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If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/Main.hs b/Main.hs new file mode 100644 --- /dev/null +++ b/Main.hs @@ -0,0 +1,17 @@ +module Main + ( main + ) where + +import System.Environment ( getArgs ) + +import Sylvia.Text.Parser +import Sylvia.UI.GTK + +main :: IO () +main = do + args <- getArgs + case args of + [input] -> case parseExp input of + Left err -> putStrLn $ show err + Right res -> showInWindow res + _ -> putStrLn "Usage: sylvia 'expression'" diff --git a/README.mkd b/README.mkd new file mode 100644 --- /dev/null +++ b/README.mkd @@ -0,0 +1,26 @@ +Sylvia +====== + +**Sylvia** is a logical puzzle game, based on a field of mathematics +called *lambda calculus*. You start with a library of functions, and +combine them together in various ways. + +See the [wiki][] for documentation. + + +Quick start +----------- + + git clone git://github.com/chrisyco/sylvia + cd sylvia + cabal configure --enable-tests + cabal install --only-dependencies + cabal build + cabal test + dist/build/sylvia + +See [Building from source][] for more detailed instructions. + + +[wiki]: https://github.com/lfairy/sylvia/wiki +[Building from source]: https://github.com/lfairy/sylvia/wiki/Building-from-source diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/Sylvia/Model.hs b/Sylvia/Model.hs new file mode 100644 --- /dev/null +++ b/Sylvia/Model.hs @@ -0,0 +1,236 @@ +{-# LANGUAGE Rank2Types #-} + +-- | +-- Module : Sylvia.Model +-- Copyright : GPLv3 +-- +-- Maintainer : chrisyco@gmail.com +-- Portability : portable (Rank2Types) +-- +-- The 'Exp' data type, for representing lambda expressions using De Bruijn +-- indices, plus basic abstraction and application operations. + +module Sylvia.Model + ( + -- * Types + Inc(..) + , Exp(..) + + -- * Conversions + , verify + , verify' + + -- * Abstracting + , abstract + , match + , shiftUp + + -- * Applying + , apply + , subst + , shiftDown + + -- * Simplifying + , evalHNF + ) where + +import Control.Applicative ( Applicative(..) ) +import Control.Monad ( ap ) +import Data.Foldable ( Foldable(foldMap) ) +import Data.Functor ( (<$>) ) +import Data.Monoid ( Monoid(..) ) +import Data.Traversable ( Traversable(traverse) ) +import Data.Void ( Void ) + +-- | A structure for representing whole numbers. +-- +-- The problem with referring to variables with plain integers is that +-- it's impossible to tell whether an expression refers to any free +-- variables. 'Inc' solves this by letting the type dictate the maximum +-- value of the number. +-- +-- For example, 3 would be represented as @S (S (S x))@, where @x@ can +-- be any value. Since it is nested three levels deep, it would have the +-- type @Inc (Inc (Inc a))@. +data Inc a + = O -- ^ Zero + | S a -- ^ Add one + deriving (Eq, Ord, Read, Show) + +instance Functor Inc where + fmap = mapI + +instance Applicative Inc where + pure = return + (<*>) = ap + +instance Monad Inc where + return = S + val >>= f = joinI (mapI f val) + +instance Foldable Inc where + foldMap _ O = mempty + foldMap f (S x) = f x + +instance Traversable Inc where + traverse _ O = pure O + traverse f (S x) = S <$> f x + +-- | Apply a function to the value inside the 'Inc', if it has one. +mapI :: (a -> b) -> Inc a -> Inc b +mapI _ O = O +mapI f (S x) = S (f x) + +-- | Remove one layer of nesting, projecting the inner value onto the outside. +joinI :: Inc (Inc a) -> Inc a +joinI (S (S x)) = S x +joinI _ = O + +-- | A lambda expression. +data Exp a + -- | Variable reference. + = Ref a + -- | Lambda abstraction. + -- Since the function introduces a variable, the expression inside + -- the lambda would have one more variable than the expression + -- outside, hence the extra 'Inc'. + | Lam (Exp (Inc a)) + -- | Function application. + | App (Exp a) (Exp a) + deriving (Eq, Ord, Read, Show) + +instance Functor Exp where + fmap = mapE + +instance Applicative Exp where + pure = return + (<*>) = ap + +instance Monad Exp where + return = Ref + e >>= f = joinE (mapE f e) + +instance Foldable Exp where + foldMap f e = case e of + Ref x -> f x + Lam e' -> foldMap (foldMap f) e' + App a b -> foldMap f a `mappend` foldMap f b + +instance Traversable Exp where + traverse f e = case e of + Ref x -> Ref <$> f x + Lam e' -> Lam <$> traverse (traverse f) e' + App a b -> App <$> traverse f a <*> traverse f b + +-- | Apply a function to every leaf value in the tree. +mapE :: (a -> b) -> Exp a -> Exp b +mapE f e = case e of + Ref x -> Ref (f x) + Lam e' -> Lam (mapE (mapI f) e') + App a b -> App (mapE f a) (mapE f b) + +-- | Flatten a nested expression by gluing its nodes onto the main tree. +joinE :: Exp (Exp a) -> Exp a +joinE e = case e of + Ref x -> x + Lam e' -> Lam (joinE (mapE distE e')) + App a b -> App (joinE a) (joinE b) + +-- | Convert a wrapped-up expression into an expression with wrapped-up +-- references. +distE :: Inc (Exp a) -> Exp (Inc a) +distE O = Ref O +distE (S x) = mapE S x + +-- | Check there are no references to free variables in the given +-- expression. If there are none, return Just the expression; otherwise, +-- return Nothing. +verify :: Exp a -> Maybe (Exp Void) +verify = traverse (const Nothing) + +-- | Like 'verify', but chucks an error instead of returning Nothing. +verify' :: Exp a -> Exp Void +verify' e = case verify e of + Just res -> res + Nothing -> error "Sylvia.Model.verify': invalid expression" + +-- | Create a lambda abstraction. +-- +-- If you are using variable names as identifiers, use: +-- +-- > abstract (match "foo") +-- +-- If you are using de Bruijn indices, use: +-- +-- > abstract shiftUp +abstract + :: (a -> Inc a) -- ^ Matching function + -> Exp a -- ^ Function body + -> Exp a -- ^ Result +abstract f = Lam . mapE f + +match + :: Eq a + => a -- ^ Value to replace + -> a -- ^ Value to check + -> Inc a -- ^ Result +match x y = if x == y then O else S y + +-- | Add one layer of 'Inc', decrementing the index inside. +-- +-- This is the inverse of 'shiftDown'. +shiftUp + :: Integral a + => a -- ^ Index to check + -> Inc a -- ^ Result +shiftUp index + | index > 0 = S (index - 1) + | index == 0 = O + | otherwise = error "matchIndex: index out of range" + +-- | Substitute a value into the body of a function. +apply + :: Exp a -- ^ Argument value + -> Exp (Inc a) -- ^ Function body + -> Exp a -- ^ Result +apply e = joinE . mapE (subst e . mapI Ref) + +-- | Shift an 'Inc' down by one. If it falls below zero, replace it with +-- the value. +-- +-- This is the inverse of 'match': for any value of @x@, +-- @subst x . match x === id@. +subst + :: a -- ^ Replacement value + -> Inc a -- ^ Value to shift + -> a -- ^ Result +subst x O = x +subst _ (S y) = y + +-- | Remove one layer of 'Inc', incrementing the index inside. +-- +-- In "Sylvia.Text.PrettyPrint", this is used to get the original +-- indices from the structure. +-- +-- This is the inverse of 'shiftUp'. +shiftDown + :: Integral a + => Inc a + -> a +shiftDown O = 0 +shiftDown (S index) = index + 1 + +-- | Evaluate an expression to head normal form. +evalHNF :: Exp a -> Exp a +evalHNF e = case e of + App a b -> let + -- Recurse in both branches + a' = evalHNF a + b' = evalHNF b + in + case a' of + -- If we have a lambda on the left side, apply it + Lam e' -> evalHNF $ apply b e' + -- Otherwise, leave them as-is + _ -> App a' b' + _ -> e diff --git a/Sylvia/Renderer/Impl.hs b/Sylvia/Renderer/Impl.hs new file mode 100644 --- /dev/null +++ b/Sylvia/Renderer/Impl.hs @@ -0,0 +1,222 @@ +-- | +-- Module : Sylvia.Renderer.Impl +-- Copyright : GPLv3 +-- +-- Maintainer : chrisyco@gmail.com +-- Portability : portable +-- +-- This module provides three things: +-- +-- 1. An interface, 'RenderImpl', that all rendering methods must +-- implement; +-- +-- 2. A function, 'render', that uses the aforementioned interface to +-- draw a pretty picture; +-- +-- 3. Another function, 'render'', that spews its internals all over the +-- place. + +module Sylvia.Renderer.Impl + ( + -- * An interface + RenderImpl(..) + + -- * A function + , render + + -- * Another function + , render' + , Result(..) + , Rhyme + , RhymeUnit(..) + ) where + +import Control.Applicative +import Data.Foldable ( foldMap ) +import Data.List ( foldl' ) +import Data.Monoid +import Data.Void ( Void, vacuous ) + +import Sylvia.Model +import Sylvia.Renderer.Pair + +-- | An action that yields an image. +-- +-- 'mempty' should yield an empty image and 'mappend' should stack two +-- images together. +class Monoid r => RenderImpl r where + -- | Draw a dotted rectangle. + drawDottedRectangle + :: PInt -- ^ Corner position + -> PInt -- ^ Size + -> r + + -- | Draw a line segment from one point to another. + drawLine :: PInt -> PInt -> r + + -- | Draw a line, but instead of drawing a diagonal line, draw a + -- zigzag instead. + drawZigzag :: PInt -> PInt -> r + + -- | Draw a simple circle segment, centered at a point. + drawCircleSegment + :: PInt -- ^ Center point + -> Double -- ^ Start angle, in radians + -> Double -- ^ End angle, also in radians. Radians are cool. + -> r + + -- | Translate the given image by a vector. + relativeTo :: PInt -> r -> r + +-- | Draw a full circle, centered at a point. +drawDot :: RenderImpl r => PInt -> r +drawDot center = drawCircleSegment center 0 (2 * pi) + +-- | Draw a box, complete with a throat and ear. +drawBox + :: RenderImpl r + => PInt -- ^ Top-left corner point + -> PInt -- ^ Size + -> Int -- ^ Y offset of ear and throat + -> r +drawBox corner size throatY + = drawDottedRectangle corner size + <> drawCircleSegment (corner |+| ( 0 :| height + throatY)) (1 * rightAngle) (3 * rightAngle) + <> drawCircleSegment (corner |+| (width :| height + throatY)) (3 * rightAngle) (1 * rightAngle) + where + width :| height = size + rightAngle = pi / 2 + +type Rhyme = [RhymeUnit] + +-- | Specifies a /rhyme line/: a straight line protruding from the left +-- edge of a bounding box, connecting a variable to the sub-expression +-- that uses it. +data RhymeUnit = RhymeUnit + { ruIndex :: Integer + , ruDest :: Int + } + deriving (Show) + +-- | The result of a rendering operation. +data Result r = Result + { resultImage :: r + -- ^ The rendered image. + , resultSize :: PInt + -- ^ The size of the image's bounding box in grid units, when all + -- round things are removed. + , resultRhyme :: Rhyme + -- ^ The expression's rhyme. + , resultThroatY :: Int + -- ^ The Y offset of the expression's ear and throat, measured + -- from the /bottom/ of its bounding box. + } + deriving (Show) + +-- | Render an expression, returning an image along with its size. +render :: RenderImpl r => Exp Void -> (r, PInt) +render e = + let Result image size rhyme _ = render' $ vacuous e + in case rhyme of + [] -> (image, size) + _ -> error $ "render: the impossible happened -- " + ++ "extra free variables: " ++ show rhyme + +-- | Render an expression, with extra juicy options. +render' :: RenderImpl r => Exp Integer -> Result r +render' e = case e of + Ref x -> Result mempty (0 :| 0) [RhymeUnit x 0] 0 + Lam e' -> renderLambda e' + App a b -> Result image size rhyme bThroatY + where + image = mconcat $ + -- Draw the two sub-expressions + [ aImage + , bImage + -- Extend the shorter sub-expression so it matches up with + -- the bigger one + , extendRhyme (-aWidth) (-bWidth) bRhyme + -- Connect them with a vertical line + , drawLine (0 :| aThroatY) (0 :| bThroatY) + -- Application dot + , drawDot (0 :| bThroatY) + ] + Result aImage (aWidth :| aHeight) aRhyme aThroatY + = shiftY (-1 - bHeight) $ renderWithThroatLine False bWidth a + Result bImage (bWidth :| bHeight) bRhyme bThroatY + = renderWithThroatLine False 1 b + size = (aWidth :| aHeight + bHeight + 1) + rhyme = aRhyme ++ bRhyme + +-- | Render an expression with a horizontal line sticking out of its +-- throat. Doesn't sound too comfortable, to be honest. +-- +-- The 'resultSize' includes the length of this extra line. +renderWithThroatLine + :: RenderImpl r + => Bool -- ^ Whether the enclosing expression is a lambda. + -> Int -- ^ Length of the throat line. This should be positive. + -> Exp Integer -> Result r +renderWithThroatLine outerIsLam lineLength e = Result image size rhyme throatY + where + Result image' size' rhyme throatY' = render' e + -- Shift the main image to the left, then draw a line next to it + image = relativeTo (-lineLength :| 0) image' <> throatLine + throatLine = drawZigzag (-lineLength :| throatY') (0 :| throatY) + throatY = if outerIsLam && isLambda e then throatY' - 1 else throatY' + size = size' |+| (lineLength :| 0) + +isLambda :: Exp a -> Bool +isLambda (Lam _) = True +isLambda _ = False + +-- | Render a lambda expression. +renderLambda :: RenderImpl r => Exp (Inc Integer) -> Result r +renderLambda e' = Result image size rhyme throatY + where + Result image' (innerWidth :| innerHeight) innerRhyme throatY + = shiftY (-1) . renderWithThroatLine True 1 $ fmap shiftDown e' + image = drawBox (negateP size) size throatY + <> relativeTo (-width :| 0) rhymeImage + <> image' + (rhymeImage, rhyme) = renderRhyme throatY innerRhyme + rhymeHeight = fromInteger . maximumOr 0 $ map ruIndex innerRhyme + size@(width :| _) = (innerWidth + 1 :| (max innerHeight rhymeHeight) + 2) + +-- | Like 'maximum', but returns a default value on an empty list rather +-- than throwing a hissy fit. +maximumOr :: Ord a => a -> [a] -> a +maximumOr def = foldl' max def + +-- | Render an expression's rhyme. +renderRhyme + :: RenderImpl r + => Int -- ^ Throat offset (see 'resultThroatY') + -> Rhyme -- ^ The inner expression's rhyme + -> (r, Rhyme) -- ^ The resulting image, along with the outer rhyme +renderRhyme throatY innerRhyme = (foldMap renderOne innerRhyme, outerRhyme) + where + renderOne (RhymeUnit index dest) = drawLine (0 :| throatY - fromInteger index) (1 :| dest) + outerRhyme = + [ RhymeUnit (pred index) (throatY - fromInteger index) + | RhymeUnit index _ <- innerRhyme + , index > 0 + ] + +-- | Shift an image vertically by a specified amount, changing the rhyme +-- and throat position to compensate. +shiftY :: RenderImpl r => Int -> Result r -> Result r +shiftY dy (Result image size rhyme throatY) + = Result image' size rhyme' throatY' + where + image' = relativeTo (0 :| dy) image + rhyme' = map shiftRhyme rhyme + throatY' = throatY + dy + + shiftRhyme :: RhymeUnit -> RhymeUnit + shiftRhyme (RhymeUnit index dest) = RhymeUnit index (dest + dy) + +extendRhyme :: RenderImpl r => Int -> Int -> Rhyme -> r +extendRhyme srcX destX = foldMap $ drawLine + <$> (srcX :|) . ruDest + <*> (destX :|) . ruDest diff --git a/Sylvia/Renderer/Impl/Cairo.hs b/Sylvia/Renderer/Impl/Cairo.hs new file mode 100644 --- /dev/null +++ b/Sylvia/Renderer/Impl/Cairo.hs @@ -0,0 +1,161 @@ +-- | +-- Module : Sylvia.Renderer.Impl.Cairo +-- Copyright : GPLv3 +-- +-- Maintainer : chrisyco@gmail.com +-- Portability : non-portable (requires FFI) +-- +-- Renderer using the Cairo graphics library. + +module Sylvia.Renderer.Impl.Cairo + ( + -- * Types + Image + , runImage + , runImage' + , Context(..) + + -- * Testing + , testRender + + -- * Re-exports + , module Sylvia.Renderer.Impl + ) where + +import Control.Applicative +import Control.Arrow ( (***) ) +import Control.Monad.Trans.Class +import Control.Monad.Trans.Reader +import Data.Default +import Data.Monoid ( Monoid(..), (<>) ) +import Graphics.Rendering.Cairo + +import Sylvia.Renderer.Impl +import Sylvia.Renderer.Pair +import Sylvia.Text.Parser + +newtype Image = I { unI :: ImageM () } + +type ImageM = ReaderT Context Render + +runImage :: Context -> Image -> Render () +runImage ctx = flip runReaderT ctx . unI + +runImage' :: Context -> (Image, PInt) -> (Render (), PInt) +runImage' ctx = runImage ctx *** (ctxGridSize ctx |*|) + +-- | Lift a rendering action into the 'ImageM' monad, wrapping it in +-- calls to 'save' and 'restore' to stop its internal state from leaking +-- out. +cairo :: Render a -> ImageM a +cairo action = lift $ do + save + result <- action + restore + return result + +data Context = C + { ctxGridSize :: PInt + , ctxOffset :: PInt + } + +instance Default Context where + def = C { ctxGridSize = (20 :| 10), ctxOffset = (0 :| 0) } + +-- | Map a relative coordinate to an absolute one, scaling and shifting +-- it in the process. +getAbsolute :: PInt -> ImageM PDouble +getAbsolute pair = getRelative =<< (pair |+|) <$> asks ctxOffset + +-- | Scale a relative coordinate. +getRelative :: PInt -> ImageM PDouble +getRelative pair = fromIntegralP . (pair |*|) <$> asks ctxGridSize + +-- | Add a half-pixel offset. This can make lines noticeably sharper, by +-- aligning points to the pixel grid. +addHalf :: PDouble -> PDouble +addHalf = (|+| (0.5 :| 0.5)) + +instance Monoid Image where + mempty = I $ return () + I a `mappend` I b = I $ a >> b + +instance RenderImpl Image where + drawDottedRectangle corner size = I $ do + x :| y <- addHalf <$> getAbsolute corner + dx :| dy <- getRelative size + cairo $ do + newPath + rectangle x y dx dy + setDash [1, 1] 0.5 + setLineWidth 1 + stroke + + drawLine src dest = I $ do + x1 :| y1 <- addHalf <$> getAbsolute src + x2 :| y2 <- addHalf <$> getAbsolute dest + cairo $ do + newPath + moveTo x1 y1 + lineTo x2 y2 + setLineWidth 1 + stroke + + drawZigzag src dest = I $ do + x1 :| y1 <- addHalf <$> getAbsolute src + x2 :| y2 <- addHalf <$> getAbsolute dest + let xmid = (x1 + x2) / 2 + cairo $ do + newPath + moveTo x1 y1 + lineTo xmid y1 + lineTo xmid y2 + lineTo x2 y2 + setLineWidth 1 + stroke + + drawCircleSegment center start end = I $ do + cx :| cy <- getAbsolute center + -- A dot's diameter is approximately equal to one vertical grid unit + radius <- asks (fromIntegral . (`div` 2) . sndP . ctxGridSize) + cairo $ do + newPath + arc cx cy radius start end + setSourceRGB 0 0 0 + fill + + relativeTo delta = I . local addOffset . unI + where + addOffset ctx@C{ ctxOffset = offset } + = ctx{ ctxOffset = offset |+| delta } + +dumpPNG :: PInt -> Image -> IO () +dumpPNG size action = withImageSurface FormatRGB24 w h $ \surface -> do + -- Fill the background with white + renderWith surface $ setSourceRGB 1 1 1 >> paint + -- Render ALL the things + let action' = relativeTo (1 :| 1) action + renderWith surface $ runImage def action' + -- Save the image + surfaceWriteToPNG surface "result.png" + where + w :| h = ctxGridSize def |*| (size |+| (2 :| 2)) -- padding + +testRender :: IO () +testRender = uncurry dumpPNG $ foldl step (0 :| 0, mempty) es + where + step ((w :| h), image) e = ((w + w' + 1) :| (max h h'), image <> relativeTo ((w + w') :| h') image') + where (image', (w' :| h')) = render e + es = map (fromRight . parseExp) $ + [ "L 0" + , "LL 1" + , "LL 0" + , "LLL 2 0 (1 0)" + , "(L 0 0) (L 0 0)" + , "L (L 1 (0 0)) (L 1 (0 0))" + ] + +fromRight :: Show e => Either e a -> a +fromRight e = case e of + Left sinister -> error $ "Unexpected Left: " ++ show sinister + Right dextrous -> dextrous diff --git a/Sylvia/Renderer/Pair.hs b/Sylvia/Renderer/Pair.hs new file mode 100644 --- /dev/null +++ b/Sylvia/Renderer/Pair.hs @@ -0,0 +1,71 @@ +-- | +-- Module : Sylvia.Renderer.Pair +-- Copyright : GPLv3 +-- +-- Maintainer : chrisyco@gmail.com +-- Portability : portable +-- +-- Strict pairs, and operations on them. + +module Sylvia.Renderer.Pair + ( + -- * Building and dismantling pairs + P(..) + , fstP + , sndP + + -- * Fancy type aliases + , PInt + , PDouble + + -- * Operations on pairs + , (|+|) + , (|*|) + , negateP + , fromIntegralP + ) where + +import Control.Applicative + +-- | A strict pair. +data P a = !a :| !a + deriving (Eq, Ord, Bounded, Read, Show) + +infix 5 :| + +instance Functor P where + fmap f (x :| y) = f x :| f y + +instance Applicative P where + pure x = x :| x + f :| g <*> x :| y = f x :| g y + +-- | A pair of integers. +type PInt = P Int + +-- | A pair of doubles. +type PDouble = P Double + +-- | Add or multiply the corresponding values in two pairs. +(|+|), (|*|) :: Num a => P a -> P a -> P a +(|+|) = liftA2 (+) +(|*|) = liftA2 (*) + +infixl 6 |+| +infixl 7 |*| + +-- | Negate the contents of a pair. +negateP :: Num a => P a -> P a +negateP = fmap negate + +-- | Apply 'fromIntegral' to the contents of a pair. +fromIntegralP :: (Integral a, Num b) => P a -> P b +fromIntegralP = fmap fromIntegral + +-- | Get the first element of a pair. +fstP :: P a -> a +fstP (x :| _) = x + +-- | Get the second element of a pair. +sndP :: P a -> a +sndP (_ :| y) = y diff --git a/Sylvia/Text/Parser.hs b/Sylvia/Text/Parser.hs new file mode 100644 --- /dev/null +++ b/Sylvia/Text/Parser.hs @@ -0,0 +1,61 @@ +-- | +-- Module : Sylvia.Text.Parser +-- Copyright : GPLv3 +-- +-- Maintainer : chrisyco@gmail.com +-- Portability : portable +-- +-- Basic parser for zero-based de Bruijn index notation. +-- +-- Here are some expressions that parse: +-- +-- > identity: \ 0 +-- > omega: (\ 0 0) (\ 0 0) +-- > starling: \\ 2 0 (1 0) +-- > fixpoint: \ (\ 1 (0 0)) (\ 1 (0 0)) +-- +-- All variables must have a corresponding lambda, i.e. be bound +-- variables. This means expressions such as @\\ 9001@ will be rejected. + +module Sylvia.Text.Parser + ( + parseExp + , ParseError + ) where + +import Control.Applicative +import Data.Void ( Void ) +import Text.Parsec hiding ( (<|>), many ) +import Sylvia.Model + +parseExp :: String -> Either ParseError (Exp Void) +parseExp = parse expression' "sylvia" + where + expression' = verify' <$> expression 0 <* spaces -- Skip trailing spaces + +type Parser = Parsec String () + +expression, term, bracketed, reference, abstraction + :: Integer -- ^ The number of variables in scope. + -> Parser (Exp Integer) + +expression i = foldl1 App <$> many1 (term i) + +term i = try spaces + *> (bracketed i + <|> reference i + <|> abstraction i) + +bracketed i = char '(' *> expression i <* spaces <* char ')' + "bracketed term" + +reference i = Ref <$> (checkInRange =<< read <$> many1 digit) + "de Bruijn index" + where + -- Reject an index if it refers to a free variable + checkInRange index + | index < i = return index + | otherwise = parserFail $ "index " ++ show index ++ " out of range" + +abstraction i = abstract shiftUp <$> (oneOf "L\\" *> expression (i+1)) + "lambda abstraction" diff --git a/Sylvia/Text/PrettyPrint.hs b/Sylvia/Text/PrettyPrint.hs new file mode 100644 --- /dev/null +++ b/Sylvia/Text/PrettyPrint.hs @@ -0,0 +1,42 @@ +-- | +-- Module : Sylvia.Text.PrettyPrint +-- Copyright : GPLv3 +-- +-- Maintainer : chrisyco@gmail.com +-- Portability : portable +-- +-- Convert an expression into a form that can be parsed by +-- "Sylvia.Text.Parser". + +module Sylvia.Text.PrettyPrint + ( + pprintExp + ) where + +import Data.Void ( Void, vacuous ) +import Sylvia.Model + +pprintExp :: Exp Void -> String +pprintExp = ($ "") . pprint . vacuous + +pprint :: Exp Integer -> ShowS +pprint e = case e of + Ref a -> shows a + Lam e' -> str "(\\" . stackLams (flatten e') . str ")" + App a b -> pprint a . str " " . case b of + -- The right term only needs to be bracketed if it contains a + -- function application + App _ _ -> str "(" . pprint b . str ")" + _ -> pprint b + +-- | Allow consecutive lambda symbols without adding extra brackets. +stackLams :: Exp Integer -> ShowS +stackLams e = case e of + Lam e' -> str "\\" . stackLams (flatten e') + _ -> str " " . pprint e + +flatten :: Exp (Inc Integer) -> Exp Integer +flatten = fmap shiftDown + +str :: String -> ShowS +str = (++) diff --git a/Sylvia/UI/GTK.hs b/Sylvia/UI/GTK.hs new file mode 100644 --- /dev/null +++ b/Sylvia/UI/GTK.hs @@ -0,0 +1,70 @@ +{-# OPTIONS_GHC -fno-warn-unused-do-bind #-} + +-- | +-- Module : Sylvia.UI.GTK +-- Copyright : GPLv3 +-- +-- Maintainer : chrisyco@gmail.com +-- Portability : portable +-- +-- Graphical interface based on Cairo and GTK. + +module Sylvia.UI.GTK ( showInWindow ) where + +import Data.Default +import Data.Void +import Graphics.Rendering.Cairo +import Graphics.UI.Gtk +import System.IO ( hPutStr, hPutStrLn, stderr ) + +import Sylvia.Model +import Sylvia.Renderer.Pair +import Sylvia.Renderer.Impl.Cairo + +title :: String +title = "Sylvia" + +showInWindow :: Exp Void -> IO () +showInWindow e = do + "Initializing GTK" -:- do + initGUI + + window <- "Creating window" -:- do + window <- windowNew + set window + [ windowTitle := title + , widgetAppPaintable := True + ] + onDestroy window mainQuit + return window + + "Creating canvas" -:- do + canvas <- drawingAreaNew + let (_, (w :| h)) = renderCairo e + widgetSetSizeRequest canvas w h + set window [ containerChild := canvas ] + canvas `on` exposeEvent $ updateCanvas e + + "Show ALL the things!" -:- do + widgetShowAll window + mainGUI + +updateCanvas :: Exp Void -> EventM EExpose Bool +updateCanvas e = do + win <- eventWindow + liftIO $ do + let (action, size) = renderCairo e + let (w :| h) = fmap fromIntegral $ size |+| ctxGridSize def + renderWithDrawable win $ translate w h >> action + return True + +renderCairo :: Exp Void -> (Render (), PInt) +renderCairo = runImage' def . render + +infixr 1 -:- +(-:-) :: String -> IO a -> IO a +msg -:- action = do + hPutStr stderr msg + result <- action + hPutStrLn stderr " ... done" + return result diff --git a/sylvia.cabal b/sylvia.cabal new file mode 100644 --- /dev/null +++ b/sylvia.cabal @@ -0,0 +1,71 @@ +Name: sylvia +Version: 0.2.0.1 +Synopsis: Lambda calculus visualization +Category: Game + +Description: + The Simple Yuser-friendly Lambda Visualization Interaction Application (SYLVIA) + is a unique way to manipulate untyped lambda calculus expressions, by + representing them as boxes connected by wires. + . + It is an implementation of an idea by Keenan (1996). See + for the theory behind this application. + +Homepage: https://github.com/lfairy/sylvia +Bug-Reports: https://github.com/lfairy/sylvia/issues + +Author: Chris Wong +Maintainer: chrisyco@gmail.com + +License: GPL +License-File: LICENSE +Copyright: 2011 Chris Wong + +Build-Type: Simple +Extra-Source-Files: README.mkd +Cabal-Version: >= 1.8 + + +Executable sylvia + Main-Is: Main.hs + Build-Depends: + base == 4.* + , data-default + , parsec >= 3.1.2 && < 3.2 + , transformers + , void >= 0.5.5 && < 0.6 + , cairo + , gtk + + Other-Modules: + Sylvia.Model + Sylvia.Renderer.Impl + Sylvia.Renderer.Impl.Cairo + Sylvia.Renderer.Pair + Sylvia.Text.Parser + Sylvia.Text.PrettyPrint + Sylvia.UI.GTK + + GHC-Options: -Wall + + +Test-Suite tests + Type: exitcode-stdio-1.0 + Hs-Source-Dirs: tests, . + Main-Is: Properties.hs + Build-Depends: + base + , void + , parsec + + , test-framework >= 0.3.3 && < 0.7 + , test-framework-smallcheck + >= 0.1 && < 0.2 + , smallcheck >= 0.6 && < 0.7 + + GHC-Options: -Wall -fno-warn-orphans + + +Source-Repository head + Type: git + Location: https://github.com/lfairy/sylvia.git diff --git a/tests/Properties.hs b/tests/Properties.hs new file mode 100644 --- /dev/null +++ b/tests/Properties.hs @@ -0,0 +1,71 @@ +import Control.Applicative +import Control.Monad +import Data.Maybe ( isJust ) +import Data.Void ( Void ) + +import Test.Framework +import Test.Framework.Providers.SmallCheck +import Test.SmallCheck.Series + +import Sylvia.Model +import Sylvia.Text.Parser +import Sylvia.Text.PrettyPrint + +instance Serial Void where + series _ = [] + coseries _ _ = [] + +instance Serial a => Serial (Inc a) where + series = cons0 O \/ cons1IgnoreDepth S + where + cons1IgnoreDepth c d = [c z | z <- series d] + + coseries rs d = [ \i -> case i of + O -> z + S x -> f x + | z <- alts0 rs d + , f <- alts1 rs d + ] + +instance Serial a => Serial (Exp a) where + series = cons1 Ref \/ cons1 Lam \/ cons2 App + coseries rs d = [ \e -> case e of + Ref x -> f x + Lam e' -> g e' + App a b -> h a b + | f <- alts1 rs d + , g <- alts1 rs d + , h <- alts2 rs d + ] + +-- | Converting an expression to a string, then back again should result +-- in the same expression. +prop_parse_pprint :: Exp Void -> Bool +prop_parse_pprint orig = isJust $ do + new <- eitherToMaybe . parseExp . pprintExp $ orig + guard $ orig == new + where + eitherToMaybe = either (const Nothing) Just + +prop_subst_match :: Int -> Int -> Bool +prop_subst_match x y = (subst x . match x) y == y + +prop_shiftDown_shiftUp :: N Int -> Bool +prop_shiftDown_shiftUp (N x) = (shiftDown . shiftUp) x == x + +main :: IO () +main = defaultMain $ map (plusTestOptions options) + [ testProperty "parse.pprint" prop_parse_pprint + , testProperty "subst.match" prop_subst_match + , testProperty "shiftDown.shiftUp" prop_shiftDown_shiftUp + ] + +options :: TestOptions +options = TestOptions + { topt_maximum_test_depth = Just 5 + , topt_timeout = Nothing + , topt_seed = Nothing + , topt_maximum_generated_tests = Nothing + , topt_maximum_unsuitable_generated_tests = Nothing + , topt_maximum_test_size = Nothing + }