Refactor tests into separate modules

Earley.cabal

@@ -114,7 +114,7 @@ benchmark bench
 
 test-suite tests
   type:                exitcode-stdio-1.0
-  main-is:             Tests.hs
+  main-is:             Main.hs
   ghc-options:         -Wall
   hs-source-dirs:      tests
   default-language:    Haskell2010

tests/Empty.hs

@@ -0,0 +1,25 @@
+{-# LANGUAGE ScopedTypeVariables #-}
+module Empty where
+import Control.Applicative
+import Test.Tasty
+import Test.Tasty.QuickCheck as QC
+
+import Text.Earley
+
+tests :: TestTree
+tests = testGroup "Empty productions"
+  [ QC.testProperty "The empty production doesn't parse anything" $
+    \(input :: String) ->
+      allParses (parser (return empty :: forall r. Grammar r (Prod r () Char ()))) input
+      == (,) [] Report { position   = 0
+                       , expected   = []
+                       , unconsumed = input
+                       }
+  , QC.testProperty "Many empty productions parse very little" $
+    \(input :: String) ->
+      allParses (parser (return $ many empty <* pure "blah" :: forall r. Grammar r (Prod r () Char [()]))) input
+      == (,) [([], 0)] Report { position   = 0
+                              , expected   = []
+                              , unconsumed = input
+                              }
+  ]

tests/Expr.hs

@@ -0,0 +1,92 @@
+{-# LANGUAGE RecursiveDo #-}
+module Expr where
+import Control.Applicative
+import Data.Char
+import Test.Tasty
+import Test.Tasty.QuickCheck as QC
+
+import Text.Earley
+
+tests :: TestTree
+tests = testGroup "Expr"
+  [ QC.testProperty "Expr: parse . pretty = id" $
+    \e -> [e] === parseExpr (prettyExpr 0 e)
+  , QC.testProperty "Ambiguous Expr: parse . pretty ≈ id" $
+    \e -> e `elem` parseAmbiguousExpr (prettyExpr 0 e)
+  ]
+
+parseExpr :: String -> [Expr]
+parseExpr input = fst (fullParses (parser expr) (lexExpr input)) -- We need to annotate types for point-free version
+
+parseAmbiguousExpr :: String -> [Expr]
+parseAmbiguousExpr input = fst (fullParses (parser ambiguousExpr) (lexExpr input))
+
+data Expr
+  = Add Expr Expr
+  | Mul Expr Expr
+  | Var String
+  deriving (Eq, Ord, Show)
+
+instance Arbitrary Expr where
+  arbitrary = sized arbExpr
+    where arbIdent           = Var <$> elements ["a", "b", "c", "x", "y", "z"]
+          arbExpr n | n > 0  = oneof [ arbIdent
+                                     , Add <$> arbExpr1 <*> arbExpr1
+                                     , Mul <$> arbExpr1 <*> arbExpr1
+                                     ]
+                                     where arbExpr1 = arbExpr (n `div` 2)
+          arbExpr _          = arbIdent
+
+  shrink (Var _)    = []
+  shrink (Add a b)  = a : b : [ Add a' b | a' <- shrink a ] ++ [ Add a b' | b' <- shrink b ]
+  shrink (Mul a b)  = a : b : [ Mul a' b | a' <- shrink a ] ++ [ Mul a b' | b' <- shrink b ]
+
+expr :: Grammar r (Prod r String String Expr)
+expr = mdo
+  x1 <- rule $ Add <$> x1 <* namedSymbol "+" <*> x2
+            <|> x2
+            <?> "sum"
+  x2 <- rule $ Mul <$> x2 <* namedSymbol "*" <*> x3
+            <|> x3
+            <?> "product"
+  x3 <- rule $ Var <$> (satisfy ident <?> "identifier")
+            <|> namedSymbol "(" *> x1 <* namedSymbol ")"
+  return x1
+  where
+    ident (x:_) = isAlpha x
+    ident _     = False
+
+ambiguousExpr :: Grammar r (Prod r String String Expr)
+ambiguousExpr = mdo
+  x1 <- rule $ Add <$> x1 <* namedSymbol "+" <*> x1
+            <|> x2
+            <?> "sum"
+  x2 <- rule $ Mul <$> x2 <* namedSymbol "*" <*> x2
+            <|> x3
+            <?> "product"
+  x3 <- rule $ Var <$> (satisfy ident <?> "identifier")
+            <|> namedSymbol "(" *> x1 <* namedSymbol ")"
+  return x1
+  where
+    ident (x:_) = isAlpha x
+    ident _     = False
+
+prettyParens :: Bool -> String -> String
+prettyParens True s  = "(" ++ s ++ ")"
+prettyParens False s = s
+
+prettyExpr :: Int -> Expr -> String
+prettyExpr _ (Var s) = s
+prettyExpr d (Add a b) = prettyParens (d > 0) $ prettyExpr 0 a ++ " + " ++ prettyExpr 1 b
+prettyExpr d (Mul a b) = prettyParens (d > 1) $ prettyExpr 1 a ++ " * " ++ prettyExpr 2 b
+
+-- @words@ like lexer, but consider parentheses as separate tokens
+lexExpr :: String -> [String]
+lexExpr ""        = []
+lexExpr ('(' : s) = "(" : lexExpr s
+lexExpr (')' : s) = ")" : lexExpr s
+lexExpr (c : s)
+  | isSpace c     = lexExpr s
+  | otherwise     = let (tok, rest) = span p (c : s)
+                    in tok : lexExpr rest
+  where p x       = not (x == '(' || x == ')' || isSpace x)

tests/InlineAlts.hs

@@ -0,0 +1,26 @@
+{-# LANGUAGE RecursiveDo, ScopedTypeVariables #-}
+module InlineAlts where
+import Control.Applicative
+import Test.Tasty
+import Test.Tasty.HUnit as HU
+
+import Text.Earley
+
+tests :: TestTree
+tests = testGroup "Inline alternatives"
+  [ HU.testCase "They work" $
+      let input = "ababbbaaabaa" in
+      allParses (parser inlineAlts) input @?= allParses (parser nonInlineAlts) input
+  ]
+
+inlineAlts :: Grammar r (Prod r Char Char String)
+inlineAlts = mdo
+  p <- rule $ pure []
+           <|> (:) <$> (namedSymbol 'a' <|> namedSymbol 'b') <*> p
+  return p
+
+nonInlineAlts :: Grammar r (Prod r Char Char String)
+nonInlineAlts = mdo
+  ab <- rule $ namedSymbol 'a' <|> namedSymbol 'b'
+  p  <- rule $ pure [] <|> (:) <$> ab <*> p
+  return p

tests/Issue11.hs

@@ -0,0 +1,73 @@
+{-# LANGUAGE RecursiveDo #-}
+module Issue11 where
+import Control.Applicative
+import Test.Tasty
+import Test.Tasty.HUnit as HU
+
+import Text.Earley
+import Text.Earley.Mixfix
+
+tests :: TestTree
+tests = testGroup "Issue 11"
+  [ let x = words "+ + 5 6 7" in
+    HU.testCase "1" $
+    fullParses (parser $ grammar LeftAssoc) x
+    @?= (,) [] Report {position = 1, expected = [], unconsumed = drop 1 x}
+  , let x = words "+ 5 + 6 7" in
+    HU.testCase "2" $
+    fullParses (parser $ grammar LeftAssoc) x
+    @?= (,) [] Report {position = 2, expected = [], unconsumed = drop 2 x}
+  , let x = words "+ 5 6" in
+    HU.testCase "3" $
+    fullParses (parser $ grammar LeftAssoc) x
+    @?= (,) [Plus (Var "5") (Var "6")]
+            Report {position = 3, expected = [], unconsumed = []}
+  , let x = words "+ + 5 6 7" in
+    HU.testCase "4" $
+    fullParses (parser $ grammar RightAssoc) x
+    @?= (,) [Plus (Plus (Var "5") (Var "6")) (Var "7")]
+            Report {position = 5, expected = [], unconsumed = []}
+  , let x = words "+ 5 + 6 7" in
+    HU.testCase "5" $
+    fullParses (parser $ grammar RightAssoc) x
+    @?= (,) [Plus (Var "5") (Plus (Var "6") (Var "7"))]
+            Report {position = 5, expected = [], unconsumed = []}
+  , let x = words "+ 5 6" in
+    HU.testCase "6" $
+    fullParses (parser $ grammar RightAssoc) x
+    @?= (,) [Plus (Var "5") (Var "6")]
+            Report {position = 3, expected = [], unconsumed = []}
+  , let x = words "+ + 5 6 7" in
+    HU.testCase "7" $
+    fullParses (parser $ grammar NonAssoc) x
+    @?= (,) [Plus (Plus (Var "5") (Var "6")) (Var "7")]
+            Report {position = 5, expected = [], unconsumed = []}
+  , let x = words "+ 5 + 6 7" in
+    HU.testCase "8" $
+    fullParses (parser $ grammar NonAssoc) x
+    @?= (,) [Plus (Var "5") (Plus (Var "6") (Var "7"))]
+            Report {position = 5, expected = [], unconsumed = []}
+  , let x = words "+ 5 6" in
+    HU.testCase "9" $
+    fullParses (parser $ grammar NonAssoc) x
+    @?= (,) [Plus (Var "5") (Var "6")]
+            Report {position = 3, expected = [], unconsumed = []}
+  ]
+
+data AST
+  = Var String
+  | Plus AST AST
+  deriving (Eq, Ord, Show)
+
+grammar :: Associativity -> Grammar r (Prod r String String AST)
+grammar a = mdo
+    atomicExpr <- rule $ Var <$> satisfy (/= "+")
+
+    expr <- mixfixExpression
+               [[([Just (symbol "+"), Nothing, Nothing], a)]]
+               atomicExpr
+               (\x y -> case (x,y) of
+                  ([Just "+", Nothing, Nothing], [e1,e2]) -> Plus e1 e2
+                  _ -> undefined)
+
+    return expr

tests/Issue14.hs

@@ -0,0 +1,49 @@
+module Issue14 where
+import Control.Applicative
+import Test.Tasty
+import Test.Tasty.QuickCheck as QC
+
+import Text.Earley
+
+tests :: TestTree
+tests = testGroup "Issue 14"
+  [ QC.testProperty "The same rule in alternatives gives many results" $
+    \x -> fullParses (parser (issue14 x)) ""
+    == (,) (replicate (issue14Length x) ())
+           Report { position = 0, expected = [], unconsumed = [] }
+  ]
+
+data Issue14 a
+  = Pure a
+  | Alt (Issue14 a) (Issue14 a)
+  | Ap (Issue14 a) (Issue14 a)
+  deriving (Eq, Ord, Show)
+
+instance Arbitrary a => Arbitrary (Issue14 a) where
+  arbitrary = sized arbTree
+    where arbTree n | n > 0  = oneof [ Pure <$> arbitrary
+                                     , Alt <$> arbTree1 <*> arbTree1
+                                     , Ap <$> arbTree1 <*> arbTree1
+                                     ]
+                                     where arbTree1 = arbTree (n `div` 2)
+          arbTree _          = Pure <$> arbitrary
+
+  shrink (Pure a)  = Pure <$> shrink a
+  shrink (Alt a b) = a : b : [Alt a' b | a' <- shrink a] ++ [Alt a b' | b' <- shrink b]
+  shrink (Ap a b)  = a : b : [Ap a' b | a' <- shrink a] ++ [Ap a b' | b' <- shrink b]
+
+issue14Length :: Issue14 () -> Int
+issue14Length (Pure ()) = 1
+issue14Length (Alt a b) = issue14Length a + issue14Length b
+issue14Length (Ap a b)  = issue14Length a * issue14Length b
+
+issue14 :: Issue14 () -> Grammar r (Prod r () Char ())
+issue14 tree = do
+  emptyRule <- rule $ pure ()
+  let x = go emptyRule tree
+  return x
+  where
+    go x (Pure ())   = x
+    go x (Alt b1 b2) = go x b1 <|> go x b2
+    go x (Ap b1 b2)  = go x b1 <* go x b2
+

tests/Main.hs

@@ -0,0 +1,25 @@
+module Main where
+import Test.Tasty
+
+import qualified Empty
+import qualified Expr
+import qualified InlineAlts
+import qualified Issue11
+import qualified Issue14
+import qualified Mixfix
+import qualified Optional
+import qualified ReversedWords
+import qualified VeryAmbiguous
+
+main :: IO ()
+main = defaultMain $ testGroup "Tests"
+  [ Empty.tests
+  , Expr.tests
+  , InlineAlts.tests
+  , Issue11.tests
+  , Issue14.tests
+  , Mixfix.tests
+  , Optional.tests
+  , ReversedWords.tests
+  , VeryAmbiguous.tests
+  ]

tests/Mixfix.hs

@@ -0,0 +1,53 @@
+module Mixfix where
+import Control.Applicative
+import Test.Tasty
+import Test.Tasty.HUnit as HU
+
+import Text.Earley
+import Text.Earley.Mixfix
+
+tests :: TestTree
+tests = testGroup "Mixfix"
+  [ HU.testCase "1" $
+      let x = Ident [Just "x"] in
+      fullParses (parser mixfixGrammar) (words "if x then x else x")
+      @?= (,) [App ifthenelse [x, x, x]] Report {position = 6, expected = [], unconsumed = []}
+  , HU.testCase "2" $
+      let x = Ident [Just "x"] in
+      fullParses (parser mixfixGrammar) (words "prefix x postfix")
+      @?= (,) [App prefix [App postfix [x]]] Report {position = 3, expected = [], unconsumed = []}
+  , HU.testCase "3" $
+      let x = Ident [Just "x"] in
+      fullParses (parser mixfixGrammar) (words "x infix1 x infix2 x")
+      @?= (,) [App infix1 [x, App infix2 [x, x]]] Report {position = 5, expected = [], unconsumed = []}
+  , HU.testCase "4" $
+      let x = Ident [Just "x"] in
+      fullParses (parser mixfixGrammar) (words "[ x ]")
+      @?= (,) [App closed [x]] Report {position = 3, expected = [], unconsumed = []}
+  ]
+
+data MixfixExpr = Ident (Holey String) | App (Holey String) [MixfixExpr]
+  deriving (Eq, Show)
+
+mixfixGrammar :: Grammar r (Prod r String String MixfixExpr)
+mixfixGrammar = mixfixExpression table
+                                 (Ident . pure . Just <$> namedSymbol "x")
+                                 App
+  where
+    hident = map (fmap symbol)
+    table =
+      [ [(hident ifthenelse, RightAssoc)]
+      , [(hident prefix, RightAssoc)]
+      , [(hident postfix, LeftAssoc)]
+      , [(hident infix1, LeftAssoc)]
+      , [(hident infix2, RightAssoc)]
+      , [(hident closed, NonAssoc)]
+      ]
+
+ifthenelse, prefix, postfix, infix1, infix2, closed :: Holey String
+ifthenelse = [Just "if", Nothing, Just "then", Nothing, Just "else", Nothing]
+prefix = [Just "prefix", Nothing]
+postfix = [Nothing, Just "postfix"]
+infix1 = [Nothing, Just "infix1", Nothing]
+infix2 = [Nothing, Just "infix2", Nothing]
+closed = [Just "[", Nothing, Just "]"]