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gyehoek-hs/src/Gyehoek/Scheme/Syntax.hs
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Haskell

{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedLists #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE OverloadedLabels #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE DerivingStrategies #-}
{-# LANGUAGE OrPatterns #-}
{-# LANGUAGE PatternSynonyms #-}
{-# LANGUAGE DeriveAnyClass #-}
module Gyehoek.Scheme.Syntax
( Name(..)
, Prim(..)
, Lit(..)
, Def(..)
, Exp(..)
, ExpF(..)
, Sexp(..)
, Program(..)
, CommandOrDef(..)
, primSexpIso
, pattern Void
, free
, subst
, getName
, scm
, readExp
, readProgram
, free'
, freeWithBound'
, freeO
, encodeProgram
)
where
import Data.List (intersperse)
import Language.SexpGrammar
( SexpIso(..), list, el, rest, sym, symbol )
import Language.SexpGrammar qualified as Sexp
import Language.SexpGrammar.Generic
import Effectful
import Prelude hiding ((.), id)
import Control.Category
import Gyehoek.Sexp qualified as GS
import Gyehoek.GenSym (Gen)
import Control.Lens
import Data.Generics.Labels ()
import Data.String (IsString)
import Data.Functor.Foldable.TH (makeBaseFunctor)
import Data.Functor.Foldable hiding (fold)
import qualified Data.HashSet as HS
import Data.Foldable (fold, toList)
import Language.Haskell.TH.Quote (QuasiQuoter)
import Effectful.FileSystem (runFileSystem)
import qualified Effectful.FileSystem.IO as FS
import qualified Data.Text.Encoding as T
import qualified Effectful.FileSystem.IO.ByteString as FB
import qualified Data.Set.Ordered as O
import Gyehoek.Prelude
newtype Name = MkName { inner :: Text }
deriving newtype (Show, Eq, Ord, IsString, Gen, Hashable)
deriving stock (Generic, Data)
deriving anyclass (Wrapped, NFData)
instance Prefixed Name where
prefixed (MkName s) = _Wrapped' . prefixed @Text s . from _Wrapped'
getName :: Name -> Text
getName (MkName x) = x
data Prim e
= PrimAdd e e
| PrimSub e e
| PrimMul e e
| PrimDiv e e
| PrimCons e e
| PrimCar e
| PrimCdr e
| PrimImmediateP e
| PrimConsP e
| PrimIntegerP e
| PrimWrite e
| PrimZeroP e
| PrimNewline
| PrimMakeClosure { code :: e, env :: List e }
| PrimEnvRef e Int
| PrimEnvCode e
| PrimCallCC e
deriving stock (Show, Generic, Functor, Foldable, Traversable, Data, Eq)
deriving anyclass (NFData)
instance Each (Prim e) (Prim e') e e'
data Lit
= LitInt Int
| LitNil
| LitBool Bool
| LitString Text
| LitQuote Sexp
deriving stock (Show, Generic, Data, Eq)
deriving anyclass (NFData)
pattern Void :: Lit
pattern Void = LitNil
data Def
= DefConstant Name Exp
| DefProcedure Name (List Name) (List Exp)
deriving stock (Show, Generic, Data)
deriving anyclass (NFData)
data Exp
= ExpLet (List (Name, Exp)) Exp
| ExpLetRec (List (Name, Exp)) Exp
| ExpPrim (Prim Exp)
| ExpBegin (List Exp)
| ExpIf Exp Exp Exp
| ExpLit Lit
| ExpLambda (List Name) Exp
| ExpVar Name
| ExpApply Exp (List Exp)
deriving stock (Show, Generic, Data)
deriving anyclass (NFData)
data Sexp
= SexpCons Sexp Sexp
| SexpSymbol Text
| SexpLit Lit
deriving stock (Show, Generic, Data, Eq)
deriving anyclass (NFData)
data CommandOrDef
= Command Exp
| Definition Def
| Begin (List CommandOrDef)
deriving stock (Show, Generic, Data)
deriving anyclass (NFData)
data Program = MkProgram
{ commandsAndDefs :: List CommandOrDef
}
deriving stock (Show, Generic, Data)
deriving anyclass (NFData)
instance Each Program Program (Either Exp Def) (Either Exp Def) where
each = #commandsAndDefs . each . go
where
inj = either Command Definition
go :: Traversal' CommandOrDef (Either Exp Def)
go k (Command e) = inj <$> k (Left e)
go k (Definition d) = inj <$> k (Right d)
go k (Begin xs) = Begin <$> traverse (go k) xs
makeBaseFunctor ''Exp
instance SexpIso Name where
sexpIso = symbol >>> Sexp.partialOsi f g
where
f = Right . MkName
g (MkName s) = s
primSexpIso :: (Text -> Text) -> Sexp.SexpGrammar a -> Sexp.SexpGrammar (Prim a)
primSexpIso namefn a = match
$ With (. ht2 "+")
$ With (. ht2 "-")
$ With (. ht2 "*")
$ With (. ht2 "/")
$ With (. ht2 "cons")
$ With (. ht1 "car")
$ With (. ht1 "cdr")
$ With (. ht1 "immediate?")
$ With (. ht1 "cons?")
$ With (. ht1 "integer?")
$ With (. ht1 "write")
$ With (. ht1 "zero?")
$ With (. nullop "newline")
$ With (. ht1' "make-closure")
$ With (. GS.headTagged2 (namefn "env-ref") a Sexp.int)
$ With (. ht1 "env-code")
$ With (. ht1 "call/cc")
$ End
where
idn s = el (sym (namefn s))
nullop s = list $ idn s
ht1 s = GS.headTagged1 (namefn s) a
ht2 s = GS.headTagged2 (namefn s) a a
ht1' s = GS.headTagged1' (namefn s) a a
instance SexpIso a => SexpIso (Prim a) where
-- sexpIso = primSexpIso ("prim:"<>) sexpIso
sexpIso = primSexpIso id sexpIso
instance SexpIso Lit where
sexpIso = match
$ With (. sexpIso)
$ With (. sym "nil")
$ With (. GS.schemeBool)
$ With (. sexpIso)
$ With (. GS.prefixSugar "quote" Sexp.Quote sexpIso)
$ End
instance SexpIso Sexp where
sexpIso = match
$ With (\conss -> conss . GS.todo)
$ With (\s -> s . symbol)
$ With (\lit -> lit . sexpIso)
$ End
instance SexpIso Def where
sexpIso = match
$ With (. defconst)
$ With (. defun)
$ End
where
defconst = list $ el (sym "define") >>> el sexpIso >>> el sexpIso
defun = list $ el (sym "define") >>> el args >>> rest sexpIso
args = list $ el sexpIso >>> rest sexpIso
instance SexpIso Exp where
sexpIso = match
$ With (. GS.let_ "let" sexpIso sexpIso sexpIso)
$ With (. GS.let_ "letrec" sexpIso sexpIso sexpIso)
$ With (. sexpIso)
$ With (\bgn -> bgn . list (el (sym "begin") >>> rest sexpIso))
$ With (. if_)
$ With (. sexpIso)
$ With (. lam)
$ With (. sexpIso)
$ With (\app -> app . list (el sexpIso >>> rest sexpIso))
$ End
where
if_ = list $ el (sym "if") >>> el sexpIso >>> el sexpIso >>> el sexpIso
lam = list
( el GS.lambdaKeyword
>>> el (sexpIso @(List Name))
>>> el sexpIso )
instance SexpIso CommandOrDef where
sexpIso = match
$ With (\_Command -> _Command . sexpIso)
$ With (\_Definition -> _Definition . sexpIso)
$ With (\_Begin -> _Begin . bgn)
$ End
where
bgn = list $ el (sym "begin") >>> rest sexpIso
-- utilities
scm :: QuasiQuoter
scm = GS.makeSx [|| GS.fromSexp @Exp ||]
freeWithBound' :: Foldable f => f Name -> Exp -> List Name
freeWithBound' bound = filter (`elem` bound) . free'
freeO :: Exp -> O.OSet Name
freeO = O.unbiased . cata \case
ExpVarF x -> O.Bias @O.L $ O.singleton x
ExpLetF bs e ->
foldOf (each . _2) bs
<> (e & coerced %~ deleteFromO (bs ^.. each . _1))
ExpLetRecF bs e ->
(foldOf (each . _2) bs & coerced %~ deleteFromO binds)
<> (e & coerced %~ deleteFromO binds)
where binds = bs ^.. each . _1
ExpLambdaF bs e -> e & coerced %~ deleteFromO bs
e -> fold e
free' :: Exp -> List Name
free' = toList @O.OSet . O.unbiased . cata \case
ExpVarF x -> O.Bias @O.L $ O.singleton x
ExpLetF bs e ->
foldOf (each . _2) bs
<> (e & coerced %~ deleteFromO (bs ^.. each . _1))
ExpLetRecF bs e ->
(foldOf (each . _2) bs & coerced %~ deleteFromO binds)
<> (e & coerced %~ deleteFromO binds)
where binds = bs ^.. each . _1
ExpLambdaF bs e -> e & coerced %~ deleteFromO bs
e -> fold e
free :: Exp -> HashSet Name
free = cata \case
ExpVarF x -> HS.singleton x
ExpLetF bs e -> error "todo lol"
ExpLambdaF binders vs -> deleteFrom binders vs
e -> fold e
deleteFromO :: (Foldable f, Ord a) => f a -> O.OSet a -> O.OSet a
deleteFromO = flip $ foldr O.delete
deleteFrom :: (Foldable f, Hashable a) => f a -> HashSet a -> HashSet a
deleteFrom = flip $ foldr HS.delete
insertFrom :: (Foldable f, Hashable a) => f a -> HashSet a -> HashSet a
insertFrom = flip $ foldr HS.insert
subst :: (Name -> Maybe Exp) -> Exp -> Exp
subst f = \e -> cata go e mempty where
go (ExpVarF x) bound
| not (x `HS.member` bound), Just e' <- f x = e'
| otherwise = ExpVar x
go (ExpLetF _ _) _ = error "todo lol"
go (ExpLambdaF bs e) bound = e $ insertFrom bs bound
go e bound = embed $ fmap ($ bound) e
fileName :: FilePath -> FilePath
fileName "-" = "<interactive>"
fileName e = e
hGetContents :: FS.FileSystem :> es => FS.Handle -> Eff es Text
hGetContents h = T.decodeUtf8 <$> FB.hGetContents h
readProgram :: IOE :> es => FilePath -> Eff es Program
readProgram fp = runFileSystem $
FS.withFile fp FS.ReadMode $ \h ->
GS.parseSexps @CommandOrDef (fileName fp) <$> hGetContents h
>>= either error (pure . MkProgram)
readExp :: IOE :> es => FilePath -> Eff es Exp
readExp fp = readProgram fp <&> (^?! #commandsAndDefs . _head . #Command)
encodeProgram :: Program -> Text
encodeProgram p = p.commandsAndDefs
& fmap ((^?! _Right) . GS.encodePretty)
& intersperse "\n\n"
& mconcat