doc

doc/index.org

@@ -0,0 +1,53 @@
+#+title: Gyehoek Scheme
+
+#+begin_center
+(this document is written in present tense as if the project is complete, but Gyehoek is a work-in-progress.)
+#+end_center
+
+Gyehoek is an R⁷RS-compliant Scheme compiler targeting WebAssembly 3.0, relying principally on the recently standardised garbage collector and tail call proposals. the Gyehoek compiler is implemented in Haskell, and the Gyehoek runtime is a Rust program providing primitive routines and WebAssembly execution via the Wasmtime library.
+
+primitives are implemented as native Rust functions made available to the guest by Wasmtime. in the future, it would be ideal to provide the primitives as a WASI interface to help decouple ourselves from a specific Wasm runtime, but it is not a priority.
+
+Gyehoek allows separate compilation, ~eval~, first-class continuations, and so on.
+
+* pipeline
+
+a Scheme program's journey through Gyehoek is as follows:
+1. read (source code → Scheme data)
+2. parse (Scheme data → AST)
+3. expand(?) (AST → AST)
+4. contify (AST → CPS)
+5. close (CPS → CPS)
+6. lower (CPS → Wasm)
+
+** read
+
+in the read phase, Gyehoek's reader serialises textual source code into a sequence of tokens, which are then parsed into S-expressions. this phase is completely agnostic towards any interpretation of the data — it's just data, not code (yet). this distinction between reading and parsing is made so that the reader can easily be shared amongst many parsers, allowing convenient definition of human-readable representations for all sorts of compiler internals. Gyehoek's intermediate languages and WebAssembly text format are of particular interest.
+
+the reader may be configured to extend R⁷RS's syntax with a special "antiquotation" notation, used internally in the compiler to elegantly interpolate and splice S-expression literals via Haskell's quasiquotation.
+#+begin_src haskell
+  let meta = 123 :: Int
+  in [sx|(a b c #{meta} d)|] -- ⇒ (a b c 123 d)
+
+  let metas = ["c","d"] :: List Text
+  in [sx|(a b ##{metas} e f)|] -- ⇒ (a b "c" "d" e f)
+#+end_src
+
+Gyehoek's lexer and parser are generated by Alex and Happy, respectively.
+
+unless otherwise noted, the term "parse" will be used in reference to the phase taking S-expressions to ASTs, while "read" refers to the combined Alex/Happy process. if the tokenisation process (Alex) must be distinguished from the "parse" process (Happy), the former is called "lexical analysis" and the latter "syntactic analysis."
+
+** parse
+
+- use invertible-grammar library
+
+** expand
+
+** contify
+
+- procedures are distinguished from continuations, and procedure applications are distinguished from continuation jumps.
+- all continuations and lambda will be named i think. the exception is continuations for primitive calls.
+
+** close
+
+** lower

gyehoek.cabal

@@ -66,7 +66,7 @@ library
     , base                  ^>=4.21.2.0
     , binary
     , containers
-    , cradle
+    , typed-process
     , effectful
     , effectful-core
     , effectful-plugin
@@ -89,6 +89,7 @@ library
     , text-short
     , unordered-containers
     , vector
+    , bytestring
 
   hs-source-dirs:   src
   default-language: GHC2024

src/Gyehoek/CPS/Lower.hs

@@ -183,10 +183,10 @@ lower' g e@(ExpApply f xs ktail) = do
     (ref.cast (ref $closure))
     (struct.get $closure $code)
     (return_call_ref $cont-type)
-    ;; (@gyehoek todo
-    ;;  (f' ##{f'})
-    ;;  (ktail #{l}))
-     |]
+    (@gyehoek todo
+     (f' ##{f'})
+     (ktail #{l}))
+  |]
 
 lower' g e@(ExpContinue k xs) = do
   let nargs = length xs

src/Gyehoek/CPS/Syntax.hs

@@ -3,6 +3,7 @@
 {-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE ViewPatterns #-}
 {-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE FunctionalDependencies #-}
 module Gyehoek.CPS.Syntax
   ( Val(..)
   , Kappa(..)
@@ -19,6 +20,11 @@ module Gyehoek.CPS.Syntax
   , _ExpPrim
   , _ExpLetRec
   , _ExpApply
+  , binders
+  , body
+  , op
+  , args
+  , cont
   , cps
   , pattern AbsLambda'
   , pattern AbsKappa'
@@ -48,6 +54,7 @@ import Data.HashSet (HashSet)
 import qualified Data.HashSet as HS
 import Data.Hashable (Hashable)
 import Data.Monoid (Endo)
+import Data.Containers.ListUtils (nubOrd)
 
 -- Data types
 
@@ -56,10 +63,10 @@ data Val
   | ValLit Lit
   deriving (Show, Generic, Data, Eq)
 
-data Kappa = MkKappa (List Name) Exp
+data Kappa = MkKappa { binders :: List Name, body :: Exp }
   deriving (Show, Generic, Data, Eq)
 
-data Lambda = MkLambda (List Name) Name Exp
+data Lambda = MkLambda { binders :: List Name, ktail :: Name, body :: Exp }
   deriving (Show, Generic, Data, Eq)
 
 data Abs
@@ -72,7 +79,7 @@ pattern AbsLambda' xs e ktail = AbsLambda (MkLambda xs e ktail)
 
 data Exp
   = ExpPrim (Prim Val) Kappa
-  | ExpLetRec (NonEmpty (Name, Abs)) Exp
+  | ExpLetRec { binders :: NonEmpty (Name, Abs), body :: Exp }
   | ExpContinue Name (List Val)
   | ExpIf Val Exp Exp
   | ExpApply
@@ -97,7 +104,24 @@ data Program = MkProgram
   deriving (Show, Generic, Data)
 
 makePrisms ''Kappa
+-- makeLenses ''Kappa
 makePrisms ''Exp
+-- makeLenses ''Exp
+-- makeFieldsNoPrefix ''Exp
+-- makeFieldsNoPrefix ''Kappa
+-- makeLensesWith abbreviatedFields ''Exp
+-- makeLensesFor [("binders", "_binders"), ("body", "_body")] ''Exp
+makeFieldsId ''Exp
+makeFieldsId ''Kappa
+makeFieldsId ''Lambda
+
+instance HasBinders Abs (List Name) where
+  binders k (AbsKappa kap) = AbsKappa <$> binders k kap
+  binders k (AbsLambda lam) = AbsLambda <$> binders k lam
+
+instance HasBody Abs Exp where
+  body k (AbsKappa kap) = AbsKappa <$> body k kap
+  body k (AbsLambda lam) = AbsLambda <$> body k lam
 
 
 -- SexpIso instances
@@ -230,24 +254,29 @@ free = go where
 
 -- | Free variables given in the order of their appearance.
 free' :: Exp -> List Name
-free' = go HS.empty where
-  gokap bound (MkKappa xs m) = go (bound & insertFrom xs) m
-  golam bound (MkLambda xs k m) = go (bound & insertFrom (k:xs)) m
-  goabs bound = \case
-    AbsKappa kap -> gokap bound kap
-    AbsLambda lam -> golam bound lam
-  go :: HashSet Name -> Exp -> List Name
-  go bound = \case
-    ExpPrim p k ->
-      p & toListOf (folded . #ValVar . filtered (`notElem` bound))
-        & (<> gokap bound k)
-    ExpLetRec bs m ->
-      foldMapOf (each . _2) (goabs bound') bs <> go bound' m
-      where bound' = bound & insertFrom (bs ^.. each . _1)
-    ExpContinue k xs -> filter (`notElem` bound) (k : xs ^.. each . #ValVar)
-    ExpIf c t f ->
-      (c ^.. #ValVar . filtered (`notElem` bound))
-      <> go bound t <> go bound f
-    ExpApply f xs k ->
-      (f:xs) ^.. (each . #ValVar . filtered (`notElem` bound))
-      <> (k ^.. filtered (`notElem` bound))
+free' = nubOrd . goFree HS.empty where
+
+goFreeKap bound (MkKappa xs m) = goFree (bound & insertFrom xs) m
+goFreeLam bound (MkLambda xs k m) = goFree (bound & insertFrom (k:xs)) m
+goFreeAbs bound = \case
+  AbsKappa kap -> goFreeKap bound kap
+  AbsLambda lam -> goFreeLam bound lam
+
+goFree :: HashSet Name -> Exp -> List Name
+goFree bound = \case
+  ExpPrim p k ->
+    p & toListOf (folded . #ValVar . filtered (`notElem` bound))
+      & (<> goFreeKap bound k)
+  ExpLetRec bs m ->
+    foldMapOf (each . _2) (goFreeAbs bound') bs <> goFree bound' m
+    where bound' = bound & insertFrom (bs ^.. each . _1)
+  ExpContinue k xs -> filter (`notElem` bound) (k : xs ^.. each . #ValVar)
+  ExpIf c t f ->
+    (c ^.. #ValVar . filtered (`notElem` bound))
+    <> goFree bound t <> goFree bound f
+  ExpApply f xs k ->
+    (f:xs) ^.. (each . #ValVar . filtered (`notElem` bound))
+    <> (k ^.. filtered (`notElem` bound))
+
+freeLambda :: Lambda -> List Name
+freeLambda (MkLambda {binders,ktail,body}) = _

src/Gyehoek/Driver.hs

@@ -16,11 +16,18 @@ import qualified Gyehoek.Sexp as Sexp
 import qualified Gyehoek.Scheme.Syntax as Scm
 import qualified Data.Text.Encoding as T
 import System.IO (Handle)
+import System.IO qualified as IO
 import Gyehoek.CPS.Convert
 import Gyehoek.CPS.Lower
 import Gyehoek.CPS.Syntax qualified as Cps
 import Control.Monad
 import Text.Pretty.Simple (pShowNoColor)
+import System.Process.Typed
+import Data.Text.Encoding (encodeUtf8)
+import System.Environment.Blank (getEnvDefault)
+import GHC.Conc (atomically)
+import qualified Data.Text.IO as TIO
+import qualified Data.ByteString.Lazy as BS
 
 
 main :: IO ()
@@ -59,6 +66,31 @@ readScm f =
     Sexp.parseSexps @Scm.CommandOrDef (fileName f) <$> hGetContents h
      >>= either error (pure . Scm.MkProgram)
 
+inspectWasm :: IOE :> es => Text -> Eff es ()
+inspectWasm wat = do
+  pager_cmd <- liftIO $ getEnvDefault "PAGER" "less"
+  let wasmtools_cfg
+        = proc "wasm-tools" ["print", "-pf", "--print-operand-stack"
+                            ,"--color", "always", "-"]
+          -- & setStdin (byteStringInput . view lazy . encodeUtf8 $ wat)
+          -- & setStdout byteStringOutput
+          & setStdin createPipe
+          & setStdout createPipe
+          & setStderr inherit
+  let pager_cfg = proc pager_cmd []
+                & setStdin createPipe
+                & setStdout inherit
+                & setStderr inherit
+  liftIO $ withProcessWait_ wasmtools_cfg \wasmtools -> do
+    TIO.hPutStrLn (getStdin wasmtools) wat
+    IO.hFlush (getStdin wasmtools)
+    IO.hClose (getStdin wasmtools)
+    withProcessWait_ pager_cfg \pager -> do
+      t <- BS.hGetContents (getStdout wasmtools)
+      BS.hPut (getStdin pager) t
+      IO.hFlush (getStdin pager)
+      IO.hClose (getStdin pager)
+
 driver
   :: (GenSym :> es, FileSystem :> es, IOE :> es)
   => Options -> Eff es ()
@@ -70,8 +102,11 @@ driver opts = do
   when opts.dumpCPS do
     hPutStrLn FS.stdout $ Sexp.encodePretty cps ^?! _Right
   wat <- lowerProgram cps
-  withFile opts.output FS.WriteMode \h ->
-    hPutStrLn h wat
+  if not opts.inspectWasm then
+    withFile opts.output FS.WriteMode \h ->
+      hPutStrLn h wat
+  else
+    inspectWasm wat
 
 parse_e2e :: FilePath -> IO Scm.Program
 parse_e2e = runEff . runFileSystem . readScm

src/Gyehoek/Options.hs

@@ -19,6 +19,7 @@ data Options = MkOptions
   -- , dumpQBE :: Maybe FilePath
   dumpCPS :: Bool
   , dumpParsed :: Bool
+  , inspectWasm :: Bool
   , output :: FilePath
   , sourceFile :: FilePath
   }
@@ -49,10 +50,12 @@ parseOutput = strOption
 
 parseDumpCPS = switch (long "dump-cps")
 parseDumpParsed = switch (long "dump-parsed")
+parseInspectWasm = switch $ long "inspect-wasm" <> short 'p'
 
 parser :: Parser Options
 parser = MkOptions
   <$> parseDumpCPS
   <*> parseDumpParsed
+  <*> parseInspectWasm
   <*> parseOutput
   <*> argument str (metavar "FILE")

src/Gyehoek/Scheme/Syntax.hs

@@ -52,7 +52,7 @@ import Language.Haskell.TH.Quote (QuasiQuoter)
 
 
 newtype Name = MkName { inner :: Text }
-  deriving newtype (Show, Eq, IsString, Gen, Hashable)
+  deriving newtype (Show, Eq, Ord, IsString, Gen, Hashable)
   deriving stock (Generic, Data)
 
 getName :: Name -> Text