ openP) (void closeP)
  where
   asList (a, tok, _) = [a, tok]
 
 delimitedSymmetric :: Parser a -> Token -> Token -> Parser [LocatedToken]
 delimitedSymmetric s = delimited s s
 
+--- End of line // end of file
 eol :: Parser ()
 eol = void "\n" <|> void "\r\n" <|> Parsec.eof
 
+-- Start of line // start of file
+sol :: Parser ()
+sol = do
+  p <- getPosition
+  if sourceLine p == 1 && sourceColumn p == 1
+    then pure ()
+    else fail "Not at start of line/document"
+
 header1 :: Lexer
 header1 = delimitedNoTrailing "= " eol (Header One)
 
@@ -256,7 +268,13 @@ mathInline = delimited "\\(" "\\)" MathInlineOpen MathInlineClose
 
 -- TODO: make sure this starts at column 0?
 birdTrack :: Lexer
-birdTrack = delimitedNoTrailing ">> " eol BirdTrack
+birdTrack = delimitedNoTrailing (sol <* "> ") eol BirdTrack
+
+-- TODO: also match following lines iff:
+-- they start with alphanum
+-- they're not empty
+expression :: Lexer
+expression = delimitedNoTrailing (sol <* ">>> ") eol Expression
 
 escape :: Lexer
 escape = delimitedNoTrailing "\\" eol Escape

test/Spec.hs

@@ -18,7 +18,7 @@ main = hspec $ do
     describe "minimal" do
       it "handles unicode" unicode
       it "escapes" escaping
-      it "maths" math
+      it "maths" maths
       it "anchors" anchor
       it "space chars" space
       it "bare string" someString
@@ -29,6 +29,7 @@ main = hspec $ do
       it "bird tracks" birdTracks
       it "module names" modules
       it "quotes" quotes
+      it "expressions" expressions
       it "numeric entity" numericEntity
       it "ignores nesting" ignoreNesting
 
@@ -91,8 +92,8 @@ anchor =
     `shouldLexTo` [ (1, 1, Anchor "myAnchor")
                   ]
 
-math :: IO ()
+maths :: IO ()
-math = do
+maths = do
   "\\[some math\\]"
     `shouldLexTo` [ (1, 1, MathMultilineOpen)
                   , (1, 3, Token "some math")
@@ -128,10 +129,35 @@ ignoreNesting =
                   ]
 
 birdTracks :: Expectation
-birdTracks =
+birdTracks = do
-  ">> code"
+  "> code line"
     `shouldLexTo` [ (1, 1, BirdTrack)
-                  , (1, 4, Token "code")
+                  , (1, 3, Token "code line")
+                  ]
+  " > not code"
+    `shouldLexTo` [ (1, 1, Space)
+                  , (1, 2, Token ">")
+                  , (1, 3, Space)
+                  , (1, 4, Token "not")
+                  , (1, 7, Space)
+                  , (1, 8, Token "code")
+                  ]
+
+expressions :: Expectation
+expressions = do
+  ">>> eval this"
+    `shouldLexTo` [ (1, 1, Expression)
+                  , (1, 5, Token "eval this")
+                  ]
+  " >>> not eval this"
+    `shouldLexTo` [ (1, 1, Space)
+                  , (1, 2, Token ">>>")
+                  , (1, 5, Space)
+                  , (1, 6, Token "not")
+                  , (1, 9, Space)
+                  , (1, 10, Token "eval")
+                  , (1, 14, Space)
+                  , (1, 15, Token "this")
                   ]
 
 quotes :: Expectation