Additional test coverage for lexing and parsing

src/Parser.hs

@@ -123,8 +123,6 @@ parseListLiteral = do
   satisfy (== LCloseBracket)
   return (SList elements)
 
---parseListItem :: Parser SaplingAST
---parseListItem = parseGroupedItem <|> parseSingleItem
 parseListItem :: Parser SaplingAST
 parseListItem = choice
   [ parseGroupedItem  -- Handle expressions inside parentheses

test/Spec.hs

@@ -41,6 +41,22 @@ lexerTests = testGroup "Lexer Tests"
       case runParser saplingLexer "" input of
         Left _ -> return ()
         Right _ -> assertFailure "Expected failure on invalid input"
+
+  , testCase "Lex escaped characters in strings" $ do
+      let input = "\"hello\\nworld\""
+      let expected = Right [LStringLiteral "hello\\nworld"]
+      runParser saplingLexer "" input @?= expected
+
+  , testCase "Lex mixed literals" $ do
+      let input = "t \"string\" 42"
+      let expected = Right [LKeywordT, LStringLiteral "string", LIntegerLiteral 42]
+      runParser saplingLexer "" input @?= expected
+
+  , testCase "Lex invalid token" $ do
+      let input = "$invalid"
+      case runParser saplingLexer "" input of
+          Left _ -> return ()
+          Right _ -> assertFailure "Expected lexer to fail on invalid token"
   ]
 
 parserTests :: TestTree
@@ -61,7 +77,7 @@ parserTests = testGroup "Parser Tests"
       parseSapling input @?= expected
 
   , testCase "Parse mixed list literals" $ do
-      -- You must put non-listliterals in parentheses
+      -- You must put non-list literals in parentheses
       let input = "[t (\"hello\") t]" 
       let expected = SList [TLeaf, SStr "hello", TLeaf]
       parseSapling input @?= expected
@@ -97,6 +113,28 @@ parserTests = testGroup "Parser Tests"
       let expected = SList [TLeaf, TLeaf]
       parseSapling input1 @?= expected
       parseSapling input2 @?= expected
+
+  , testCase "Parse string in list" $ do
+      let input = "[(\"hello\")]"
+      let expected = SList [SStr "hello"]
+      parseSapling input @?= expected
+
+  , testCase "Parse parentheses inside list" $ do
+      let input = "[t (t t)]"
+      let expected = SList [TLeaf, TStem TLeaf]
+      parseSapling input @?= expected
+
+  -- Do I want to allow multi-line indentation-sensitive syntax?
+  -- Probably not.
+  --, testCase "Parse multi-line function definition" $ do
+  --    let input = "f x y =\n  t t"
+  --    let expected = SFunc "f" ["x", "y"] (TStem TLeaf)
+  --    parseSapling input @?= expected
+
+  , testCase "Parse nested parentheses in function body" $ do
+      let input = "f = t (t (t t))"
+      let expected = SFunc "f" [] (TStem (TStem (TStem TLeaf)))
+      parseSapling input @?= expected
   ]
 
 integrationTests :: TestTree
@@ -191,3 +229,4 @@ propertyTests = testGroup "Property Tests"
           Left _ -> property True
           Right ast -> parseSapling input === ast
   ]
+