idk ^w^

src/Gyehoek/CPS/Lower.hs

@@ -28,6 +28,7 @@ import qualified Gyehoek.Sexp
 import Data.Text qualified as T
 import Data.Foldable (fold)
 import Gyehoek.Sexp (encodeOrShow, toSexp)
+import Debug.Pretty.Simple
 
 
 data Env = MkEnv

src/Gyehoek/CPS/Syntax.hs

@@ -2,6 +2,7 @@
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE TypeFamilies #-}
 module Gyehoek.CPS.Syntax
   ( Val(..)
   , Kappa(..)
@@ -22,6 +23,8 @@ module Gyehoek.CPS.Syntax
   , pattern AbsLambda'
   , pattern AbsKappa'
   , Abs(..)
+  , free
+  , free'
   )
   where
 
@@ -41,6 +44,10 @@ import Language.Sexp.Located (Sexp)
 import qualified Data.InvertibleGrammar.Base as IG
 import qualified Gyehoek.Scheme.Syntax as Gyehoek
 import Data.InvertibleGrammar.Base (type (:-)((:-)))
+import Data.HashSet (HashSet)
+import qualified Data.HashSet as HS
+import Data.Hashable (Hashable)
+import Data.Monoid (Endo)
 
 -- Data types
 
@@ -97,7 +104,6 @@ makePrisms ''Exp
 
 instance S.SexpIso Val where
   sexpIso = match
-    --  $ With (. label)
     $ With (\var -> var . S.sexpIso)
     $ With (\lit -> lit . S.sexpIso)
     $ End
@@ -192,3 +198,56 @@ instance CPS Abs where toCPS = Gyehoek.Sexp.fromSexp
 
 cps :: QuasiQuoter
 cps = Gyehoek.Sexp.makeSx' [| toCPS |]
+
+
+
+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
+
+toHashSetOf :: Hashable a => Getting (Endo (HashSet a)) s a -> s -> HashSet a
+toHashSetOf l = foldrOf l HS.insert mempty
+
+free :: Exp -> HashSet Name
+free = go where
+  gokap (MkKappa xs m) = go m & deleteFrom xs
+  golam (MkLambda xs k m) = go m & deleteFrom xs & sans k
+  goabs = \case
+    AbsKappa kap -> gokap kap
+    AbsLambda lam -> golam lam
+  go = \case
+    ExpPrim p k ->
+      p & toHashSetOf (folded . #ValVar)
+        & HS.union (gokap k)
+    ExpLetRec bs m ->
+      foldMapOf (each . _2) goabs bs <> go m
+      & deleteFrom (bs ^.. each . _1)
+    ExpContinue k xs -> HS.fromList $ k : xs ^.. each . #ValVar
+    ExpIf c t f -> toHashSetOf #ValVar c <> go t <> go f
+    ExpApply f xs k -> toHashSetOf (each . #ValVar) (f:xs) <> HS.singleton k
+
+-- | 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))

t.scm

@@ -0,0 +1 @@
+(values 1 2)

t.wat

@@ -0,0 +1,265 @@
+(module
+  (import
+    "gyehoek"
+    "write"
+    (func $gh-write (param (ref eq))))
+  (import
+    "gyehoek"
+    "truthy?"
+    (func $gh-truthy? (param (ref eq)) (result i32)))
+  (type $heap-object (sub (struct (field $hash (mut i32)))))
+  (type $cont-type (func (param i32)))
+  (type $cont-stack-type (array (mut (ref null $cont-type))))
+  (type
+    $closure
+    (sub
+      $heap-object
+      (struct
+        (field $hash (mut i32))
+        (field $code (ref $cont-type)))))
+  (global $cont-stack-top (mut i32) (i32.const 0))
+  (global
+    $cont-stack
+    (ref $cont-stack-type)
+    (array.new_default $cont-stack-type (i32.const 128)))
+  (type $arg-array-type (array (mut (ref null eq))))
+  (global
+    $arg-array
+    (ref $arg-array-type)
+    (array.new_default $arg-array-type (i32.const 32)))
+  (global $result (mut (ref null eq)) (ref.null eq))
+  (func
+    $halt
+    (param i32)
+    (@gyehoek "pop argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (array.get $arg-array-type)
+    ref.as_non_null
+    (global.set $result))
+  (func
+    (param i32)
+    (@gyehoek :origin "(κ (x5) (continue λ-tail1 x5))")
+    (local (ref eq) (ref eq) (ref eq) (ref eq) (ref eq))
+    (@gyehoek "pop argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (array.get $arg-array-type)
+    ref.as_non_null
+    (local.set 1)
+    (@gyehoek :origin "(continue λ-tail1 x5)")
+    (@gyehoek "push args")
+    (@gyehoek "push argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (local.get 4)
+    (array.set $arg-array-type)
+    (@gyehoek "nargs")
+    (i32.const 1)
+    (@gyehoek "pop cont stack")
+    (global.get $cont-stack-top)
+    (i32.const 1)
+    i32.sub
+    (global.set $cont-stack-top)
+    (global.get $cont-stack)
+    (global.get $cont-stack-top)
+    (array.get $cont-stack-type)
+    ref.as_non_null
+    (return_call_ref $cont-type))
+  (elem declare funcref (ref.func 3))
+  (func
+    (param i32)
+    (@gyehoek
+      :origin
+      "(κ (x3) (letrec ((r4 (κ (x5) (continue λ-tail1 x5)))) (f x3 r4)))")
+    (local (ref eq) (ref eq) (ref eq) (ref eq) (ref eq))
+    (@gyehoek "pop argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (array.get $arg-array-type)
+    ref.as_non_null
+    (local.set 1)
+    (@gyehoek :origin "(f x3 r4)")
+    (@gyehoek "push cont" :idx 3)
+    (array.set
+      $cont-stack-type
+      (global.get $cont-stack)
+      (global.get $cont-stack-top)
+      (ref.func 3))
+    (global.set
+      $cont-stack-top
+      (i32.add (global.get $cont-stack-top) (i32.const 1)))
+    (@gyehoek :origin "(f x3 r4)")
+    (@gyehoek "load args")
+    (@gyehoek "push argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (local.get 3)
+    (array.set $arg-array-type)
+    (i32.const 1)
+    (local.get 1)
+    (ref.cast (ref $closure))
+    (struct.get $closure $code)
+    (return_call_ref $cont-type))
+  (elem declare funcref (ref.func 4))
+  (func
+    (param i32)
+    (@gyehoek
+      :origin
+      "(λ (f x λ-tail1) (letrec ((r2 (κ (x3) (letrec ((r4 (κ (x5) (continue λ-tail1 x5)))) (f x3 r4))))) (f x r2)))")
+    (local (ref eq) (ref eq) (ref eq) (ref eq) (ref eq))
+    (@gyehoek "pop argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (array.get $arg-array-type)
+    ref.as_non_null
+    (local.set 1)
+    (@gyehoek "pop argument")
+    (global.get $arg-array)
+    (i32.const 1)
+    (array.get $arg-array-type)
+    ref.as_non_null
+    (local.set 2)
+    (@gyehoek :origin "(f x r2)")
+    (@gyehoek "push cont" :idx 4)
+    (array.set
+      $cont-stack-type
+      (global.get $cont-stack)
+      (global.get $cont-stack-top)
+      (ref.func 4))
+    (global.set
+      $cont-stack-top
+      (i32.add (global.get $cont-stack-top) (i32.const 1)))
+    (@gyehoek :origin "(f x r2)")
+    (@gyehoek "load args")
+    (@gyehoek "push argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (local.get 2)
+    (array.set $arg-array-type)
+    (i32.const 1)
+    (local.get 1)
+    (ref.cast (ref $closure))
+    (struct.get $closure $code)
+    (return_call_ref $cont-type))
+  (elem declare funcref (ref.func 5))
+  (func
+    (param i32)
+    (@gyehoek
+      :origin
+      "(λ (x λ-tail7) (prim (+ x 4) (κ (r8) (continue λ-tail7 r8))))")
+    (local (ref eq) (ref eq) (ref eq) (ref eq) (ref eq))
+    (@gyehoek "pop argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (array.get $arg-array-type)
+    ref.as_non_null
+    (local.set 1)
+    (@gyehoek
+      :origin
+      "(prim (+ x 4) (κ (r8) (continue λ-tail7 r8)))")
+    (local.get 1)
+    (i31.get_s (ref.cast (ref i31)))
+    (i32.const 1)
+    i32.shr_u
+    (i32.const 4)
+    (@gyehoek "construct small fixnum")
+    (i32.const 1)
+    i32.shl
+    ref.i31
+    (i31.get_s (ref.cast (ref i31)))
+    (i32.const 1)
+    i32.shr_u
+    i32.add
+    (@gyehoek "construct small fixnum")
+    (i32.const 1)
+    i32.shl
+    ref.i31
+    (local.set 2)
+    (@gyehoek :origin "(continue λ-tail7 r8)")
+    (@gyehoek "push args")
+    (@gyehoek "push argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (local.get 2)
+    (array.set $arg-array-type)
+    (@gyehoek "nargs")
+    (i32.const 1)
+    (@gyehoek "pop cont stack")
+    (global.get $cont-stack-top)
+    (i32.const 1)
+    i32.sub
+    (global.set $cont-stack-top)
+    (global.get $cont-stack)
+    (global.get $cont-stack-top)
+    (array.get $cont-stack-type)
+    ref.as_non_null
+    (return_call_ref $cont-type))
+  (elem declare funcref (ref.func 6))
+  (func
+    (param i32)
+    (@gyehoek :origin "(κ (x10) (continue halt x10))")
+    (local (ref eq) (ref eq) (ref eq) (ref eq) (ref eq))
+    (@gyehoek "pop argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (array.get $arg-array-type)
+    ref.as_non_null
+    (local.set 1)
+    (@gyehoek "push argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (local.get 3)
+    (array.set $arg-array-type)
+    (return_call $halt (i32.const 1)))
+  (elem declare funcref (ref.func 7))
+  (func
+    $scm-entry
+    (param i32)
+    (@gyehoek
+      :origin
+      "(letrec ((λ-body0 (λ (f x λ-tail1) (letrec ((r2 (κ (x3) (letrec ((r4 (κ (x5) (continue λ-tail1 x5)))) (f x3 r4))))) (f x r2))))) (letrec ((λ-body6 (λ (x λ-tail7) (prim (+ x 4) (κ (r8) (continue λ-tail7 r8)))))) (letrec ((r9 (κ (x10) (continue halt x10)))) (λ-body0 λ-body6 9 r9))))")
+    (local (ref eq) (ref eq) (ref eq) (ref eq) (ref eq))
+    (i32.const 0)
+    (ref.func 5)
+    (struct.new $closure)
+    (local.set 1)
+    (i32.const 0)
+    (ref.func 6)
+    (struct.new $closure)
+    (local.set 2)
+    (@gyehoek :origin "(λ-body0 λ-body6 9 r9)")
+    (@gyehoek "push cont" :idx 7)
+    (array.set
+      $cont-stack-type
+      (global.get $cont-stack)
+      (global.get $cont-stack-top)
+      (ref.func 7))
+    (global.set
+      $cont-stack-top
+      (i32.add (global.get $cont-stack-top) (i32.const 1)))
+    (@gyehoek :origin "(λ-body0 λ-body6 9 r9)")
+    (@gyehoek "load args")
+    (@gyehoek "push argument")
+    (global.get $arg-array)
+    (i32.const 0)
+    (local.get 2)
+    (array.set $arg-array-type)
+    (@gyehoek "push argument")
+    (global.get $arg-array)
+    (i32.const 1)
+    (i32.const 9)
+    (@gyehoek "construct small fixnum")
+    (i32.const 1)
+    i32.shl
+    ref.i31
+    (array.set $arg-array-type)
+    (i32.const 1)
+    (local.get 1)
+    (ref.cast (ref $closure))
+    (struct.get $closure $code)
+    (return_call_ref $cont-type))
+  (func
+    (export "main")
+    (call $scm-entry (i32.const 0))
+    (call $gh-write (ref.as_non_null (global.get $result)))))

test/Gyehoek/Test/CPS/Syntax.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE OverloadedLists #-}
 module Gyehoek.Test.CPS.Syntax (root) where
 
 import Test.Tasty (TestTree, testGroup)
@@ -13,8 +14,20 @@ import Gyehoek.Test.Sexp (equivto)
 root :: IO TestTree
 root = pure . testGroup "cps syntax" $
   [ qqTree
+  , freeTree
   ]
 
+freeTree :: TestTree
+freeTree = testCase "free" do
+  Sut.free [cps|
+    (letrec ((x (lambda (r k1) (continue k1 y)))
+             (y (lambda (r k2) (continue k2 x))))
+      (continue x y k3))|] @=? ["k3"]
+  Sut.free' [cps|
+    (letrec ((x (lambda (r k1) (continue k1 y)))
+             (y (lambda (r k2) (continue k2 x))))
+      (continue x y k3))|] @=? ["k3"]
+
 qqTree :: TestTree
 qqTree = testGroup "parser"
   [ testCase "lambda" do