seems to work

i'm honestly rather disappointed in myself for not implementing a comonadic algo J.
cross my heart i'll come back to this and return stronger!
in the mean time, i really need to get this thing into a presentable state...

Makefile_happysrcs

@@ -1,19 +1,24 @@
+GHC_VERSION = $(shell ghc --numeric-version)
 HAPPY = happy
 HAPPY_OPTS = -a -g -c -i/tmp/t.info
 ALEX = alex
 ALEX_OPTS = -g
 
 SRC = src
-CABAL_BUILD = dist-newstyle/build/x86_64-osx/ghc-9.6.2/rlp-0.1.0.0/build
+CABAL_BUILD = $(shell ./find-build.cl)
 
 all: parsers lexers
 
-parsers: $(CABAL_BUILD)/Rlp/Parse.hs $(CABAL_BUILD)/Core/Parse.hs
+parsers: $(CABAL_BUILD)/Rlp/Parse.hs $(CABAL_BUILD)/Core/Parse.hs \
+		$(CABAL_BUILD)/Rlp/AltParse.hs
 lexers: $(CABAL_BUILD)/Rlp/Lex.hs $(CABAL_BUILD)/Core/Lex.hs
 
 $(CABAL_BUILD)/Rlp/Parse.hs: $(SRC)/Rlp/Parse.y
 	$(HAPPY) $(HAPPY_OPTS) $< -o $@
 
+$(CABAL_BUILD)/Rlp/AltParse.hs: $(SRC)/Rlp/AltParse.y
+	$(HAPPY) $(HAPPY_OPTS) $< -o $@
+
 $(CABAL_BUILD)/Rlp/Lex.hs: $(SRC)/Rlp/Lex.x
 	$(ALEX) $(ALEX_OPTS) $< -o $@
 

examples/Core/factorial.cr

@@ -1,7 +1,9 @@
+fac : Int# -> Int#
 fac n = case (==#) n 0 of
     { <1> -> 1
     ; <0> -> *# n (fac (-# n 1))
     };
 
+main : IO ()
 main = fac 3;
 

find-build.cl

@@ -0,0 +1,8 @@
+#!/usr/bin/env sbcl --script
+
+(let* ((paths (directory "dist-newstyle/build/*/*/rlp-*/build/"))
+       (n (length paths)))
+  (cond ((< 1 n) (error ">1 build directories found. run `cabal clean`."))
+        ((< n 1) (error "no build directories found. this shouldn't happen lol"))
+        (t       (format t "~A" (car paths)))))
+

rlp.cabal

@@ -32,8 +32,13 @@ library
                     , Core.HindleyMilner
                     , Control.Monad.Errorful
                     , Rlp.Syntax
+                    , Rlp.AltSyntax
+                    , Rlp.AltParse
+                    , Rlp.HindleyMilner
+                    , Rlp.HindleyMilner.Types
                     , Rlp.Syntax.Backstage
                     , Rlp.Syntax.Types
+                    , Rlp.Syntax.Good
                     -- , Rlp.Parse.Decls
                     , Rlp.Parse
                     , Rlp.Parse.Associate
@@ -44,10 +49,14 @@ library
                     , Data.Heap
                     , Data.Pretty
                     , Core.Parse
+                    , Core.Parse.Types
                     , Core.Lex
                     , Core2Core
                     , Rlp2Core
                     , Control.Monad.Utils
+                    , Misc
+                    , Misc.Lift1
+                    , Core.SystemF
 
     build-tool-depends: happy:happy, alex:alex
 
@@ -62,7 +71,8 @@ library
                     , data-default-class >= 0.1.2 && < 0.2
                     , hashable >= 1.4.3 && < 1.5
                     , mtl >= 2.3.1 && < 2.4
-                    , text >= 2.0.2 && < 2.1
+                    , transformers
+                    , text >= 2.0.2 && < 2.2
                     , unordered-containers >= 0.2.20 && < 0.3
                     , recursion-schemes >= 5.2.2 && < 5.3
                     , data-fix >= 0.3.2 && < 0.4
@@ -76,6 +86,7 @@ library
                     , deriving-compat ^>=0.6.0
                     , these >=0.2 && <2.0
                     , free >=5.2
+                    , bifunctors >=5.2
 
     hs-source-dirs:   src
     default-language: GHC2021
@@ -89,6 +100,7 @@ library
         DerivingVia
         StandaloneDeriving
         DerivingStrategies
+        BlockArguments
 
 executable rlpc
     import:           warnings
@@ -102,7 +114,7 @@ executable rlpc
                  , mtl >= 2.3.1 && < 2.4
                  , unordered-containers >= 0.2.20 && < 0.3
                  , lens >=5.2.3 && <6.0
-                 , text >= 2.0.2 && < 2.1
+                 , text >= 2.0.2 && < 2.2
 
     hs-source-dirs:   app
     default-language: GHC2021

src/Compiler/JustRun.hs

@@ -10,15 +10,17 @@ types such as @RLPC@ or @Text@.
 module Compiler.JustRun
     ( justLexCore
     , justParseCore
+    , justParseRlp
     , justTypeCheckCore
     , justHdbg
+    , makeItPretty, makeItPretty'
     )
     where
 ----------------------------------------------------------------------------------
 import Core.Lex
 import Core.Parse
 import Core.HindleyMilner
-import Core.Syntax                      (Program')
+import Core.Syntax
 import Compiler.RLPC
 import Control.Arrow                    ((>>>))
 import Control.Monad                    ((>=>), void)
@@ -28,30 +30,47 @@ import Data.Text                        qualified as T
 import Data.Function                    ((&))
 import System.IO
 import GM
-import Rlp.Parse
 import Rlp2Core
+import Data.Pretty
+
+import Rlp.AltParse
+import Rlp.AltSyntax                    qualified as Rlp
 ----------------------------------------------------------------------------------
 
 justHdbg :: String -> IO GmState
-justHdbg s = do
-    p <- evalRLPCIO def (parseRlpProgR >=> desugarRlpProgR $ T.pack s)
-    withFile "/tmp/t.log" WriteMode $ hdbgProg p
+justHdbg = undefined
+-- justHdbg s = do
+--     p <- evalRLPCIO def (parseRlpProgR >=> desugarRlpProgR $ T.pack s)
+--     withFile "/tmp/t.log" WriteMode $ hdbgProg p
 
 justLexCore :: String -> Either [MsgEnvelope RlpcError] [CoreToken]
 justLexCore s = lexCoreR (T.pack s)
               & mapped . each %~ extract
               & rlpcToEither
 
-justParseCore :: String -> Either [MsgEnvelope RlpcError] Program'
+justParseCore :: String -> Either [MsgEnvelope RlpcError] (Program Var)
 justParseCore s = parse (T.pack s)
                 & rlpcToEither
-    where parse = lexCoreR >=> parseCoreProgR
+    where parse = lexCoreR @Identity >=> parseCoreProgR
+
+justParseRlp :: String
+             -> Either [MsgEnvelope RlpcError]
+                       (Rlp.Program Name (Rlp.RlpExpr Name))
+justParseRlp s = parse (T.pack s)
+               & rlpcToEither
+    where parse = parseRlpProgR @Identity
 
 justTypeCheckCore :: String -> Either [MsgEnvelope RlpcError] Program'
 justTypeCheckCore s = typechk (T.pack s)
                     & rlpcToEither
     where typechk = lexCoreR >=> parseCoreProgR >=> checkCoreProgR
 
+makeItPretty :: (Pretty a) => Either e a -> Either e Doc
+makeItPretty = fmap pretty
+
+makeItPretty' :: (Pretty (WithTerseBinds a)) => Either e a -> Either e Doc
+makeItPretty' = fmap (pretty . WithTerseBinds)
+
 rlpcToEither :: RLPC a -> Either [MsgEnvelope RlpcError] a
 rlpcToEither r = case evalRLPC def r of
     (Just a,   _) -> Right a

src/Compiler/RLPC.hs

@@ -27,7 +27,7 @@ module Compiler.RLPC
     -- ** Lenses
     , rlpcLogFile, rlpcDFlags, rlpcEvaluator, rlpcInputFiles, rlpcLanguage
     -- * Misc. MTL-style functions
-    , liftErrorful, hoistRlpcT
+    , liftErrorful, liftMaybe, hoistRlpcT
     -- * Misc. Rlpc Monad -related types
     , RLPCOptions(RLPCOptions), IsRlpcError(..), RlpcError(..)
     , MsgEnvelope(..), Severity(..)
@@ -108,6 +108,9 @@ evalRLPCT opt r = runRLPCT r
 liftErrorful :: (Monad m, IsRlpcError e) => ErrorfulT (MsgEnvelope e) m a -> RLPCT m a
 liftErrorful e = RLPCT $ lift (fmap liftRlpcError `mapErrorful` e)
 
+liftMaybe :: (Monad m) => Maybe a -> RLPCT m a
+liftMaybe m = RLPCT . lift . ErrorfulT . pure $ (m, [])
+
 hoistRlpcT :: (forall a. m a -> n a)
          -> RLPCT m a -> RLPCT n a
 hoistRlpcT f rma = RLPCT $ ReaderT $ \opt ->

src/Compiler/RlpcError.hs

@@ -14,6 +14,9 @@ module Compiler.RlpcError
     -- * Located Comonad
     , Located(..)
     , SrcSpan(..)
+
+    -- * Common error messages
+    , undefinedVariableErr
     )
     where
 ----------------------------------------------------------------------------------
@@ -74,3 +77,8 @@ debugMsg tag e = MsgEnvelope
     , _msgSeverity = SevDebug tag
     }
 
+undefinedVariableErr :: Text -> RlpcError
+undefinedVariableErr n = Text
+    [ "Variable not in scope: `" <> n <> "'."
+    ]
+

src/Compiler/Types.hs

@@ -46,8 +46,6 @@ import Data.Function                (on)
 data Located a = Located SrcSpan a
     deriving (Show, Lift, Functor)
 
-data Floc f = Floc SrcSpan (f (Floc f))
-
 pattern (:<$) :: a -> f b -> Trans.Cofree.CofreeF f a b
 pattern a :<$ b = a Trans.Cofree.:< b
 
@@ -56,10 +54,10 @@ pattern a :<$ b = a Trans.Cofree.:< b
 
 infixl 5 <~>
 
--- (~>) :: (CanGet k, CanSet k', HasLocation k a, HasLocation k' b)
---      => a -> b -> b
--- a ~> b = 
-(~>) = undefined
+(~>) :: (CanGet k, CanSet k', HasLocation k a, HasLocation k' b)
+     => a -> b -> b
+a ~> b = b & fromSet getSetLocation .~ (a ^. fromGet getSetLocation)
+-- (~>) = undefined
 
 infixl 4 ~>
 
@@ -97,15 +95,15 @@ data SrcSpan = SrcSpan
     !Int -- ^ Length
     deriving (Show, Eq, Lift)
 
-tupling :: Iso' SrcSpan (Int, Int, Int, Int)
-tupling = iso (\ (SrcSpan a b c d) -> (a,b,c,d))
+_SrcSpan :: Iso' SrcSpan (Int, Int, Int, Int)
+_SrcSpan = iso (\ (SrcSpan a b c d) -> (a,b,c,d))
               (\ (a,b,c,d) -> SrcSpan a b c d)
 
 srcSpanLine, srcSpanColumn, srcSpanAbs, srcSpanLen :: Lens' SrcSpan Int
-srcSpanLine = tupling . _1
-srcSpanColumn = tupling . _2
-srcSpanAbs = tupling . _3
-srcSpanLen = tupling . _4
+srcSpanLine = _SrcSpan . _1
+srcSpanColumn = _SrcSpan . _2
+srcSpanAbs = _SrcSpan . _3
+srcSpanLen = _SrcSpan . _4
 
 -- | debug tool
 nolo :: a -> Located a
@@ -228,3 +226,4 @@ lochead afs (Located ss fss) = ss :< unwrap (lochead afs $ Located ss fss)
 --------------------------------------------------------------------------------
 
 makePrisms ''Located
+

src/Control/Monad/Errorful.hs

@@ -14,7 +14,9 @@ module Control.Monad.Errorful
     where
 ----------------------------------------------------------------------------------
 import Control.Monad.State.Strict
+import Control.Monad.Writer
 import Control.Monad.Reader
+import Control.Monad.Accum
 import Control.Monad.Trans
 import Data.Functor.Identity
 import Data.Coerce
@@ -85,3 +87,16 @@ instance (Monad m, MonadErrorful e m) => MonadErrorful e (ReaderT r m) where
     addWound = lift . addWound
     addFatal = lift . addFatal
 
+instance (Monad m, MonadState s m) => MonadState s (ErrorfulT e m) where
+    state = lift . state
+
+instance (Monoid w, Monad m, MonadWriter w m) => MonadWriter w (ErrorfulT e m) where
+    tell = lift . tell
+    listen (ErrorfulT m) = ErrorfulT $ listen m <&> \ ((ma,es),w) ->
+        ((,w) <$> ma, es)
+    pass (ErrorfulT m) = undefined
+
+instance (Monoid w, Monad m, MonadAccum w m)
+      => MonadAccum w (ErrorfulT e m) where
+    accum = lift . accum
+

src/Core.hs

@@ -1,6 +1,5 @@
 module Core
     ( module Core.Syntax
-    , parseCore
     , parseCoreProg
     , parseCoreExpr
     , lexCore

src/Core/Examples.hs

@@ -10,12 +10,9 @@ import Core.Syntax
 import Core.TH
 ----------------------------------------------------------------------------------
 
--- fac3 = undefined
--- sumList = undefined
--- constDivZero = undefined
--- idCase = undefined
+letRecExample = undefined
 
----
+{--
 
 letrecExample :: Program'
 letrecExample = [coreProg|

src/Core/HindleyMilner.hs

@@ -35,6 +35,12 @@ import Text.Printf
 import Core.Syntax
 ----------------------------------------------------------------------------------
 
+infer = undefined
+check = undefined
+checkCoreProg = undefined
+checkCoreProgR = undefined
+checkCoreExprR = undefined
+
 -- | Annotated typing context -- I have a feeling we're going to want this in the
 -- future.
 type Context b = [(b, Type)]
@@ -74,6 +80,8 @@ instance IsRlpcError TypeError where
 -- throw any number of fatal or nonfatal errors. Run with @runErrorful@.
 type HMError = Errorful TypeError
 
+{--
+
 -- | Assert that an expression unifies with a given type
 --
 -- >>> let e = [coreProg|3|]
@@ -276,3 +284,4 @@ demoContext =
     , ("False", TyCon "Bool")
     ]
 
+--}

src/Core/Lex.x

@@ -78,7 +78,7 @@ rlp :-
     "{"                     { constTok TokenLBrace }
     "}"                     { constTok TokenRBrace }
     ";"                     { constTok TokenSemicolon }
-    "::"                    { constTok TokenHasType }
+    ":"                     { constTok TokenHasType }
     "@"                     { constTok TokenTypeApp }
     "{-#"                   { constTok TokenLPragma `andBegin` pragma }
 

src/Core/Parse.y

@@ -5,14 +5,12 @@ Description : Parser for the Core language
 -}
 {-# LANGUAGE OverloadedStrings, ViewPatterns #-}
 module Core.Parse
-    ( parseCore
-    , parseCoreExpr
+    ( parseCoreExpr
     , parseCoreExprR
     , parseCoreProg
     , parseCoreProgR
     , module Core.Lex -- temp convenience
     , SrcError
-    , Module
     )
     where
 
@@ -32,19 +30,19 @@ import Data.Text.IO         qualified as TIO
 import Data.Text            (Text)
 import Data.Text            qualified as T
 import Data.HashMap.Strict  qualified as H
+
+import Core.Parse.Types
 }
 
-%name parseCore Module
 %name parseCoreExpr StandaloneExpr
 %name parseCoreProg StandaloneProgram
 %tokentype { Located CoreToken }
 %error { parseError }
-%monad { RLPC } { happyBind } { happyPure }
+%monad { P }
 
 %token
       let             { Located _ TokenLet }
       letrec          { Located _ TokenLetrec }
-      module          { Located _ TokenModule }
       where           { Located _ TokenWhere }
       case            { Located _ TokenCase }
       of              { Located _ TokenOf }
@@ -68,27 +66,25 @@ import Data.HashMap.Strict  qualified as H
       '{-#'           { Located _ TokenLPragma }
       '#-}'           { Located _ TokenRPragma }
       ';'             { Located _ TokenSemicolon }
-      '::'            { Located _ TokenHasType }
+      ':'             { Located _ TokenHasType }
       eof             { Located _ TokenEOF }
 
-%%
+%right '->'
 
-Module          :: { Module Name }
-Module          : module conname where Program Eof { Module (Just ($2, [])) $4 }
-                | Program Eof                      { Module Nothing $1 }
+%%
 
 Eof             :: { () }
 Eof             : eof           { () }
                 | error         { () }
 
-StandaloneProgram :: { Program Name }
+StandaloneProgram :: { Program Var }
 StandaloneProgram : Program eof                 { $1 }
 
-Program         :: { Program Name }
-Program         : ScTypeSig ';' Program         { insTypeSig $1 $3 }
-                | ScTypeSig OptSemi             { singletonTypeSig $1 }
-                | ScDef     ';' Program         { insScDef $1 $3 }
-                | ScDef     OptSemi             { singletonScDef $1 }
+Program         :: { Program Var }
+                : TypedScDef ';' Program    { $3 & insTypeSig (fst $1)
+                                                 & insScDef (snd $1) }
+                | TypedScDef OptSemi        { mempty & insTypeSig (fst $1)
+                                                     & insScDef (snd $1) }
                 | TLPragma Program          {% doTLPragma $1 $2 }
                 | TLPragma                  {% doTLPragma $1 mempty }
 
@@ -104,137 +100,149 @@ OptSemi         : ';'                           { () }
                 | {- epsilon -}                 { () }
 
 ScTypeSig       :: { (Name, Type) }
-ScTypeSig       : Var '::' Type                 { ($1,$3) }
+ScTypeSig       : Id ':' Type                   { ($1, $3) }
 
-ScDefs          :: { [ScDef Name] }
-ScDefs          : ScDef ';' ScDefs              { $1 : $3 }
-                | ScDef ';'                     { [$1] }
-                | ScDef                         { [$1] }
+TypedScDef      :: { (Var, ScDef Var) }
+                : Id ':' Type ';' Id ParList '=' Expr
+                            { (MkVar $1 $3, mkTypedScDef $1 $3 $5 $6 $8) }
 
-ScDef           :: { ScDef Name }
-ScDef           : Var ParList '=' Expr          { ScDef $1 $2 $4 }
-                -- hack to allow constructors to be compiled into scs
-                | Con ParList '=' Expr          { ScDef $1 $2 $4 }
+-- ScDefs          :: { [ScDef PsName] }
+-- ScDefs          : ScDef ';' ScDefs              { $1 : $3 }
+--                 | ScDef ';'                     { [$1] }
+--                 | ScDef                         { [$1] }
+-- 
+-- ScDef           :: { ScDef PsName }
+-- ScDef           : Id ParList '=' Expr   { ScDef (Left $1) $2
+--                                                 ($4 & binders %~ Right) }
 
 Type            :: { Type }
-Type            : Type1                         { $1 }
+                : TypeApp '->' TypeApp              { $1 :-> $3 }
+                | TypeApp                         { $1 }
+
+TypeApp         :: { Type }
+                : TypeApp Type1                 { TyApp $1 $2 }
+                | Type1                         { $1 }
+
+-- do we want to allow symbolic names for tyvars and tycons?
 
 Type1           :: { Type }
 Type1           : '(' Type ')'                  { $2 }
-                | Type1 '->' Type               { $1 :-> $3 }
-                -- do we want to allow symbolic names for tyvars and tycons?
                 | varname                       { TyVar $1 }
-                | conname                       { TyCon $1 }
+                | conname                       { if $1 == "Type"
+                                                    then TyKindType else TyCon $1 }
 
 ParList      :: { [Name] }
-ParList         : Var ParList                   { $1 : $2 }
+ParList      : varname ParList            { $1 : $2 }
              | {- epsilon -}                 { [] }
 
-StandaloneExpr  :: { Expr Name }
+StandaloneExpr  :: { Expr Var }
 StandaloneExpr  : Expr eof                      { $1 }
 
-Expr            :: { Expr Name }
+Expr            :: { Expr Var }
 Expr            : LetExpr                       { $1 }
                 | 'λ' Binders '->' Expr         { Lam $2 $4 }
                 | Application                   { $1 }
                 | CaseExpr                      { $1 }
                 | Expr1                         { $1 }
 
-LetExpr         :: { Expr Name }
+LetExpr         :: { Expr Var }
 LetExpr         : let    '{'   Bindings '}'    in Expr { Let NonRec $3 $6 }
                 | letrec '{'   Bindings '}'    in Expr { Let Rec $3 $6 }
 
-Binders         :: { [Name] }
+Binders         :: { [Var] }
 Binders         : Var Binders                  { $1 : $2 }
                 | Var                          { [$1] }
 
-Application     :: { Expr Name }
-Application     : Expr1 AppArgs                { foldl' App $1 $2 }
+Application     :: { Expr Var }
+Application     : Application AppArg           { App $1 $2 }
+                | Expr1       AppArg           { App $1 $2 }
 
-AppArgs         :: { [Expr Name] }
-AppArgs         : Expr1 AppArgs                 { $1 : $2 }
-                | Expr1                         { [$1] }
+AppArg          :: { Expr Var }
+                : '@' Type1                     { Type $2 }
+                | Expr1                         { $1 }
 
-CaseExpr        :: { Expr Name }
+CaseExpr        :: { Expr Var }
 CaseExpr        : case Expr of '{' Alters '}'   { Case $2 $5 }
 
-Alters          :: { [Alter Name] }
+Alters          :: { [Alter Var] }
 Alters          : Alter ';' Alters              { $1 : $3 }
                 | Alter ';'                     { [$1] }
                 | Alter                         { [$1] }
 
-Alter           :: { Alter Name }
-Alter           : alttag ParList '->' Expr      { Alter (AltTag  $1) $2 $4 }
-                | Con    ParList '->' Expr      { Alter (AltData $1) $2 $4 }
+Alter           :: { Alter Var }
+Alter           : alttag  AltParList '->' Expr     { Alter (AltTag  $1) $2 $4 }
+                | conname AltParList '->' Expr     { Alter (AltData $1) $2 $4 }
 
-Expr1           :: { Expr Name }
+AltParList      :: { [Var] }
+                : Var AltParList                { $1 : $2 }
+                | {- epsilon -}                 { [] }
+
+Expr1           :: { Expr Var }
 Expr1           : litint                        { Lit $ IntL $1 }
                 | Id                            { Var $1 }
                 | PackCon                       { $1 }
                 | '(' Expr ')'                  { $2 }
 
-PackCon         :: { Expr Name }
+PackCon         :: { Expr Var }
 PackCon         : pack '{' litint litint '}'    { Con $3 $4 }
 
-Bindings        :: { [Binding Name] }
+Bindings        :: { [Binding Var] }
 Bindings        : Binding ';' Bindings          { $1 : $3 }
                 | Binding ';'                   { [$1] }
                 | Binding                       { [$1] }
 
-Binding         :: { Binding Name }
+Binding         :: { Binding Var }
 Binding         : Var '=' Expr                  { $1 := $3 }
 
 Id              :: { Name }
-Id              : Var                                { $1 }
-                | Con                                { $1 }
+                : varname                           { $1 }
+                | conname                           { $1 }
 
-Var             :: { Name }
-Var             : varname                           { $1 }
-                | varsym                            { $1 }
-
-Con             :: { Name }
-Con             : conname                           { $1 }
-                | consym                            { $1 }
+Var             :: { Var }
+Var             : '(' varname ':' Type ')'          { MkVar $2 $4 }
 
 {
 
-parseError :: [Located CoreToken] -> RLPC a
+parseError :: [Located CoreToken] -> P a
 parseError (Located _ t : _) =
     error $ "<line>" <> ":" <> "<col>"
          <> ": parse error at token `" <> show t <> "'"
 
-{-# WARNING parseError "unimpl" #-}
-
-exprPragma :: [String] -> RLPC (Expr Name)
+exprPragma :: [String] -> RLPC (Expr Var)
 exprPragma ("AST" : e) = undefined
 exprPragma _           = undefined
 
-{-# WARNING exprPragma "unimpl" #-}
-
-astPragma :: [String] -> RLPC (Expr Name)
+astPragma :: [String] -> RLPC (Expr Var)
 astPragma _ = undefined
 
-{-# WARNING astPragma "unimpl" #-}
+-- insTypeSig :: (Hashable b) => (b, Type) -> Program b -> Program b
+-- insTypeSig ts = programTypeSigs %~ uncurry H.insert ts
 
-insTypeSig :: (Hashable b) => (b, Type) -> Program b -> Program b
-insTypeSig ts = programTypeSigs %~ uncurry H.insert ts
+insTypeSig :: Var -> Program Var -> Program Var
+insTypeSig w@(MkVar _ t) = programTypeSigs %~ H.insert w t
 
-singletonTypeSig :: (Hashable b) => (b, Type) -> Program b
-singletonTypeSig ts = insTypeSig ts mempty
+-- singletonTypeSig :: (Hashable b) => (b, Type) -> Program b
+-- singletonTypeSig ts = insTypeSig ts mempty
 
 insScDef :: (Hashable b) => ScDef b -> Program b -> Program b
 insScDef sc = programScDefs %~ (sc:)
 
-singletonScDef :: (Hashable b) => ScDef b -> Program b
-singletonScDef sc = insScDef sc mempty
+-- singletonScDef :: (Hashable b) => ScDef b -> Program b
+-- singletonScDef sc = insScDef sc mempty
 
-parseCoreExprR :: (Monad m) => [Located CoreToken] -> RLPCT m Expr'
-parseCoreExprR = hoistRlpcT generalise . parseCoreExpr
+parseCoreExprR :: (Monad m) => [Located CoreToken] -> RLPCT m (Expr Var)
+parseCoreExprR = liftMaybe . snd . flip runP def . parseCoreExpr
 
-parseCoreProgR :: forall m. (Monad m) => [Located CoreToken] -> RLPCT m Program'
-parseCoreProgR = ddumpast <=< (hoistRlpcT generalise . parseCoreProg)
+parseCoreProgR :: forall m. (Monad m)
+               => [Located CoreToken] -> RLPCT m (Program Var)
+parseCoreProgR s = do
+    let p = runP (parseCoreProg s) def
+    case p of
+        (st, Just a) -> do
+            ddumpast a
+            pure a
   where
-        ddumpast :: Program' -> RLPCT m Program'
+    ddumpast :: Show a => Program a -> RLPCT m (Program a)
     ddumpast p = do
         addDebugMsg "dump-parsed-core" . show $ p
         pure p
@@ -245,7 +253,7 @@ happyBind m k = m >>= k
 happyPure :: a -> RLPC a
 happyPure a = pure a
 
-doTLPragma :: Pragma -> Program' -> RLPC Program'
+doTLPragma :: Pragma -> Program Var -> P (Program Var)
 -- TODO: warn unrecognised pragma
 doTLPragma (Pragma []) p = pure p
 

src/Core/Parse/Types.hs

@@ -0,0 +1,62 @@
+{-# LANGUAGE TemplateHaskell #-}
+module Core.Parse.Types
+    ( P(..)
+    , psTyVars
+    , def
+    , PsName
+    , mkTypedScDef
+    )
+    where
+--------------------------------------------------------------------------------
+import Control.Applicative
+import Control.Monad
+import Control.Monad.State
+import Data.Default
+import Data.Maybe
+import Data.Tuple               (swap)
+
+import Control.Lens
+
+import Core.Syntax
+--------------------------------------------------------------------------------
+
+newtype P a = P { runP :: PState -> (PState, Maybe a) }
+    deriving Functor
+
+data PState = PState
+    { _psTyVars :: [(Name, Kind)]
+    }
+
+instance Applicative P where
+    pure a = P (, Just a)
+
+    P pf <*> P pa = P \st ->
+        let (st',mf) = pf st
+            (st'',ma) = pa st'
+        in (st'', mf <*> ma)
+
+instance Monad P where
+    P pa >>= k = P \st ->
+        let (st',ma) = pa st
+        in case ma of
+            Just a -> runP (k a) st'
+            Nothing -> (st', Nothing)
+
+instance MonadState PState P where
+    state = P . fmap ((_2 %~ Just) . review swapped)
+
+instance Default PState where
+    def = undefined
+
+makeLenses ''PState
+
+type PsName = Either Name Var
+
+--------------------------------------------------------------------------------
+
+mkTypedScDef :: Name -> Type -> Name -> [Name] -> Expr Var -> ScDef Var
+mkTypedScDef nt tt n as e | nt == n = ScDef n' as' e
+    where
+        n' = MkVar n tt
+        as' = zipWith MkVar as (tt ^.. arrowStops)
+

src/Core/Syntax.hs

@@ -7,39 +7,39 @@ Description : Core ASTs and the like
 {-# LANGUAGE TemplateHaskell #-}
 -- for recursion-schemes
 {-# LANGUAGE DeriveTraversable, TypeFamilies #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE QuantifiedConstraints #-}
 module Core.Syntax
-    ( Expr(..)
-    , ExprF(..)
-    , ExprF'(..)
-    , Type(..)
-    , pattern TyInt
-    , Lit(..)
-    , pattern (:$)
-    , pattern (:@)
-    , pattern (:->)
-    , Binding(..)
-    , AltCon(..)
-    , pattern (:=)
-    , Rec(..)
-    , Alter(..)
-    , Name
-    , Tag
-    , ScDef(..)
-    , Module(..)
-    , Program(..)
-    , Program'
+    (
+    -- * Core AST
+      ExprF(..), ExprF'
+    , ScDef(..), ScDef'
+    , Program(..), Program'
+    , Type(..), Kind, pattern (:->), pattern TyInt
+    , AlterF(..), Alter(..), Alter', AltCon(..)
+    , pattern Binding, pattern Alter
+    , Rec(..), Lit(..)
     , Pragma(..)
-    , unliftScDef
-    , programScDefs
-    , programTypeSigs
-    , programDataTags
-    , Expr'
-    , ScDef'
-    , Alter'
-    , Binding'
-    , HasRHS(_rhs)
-    , HasLHS(_lhs)
-    , Pretty(pretty)
+    -- ** Variables and identifiers
+    , Name, Var(..), Tag, pattern (:^)
+    , Binding, BindingF(..), pattern (:=), pattern (:$)
+    , type Binding'
+    -- ** Working with the fixed point of ExprF
+    , Expr, Expr'
+    , pattern Con, pattern Var, pattern App, pattern Lam, pattern Let
+    , pattern Case, pattern Type, pattern Lit
+
+    -- * Pretty-printing
+    , Pretty(pretty), WithTerseBinds(..)
+
+    -- * Optics
+    , HasArrowSyntax(..)
+    , programScDefs, programTypeSigs, programDataTags, programTyCons
+    , formalising, lambdaLifting
+    , HasRHS(_rhs), HasLHS(_lhs)
+    , _BindingF, _MkVar, _ScDef
+    -- ** Classy optics
+    , HasBinders(..), HasArrowStops(..), HasApplicants1(..), HasApplicants(..)
     )
     where
 ----------------------------------------------------------------------------------
@@ -47,109 +47,199 @@ import Data.Coerce
 import Data.Pretty
 import Data.List                    (intersperse)
 import Data.Function                ((&))
-import Data.Functor.Foldable
-import Data.Functor.Foldable.TH     (makeBaseFunctor)
 import Data.String
 import Data.HashMap.Strict          (HashMap)
 import Data.HashMap.Strict          qualified as H
 import Data.Hashable
+import Data.Hashable.Lifted
+import Data.Foldable                (traverse_)
+import Data.Functor
+import Data.Monoid
+import Data.Functor.Classes
 import Data.Text                    qualified as T
 import Data.Char
 import Data.These
-import Data.Bifoldable              (bifoldr)
-import GHC.Generics                 (Generic, Generically(..))
+import GHC.Generics                 (Generic, Generic1, Generically(..))
+import Text.Show.Deriving
+import Data.Eq.Deriving
+import Data.Kind                    qualified
+
+import Data.Fix                     hiding (cata, ana)
+import Data.Bifunctor               (Bifunctor(..))
+import Data.Bifoldable              (bifoldr, Bifoldable(..))
+import Data.Bifunctor.TH
+import Data.Bitraversable
+import Data.Functor.Foldable
+import Data.Functor.Foldable.TH     (makeBaseFunctor)
+
 -- Lift instances for the Core quasiquoters
-import Language.Haskell.TH.Syntax   (Lift)
+import Misc
+import Misc.Lift1
 import Control.Lens
 ----------------------------------------------------------------------------------
 
-data Expr b = Var Name
-            | Con Tag Int -- ^ Con Tag Arity
-            | Case (Expr b) [Alter b]
-            | Lam [b] (Expr b)
-            | Let Rec [Binding b] (Expr b)
-            | App (Expr b) (Expr b)
-            | Lit Lit
-            deriving (Show, Read, Lift)
+data ExprF b a = VarF Name
+               | ConF Tag Int -- ^ Con Tag Arity
+               | CaseF a [AlterF b a]
+               | LamF [b] a
+               | LetF Rec [BindingF b a] a
+               | AppF a a
+               | LitF Lit
+               | TypeF Type
+               deriving (Functor, Foldable, Traversable)
 
-deriving instance (Eq b) => Eq (Expr b)
+type Expr b = Fix (ExprF b)
+
+instance IsString (ExprF b a) where
+    fromString = VarF . fromString
+
+instance (IsString (f (Fix f))) => IsString (Fix f) where
+    fromString = Fix . fromString
 
 data Type = TyFun
           | TyVar Name
           | TyApp Type Type
           | TyCon Name
-          deriving (Show, Read, Lift, Eq)
+          | TyForall Var Type
+          | TyKindType
+          deriving (Show, Eq, Lift)
+
+type Kind = Type
+
+-- data TyCon = MkTyCon Name Kind
+--     deriving (Eq, Show, Lift)
+
+data Var = MkVar Name Type
+    deriving (Eq, Show, Lift)
+
+pattern (:^) :: Name -> Type -> Var
+pattern n :^ t = MkVar n t
+
+instance Hashable Var where
+    hashWithSalt s (MkVar n _) = hashWithSalt s n
+
+pattern Con :: Tag -> Int -> Expr b
+pattern Con t a = Fix (ConF t a)
+
+pattern Var :: Name -> Expr b
+pattern Var b = Fix (VarF b)
+
+pattern App :: Expr b -> Expr b -> Expr b
+pattern App f x = Fix (AppF f x)
+
+pattern Lam :: [b] -> Expr b -> Expr b
+pattern Lam bs e = Fix (LamF bs e)
+
+pattern Let :: Rec -> [Binding b] -> Expr b -> Expr b
+pattern Let r bs e = Fix (LetF r bs e)
+
+pattern Case :: Expr b -> [Alter b] -> Expr b
+pattern Case e as = Fix (CaseF e as)
+
+pattern Type :: Type -> Expr b
+pattern Type t = Fix (TypeF t)
+
+pattern Lit :: Lit -> Expr b
+pattern Lit t = Fix (LitF t)
 
 pattern TyInt :: Type
 pattern TyInt = TyCon "Int#"
 
-infixl 2 :$
-pattern (:$) :: Expr b -> Expr b -> Expr b 
-pattern f :$ x = App f x
+class HasArrowSyntax s a b | s -> a b where
+    _arrowSyntax :: Prism' s (a, b)
 
-infixl 2 :@
-pattern (:@) :: Type -> Type -> Type
-pattern f :@ x = TyApp f x
+instance HasArrowSyntax Type Type Type where
+    _arrowSyntax = prism make unmake where
+        make (s,t) = TyFun `TyApp` s `TyApp` t
+
+        unmake (TyFun `TyApp` s `TyApp` t) = Right (s,t)
+        unmake s                           = Left s
 
 infixr 1 :->
-pattern (:->) :: Type -> Type -> Type
-pattern a :-> b = TyApp (TyApp TyFun a) b
+pattern (:->) :: HasArrowSyntax s a b
+              => a -> b -> s
+-- pattern (:->) :: Type -> Type -> Type
+pattern a :-> b <- (preview _arrowSyntax -> Just (a, b))
+    where a :-> b = _arrowSyntax # (a, b)
 
-{-# COMPLETE Binding :: Binding #-}
-{-# COMPLETE (:=) :: Binding #-}
-data Binding b = Binding b (Expr b)
-    deriving (Show, Read, Lift)
+data BindingF b a = BindingF b (ExprF b a)
+    deriving (Functor, Foldable, Traversable)
 
-deriving instance (Eq b) => Eq (Binding b)
+type Binding b = BindingF b (Fix (ExprF b))
+
+type Binding' = Binding Name
+
+-- collapse = foldFix embed
+
+pattern Binding :: b -> Expr b -> Binding b
+pattern Binding k v <- BindingF k (wrapFix -> v)
+    where Binding k v = BindingF k (unwrapFix v)
+
+{-# COMPLETE (:=) #-}
+{-# COMPLETE Binding #-}
 
 infixl 1 :=
 pattern (:=) :: b -> Expr b -> Binding b
 pattern k := v = Binding k v
 
-data Alter b = Alter AltCon [b] (Expr b)
-    deriving (Show, Read, Lift)
+infixl 2 :$
+pattern (:$) :: Expr b -> Expr b -> Expr b
+pattern f :$ x = App f x
 
-deriving instance (Eq b) => Eq (Alter b)
+data AlterF b a = AlterF AltCon [b] (ExprF b a)
+    deriving (Functor, Foldable, Traversable)
+
+pattern Alter :: AltCon -> [b] -> Expr b -> Alter b
+pattern Alter con bs e <- AlterF con bs (wrapFix -> e)
+    where Alter con bs e = AlterF con bs (unwrapFix e)
+
+type Alter b = AlterF b (Fix (ExprF b))
+
+type Alter' = Alter Name
+
+-- pattern Alter :: AltCon -> [b] -> Expr b -> Alter b
+-- pattern Alter con bs e <- Fix (AlterF con bs (undefined -> e))
+--     where Alter con bs e = Fix (AlterF con bs undefined)
 
 newtype Pragma = Pragma [T.Text]
 
 data Rec = Rec
          | NonRec
-         deriving (Show, Read, Eq, Lift)
+         deriving (Show, Eq, Lift)
 
 data AltCon = AltData Name
             | AltTag Tag
             | AltLit Lit
             | AltDefault
-            deriving (Show, Read, Eq, Lift)
+            deriving (Show, Eq, Lift)
 
 newtype Lit = IntL Int
-    deriving (Show, Read, Eq, Lift)
+    deriving (Show, Eq, Lift)
 
 type Name = T.Text
 type Tag = Int
 
 data ScDef b = ScDef b [b] (Expr b)
-    deriving (Show, Lift)
 
-unliftScDef :: ScDef b -> Expr b
-unliftScDef (ScDef _ as e) = Lam as e
+-- unliftScDef :: ScDef b -> Expr b
+-- unliftScDef (ScDef _ as e) = Lam as e
 
 data Module b = Module (Maybe (Name, [Name])) (Program b)
-    deriving (Show, Lift)
 
 data Program b = Program
     { _programScDefs   :: [ScDef b]
     , _programTypeSigs :: HashMap b Type
-    , _programDataTags :: HashMap b (Tag, Int)
+    , _programDataTags :: HashMap Name (Tag, Int)
     -- ^ map constructors to their tag and arity
+    , _programTyCons   :: HashMap Name Kind
+    -- ^ map type constructors to their kind
     }
-    deriving (Show, Lift, Generic)
+    deriving (Generic)
     deriving (Semigroup, Monoid)
         via Generically (Program b)
 
 makeLenses ''Program
-makeBaseFunctor ''Expr
+-- makeBaseFunctor ''Expr
 pure []
 
 -- this is a weird optic, stronger than Lens and Prism, but weaker than Iso.
@@ -163,65 +253,97 @@ type ExprF' = ExprF Name
 type Program' = Program Name
 type Expr' = Expr Name
 type ScDef' = ScDef Name
-type Alter' = Alter Name
-type Binding' = Binding Name
+-- type Alter' = Alter Name
+-- type Binding' = Binding Name
 
-instance IsString (Expr b) where
-    fromString = Var . fromString
+-- instance IsString (Expr b) where
+--     fromString = Var . fromString
 
-instance IsString Type where
-    fromString "" = error "IsString Type string may not be empty"
-    fromString s
-        | isUpper c     = TyCon . fromString $ s
-        | otherwise     = TyVar . fromString $ s
-        where (c:_) = s
+lambdaLifting :: Iso (ScDef b) (ScDef b') (b, Expr b) (b', Expr b')
+lambdaLifting = iso sa bt where
+    sa (ScDef n as e) = (n, e') where
+        e' = Lam as e
+
+    bt (n, Lam as e) = ScDef n as e
+    bt (n, e)        = ScDef n [] e
 
 ----------------------------------------------------------------------------------
 
 class HasRHS s t a b | s -> a, t -> b, s b -> t, t a -> s where
     _rhs :: Lens s t a b
 
-instance HasRHS (Alter b) (Alter b) (Expr b) (Expr b) where
+instance HasRHS (AlterF b a) (AlterF b a') (ExprF b a) (ExprF b a') where
     _rhs = lens
-        (\ (Alter _ _ e) -> e)
-        (\ (Alter t as _) e' -> Alter t as e')
+        (\ (AlterF _ _ e) -> e)
+        (\ (AlterF t as _) e' -> AlterF t as e')
 
 instance HasRHS (ScDef b) (ScDef b) (Expr b) (Expr b) where
     _rhs = lens
         (\ (ScDef _ _ e) -> e)
         (\ (ScDef n as _) e' -> ScDef n as e')
 
-instance HasRHS (Binding b) (Binding b) (Expr b) (Expr b) where
-    _rhs = lens
-        (\ (_ := e) -> e)
-        (\ (k := _) e' -> k := e')
+instance HasRHS (BindingF b a) (BindingF b' a') (ExprF b a) (ExprF b' a')
 
 class HasLHS s t a b | s -> a, t -> b, s b -> t, t a -> s where
     _lhs :: Lens s t a b
 
-instance HasLHS (Alter b) (Alter b) (AltCon, [b]) (AltCon, [b]) where
-    _lhs = lens
-        (\ (Alter a bs _) -> (a,bs))
-        (\ (Alter _ _ e) (a',bs') -> Alter a' bs' e)
-
 instance HasLHS (ScDef b) (ScDef b) (b, [b]) (b, [b]) where
     _lhs = lens
         (\ (ScDef n as _) -> (n,as))
         (\ (ScDef _ _ e) (n',as') -> ScDef n' as' e)
 
-instance HasLHS (Binding b) (Binding b) b b where
-    _lhs = lens
-        (\ (k := _) -> k)
-        (\ (_ := e) k' -> k' := e)
+-- instance HasLHS (Binding b) (Binding b) b b where
+    -- _lhs = lens
+    --     (\ (k := _) -> k)
+    --     (\ (_ := e) k' -> k' := e)
+
+-- | This is not a valid isomorphism for expressions containing lambdas whose
+-- bodies are themselves lambdas with multiple arguments:
+--
+-- >>> [coreExpr|\x -> \y z -> x|] ^. from (from formalising)
+-- Lam ["x"] (Lam ["y"] (Lam ["z"] (Var "x")))
+-- >>> [coreExpr|\x -> \y z -> x|]
+-- Lam ["x"] (Lam ["y","z"] (Var "x"))
+--
+-- For this reason, it's best to consider 'formalising' as if it were two
+-- unrelated unidirectional getters.
+
+formalising :: Iso (Expr a) (Expr b) (Expr a) (Expr b)
+formalising = iso sa bt where
+    sa :: Expr a -> Expr a
+    sa = ana \case
+        Lam [b] e      -> LamF [b] e
+        Lam (b:bs) e   -> LamF [b] (Lam bs e)
+        Let r (b:bs) e -> LetF r [b] (Let r bs e)
+        x              -> project x
+
+    bt :: Expr b -> Expr b
+    bt = cata \case
+        LamF [b] (Lam bs e)                -> Lam (b:bs) e
+        LetF r [b] (Let r' bs e) | r == r' -> Let r (b:bs) e
+        x                                  -> embed x
 
 --------------------------------------------------------------------------------
 
--- TODO: print type sigs with corresponding scdefs
--- TODO: emit pragmas for datatags
-instance (Hashable b, Pretty b) => Pretty (Program b) where
-    pretty p = ifoldrOf (programDataTags . ifolded) cataDataTag mempty p
-           $+$ vlinesOf (programJoinedDefs . to prettyGroup) p
+newtype WithTerseBinds a = WithTerseBinds a
+
+class MakeTerse a where
+    type AsTerse a :: Data.Kind.Type
+    asTerse :: a -> AsTerse a
+
+instance MakeTerse Var where
+    type AsTerse Var = Name
+    asTerse (MkVar n _) = n
+
+instance (Hashable b, Pretty b, Pretty (AsTerse b), MakeTerse b)
+      => Pretty (WithTerseBinds (Program b)) where
+    pretty (WithTerseBinds p)
+            = (datatags <> "\n")
+          $+$ defs
         where
+            datatags = ifoldrOf (programDataTags . ifolded) cataDataTag mempty p
+            defs = vlinesOf (programJoinedDefs . to prettyGroup) p
+
             programJoinedDefs :: Fold (Program b) (These (b, Type) (ScDef b))
             programJoinedDefs = folding $ \p ->
                 foldMapOf programTypeSigs thisTs p
@@ -234,67 +356,427 @@ instance (Hashable b, Pretty b) => Pretty (Program b) where
                 H.singleton (sc ^. _lhs . _1) (That sc)
 
             prettyGroup :: These (b, Type) (ScDef b) -> Doc
-            prettyGroup = bifoldr ($$) ($$) mempty . bimap prettyTySig pretty
+            prettyGroup = bifoldr vs vs mempty
+                        . bimap (uncurry prettyTySig')
+                                (pretty . WithTerseBinds)
+                where vs = vsepTerm ";"
 
-            prettyTySig (n,t) = hsep [ttext n, "::", pretty t]
+            cataDataTag n (t,a) acc = prettyDataTag n t a $+$ acc
 
+instance (Hashable b, Pretty b) => Pretty (Program b) where
+    pretty p = (datatags <> "\n")
+           $+$ defs
+        where
+            datatags = ifoldrOf (programDataTags . ifolded) cataDataTag mempty p
+            defs = vlinesOf (programJoinedDefs . to prettyGroup) p
+
+            programJoinedDefs :: Fold (Program b) (These (b, Type) (ScDef b))
+            programJoinedDefs = folding $ \p ->
+                foldMapOf programTypeSigs thisTs p
+                `u` foldMapOf programScDefs thatSc p
+              where u = H.unionWith unionThese
+
+            thisTs = ifoldMap @b @(HashMap b)
+                (\n t -> H.singleton n (This (n,t)))
+            thatSc = foldMap $ \sc ->
+                H.singleton (sc ^. _lhs . _1) (That sc)
+
+            prettyGroup :: These (b, Type) (ScDef b) -> Doc
+            prettyGroup = bifoldr vs vs mempty
+                        . bimap (uncurry prettyTySig) pretty
+                where vs = vsepTerm ";"
+
+            cataDataTag n (t,a) acc = prettyDataTag n t a $+$ acc
+
+unionThese :: These a b -> These a b -> These a b
 unionThese (This a) (That b) = These a b
 unionThese (That b) (This a) = These a b
 unionThese (These a b) _     = These a b
 
-            cataDataTag n (t,a) acc = prettyDataTag n t a $+$ acc
-
+prettyDataTag :: (Pretty n, Pretty t, Pretty a)
+              => n -> t -> a -> Doc
 prettyDataTag n t a =
     hsep ["{-#", "PackData", ttext n, ttext t, ttext a, "#-}"]
 
+prettyTySig :: (Pretty n, Pretty t) => n -> t -> Doc
+prettyTySig n t = hsep [ttext n, ":", pretty t]
+
+prettyTySig' :: (MakeTerse n, Pretty (AsTerse n), Pretty t) => n -> t -> Doc
+prettyTySig' n t = hsep [ttext (asTerse n), ":", pretty t]
+
+-- Pretty Type
+-- TyApp | appPrec   | left
+-- (:->) | appPrec-1 | right
+
 instance Pretty Type where
     prettyPrec _ (TyVar n)   = ttext n
     prettyPrec _ TyFun       = "(->)"
     prettyPrec _ (TyCon n)   = ttext n
-    prettyPrec p (a :-> b) = maybeParens (p>0) $
-        hsep [prettyPrec 1 a, "->", prettyPrec 0 b]
-    prettyPrec p (TyApp f x) = maybeParens (p>1) $
-        prettyPrec 1 f <+> prettyPrec 2 x
+    prettyPrec p (a :-> b)   = maybeParens (p>appPrec-1) $
+        hsep [prettyPrec appPrec a, "->", prettyPrec (appPrec-1) b]
+    prettyPrec p (TyApp f x) = maybeParens (p>appPrec) $
+        prettyPrec appPrec f <+> prettyPrec appPrec1 x
+    prettyPrec p (TyForall a m) = maybeParens (p>appPrec-2) $
+        "∀" <+> (prettyPrec appPrec1 a <> ".") <+> pretty m
+    prettyPrec _ TyKindType = "Type"
+
+instance (Pretty b, Pretty (AsTerse b), MakeTerse b)
+      => Pretty (WithTerseBinds (ScDef b)) where
+    pretty (WithTerseBinds sc) = hsep [name, as, "=", hang empty 1 e]
+        where
+            name = ttext $ sc ^. _lhs . _1 . to asTerse
+            as = sc & hsepOf (_lhs . _2 . each . to asTerse . to ttext)
+            e = pretty $ sc ^. _rhs
 
 instance (Pretty b) => Pretty (ScDef b) where
-    pretty sc = hsep [name, as, "=", hang empty 1 e, ";"]
+    pretty sc = hsep [name, as, "=", hang empty 1 e]
         where
             name = ttext $ sc ^. _lhs . _1
             as = sc & hsepOf (_lhs . _2 . each . to ttext)
             e = pretty $ sc ^. _rhs
 
-instance (Pretty b) => Pretty (Expr b) where
-    prettyPrec _ (Var n)      = ttext n
-    prettyPrec _ (Con t a)    = "Pack{" <> (ttext t <+> ttext a) <> "}"
-    prettyPrec _ (Lam bs e)   = hsep ["λ", hsep (prettyPrec 1 <$> bs), "->", pretty e]
-    prettyPrec _ (Let r bs e) = hsep [word, explicitLayout bs]
-                            $+$ hsep ["in", pretty e]
-        where word = if r == Rec then "letrec" else "let"
-    prettyPrec p (App f x)    = maybeParens (p>0) $
-        prettyPrec 0 f <+> prettyPrec 1 x
-    prettyPrec _ (Lit l)      = pretty l
-    prettyPrec p (Case e as)  = maybeParens (p>0) $
-        "case" <+> pretty e <+> "of"
-        $+$ nest 2 (explicitLayout as)
+-- Pretty Expr
+-- LamF | appPrec1 | right
+-- AppF | appPrec  | left
 
-instance (Pretty b) => Pretty (Alter b) where
-    pretty (Alter c as e) =
-        hsep [pretty c, hsep (pretty <$> as), "->", pretty e]
+instance (Pretty b, Pretty a) => Pretty (ExprF b a) where
+    prettyPrec = prettyPrec1
+
+    -- prettyPrec _ (VarF n) = ttext n
+    -- prettyPrec _ (ConF t a) = "Pack{" <> (ttext t <+> ttext a) <> "}"
+    -- prettyPrec p (LamF bs e) = maybeParens (p>0) $
+    --     hsep ["λ", hsep (prettyPrec appPrec1 <$> bs), "->", pretty e]
+    -- prettyPrec p (LetF r bs e) = maybeParens (p>0)
+    --                            $ hsep [pretty r, explicitLayout bs]
+    --                          $+$ hsep ["in", pretty e]
+    -- prettyPrec p (AppF f x) = maybeParens (p>appPrec) $
+    --     prettyPrec appPrec f <+> prettyPrec appPrec1 x
+    -- prettyPrec p (LitF l) = prettyPrec p l
+    -- prettyPrec p (CaseF e as) = maybeParens (p>0) $
+    --     "case" <+> pretty e <+> "of"
+    --     $+$ nest 2 (explicitLayout as)
+    -- prettyPrec p (TypeF t) = "@" <> prettyPrec appPrec1 t
+
+instance (Pretty b) => Pretty1 (ExprF b) where
+    liftPrettyPrec pr _ (VarF n) = ttext n
+    liftPrettyPrec pr _ (ConF t a) = "Pack{" <> (ttext t <+> ttext a) <> "}"
+    liftPrettyPrec pr p (LamF bs e) = maybeParens (p>0) $
+        hsep ["λ", hsep (prettyPrec appPrec1 <$> bs), "->", pr 0 e]
+    liftPrettyPrec pr p (LetF r bs e) = maybeParens (p>0)
+                               $ hsep [pretty r, bs']
+                             $+$ hsep ["in", pr 0 e]
+        where bs' = liftExplicitLayout (liftPrettyPrec pr 0) bs
+    liftPrettyPrec pr p (AppF f x) = maybeParens (p>appPrec) $
+        pr appPrec f <+> pr appPrec1 x
+    liftPrettyPrec pr p (LitF l) = prettyPrec p l
+    liftPrettyPrec pr p (CaseF e as) = maybeParens (p>0) $
+            "case" <+> pr 0 e <+> "of"
+            $+$ nest 2 as'
+        where as' = liftExplicitLayout (liftPrettyPrec pr 0) as
+    liftPrettyPrec pr p (TypeF t) = "@" <> prettyPrec appPrec1 t
+
+instance Pretty Rec where
+    pretty Rec = "letrec"
+    pretty NonRec = "let"
+
+instance (Pretty b, Pretty a) => Pretty (AlterF b a) where
+    prettyPrec = prettyPrec1
+
+instance (Pretty b) => Pretty1 (AlterF b) where
+    liftPrettyPrec pr _ (AlterF c as e) =
+        hsep [pretty c, hsep (pretty <$> as), "->", liftPrettyPrec pr 0 e]
 
 instance Pretty AltCon where
     pretty (AltData n) = ttext n
     pretty (AltLit l) = pretty l
-    pretty (AltTag t) = ttext t
+    pretty (AltTag t) = "<" <> ttext t <> ">"
     pretty AltDefault = "_"
 
 instance Pretty Lit where
     pretty (IntL n) = ttext n
 
-instance (Pretty b) => Pretty (Binding b) where
-    pretty (k := v) = hsep [pretty k, "=", pretty v]
+instance (Pretty b, Pretty a) => Pretty (BindingF b a) where
+    prettyPrec = prettyPrec1
+
+instance Pretty b => Pretty1 (BindingF b) where
+    liftPrettyPrec pr _ (BindingF k v) = hsep [pretty k, "=", liftPrettyPrec pr 0 v]
+
+liftExplicitLayout :: (a -> Doc) -> [a] -> Doc
+liftExplicitLayout pr as = vcat inner <+> "}" where
+    inner = zipWith (<+>) delims (pr <$> as)
+    delims = "{" : repeat ";"
 
 explicitLayout :: (Pretty a) => [a] -> Doc
 explicitLayout as = vcat inner <+> "}" where
     inner = zipWith (<+>) delims (pretty <$> as)
     delims = "{" : repeat ";"
 
+instance Pretty Var where
+    prettyPrec p (MkVar n t) = maybeParens (p>0) $
+        hsep [pretty n, ":", pretty t]
+
+--------------------------------------------------------------------------------
+
+-- instance Functor Alter where
+--     fmap f (Alter con bs e) = Alter con (f <$> bs) e'
+--         where
+--             e' = foldFix (embed . bimap' f id) e
+--             bimap' = $(makeBimap ''ExprF)
+
+-- instance Foldable Alter where
+-- instance Traversable Alter where
+-- instance Functor Binding where
+-- instance Foldable Binding where
+-- instance Traversable Binding where
+
+liftShowsPrecExpr :: (Show b)
+                  => (Int -> a -> ShowS)
+                  -> ([a] -> ShowS)
+                  -> Int -> ExprF b a -> ShowS
+liftShowsPrecExpr = $(makeLiftShowsPrec ''ExprF)
+
+showsPrec1Expr :: (Show b, Show a)
+               => Int -> ExprF b a -> ShowS
+showsPrec1Expr = $(makeShowsPrec1 ''ExprF)
+
+instance (Show b) => Show1 (AlterF b) where
+    liftShowsPrec sp spl d (AlterF con bs e) =
+        showsTernaryWith showsPrec showsPrec (liftShowsPrecExpr sp spl)
+                         "AlterF" d con bs e
+
+instance (Show b) => Show1 (BindingF b) where
+    liftShowsPrec sp spl d (BindingF k v) =
+        showsBinaryWith showsPrec (liftShowsPrecExpr sp spl)
+                        "BindingF" d k v
+
+instance (Show b, Show a) => Show (BindingF b a) where
+    showsPrec d (BindingF k v)
+        = showParen (d > 10)
+        $ showString "BindingF" . showChar ' '
+        . showsPrec 11 k . showChar ' '
+        . showsPrec1Expr 11 v
+
+instance (Show b, Show a) => Show (AlterF b a) where
+    showsPrec d (AlterF con bs e)
+        = showParen (d > 10)
+        $ showString "AlterF" . showChar ' '
+        . showsPrec 11 con . showChar ' '
+        . showsPrec 11 bs . showChar ' '
+        . showsPrec1Expr 11 e
+
+deriveShow1 ''ExprF
+
+deriving instance (Show b, Show a) => Show (ExprF b a)
+-- deriving instance (Show b, Show a) => Show (BindingF b a)
+-- deriving instance (Show b, Show a) => Show (AlterF b a)
+deriving instance Show b => Show (ScDef b)
+deriving instance Show b => Show (Program b)
+
+bimapExpr :: (b -> b') -> (a -> a')
+          -> ExprF b a -> ExprF b' a'
+bimapExpr = $(makeBimap ''ExprF)
+
+bifoldrExpr :: (b -> c -> c)
+            -> (a -> c -> c)
+            -> c -> ExprF b a -> c
+bifoldrExpr = $(makeBifoldr ''ExprF)
+
+bitraverseExpr :: Applicative f
+               => (b -> f b')
+               -> (a -> f a')
+               -> ExprF b a -> f (ExprF b' a')
+bitraverseExpr = $(makeBitraverse ''ExprF)
+
+instance Bifunctor AlterF where
+    bimap f g (AlterF con bs e) = AlterF con (f <$> bs) (bimapExpr f g e)
+
+instance Bifunctor BindingF where
+    bimap f g (BindingF k v) = BindingF (f k) (bimapExpr f g v)
+
+instance Bifoldable AlterF where
+    bifoldr f g z (AlterF con bs e) = bifoldrExpr f g z' e where
+        z' = foldr f z bs
+
+instance Bitraversable AlterF where
+    bitraverse f g (AlterF con bs e) =
+        AlterF con <$> traverse f bs <*> bitraverseExpr f g e
+
+instance Bifoldable BindingF where
+    bifoldr f g z (BindingF k v) = bifoldrExpr f g (f k z) v
+
+instance Bitraversable BindingF where
+    bitraverse f g (BindingF k v) =
+        BindingF <$> f k <*> bitraverseExpr f g v
+
+deriveBifunctor ''ExprF
+deriveBifoldable ''ExprF
+deriveBitraversable ''ExprF
+
+instance Lift b => Lift1 (BindingF b) where
+    liftLift lf (BindingF k v) = liftCon2 'BindingF (lift k) (liftLift lf v)
+
+instance Lift b => Lift1 (AlterF b) where
+    liftLift lf (AlterF con bs e) =
+        liftCon3 'AlterF (lift con) (lift1 bs) (liftLift lf e)
+
+instance Lift b => Lift1 (ExprF b) where
+    liftLift lf (VarF k)      = liftCon 'VarF (lift k)
+    liftLift lf (AppF f x)    = liftCon2 'AppF (lf f) (lf x)
+    liftLift lf (LamF b e)    = liftCon2 'LamF (lift b) (lf e)
+    liftLift lf (LetF r bs e) = liftCon3 'LetF (lift r) bs' (lf e)
+        where bs' = liftLift (liftLift lf) bs
+    liftLift lf (CaseF e as)  = liftCon2 'CaseF (lf e) as'
+        where as' = liftLift (liftLift lf) as
+    liftLift lf (TypeF t)     = liftCon 'TypeF (lift t)
+    liftLift lf (LitF l)      = liftCon 'LitF (lift l)
+    liftLift lf (ConF t a)    = liftCon2 'ConF (lift t) (lift a)
+
+deriving instance (Lift b, Lift a) => Lift (ExprF b a)
+deriving instance (Lift b, Lift a) => Lift (BindingF b a)
+deriving instance (Lift b, Lift a) => Lift (AlterF b a)
+deriving instance Lift b => Lift (ScDef b)
+deriving instance Lift b => Lift (Program b)
+
+--------------------------------------------------------------------------------
+
+class HasApplicants1 s t a b | s -> a, t -> b, s b -> t, t a -> s where
+    applicants1 :: Traversal s t a b
+
+class HasApplicants s t a b | s -> a, t -> b, s b -> t, t a -> s where
+    applicants :: Traversal s t a b
+
+instance HasApplicants1 Type Type Type Type where
+    applicants1 k (TyApp f x) = TyApp <$> applicants1 k f <*> k x
+    applicants1 k x           = k x
+
+instance HasApplicants Type Type Type Type where
+    applicants k (TyApp f x) = TyApp <$> applicants k f <*> k x
+    applicants k x           = pure x
+
+-- instance HasArguments (ExprF b (Fix (ExprF b))) (ExprF b (Fix (ExprF b)))
+--                        (Fix (ExprF b)) (Fix (ExprF b)) where
+--     arguments k (AppF f x) = AppF <$> arguments k f <*> k x
+--     arguments k x          = unwrapFix <$> k (wrapFix x)
+
+-- instance HasArguments (f (Fix f)) (f (Fix f)) (Fix f) (Fix f)
+--       => HasArguments (Fix f) (Fix f) (Fix f) (Fix f) where
+--     arguments :: forall g. Applicative g
+--                => LensLike' g (Fix f) (Fix f)
+--     arguments k (Fix f) = Fix <$> arguments k f
+
+-- arguments :: Traversal' (Expr b) (Expr b)
+-- arguments k (App f x) = App <$> arguments k f <*> k x
+-- arguments k x         = k x
+
+class HasBinders s t a b | s -> a, t -> b, s b -> t, t a -> s where
+    binders :: Traversal s t a b
+
+instance HasBinders (ScDef b) (ScDef b') b b' where
+    binders k (ScDef b as e) = ScDef <$> k b <*> traverse k as <*> binders k e
+
+instance (Hashable b, Hashable b')
+      => HasBinders (Program b) (Program b') b b' where
+    binders :: forall f. (Applicative f)
+            => LensLike f (Program b) (Program b') b b'
+    binders k p
+        = Program
+        <$> traverse (binders k) (_programScDefs p)
+        <*> (getAp . ifoldMap toSingleton $ _programTypeSigs p)
+        <*> pure (_programDataTags p)
+        <*> pure (_programTyCons p)
+      where
+        toSingleton :: b -> Type -> Ap f (HashMap b' Type)
+        toSingleton b t = Ap $ (`H.singleton` t) <$> k b
+
+instance HasBinders a a' b b'
+    => HasBinders (ExprF b a) (ExprF b' a') b b' where
+    binders :: forall f. (Applicative f)
+                    => LensLike f (ExprF b a) (ExprF b' a') b b'
+    binders k = go where
+        go :: ExprF b a -> f (ExprF b' a')
+        go (LamF bs e)   = LamF <$> traverse k bs <*> binders k e
+        go (CaseF e as)  = CaseF <$> binders k e <*> eachbind as
+        go (LetF r bs e) = LetF r <$> eachbind bs <*> binders k e
+        go f             = bitraverse k (binders k) f
+
+        eachbind :: forall p. Bitraversable p => [p b a] -> f [p b' a']
+        eachbind bs = bitraverse k (binders k) `traverse` bs
+
+instance HasBinders a a b b'
+      => HasBinders (AlterF b a) (AlterF b' a) b b' where
+    binders k (AlterF con bs e) =
+        AlterF con <$> traverse k bs <*> traverseOf binders k e
+
+instance HasBinders a a b b'
+      => HasBinders (BindingF b a) (BindingF b' a) b b' where
+    binders k (BindingF b v) = BindingF <$> k b <*> binders k v
+
+instance (HasBinders (f b (Fix (f b))) (f b' (Fix (f b'))) b b')
+      => HasBinders (Fix (f b)) (Fix (f b')) b b' where
+    binders k (Fix f) = Fix <$> binders k f
+
+class HasArrowStops s t a b | s -> a, t -> b, s b -> t, t a -> s where
+    arrowStops :: Traversal s t a b
+
+instance HasArrowStops Type Type Type Type where
+    arrowStops k (s :-> t) = (:->) <$> k s <*> arrowStops k t
+    arrowStops k t = k t
+
+--------------------------------------------------------------------------------
+
+liftEqExpr :: (Eq b)
+           => (a -> a' -> Bool)
+           -> ExprF b a -> ExprF b a' -> Bool
+liftEqExpr = $(makeLiftEq ''ExprF)
+
+instance (Eq b, Eq a) => Eq (BindingF b a) where
+    BindingF ka va == BindingF kb vb =
+        ka == kb && va `eq` vb
+      where eq = liftEqExpr (==)
+
+instance (Eq b, Eq a) => Eq (AlterF b a) where
+    AlterF cona bsa ea == AlterF conb bsb eb =
+        cona == conb && bsa == bsb && ea `eq` eb
+      where eq = liftEqExpr (==)
+
+instance (Eq b) => Eq1 (AlterF b) where
+    liftEq f (AlterF cona bsa ea) (AlterF conb bsb eb) =
+        cona == conb && bsa == bsb && ea `eq` eb
+      where eq = liftEqExpr f
+
+instance (Eq b) => Eq1 (BindingF b) where
+    liftEq f (BindingF ka va) (BindingF kb vb) =
+        ka == kb && va `eq` vb
+      where eq = liftEqExpr f
+
+deriveEq1 ''ExprF
+
+deriving instance (Eq b, Eq a) => Eq (ExprF b a)
+
+makePrisms ''BindingF
+makePrisms ''Var
+makePrisms ''ScDef
+
+deriving instance Generic (ExprF b a)
+deriving instance Generic1 (ExprF b)
+deriving instance Generic1 (AlterF b)
+deriving instance Generic1 (BindingF b)
+deriving instance Generic (AlterF b a)
+deriving instance Generic (BindingF b a)
+deriving instance Generic AltCon
+deriving instance Generic Lit
+deriving instance Generic Rec
+deriving instance Generic Type
+
+instance Hashable Lit
+instance Hashable AltCon
+instance Hashable Rec
+instance Hashable Type
+instance (Hashable b, Hashable a) => Hashable (BindingF b a)
+instance (Hashable b, Hashable a) => Hashable (AlterF b a)
+instance (Hashable b, Hashable a) => Hashable (ExprF b a)
+
+instance Hashable b => Hashable1 (AlterF b)
+instance Hashable b => Hashable1 (BindingF b)
+instance Hashable b => Hashable1 (ExprF b)
+

src/Core/SystemF.hs

@@ -0,0 +1,268 @@
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE OverloadedLists #-}
+module Core.SystemF
+    ( lintCoreProgR
+    )
+    where
+--------------------------------------------------------------------------------
+import GHC.Generics                 (Generic, Generically(..))
+import Data.HashMap.Strict          (HashMap)
+import Data.HashMap.Strict          qualified as H
+import Data.Function                (on)
+import Data.Traversable
+import Data.Foldable
+import Data.List.Extra
+import Control.Monad.Utils
+import Control.Monad
+import Data.Text                    qualified as T
+import Data.Pretty
+import Text.Printf
+
+import Control.Comonad
+import Control.Comonad.Cofree
+import Data.Fix
+import Data.Functor
+
+import Control.Lens                 hiding ((:<))
+import Control.Lens.Unsound
+
+import Compiler.RLPC
+import Compiler.RlpcError
+import Core
+--------------------------------------------------------------------------------
+
+data Gamma = Gamma
+    { _gammaVars   :: HashMap Name Type
+    , _gammaTyVars :: HashMap Name Kind
+    , _gammaTyCons :: HashMap Name Kind
+    }
+    deriving (Generic)
+    deriving (Semigroup, Monoid)
+        via (Generically Gamma)
+
+makeLenses ''Gamma
+
+lintCoreProgR :: (Monad m) => Program Var -> RLPCT m (Program Name)
+lintCoreProgR = undefined
+
+lintDontCheck :: Program Var -> Program Name
+lintDontCheck = binders %~ view (_MkVar . _1)
+
+lint :: Program Var -> SysF (Program Name)
+lint p = do
+    scs <- traverse (lintScDef g0) $ p ^. programScDefs
+    pure $ lintDontCheck p & programScDefs .~ scs
+  where
+    g0 = mempty & gammaVars .~ typeSigs
+                & gammaTyCons .~ p ^. programTyCons
+    -- 'p' stores the type signatures as 'HashMap Var Type',
+    -- while our typechecking context demands a 'HashMap Name Type'.
+    -- This conversion is perfectly safe, as the 'Hashable' instance for
+    -- 'Var' hashes exactly the internal 'Name'. i.e.
+    -- `hash (MkVar n t) = hash n`.
+    typeSigs = p ^. programTypeSigs
+             & H.mapKeys (view $ _MkVar . _1)
+
+lintScDef :: Gamma -> ScDef Var -> SysF (ScDef Name)
+lintScDef g = traverseOf lambdaLifting $ \ (MkVar n t, e) -> do
+    e'@(t' :< _) <- lintE g e
+    assertUnify t t'
+    let e'' = stripVars . stripTypes $ e'
+    pure (n, e'')
+
+stripTypes :: ET -> Expr Var
+stripTypes (_ :< as) = Fix (stripTypes <$> as)
+
+stripVars :: Expr Var -> Expr Name
+stripVars = binders %~ view (_MkVar . _1)
+
+type ET = Cofree (ExprF Var) Type
+
+type SysF = Either SystemFError
+
+data SystemFError = SystemFErrorUndefinedVariable Name
+                  | SystemFErrorKindMismatch Kind Kind
+                  | SystemFErrorCouldNotMatch Type Type
+                  deriving Show
+
+instance IsRlpcError SystemFError where
+    liftRlpcError = \case
+        SystemFErrorUndefinedVariable n ->
+            undefinedVariableErr n
+        SystemFErrorKindMismatch k k' ->
+            Text [ T.pack $ printf "Could not match kind `%s' with `%s'"
+                                   (pretty k) (pretty k')
+                 ]
+        SystemFErrorCouldNotMatch t t' ->
+            Text [ T.pack $ printf "Could not match type `%s' with `%s'"
+                                   (pretty t) (pretty t')
+                 ]
+
+justLintCoreExpr = fmap (fmap (prettyPrec appPrec1)) . lintE demoContext
+
+lintE :: Gamma -> Expr Var -> SysF ET
+lintE g = \case
+    Var n -> lookupVar g n <&> (:< VarF n)
+    Lit (IntL n) -> pure $ TyInt :< LitF (IntL n)
+
+    Type t -> kindOf g t <&> (:< TypeF t)
+
+    App f x
+        -- type application
+        | Right (TyForall (a :^ k) m :< f') <- lintE g f
+        , Right (k' :< TypeF t) <- lintE g x
+        , k == k'
+        -> pure $ subst a t m :< f'
+
+        -- value application
+        | Right fw@((s :-> t) :< _) <- lintE g f
+        , Right xw@(s' :< _) <- lintE g x
+        , s == s'
+        -> pure $ t :< AppF fw xw
+
+    Lam bs e -> do
+        e'@(t :< _) <- lintE g' e
+        pure $ foldr arrowify t bs :< LamF bs e'
+      where
+        g' = foldMap suppl bs <> g
+
+        suppl (MkVar n t)
+            | isKind t  = mempty & gammaTyVars %~ H.insert n t
+            | otherwise = mempty & gammaVars %~ H.insert n t
+
+        arrowify (MkVar n s) s'
+            | isKind s  = TyForall (n :^ s) s'
+            | otherwise = s :-> s'
+
+    Let Rec bs e -> do
+        e'@(t :< _) <- lintE g' e
+        bs' <- (uncurry checkBind . (_2 %~ wrapFix)) `traverse` binds
+        pure $ t :< LetF Rec bs' e'
+      where
+        binds = bs ^.. each . _BindingF
+        vs = binds ^.. each . _1 . _MkVar
+        g' = supplementVars vs g
+        checkBind v@(MkVar n t) e = case lintE g' e of
+            Right (t' :< e') | t == t'   -> Right (BindingF v e')
+                             | otherwise -> Left (SystemFErrorCouldNotMatch t t')
+            Left e -> Left e
+    Let NonRec bs e -> do
+        (g',bs') <- mapAccumLM checkBind g bs
+        e'@(t :< _) <- lintE g' e
+        pure $ t :< LetF NonRec bs' e'
+      where
+        checkBind :: Gamma -> BindingF Var (Expr Var)
+                  -> SysF (Gamma, BindingF Var ET)
+        checkBind g (BindingF v@(n :^ t) e) = case lintE g (wrapFix e) of
+            Right (t' :< e')
+                | t == t'   -> Right (supplementVar n t g, BindingF v e')
+                | otherwise -> Left (SystemFErrorCouldNotMatch t t')
+            Left e -> Left e
+
+    Case e as -> do
+        e'@(et :< _) <- lintE g e
+        (ts,as') <- unzip <$> checkAlt et `traverse` as
+        case allUnify ts of
+            Just err -> Left err
+            Nothing  -> pure $ head ts  :< CaseF e' as'
+      where
+        checkAlt :: Type -> Alter Var -> SysF (Type, AlterF Var ET)
+        checkAlt scrutineeType (AlterF (AltData con) bs e) = do
+            ct <- lookupVar g con
+            ct' <- foldrMOf applicants (elimForall g) ct scrutineeType
+            zipWithM_ fzip bs (ct' ^.. arrowStops)
+            (t :< e') <- lintE (supplementVars (varsToPairs bs) g) (wrapFix e)
+            pure (t, AlterF (AltData con) bs e')
+          where
+            fzip (MkVar _ t) t'
+                | t == t'   = Right ()
+                | otherwise = Left (SystemFErrorCouldNotMatch t t')
+
+assertUnify :: Type -> Type -> SysF ()
+assertUnify t t'
+    | t == t'   = pure ()
+    | otherwise = Left (SystemFErrorCouldNotMatch t t')
+
+allUnify :: [Type] -> Maybe SystemFError
+allUnify [] = Nothing
+allUnify [t] = Nothing
+allUnify (t:t':ts)
+    | t == t'   = allUnify ts
+    | otherwise = Just (SystemFErrorCouldNotMatch t t')
+
+elimForall :: Gamma -> Type -> Type -> SysF Type
+elimForall g t (TyForall (n :^ k) m) = do
+    k' <- kindOf g t
+    case k == k' of
+        True -> pure $ subst n t m
+        False -> Left $ SystemFErrorKindMismatch k k'
+elimForall _ m _ = pure m
+ 
+varsToPairs :: [Var] -> [(Name, Type)]
+varsToPairs = toListOf (each . _MkVar)
+
+checkAgainst :: Gamma -> Var -> Expr Var -> SysF ET
+checkAgainst g v@(MkVar n t) e = case lintE g e of
+    Right e'@(t' :< _) | t == t'      -> Right e'
+                       | otherwise    -> Left (SystemFErrorCouldNotMatch t t')
+    Left a -> Left a
+
+supplementVars :: [(Name, Type)] -> Gamma -> Gamma
+supplementVars vs = gammaVars <>~ H.fromList vs
+
+supplementVar :: Name -> Type -> Gamma -> Gamma
+supplementVar n t = gammaVars %~ H.insert n t
+
+supplementTyVar :: Name -> Kind -> Gamma -> Gamma
+supplementTyVar n t = gammaTyVars %~ H.insert n t
+
+subst :: Name -> Type -> Type -> Type
+subst k v (TyVar n) | k == n = v
+subst k v (TyForall (MkVar n k') t)
+    | k /= n                 = TyForall (MkVar n k') (subst k v t)
+    | otherwise              = TyForall (MkVar n k') t
+subst k v (TyApp f x)        = (TyApp `on` subst k v) f x
+subst _ _ x                  = x
+
+isKind :: Type -> Bool
+isKind (s :-> t)  = isKind s && isKind t
+isKind TyKindType = True
+isKind _          = False
+
+kindOf :: Gamma -> Type -> SysF Kind
+kindOf g (TyVar n)  = lookupTyVar g n
+kindOf _ TyKindType = pure TyKindType
+kindOf g (TyCon n)  = lookupCon g n
+kindOf _ e          = error (show e)
+
+lookupCon :: Gamma -> Name -> SysF Kind
+lookupCon g n = case g ^. gammaTyCons . at n of
+    Just k  -> Right k
+    Nothing -> Left (SystemFErrorUndefinedVariable n)
+
+lookupVar :: Gamma -> Name -> SysF Type
+lookupVar g n = case g ^. gammaVars . at n of
+    Just t -> Right t
+    Nothing -> Left (SystemFErrorUndefinedVariable n)
+
+lookupTyVar :: Gamma -> Name -> SysF Kind
+lookupTyVar g n = case g ^. gammaTyVars . at n of
+    Just k -> Right k
+    Nothing -> Left (SystemFErrorUndefinedVariable n)
+
+demoContext :: Gamma
+demoContext = Gamma
+    { _gammaVars =
+        [ ("id", TyForall ("a" :^ TyKindType) $ TyVar "a" :-> TyVar "a")
+        , ("Just", TyForall ("a" :^ TyKindType) $
+            TyVar "a" :-> (TyCon "Maybe" `TyApp` TyVar "a"))
+        , ("Nothing", TyForall ("a" :^ TyKindType) $
+            TyCon "Maybe" `TyApp` TyVar "a")
+        ]
+    , _gammaTyVars = []
+    , _gammaTyCons =
+        [ ("Int#", TyKindType)
+        , ("Maybe", TyKindType :-> TyKindType)
+        ]
+    }
+

src/Core/TH.hs

@@ -5,8 +5,8 @@ Description : Core quasiquoters
 module Core.TH
     ( coreExpr
     , coreProg
-    , coreExprT
-    , coreProgT
+    -- , coreExprT
+    -- , coreProgT
     )
     where
 ----------------------------------------------------------------------------------
@@ -33,16 +33,18 @@ coreExpr :: QuasiQuoter
 coreExpr = mkqq $ lexCoreR >=> parseCoreExprR
 
 -- | Type-checked @coreProg@
-coreProgT :: QuasiQuoter
-coreProgT = mkqq $ lexCoreR >=> parseCoreProgR >=> checkCoreProgR
+-- coreProgT :: QuasiQuoter
+-- coreProgT = mkqq $ lexCoreR >=> parseCoreProgR >=> checkCoreProgR
 
-coreExprT :: QuasiQuoter
-coreExprT = mkqq $ lexCoreR >=> parseCoreExprR >=> checkCoreExprR g
-    where
-        g = [ ("+#", TyCon "Int#" :-> TyCon "Int#" :-> TyCon "Int#")
-            , ("id", TyCon "a" :-> TyCon "a")
-            , ("fix", (TyCon "a" :-> TyCon "a") :-> TyCon "a")
-            ]
+-- coreExprT :: QuasiQuoter
+-- coreExprT = mkqq $ lexCoreR >=> parseCoreExprR >=> checkCoreExprR g
+--     where
+--         g = [ ("+#", TyInt :-> TyInt :-> TyInt)
+--             , ("id", TyForall (MkVar "a" TyKindType) $
+--                     TyVar "a" :-> TyVar "a")
+--             , ("fix", TyForall (MkVar "a" TyKindType) $
+--                     (TyVar "a" :-> TyVar "a") :-> TyVar "a")
+--             ]
 
 mkqq :: (Lift a) => (Text -> RLPCIO a) -> QuasiQuoter
 mkqq p = QuasiQuoter

src/Core/Utils.hs

@@ -2,8 +2,6 @@ module Core.Utils
     ( programRhss
     , programGlobals
     , isAtomic
-    -- , insertModule
-    , extractProgram
     , freeVariables
     )
     where
@@ -30,34 +28,29 @@ isAtomic _        = False
 
 ----------------------------------------------------------------------------------
 
--- TODO: export list awareness
--- insertModule :: Module b -> Program b -> Program b
--- insertModule (Module _ p) = programScDefs %~ (<>m)
+freeVariables :: Expr b -> Set b
+freeVariables = undefined
 
-extractProgram :: Module b -> Program b
-extractProgram (Module _ p) = p
+-- freeVariables :: Expr' -> Set Name
+-- freeVariables = cata go
+--     where
+--         go :: ExprF Name (Set Name) -> Set Name
+--         go (VarF k)         = S.singleton k
+--         -- TODO: collect free vars in rhss of bs
+--         go (LetF _ bs e)    = (e `S.union` esFree) `S.difference` ns
+--             where
+--                 es = bs ^.. each . _rhs :: [Expr']
+--                 ns = S.fromList $ bs ^.. each . _lhs
+--                 -- TODO: this feels a little wrong. maybe a different scheme is
+--                 -- appropriate
+--                 esFree = foldMap id $ freeVariables <$> es
 
-----------------------------------------------------------------------------------
-
-freeVariables :: Expr' -> Set Name
-freeVariables = cata go
-    where
-        go :: ExprF Name (Set Name) -> Set Name
-        go (VarF k)         = S.singleton k
-        -- TODO: collect free vars in rhss of bs
-        go (LetF _ bs e)    = (e `S.union` esFree) `S.difference` ns
-            where
-                es = bs ^.. each . _rhs :: [Expr']
-                ns = S.fromList $ bs ^.. each . _lhs
-                -- TODO: this feels a little wrong. maybe a different scheme is
-                -- appropriate
-                esFree = foldMap id $ freeVariables <$> es
-
-        go (CaseF e as)     = e `S.union` asFree
-            where
-                asFree = foldMap id $ freeVariables <$> (fmap altToLam as)
-                -- we map alts to lambdas to avoid writing a 'freeVariablesAlt'
-                altToLam (Alter _ ns e) = Lam ns e
-        go (LamF bs e)      = e `S.difference` (S.fromList bs)
-        go e                = foldMap id e
+--         go (CaseF e as)     = e `S.union` asFree
+--             where
+--                 -- asFree = foldMap id $ freeVariables <$> (fmap altToLam as)
+--                 asFree = foldMap (freeVariables . altToLam) as
+--                 -- we map alts to lambdas to avoid writing a 'freeVariablesAlt'
+--                 altToLam (Alter _ ns e) = Lam ns e
+--         go (LamF bs e)      = e `S.difference` (S.fromList bs)
+--         go e                = foldMap id e
 

src/Core2Core.hs

@@ -116,7 +116,7 @@ floatNonStrictCases g = goE
             goE e
             traverse_ goE altBodies
             pure e'
-        goC (f :$ x)            = (:$) <$> goC f <*> goC x
+        goC (App f x)           = App <$> goC f <*> goC x
         goC (Let r bs e)        = Let r <$> bs' <*> goE e
             where bs' = travBs goC bs
         goC (Lit l)             = pure (Lit l)
@@ -128,10 +128,9 @@ floatNonStrictCases g = goE
         -- extract the right-hand sides of a list of bindings, traverse each
         -- one, and return the original list of bindings
         travBs :: (Expr' -> Floater Expr') -> [Binding'] -> Floater [Binding']
-        travBs c bs = bs ^.. each . _rhs
-                    & traverse goC
-                    & const (pure bs)
+        travBs c bs = undefined
         -- ^ ??? what the fuck?
+        -- ^ 24/02/22: what is this shit lol?
 
 -- when provided with a case expr, floatCase will float the case into a
 -- supercombinator of its free variables. the sc is returned along with an

src/Data/Pretty.hs

@@ -1,13 +1,17 @@
+{-# LANGUAGE QuantifiedConstraints, UndecidableInstances #-}
 module Data.Pretty
-    ( Pretty(..)
+    ( Pretty(..), Pretty1(..)
+    , prettyPrec1
     , rpretty
     , ttext
+    , Showing(..)
     -- * Pretty-printing lens combinators
-    , hsepOf, vsepOf
-    , vcatOf
-    , vlinesOf
+    , hsepOf, vsepOf, vcatOf, vlinesOf, vsepTerm
+    , vsep
     , module Text.PrettyPrint
     , maybeParens
+    , appPrec
+    , appPrec1
     )
     where
 ----------------------------------------------------------------------------------
@@ -15,10 +19,15 @@ import Text.PrettyPrint             hiding ((<>))
 import Text.PrettyPrint.HughesPJ    hiding ((<>))
 import Text.Printf
 import Data.String                  (IsString(..))
-import Data.Text.Lens
-import Data.Monoid
-import Data.Text                    qualified as T
+import Data.Text.Lens               hiding ((:<))
+import Data.Monoid                  hiding (Sum)
 import Control.Lens
+
+-- instances
+import Control.Comonad.Cofree
+import Data.Text                    qualified as T
+import Data.Functor.Sum
+import Data.Fix                     (Fix(..))
 ----------------------------------------------------------------------------------
 
 class Pretty a where
@@ -27,7 +36,7 @@ class Pretty a where
 
     {-# MINIMAL pretty | prettyPrec #-}
     pretty = prettyPrec 0
-    prettyPrec a _ = pretty a
+    prettyPrec = const pretty
 
 rpretty :: (IsString s, Pretty a) => a -> s
 rpretty = fromString . render . pretty
@@ -45,6 +54,26 @@ instance (Show a) => Pretty (Showing a) where
 
 deriving via Showing Int instance Pretty Int
 
+class (forall a. Pretty a => Pretty (f a)) => Pretty1 f where
+    liftPrettyPrec :: (Int -> a -> Doc) -> Int -> f a -> Doc
+
+prettyPrec1 :: (Pretty1 f, Pretty a) => Int -> f a -> Doc
+prettyPrec1 = liftPrettyPrec prettyPrec
+
+instance (Pretty1 f, Pretty1 g, Pretty a) => Pretty (Sum f g a) where
+    prettyPrec p (InL fa) = prettyPrec1 p fa
+    prettyPrec p (InR ga) = prettyPrec1 p ga
+
+instance (Pretty1 f, Pretty1 g) => Pretty1 (Sum f g) where
+    liftPrettyPrec pr p (InL fa) = liftPrettyPrec pr p fa
+    liftPrettyPrec pr p (InR ga) = liftPrettyPrec pr p ga
+
+instance (Pretty (f (Fix f))) => Pretty (Fix f) where
+    prettyPrec d (Fix f) = prettyPrec d f
+
+-- instance (Pretty1 f) => Pretty (Fix f) where
+--     prettyPrec d (Fix f) = prettyPrec1 d f
+
 --------------------------------------------------------------------------------
 
 ttext :: Pretty t => t -> Doc
@@ -63,3 +92,22 @@ vlinesOf :: Getting (Endo Doc) s Doc -> s -> Doc
 vlinesOf l = foldrOf l (\a b -> a $+$ "" $+$ b) mempty
 -- hack(?) to separate chunks with a blankline
 
+vsepTerm :: Doc -> Doc -> Doc -> Doc
+vsepTerm term a b = (a <> term) $+$ b
+
+vsep :: [Doc] -> Doc
+vsep = foldr ($+$) mempty
+
+--------------------------------------------------------------------------------
+
+appPrec, appPrec1 :: Int
+appPrec  = 10
+appPrec1 = 11
+
+instance PrintfArg Doc where
+    formatArg d fmt
+        | fmtChar (vFmt 'D' fmt) == 'D' = formatString (render d) fmt'
+        | otherwise                     = errorBadFormat $ fmtChar fmt
+      where
+        fmt' = fmt { fmtChar = 's', fmtPrecision = Nothing }
+

src/Misc.hs

@@ -0,0 +1,17 @@
+module Misc where
+--------------------------------------------------------------------------------
+import Data.Functor.Classes
+--------------------------------------------------------------------------------
+
+
+showsTernaryWith :: (Int -> a -> ShowS)
+                 -> (Int -> b -> ShowS)
+                 -> (Int -> c -> ShowS)
+                 -> String -> Int -> a -> b -> c -> ShowS
+showsTernaryWith sp1 sp2 sp3 name d x y z
+    = showParen (d > 10)
+    $ showString name . showChar ' '
+    . sp1 11 x . showChar ' '
+    . sp2 11 y . showChar ' '
+    . sp3 11 z
+

src/Misc/Lift1.hs

@@ -0,0 +1,54 @@
+{-# LANGUAGE TemplateHaskell #-}
+module Misc.Lift1
+    ( Lift1(..), lift1
+    , liftCon, liftCon2, liftCon3
+    , Lift(..)
+    )
+    where
+--------------------------------------------------------------------------------
+import Language.Haskell.TH              hiding (Type, Name)
+import Language.Haskell.TH.Syntax       hiding (Type, Name)
+import Language.Haskell.TH.Syntax       qualified as TH
+import Language.Haskell.TH.Quote
+import Data.Kind                        qualified
+import GHC.Generics
+
+-- instances
+import Data.Fix
+import Data.Functor.Sum
+--------------------------------------------------------------------------------
+
+class Lift1 (f :: Data.Kind.Type -> Data.Kind.Type) where
+    -- lift1 :: (Quote m, Lift t) => f t -> m Exp
+    liftLift :: (Quote m) => (a -> m Exp) -> f a -> m Exp
+
+lift1 :: (Lift1 f, Lift a, Quote m) => f a -> m Exp
+lift1 = liftLift lift
+
+liftCon :: Quote m => TH.Name -> m Exp -> m Exp
+liftCon n = fmap (AppE (ConE n))
+
+liftCon2 :: Quote m => TH.Name -> m Exp -> m Exp -> m Exp
+liftCon2 n a b = do
+    a' <- a
+    b' <- b
+    pure $ ConE n `AppE` a' `AppE` b'
+
+liftCon3 :: Quote m => TH.Name -> m Exp -> m Exp -> m Exp -> m Exp
+liftCon3 n a b c = do
+    a' <- a
+    b' <- b
+    c' <- c
+    pure $ ConE n `AppE` a' `AppE` b' `AppE` c'
+
+instance Lift1 f => Lift (Fix f) where
+    lift (Fix f) = AppE (ConE 'Fix) <$> lift1 f
+
+instance Lift1 [] where
+    liftLift lf []     = pure $ ConE '[]
+    liftLift lf (a:as) = liftCon2 '(:) (lf a) (liftLift lf as)
+
+instance (Lift1 f, Lift1 g) => Lift1 (Sum f g) where
+    liftLift lf (InL fa) = liftCon 'InL $ liftLift lf fa
+    liftLift lf (InR ga) = liftCon 'InR $ liftLift lf ga
+

src/Rlp/AltParse.y

@@ -0,0 +1,232 @@
+{
+module Rlp.AltParse
+    ( parseRlpProg
+    , parseRlpProgR
+    , parseRlpExprR
+    , runP'
+    )
+    where
+import Data.List.Extra
+import Data.Text                (Text)
+
+import Control.Comonad
+import Control.Comonad.Cofree
+import Control.Lens             hiding (snoc)
+
+import Compiler.RlpcError
+import Compiler.RLPC
+import Control.Monad.Errorful
+
+import Rlp.Lex
+import Rlp.AltSyntax
+import Rlp.Parse.Types          hiding (PsName)
+import Core.Syntax              qualified as Core
+}
+
+%name parseRlpProg StandaloneProgram
+%name parseRlpExpr StandaloneExpr
+
+%monad { P }
+%lexer { lexCont } { Located _ TokenEOF }
+%error { parseError }
+%errorhandlertype explist
+%tokentype { Located RlpToken }
+
+%token
+    varname         { Located _ (TokenVarName _) }
+    conname         { Located _ (TokenConName _) }
+    consym          { Located _ (TokenConSym _) }
+    varsym          { Located _ (TokenVarSym _) }
+    data            { Located _ TokenData }
+    case            { Located _ TokenCase }
+    of              { Located _ TokenOf }
+    litint          { Located _ (TokenLitInt _) }
+    '='             { Located _ TokenEquals }
+    '|'             { Located _ TokenPipe }
+    '::'            { Located _ TokenHasType }
+    ';'             { Located _ TokenSemicolon }
+    'λ'             { Located _ TokenLambda }
+    '('             { Located _ TokenLParen }
+    ')'             { Located _ TokenRParen }
+    '->'            { Located _ TokenArrow }
+    vsemi           { Located _ TokenSemicolonV }
+    '{'             { Located _ TokenLBrace }
+    '}'             { Located _ TokenRBrace }
+    vlbrace         { Located _ TokenLBraceV }
+    vrbrace         { Located _ TokenRBraceV }
+    infixl          { Located _ TokenInfixL }
+    infixr          { Located _ TokenInfixR }
+    infix           { Located _ TokenInfix }
+    let             { Located _ TokenLet }
+    letrec          { Located _ TokenLetrec }
+    in              { Located _ TokenIn }
+
+%nonassoc '='
+%right '->'
+%right in
+
+%%
+
+StandaloneProgram :: { Program Name (RlpExpr PsName) }
+                  : layout0(Decl)       { Program $1 }
+
+
+StandaloneExpr :: { RlpExpr PsName }
+               : VL Expr VR             { $2 }
+
+VL  :: { () }
+VL  : vlbrace       { () }
+
+VR  :: { () }
+VR  : vrbrace       { () }
+    | error         { () }
+
+VS                  :: { () }
+VS                  : ';'                   { () }
+                    | vsemi                 { () }
+
+Decl                :: { Decl PsName (RlpExpr PsName) }
+                    : FunD                  { $1 }
+                    | DataD                 { $1 }
+                    | TySigD                { $1 }
+
+TySigD              :: { Decl PsName (RlpExpr PsName) }
+                    : Var '::' Type         { TySigD $1 $3 }
+
+DataD               :: { Decl PsName (RlpExpr PsName) }
+                    : data Con TyVars               { DataD $2 $3 [] }
+                    | data Con TyVars '=' DataCons  { DataD $2 $3 $5 }
+
+DataCons            :: { [DataCon PsName] }
+                    : DataCon '|' DataCons  { $1 : $3 }
+                    | DataCon               { [$1] }
+
+DataCon             :: { DataCon PsName }
+                    : Con list0(Type1)      { DataCon $1 $2 }
+
+Type1               :: { Type PsName }
+                    : varname               { VarT $ extractVarName $1 }
+                    | Con                   { ConT $1 }
+                    | '(' Type ')'          { $2 }
+
+Type                :: { Type PsName }
+                    : Type '->' Type        { $1 :-> $3 }
+                    | AppT                  { $1 }
+
+AppT                :: { Type PsName }
+                    : Type1                 { $1 }
+                    | AppT Type1            { AppT $1 $2 }
+
+TyVars              :: { [PsName] }
+                    : list0(varname)     { $1 <&> view ( to extract
+                                                       . singular _TokenVarName ) }
+
+FunD                :: { Decl PsName (RlpExpr PsName) }
+                    : Var Pat1s '=' Expr    { FunD $1 $2 $4 }
+
+Expr                :: { RlpExpr PsName }
+                    : AppE                  { $1 }
+                    | LetE                  { $1 }
+                    | CaseE                 { $1 }
+                    | LamE                  { $1 }
+
+LamE                :: { RlpExpr PsName }
+                    : 'λ' list0(varname) '->' Expr { Finl $ Core.LamF (fmap extractName $2) $4 }
+
+CaseE               :: { RlpExpr PsName }
+                    : case Expr of CaseAlts { Finr $ CaseEF $2 $4 }
+
+CaseAlts            :: { [Alter PsName (RlpExpr PsName)] }
+                    : layout1(CaseAlt)      { $1 }
+
+CaseAlt             :: { Alter PsName (RlpExpr PsName) }
+                    : Pat '->' Expr    { Alter $1 $3 }
+
+LetE                :: { RlpExpr PsName }
+                    : let layout1(Binding) in Expr
+                        { Finr $ LetEF Core.NonRec $2 $4 }
+
+Binding             :: { Binding PsName (RlpExpr PsName) }
+                    : Pat '=' Expr          { VarB $1 $3 }
+
+Expr1               :: { RlpExpr PsName }
+                    : VarE                  { $1 }
+                    | litint                { $1 ^. to extract
+                                                  . singular _TokenLitInt
+                                                  . to (Finl . Core.LitF . Core.IntL) }
+                    | '(' Expr ')'          { $2 }
+
+AppE                :: { RlpExpr PsName }
+                    : AppE Expr1            { Finl $ Core.AppF $1 $2 }
+                    | Expr1                 { $1 }
+
+VarE                :: { RlpExpr PsName }
+                    : Var                   { Finl $ Core.VarF $1 }
+
+Pat1s               :: { [Pat PsName] }
+                    : list0(Pat1)           { $1 }
+
+Pat1                :: { Pat PsName }
+                    : Var                   { VarP $1 }
+                    | Con                   { ConP $1 }
+                    | '(' Pat ')'           { $2 }
+
+Pat                 :: { Pat PsName }
+                    : AppP                  { $1 }
+
+AppP                :: { Pat PsName }
+                    : Pat1                  { $1 }
+                    | AppP Pat1             { $1 `AppP` $2 }
+
+Con                 :: { PsName }
+                    : conname               { $1 ^. to extract
+                                                  . singular _TokenConName }
+                    | '(' consym ')'        { $1 ^. to extract
+                                                  . singular _TokenConSym }
+
+Var                 :: { PsName }
+                    : varname               { $1 ^. to extract
+                                                  . singular _TokenVarName }
+                    | '(' varsym ')'        { $2 ^. to extract
+                                                  . singular _TokenVarSym }
+
+-- list0(p : α) : [α]
+list0(p) : {- epsilon -}            { [] }
+         | list0(p) p             { $1 `snoc` $2 }
+
+-- layout0(p : β) :: [β]
+layout0(p)  : '{' layout_list0(';',p) '}'   { $2 }
+            | VL  layout_list0(VS,p)  VR    { $2 }
+
+-- layout_list0(sep : α, p : β) :: [β]
+layout_list0(sep,p) : p                          { [$1] }
+                    | layout_list1(sep,p) sep p  { $1 `snoc` $3 }
+                    | {- epsilon -}              { [] }
+
+-- layout1(p : β) :: [β]
+layout1(p)  : '{' layout_list1(';',p) '}'   { $2 }
+            | VL  layout_list1(VS,p) VR     { $2 }
+
+-- layout_list1(sep : α, p : β) :: [β]
+layout_list1(sep,p) : p                          { [$1] }
+                    | layout_list1(sep,p) sep p  { $1 `snoc` $3 }
+
+{
+
+extractVarName = view $ to extract . singular _TokenVarName
+
+parseRlpProgR :: (Monad m) => Text -> RLPCT m (Program Name (RlpExpr PsName))
+parseRlpProgR s = liftErrorful $ errorful (ma,es)
+    where
+        (_,es,ma) = runP' parseRlpProg s
+
+parseRlpExprR :: (Monad m) => Text -> RLPCT m (RlpExpr PsName)
+parseRlpExprR s = liftErrorful $ errorful (ma,es)
+    where
+        (_,es,ma) = runP' parseRlpExpr s
+
+parseError = error "explode"
+
+extractName = view $ to extract . singular _TokenVarName
+
+}

src/Rlp/AltSyntax.hs

@@ -0,0 +1,219 @@
+{-# LANGUAGE TemplateHaskell, PatternSynonyms #-}
+module Rlp.AltSyntax
+    (
+    -- * AST
+      Program(..), Decl(..), ExprF(..), Pat(..)
+    , RlpExprF, RlpExpr, Binding(..), Alter(..)
+    , DataCon(..), Type(..)
+    , pattern IntT
+
+    , TypeF(..)
+
+    , Core.Name, PsName
+    , pattern (Core.:->)
+
+    -- * Optics
+    , programDecls
+    , _VarP, _FunB, _VarB
+
+    -- * Functor-related tools
+    , Fix(..), Cofree(..), Sum(..), pattern Finl, pattern Finr
+    )
+    where
+--------------------------------------------------------------------------------
+import Data.Functor.Sum
+import Control.Comonad.Cofree
+import Data.Fix
+import Data.Function            (fix)
+import GHC.Generics             (Generic, Generic1)
+import Data.Hashable
+import Data.Hashable.Lifted
+import GHC.Exts                 (IsString)
+import Control.Lens
+
+import Data.Functor.Foldable.TH
+import Text.Show.Deriving
+import Data.Eq.Deriving
+import Data.Text                qualified as T
+import Data.Pretty
+import Misc.Lift1
+
+import Compiler.Types
+import Core.Syntax              qualified as Core
+--------------------------------------------------------------------------------
+
+type PsName = T.Text
+
+newtype Program b a = Program [Decl b a]
+    deriving Show
+
+programDecls :: Lens' (Program b a) [Decl b a]
+programDecls = lens (\ (Program ds) -> ds) (const Program)
+
+data Decl b a = FunD b [Pat b] a
+              | DataD b [b] [DataCon b]
+              | TySigD b (Type b)
+              deriving Show
+
+data DataCon b = DataCon b [Type b]
+    deriving (Show, Generic)
+
+data Type b = VarT b
+            | ConT b
+            | AppT (Type b) (Type b)
+            | FunT
+            | ForallT b (Type b)
+            deriving (Show, Eq, Generic, Functor, Foldable, Traversable)
+
+instance (Hashable b) => Hashable (Type b)
+
+pattern IntT :: (IsString b, Eq b) => Type b
+pattern IntT = ConT "Int#"
+
+instance Core.HasArrowSyntax (Type b) (Type b) (Type b) where
+    _arrowSyntax = prism make unmake where
+        make (s,t) = FunT `AppT` s `AppT` t
+
+        unmake (FunT `AppT` s `AppT` t) = Right (s,t)
+        unmake s                        = Left s
+
+data ExprF b a = InfixEF b a a
+               | LetEF Core.Rec [Binding b a] a
+               | CaseEF a [Alter b a]
+               deriving (Functor, Foldable, Traversable)
+               deriving (Eq, Generic, Generic1)
+
+data Alter b a = Alter (Pat b) a
+               deriving (Show, Functor, Foldable, Traversable)
+               deriving (Eq, Generic, Generic1)
+
+data Binding b a = FunB b [Pat b] a
+                 | VarB (Pat b) a
+                 deriving (Show, Functor, Foldable, Traversable)
+                 deriving (Eq, Generic, Generic1)
+
+-- type Expr b = Cofree (ExprF b)
+
+type RlpExprF b = Sum (Core.ExprF b) (ExprF b)
+
+type RlpExpr b = Fix (RlpExprF b)
+
+data Pat b = VarP b
+           | ConP b
+           | AppP (Pat b) (Pat b)
+           deriving (Eq, Show, Generic)
+
+deriveShow1 ''Alter
+deriveShow1 ''Binding
+deriveShow1 ''ExprF
+deriving instance (Show b, Show a) => Show (ExprF b a)
+
+pattern Finl :: f (Fix (Sum f g)) -> Fix (Sum f g)
+pattern Finl fa = Fix (InL fa)
+
+pattern Finr :: g (Fix (Sum f g)) -> Fix (Sum f g)
+pattern Finr ga = Fix (InR ga)
+
+--------------------------------------------------------------------------------
+
+instance (Pretty b, Pretty a) => Pretty (ExprF b a) where
+    prettyPrec = prettyPrec1
+
+instance (Pretty b, Pretty a) => Pretty (Alter b a) where
+    prettyPrec = prettyPrec1
+
+instance (Pretty b) => Pretty1 (Alter b) where
+    liftPrettyPrec pr _ (Alter p e) =
+        hsep [ pretty p, "->", pr 0 e]
+
+instance Pretty b => Pretty1 (ExprF b) where
+    liftPrettyPrec pr p (InfixEF o a b) = maybeParens (p>0) $
+        pr 1 a <+> pretty o <+> pr 1 b
+    liftPrettyPrec pr p (CaseEF e as) = maybeParens (p>0) $
+        hsep [ "case", pr 0 e, "of" ]
+        $+$ nest 2 (vcat $ liftPrettyPrec pr 0 <$> as)
+
+instance (Pretty b, Pretty a) => Pretty (Decl b a) where
+    prettyPrec = prettyPrec1
+
+instance (Pretty b) => Pretty1 (Decl b) where
+    liftPrettyPrec pr _ (FunD f as e) =
+        hsep [ ttext f, hsep (prettyPrec appPrec1 <$> as)
+             , "=", pr 0 e ]
+
+    liftPrettyPrec _ _ (DataD f as []) =
+        hsep [ "data", ttext f, hsep (pretty <$> as) ]
+
+    liftPrettyPrec _ _ (DataD f as ds) =
+        hsep [ "data", ttext f, hsep (pretty <$> as), cons ]
+      where
+        cons = vcat $ zipWith (<+>) delims (pretty <$> ds)
+        delims = "=" : repeat "|"
+
+    liftPrettyPrec _ _ (TySigD n t) =
+        hsep [ ttext n, ":", pretty t ]
+
+instance (Pretty b) => Pretty (DataCon b) where
+    pretty (DataCon n as) = ttext n <+> hsep (prettyPrec appPrec1 <$> as)
+
+-- (->) is given prec `appPrec-1`
+instance (Pretty b) => Pretty (Type b) where
+    prettyPrec _ (VarT n) = ttext n
+    prettyPrec _ (ConT n) = ttext n
+    prettyPrec p (s Core.:-> t) = maybeParens (p>appPrec-1) $
+        hsep [ prettyPrec appPrec s, "->", prettyPrec (appPrec-1) t ]
+    prettyPrec p (AppT f x) = maybeParens (p>appPrec) $
+        prettyPrec appPrec f <+> prettyPrec appPrec1 x
+    prettyPrec p FunT = maybeParens (p>0) "->"
+
+instance (Pretty b) => Pretty (Pat b) where
+    prettyPrec p (VarP b) = prettyPrec p b
+    prettyPrec p (ConP b) = prettyPrec p b
+    prettyPrec p (AppP c x) = maybeParens (p>appPrec) $
+        prettyPrec appPrec c <+> prettyPrec appPrec1 x
+
+instance (Pretty a, Pretty b) => Pretty (Program b a) where
+    prettyPrec = prettyPrec1
+
+instance (Pretty b) => Pretty1 (Program b) where
+    liftPrettyPrec pr p (Program ds) = vsep $ liftPrettyPrec pr p <$> ds
+
+makePrisms ''Pat
+makePrisms ''Binding
+
+deriving instance (Lift b, Lift a) => Lift (Program b a)
+deriving instance (Lift b, Lift a) => Lift (Decl b a)
+deriving instance (Lift b) => Lift (Pat b)
+deriving instance (Lift b) => Lift (DataCon b)
+deriving instance (Lift b) => Lift (Type b)
+
+instance Lift b => Lift1 (Binding b) where
+    liftLift lf (VarB b a) = liftCon2 'VarB (lift b) (lf a)
+
+instance Lift b => Lift1 (Alter b) where
+    liftLift lf (Alter b a) = liftCon2 'Alter (lift b) (lf a)
+
+instance Lift b => Lift1 (ExprF b) where
+    liftLift lf (InfixEF o a b) =
+        liftCon3 'InfixEF (lift o) (lf a) (lf b)
+    liftLift lf (LetEF r bs e) =
+        liftCon3 'LetEF (lift r) bs' (lf e)
+      where bs' = liftLift (liftLift lf) bs
+    liftLift lf (CaseEF e as) =
+        liftCon2 'CaseEF (lf e) as'
+      where as' = liftLift (liftLift lf) as
+
+deriveEq1 ''Binding
+deriveEq1 ''Alter
+deriveEq1 ''ExprF
+
+instance (Hashable b) => Hashable (Pat b)
+instance (Hashable b, Hashable a) => Hashable (Binding b a)
+instance (Hashable b, Hashable a) => Hashable (Alter b a)
+instance (Hashable b, Hashable a) => Hashable (ExprF b a)
+instance (Hashable b) => Hashable1 (Alter b)
+instance (Hashable b) => Hashable1 (Binding b)
+instance (Hashable b) => Hashable1 (ExprF b)
+
+makeBaseFunctor ''Type
+

src/Rlp/HindleyMilner.hs

@@ -0,0 +1,161 @@
+{-# LANGUAGE PartialTypeSignatures #-}
+{-# LANGUAGE OverloadedLists #-}
+{-# LANGUAGE TemplateHaskell #-}
+module Rlp.HindleyMilner
+    ( typeCheckRlpProgR
+    , solve
+    , TypeError(..)
+    , runHM'
+    , HM
+    )
+    where
+--------------------------------------------------------------------------------
+import Control.Lens             hiding (Context', Context, (:<), para)
+import Control.Monad.Errorful
+import Control.Monad.State
+import Control.Monad.Accum
+import Control.Monad
+import Control.Arrow            ((>>>))
+import Control.Monad.Writer.Strict
+import Data.Text                qualified as T
+import Data.Pretty
+import Data.Hashable
+import Data.HashMap.Strict      (HashMap)
+import Data.HashMap.Strict      qualified as H
+import Data.HashSet             (HashSet)
+import Data.HashSet             qualified as S
+import Data.Maybe               (fromMaybe)
+import Data.Traversable
+import GHC.Generics             (Generic(..), Generically(..))
+
+import Data.Functor
+import Data.Functor.Foldable
+import Data.Fix                 hiding (cata, para)
+import Control.Comonad.Cofree
+import Control.Comonad
+
+import Compiler.RLPC
+import Compiler.RlpcError
+import Rlp.AltSyntax            as Rlp
+import Core.Syntax              qualified as Core
+import Core.Syntax              (ExprF(..), Lit(..))
+import Rlp.HindleyMilner.Types
+--------------------------------------------------------------------------------
+
+fixCofree :: (Functor f, Functor g)
+          => Iso (Fix f) (Fix g) (Cofree f ()) (Cofree g b)
+fixCofree = iso sa bt where
+    sa = foldFix (() :<)
+    bt (_ :< as) = Fix $ bt <$> as
+
+lookupVar :: PsName -> Context -> HM (Type PsName)
+lookupVar n g = case g ^. contextVars . at n of
+    Just t -> pure t
+    Nothing -> addFatal $ TyErrUntypedVariable n
+
+gather :: RlpExpr PsName -> HM (Type PsName, PartialJudgement)
+gather e = look >>= (H.lookup e >>> maybe memoise pure)
+    where
+        memoise = do
+            r <- gather' e
+            add (H.singleton e r)
+            pure r
+
+gather' :: RlpExpr PsName -> HM (Type PsName, PartialJudgement)
+gather' = \case
+    Finl (LitF (IntL _)) -> pure (IntT, mempty)
+
+    Finl (VarF n) -> do
+        t <- freshTv
+        let j = mempty & assumptions .~ H.singleton n [t]
+        pure (t,j)
+
+    Finl (AppF f x) -> do
+        tfx <- freshTv
+        (tf,jf) <- gather f
+        (tx,jx) <- gather x
+        let jtfx = mempty & constraints .~ [Equality tf (tx :-> tfx)]
+        pure (tfx, jf <> jx <> jtfx)
+
+    Finl (LamF [b] e) -> do
+        tb <- freshTv
+        (te,je) <- gather e
+        let cs = maybe [] (fmap $ Equality tb) (je ^. assumptions . at b)
+            as = je ^. assumptions & at b .~ Nothing
+            j = mempty & constraints .~ cs & assumptions .~ as
+            t = tb :-> te
+        pure (t,j)
+
+unify :: [Constraint] -> HM Context
+
+unify [] = pure mempty
+
+unify (Equality (sx :-> sy) (tx :-> ty) : cs) =
+    unify $ Equality sx tx : Equality sy ty : cs
+
+-- elim
+unify (Equality (ConT s) (ConT t) : cs) | s == t = unify cs
+unify (Equality (VarT s) (VarT t) : cs) | s == t = unify cs
+
+unify (Equality (VarT s) t : cs)
+    | occurs s t = addFatal $ TyErrRecursiveType s t
+    | otherwise  = unify cs' <&> contextVars . at s ?~ t
+  where
+    cs' = cs & each . constraintTypes %~ subst s t
+
+-- swap
+unify (Equality s (VarT t) : cs) = unify (Equality (VarT t) s : cs)
+
+unify (Equality s t : _) = addFatal $ TyErrCouldNotUnify s t
+
+annotate :: RlpExpr PsName
+         -> HM (Cofree (RlpExprF PsName) (Type PsName, PartialJudgement))
+annotate = sequenceA . fixtend (gather . wrapFix)
+
+solveTree :: Cofree (RlpExprF PsName) (Type PsName, PartialJudgement)
+          -> HM (Type PsName)
+solveTree e = undefined
+
+infer1 :: RlpExpr PsName -> HM (Type PsName)
+infer1 e = do
+    ((t,j) :< _) <- annotate e
+    g <- unify (j ^. constraints)
+    pure $ ifoldrOf (contextVars . itraversed) subst t g
+
+solve = undefined
+-- solve g e = do
+--     (t,j) <- gather e
+--     g' <- unify cs
+--     pure $ ifoldrOf (contextVars . itraversed) subst t g'
+
+occurs :: PsName -> Type PsName -> Bool
+occurs n = cata \case
+    VarTF m | n == m -> True
+    t                -> or t
+
+subst :: PsName -> Type PsName -> Type PsName -> Type PsName
+subst n t' = para \case
+    VarTF m | n == m -> t'
+    -- shadowing
+    ForallTF x (pre,post) | x == n    -> ForallT x pre
+                          | otherwise -> ForallT x post
+    t -> embed $ t <&> view _2
+
+prettyHM :: (Pretty a)
+         => Either [TypeError] (a, [Constraint])
+         -> Either [TypeError] (String, [String])
+prettyHM = over (mapped . _1) rpretty
+         . over (mapped . _2 . each) rpretty
+
+fixtend :: Functor f => (f (Fix f) -> b) -> Fix f -> Cofree f b
+fixtend c (Fix f) = c f :< fmap (fixtend c) f
+
+infer :: RlpExpr PsName -> HM (Cofree (RlpExprF PsName) (Type PsName))
+infer = undefined
+
+typeCheckRlpProgR :: (Monad m)
+                  => Program PsName (RlpExpr PsName)
+                  -> RLPCT m (Program PsName
+                      (Cofree (RlpExprF PsName) (Type PsName)))
+typeCheckRlpProgR = undefined
+

src/Rlp/HindleyMilner/Types.hs

@@ -0,0 +1,162 @@
+{-# LANGUAGE OverloadedLists #-}
+{-# LANGUAGE TemplateHaskell #-}
+module Rlp.HindleyMilner.Types
+    where
+--------------------------------------------------------------------------------
+import Data.Hashable
+import Data.HashMap.Strict      (HashMap)
+import Data.HashMap.Strict      qualified as H
+import Data.HashSet             (HashSet)
+import Data.HashSet             qualified as S
+import GHC.Generics             (Generic(..), Generically(..))
+import Data.Kind                qualified
+import Data.Text                qualified as T
+import Control.Monad.Writer
+import Control.Monad.Accum
+import Control.Monad.Trans.Accum
+import Control.Monad.Errorful
+import Control.Monad.State
+import Text.Printf
+import Data.Pretty
+import Data.Function
+
+import Control.Lens             hiding (Context', Context)
+
+import Compiler.RlpcError
+import Rlp.AltSyntax
+--------------------------------------------------------------------------------
+
+newtype Context = Context
+    { _contextVars      :: HashMap PsName (Type PsName)
+    }
+    deriving (Show, Generic)
+    deriving (Semigroup, Monoid)
+        via Generically Context
+
+data Constraint = Equality (Type PsName) (Type PsName)
+    deriving (Eq, Generic, Show)
+
+data PartialJudgement = PartialJudgement
+    { _constraints :: [Constraint]
+    , _assumptions :: HashMap PsName [Type PsName]
+    }
+    deriving (Generic, Show)
+    deriving (Monoid)
+        via Generically PartialJudgement
+
+instance Semigroup PartialJudgement where
+    a <> b = PartialJudgement
+        { _constraints = ((<>) `on` _constraints) a b
+        , _assumptions = (H.unionWith (<>) `on` _assumptions) a b
+        }
+
+instance Hashable Constraint
+
+type Memo = HashMap (RlpExpr PsName) (Type PsName, PartialJudgement)
+
+type HM = ErrorfulT TypeError (StateT Int (Accum Memo))
+
+-- | Type error enum.
+data TypeError
+    -- | Two types could not be unified
+    = TyErrCouldNotUnify (Type Name) (Type Name)
+    -- | @x@ could not be unified with @t@ because @x@ occurs in @t@
+    | TyErrRecursiveType Name (Type Name)
+    -- | Untyped, potentially undefined variable
+    | TyErrUntypedVariable Name
+    | TyErrMissingTypeSig Name
+    | TyErrNonHomogenousCaseAlternatives (RlpExpr PsName)
+    deriving (Show)
+
+instance IsRlpcError TypeError where
+    liftRlpcError = \case
+        -- todo: use anti-parser instead of show
+        TyErrCouldNotUnify t u -> Text
+            [ T.pack $ printf "Could not match type `%s` with `%s`."
+                              (rpretty @String t) (rpretty @String u)
+            , "Expected: " <> rpretty t
+            , "Got: " <> rpretty u
+            ]
+        TyErrUntypedVariable n -> Text
+            [ "Untyped (likely undefined) variable `" <> n <> "`"
+            ]
+        TyErrRecursiveType t x -> Text
+            [ T.pack $ printf "Recursive type: `%s' occurs in `%s'"
+                              (rpretty @String t) (rpretty @String x)
+            ]
+
+-- type Memo t = HashMap t (Type PsName, PartialJudgement)
+
+-- newtype HM t a = HM { unHM :: Int -> Memo t -> (a, Int, Memo t) }
+
+-- runHM :: (Hashable t) => HM t a -> (a, Memo t)
+-- runHM hm = let (a,_,m) = unHM hm 0 mempty in (a,m)
+
+-- instance Functor (HM t) where
+--     fmap f (HM h) = HM \n m -> h n m & _1 %~ f
+
+-- instance Applicative (HM t) where
+--     pure a = HM \n m -> (a,n,m)
+--     HM hf <*> HM ha = HM \n m ->
+--         let (f',n',m') = hf n m
+--             (a,n'',m'') = ha n' m'
+--         in (f' a, n'', m'')
+
+-- instance Monad (HM t) where
+--     HM ha >>= k = HM \n m ->
+--         let (a,n',m') = ha n m
+--             (a',n'',m'') = unHM (k a) n' m'
+--         in (a',n'', m'')
+
+-- instance Hashable t => MonadWriter (Memo t) (HM t) where
+--     -- IMPORTAN! (<>) is left-biased for HashMap! append `w` to the RIGHt!
+--     writer (a,w) = HM \n m -> (a,n,m <> w)
+--     listen ma = HM \n m ->
+--         let (a,n',m') = unHM ma n m
+--         in ((a,m'),n',m')
+--     pass maww = HM \n m ->
+--         let ((a,ww),n',m') = unHM maww n m
+--         in (a,n',ww m')
+
+-- instance MonadState Int (HM t) where
+--     state f = HM \n m ->
+--         let (a,n') = f n
+--         in (a,n',m)
+
+freshTv :: HM (Type PsName)
+freshTv = do
+    n <- get
+    modify succ
+    pure . VarT $ "$a" <> T.pack (show n)
+
+runHM' :: HM a -> Either [TypeError] a
+runHM' e = maybe (Left es) Right ma
+    where
+        ((ma,es),m) = (`runAccum` mempty) . (`evalStateT` 0) . runErrorfulT $ e
+
+-- addConstraint :: Constraint -> HM ()
+-- addConstraint = tell . pure
+
+makePrisms ''PartialJudgement
+makeLenses ''PartialJudgement
+makeLenses ''Context
+makePrisms ''Constraint
+makePrisms ''TypeError
+
+supplement :: [(PsName, Type PsName)] -> Context -> Context
+supplement bs = contextVars %~ (H.fromList bs <>)
+
+demoContext :: Context
+demoContext = Context
+    { _contextVars =
+        [ ("+#", IntT :-> IntT :-> IntT)
+        ]
+    }
+
+constraintTypes :: Traversal' Constraint (Type PsName)
+constraintTypes k (Equality s t) = Equality <$> k s <*> k t
+
+instance Pretty Constraint where
+    pretty (Equality s t) =
+        hsep [prettyPrec appPrec1 s, "~", prettyPrec appPrec1 t]
+

src/Rlp/Lex.x

@@ -14,6 +14,7 @@ module Rlp.Lex
     , popLexState
     , programInitState
     , runP'
+    , popLayout
     )
     where
 import Codec.Binary.UTF8.String (encodeChar)
@@ -61,7 +62,7 @@ $asciisym       = [\!\#\$\%\&\*\+\.\/\<\=\>\?\@\\\^\|\-\~\:]
     |infixr|infixl|infix
 
 @reservedop =
-    "=" | \\ | "->" | "|" | "::"
+    "=" | \\ | "->" | "|" | ":"
 
 rlp :-
     
@@ -167,9 +168,10 @@ lexReservedName = \case
 lexReservedOp :: Text -> RlpToken
 lexReservedOp = \case
     "="     -> TokenEquals
-    "::"    -> TokenHasType
+    ":"     -> TokenHasType
     "|"     -> TokenPipe
     "->"    -> TokenArrow
+    "\\"    -> TokenLambda
     s       -> error (show s)
 
 -- | @andBegin@, with the subtle difference that the start code is set

src/Rlp/Parse.y

@@ -84,7 +84,7 @@ VL  : vlbrace       { () }
 
 VR  :: { () }
 VR  : vrbrace       { () }
-    | error         { () }
+    | error         {% void popLayout }
 
 VS                  :: { () }
 VS                  : ';'                   { () }

src/Rlp/Parse/Types.hs

@@ -18,7 +18,7 @@ module Rlp.Parse.Types
     , RlpToken(..), AlexInput(..), Position(..), spanFromPos, LexerAction
     , Located(..), PsName
     -- ** Lenses
-    , _TokenLitInt, _TokenVarName, _TokenConName, _TokenVarSym
+    , _TokenLitInt, _TokenVarName, _TokenConName, _TokenVarSym, _TokenConSym
     , aiPrevChar, aiSource, aiBytes, aiPos, posLine, posColumn
 
     -- * Error handling
@@ -277,7 +277,7 @@ initAlexInput s = AlexInput
     { _aiPrevChar   = '\0'
     , _aiSource     = s
     , _aiBytes      = []
-    , _aiPos        = (1,1,0)
+    , _aiPos        = (1,0,0)
     }
 
 --------------------------------------------------------------------------------

src/Rlp/Syntax/Good.hs

@@ -0,0 +1,56 @@
+{-# LANGUAGE TemplateHaskell #-}
+module Rlp.Syntax.Good
+    ( Decl(..), Program(..)
+    , programDecls
+    , Mistake(..)
+    )
+    where
+--------------------------------------------------------------------------------
+import Data.Kind
+import Control.Lens
+import Rlp.Syntax.Types (NameP)
+import Rlp.Syntax.Types qualified as Rlp
+--------------------------------------------------------------------------------
+
+data Program b a = Program
+    { _programDecls :: [Decl b a]
+    }
+
+data Decl p a = FunD   (NameP p) [Rlp.Pat p] a
+              | TySigD [NameP p] (Rlp.Ty p)
+              | DataD  (NameP p) [NameP p] [Rlp.ConAlt p]
+              | InfixD Rlp.Assoc Int (NameP p)
+
+type Where p a = [Binding p a]
+
+data Binding p a = PatB (Rlp.Pat p) a
+    deriving (Functor, Foldable, Traversable)
+
+makeLenses ''Program
+
+class Mistake a where
+    type family Ammend a :: Type
+    ammendMistake :: a -> Ammend a
+
+instance Mistake (Rlp.Program p a) where
+    type Ammend (Rlp.Program p a) = Program p (Rlp.Expr' p a)
+
+    ammendMistake p = Program
+        { _programDecls = ammendMistake <$> Rlp._programDecls p
+        }
+
+instance Mistake (Rlp.Decl p a) where
+    type Ammend (Rlp.Decl p a) = Decl p (Rlp.Expr' p a)
+
+    ammendMistake = \case
+        Rlp.FunD n as e _  -> FunD n as e
+        Rlp.TySigD ns t    -> TySigD ns t
+        Rlp.DataD n as cs  -> DataD n as cs
+        Rlp.InfixD ass p n -> InfixD ass p n
+
+instance Mistake (Rlp.Binding p a) where
+    type Ammend (Rlp.Binding p a) = Binding p (Rlp.ExprF p a)
+
+    ammendMistake = \case
+        Rlp.PatB k v -> PatB k v
+

src/Rlp/Syntax/Types.hs

@@ -15,7 +15,7 @@ module Rlp.Syntax.Types
     , Rec(..)
     , Lit(..)
     , Pat(..)
-    , Decl(..)
+    , Decl(..), Decl'
     , Program(..)
     , Where
 
@@ -23,6 +23,8 @@ module Rlp.Syntax.Types
     , Cofree(..)
     , Trans.Cofree.CofreeF
     , SrcSpan(..)
+
+    , programDecls
     )
     where
 ----------------------------------------------------------------------------------

src/Rlp/TH.hs

@@ -13,16 +13,14 @@ import Control.Monad.IO.Class
 import Control.Monad
 
 import Compiler.RLPC
-import Rlp.Parse
+import Rlp.AltParse
 --------------------------------------------------------------------------------
 
 rlpProg :: QuasiQuoter
-rlpProg = undefined
--- rlpProg = mkqq parseRlpProgR
+rlpProg = mkqq parseRlpProgR
 
 rlpExpr :: QuasiQuoter
-rlpExpr = undefined
--- rlpExpr = mkqq parseRlpExprR
+rlpExpr = mkqq parseRlpExprR
 
 mkq :: (Lift a) => (Text -> RLPCIO a) -> String -> Q Exp
 mkq parse = evalAndParse >=> lift where

src/Rlp2Core.hs

@@ -28,6 +28,7 @@ import Data.Functor.Bind
 import Data.Function                    (on)
 import GHC.Stack
 import Debug.Trace
+import Numeric
 
 import Effectful.State.Static.Local
 import Effectful.Labeled
@@ -35,18 +36,11 @@ import Effectful
 import Text.Show.Deriving
 
 import Core.Syntax                      as Core
+import Rlp.AltSyntax                    as Rlp
 import Compiler.Types
 import Data.Pretty                      (render, pretty)
-import Rlp.Syntax                       as Rlp
-import Rlp.Parse.Types                  (RlpcPs, PsName)
 --------------------------------------------------------------------------------
 
-desugarRlpProgR = undefined
-desugarRlpProg = undefined
-desugarRlpExpr = undefined
-
-{--
-
 type Tree a = Either Name (Name, Branch a)
 
 -- | Rose tree branch representing "nested" "patterns" in the Core language. That
@@ -65,180 +59,49 @@ deriveShow1 ''Branch
 
 --------------------------------------------------------------------------------
 
-desugarRlpProgR :: forall m. (Monad m) => RlpProgram RlpcPs -> RLPCT m Program'
+desugarRlpProgR :: forall m a. (Monad m)
+                => Rlp.Program PsName a
+                -> RLPCT m Core.Program'
 desugarRlpProgR p = do
     let p' = desugarRlpProg p
     addDebugMsg "dump-desugared" $ render (pretty p')
     pure p'
 
-desugarRlpProg :: RlpProgram RlpcPs -> Program'
-desugarRlpProg = rlpProgToCore
+desugarRlpProg = undefined
 
-desugarRlpExpr :: RlpExpr RlpcPs -> Expr'
-desugarRlpExpr = runPureEff . runNameSupply "anon" . exprToCore
+desugarRlpExpr = undefined
+
+runNameSupply :: Text -> Eff (NameSupply ': es) a -> Eff es a
+runNameSupply pre = undefined -- evalState [ pre <> "_" <> tshow name | name <- [0..] ]
 
 -- the rl' program is desugared by desugaring each declaration as a separate
 -- program, and taking the monoidal product of the lot :3
 
-rlpProgToCore :: RlpProgram RlpcPs -> Program'
-rlpProgToCore = foldMapOf (progDecls . each) declToCore
+rlpProgToCore :: Rlp.Program PsName (RlpExpr PsName) -> Program'
+rlpProgToCore = foldMapOf (programDecls . each) declToCore
 
-declToCore :: Decl' RlpcPs -> Program'
+declToCore :: Rlp.Decl PsName (RlpExpr PsName) -> Program'
 
-declToCore (TySigD'' ns t) = mempty &
-    programTypeSigs .~ H.fromList [ (n, typeToCore t) | n <- ns ]
-
-declToCore (DataD'' n as ds) = fold . getZipList $
-    constructorToCore t' <$> ZipList [0..] <*> ZipList ds
+-- assume all arguments are VarP's for now
+declToCore (FunD b as e) = mempty & programScDefs .~ [ScDef b as' e']
     where
-        -- create the appropriate type from the declared constructor and its
-        -- arguments
-        t' = foldl TyApp (TyCon n) (TyVar . dsNameToName <$> as)
+        as' = as ^.. each . singular _VarP
+        e' = runPureEff . runNameSupply b . exprToCore $ e
 
--- TODO: where-binds
-declToCore fd@(FunD'' n as e _) = mempty & programScDefs .~ [ScDef n' as' e']
+type NameSupply = State [Name]
+
+exprToCore :: (NameSupply :> es)
+           => RlpExpr PsName -> Eff es Core.Expr'
+exprToCore = foldFixM \case
+    InL e -> pure $ Fix e
+    InR e -> rlpExprToCore e
+
+rlpExprToCore :: (NameSupply :> es)
+           => Rlp.ExprF PsName Core.Expr' -> Eff es Core.Expr'
+
+-- assume all binders are simple variable patterns for now
+rlpExprToCore (LetEF r bs e) = pure $ Let r bs' e
   where
-        n' = dsNameToName n
-        e' = runPureEff . runNameSupply n . exprToCore . unXRec $ e
-        as' = as <&> \case
-            (unXRec -> VarP k) -> dsNameToName k
-            _                  -> error "no patargs yet"
-
-type NameSupply = Labeled NameSupplyLabel (State [IdP RlpcPs])
-type NameSupplyLabel = "expr-name-supply"
-
-exprToCore :: forall es. (NameSupply :> es) => RlpExpr RlpcPs -> Eff es Expr'
-
-exprToCore (VarE n) = pure $ Var (dsNameToName n)
-
-exprToCore (AppE a b) = (liftA2 App `on` exprToCore . unXRec) a b
-
-exprToCore (OAppE f a b) = (liftA2 mkApp `on` exprToCore . unXRec) a b
-    where
-        mkApp s t = (Var f `App` s) `App` t
-
-exprToCore (CaseE (unXRec -> e) as) = do
-    e' <- exprToCore e
-    Case e' <$> caseAltToCore `traverse` as
-
-exprToCore (LetE bs e) = letToCore NonRec bs e
-exprToCore (LetrecE bs e) = letToCore Rec bs e
-
-exprToCore (LitE l) = litToCore l
-
-letToCore :: forall es. (NameSupply :> es)
-          => Rec -> [Rlp.Binding' RlpcPs] -> RlpExpr' RlpcPs -> Eff es Expr'
-letToCore r bs e = do
-    -- TODO: preserve binder order.
-    (bs',as) <- getParts
-    let insbs | null bs'  = pure
-              | otherwise = pure . Let r bs'
-    appKendo (foldMap Kendo (as `snoc` insbs)) <=< exprToCore $ unXRec e
-  where
-    -- partition & map the list of binders into:
-    --  bs'   : the let-binds that may be directly translated to Core
-    --          let-binds (we do exactly that). this is all the binders that
-    --          are a simple variable rather than a pattern match.
-    -- and as : the let-binds that may **not** be directly translated to
-    --          Core let-exprs. they get turned into case alternates.
-    getParts = traverse f bs <&> partitionEithers
-
-    f :: Rlp.Binding' RlpcPs
-      -> Eff es (Either Core.Binding' (Expr' -> Eff es Expr'))
-    f (PatB'' (VarP'' n) e) = Left . (n :=) <$> exprToCore (unXRec e)
-    f (PatB'' p          e) = pure $ Right (caseify p e)
-
-litToCore :: (NameSupply :> es) => Rlp.Lit RlpcPs -> Eff es Expr'
-litToCore (Rlp.IntL n) = pure . Lit $ Core.IntL n
-
-{-
-let C x = y
-in e
-
-case y of
-    C x -> e
- -}
-
-caseify :: (NameSupply :> es)
-        => Pat' RlpcPs -> RlpExpr' RlpcPs -> Expr' -> Eff es Expr'
-caseify p (unXRec -> e) i =
-    Case <$> exprToCore e <*> ((:[]) <$> alt)
-  where
-    alt = conToRose (unXRec p) <&> foldFix (branchToCore i)
-
--- TODO: where-binds
-caseAltToCore :: (HasCallStack, NameSupply :> es)
-              => (Alt RlpcPs, Where RlpcPs) -> Eff es Alter'
-caseAltToCore (AltA (unXRec -> p) e, wh) = do
-    e' <- exprToCore . unXRec $ e
-    conToRose p <&> foldFix (branchToCore e')
-
-altToCore :: (NameSupply :> es)
-          => Alt RlpcPs -> Eff es Alter'
-altToCore (AltA p e) = altToCore' p e
-
-altToCore' :: (NameSupply :> es)
-           => Pat' RlpcPs -> RlpExpr' RlpcPs -> Eff es Alter'
-altToCore' (unXRec -> p) (unXRec -> e) = do
-    e' <- exprToCore e
-    conToRose p <&> foldFix (branchToCore e')
-
-conToRose :: forall es. (HasCallStack, NameSupply :> es) => Pat RlpcPs -> Eff es Rose
-conToRose (ConP cn as) = Fix . Branch cn <$> patToForrest `traverse` as
-    where
-        patToForrest :: Pat' RlpcPs -> Eff es (Tree Rose)
-        patToForrest (VarP'' x) = pure $ Left (dsNameToName x)
-        patToForrest p@(ConP'' _ _) =
-            Right <$> liftA2 (,) uniqueName br
-          where
-            br = unwrapFix <$> conToRose (unXRec p)
-conToRose s = error $ "conToRose: not a ConP!: " <> show s
-
-branchToCore :: Expr' -> Branch Alter' -> Alter'
-branchToCore e (Branch cn as) = Alter (AltData cn) myBinds e'
-    where
-        -- gather binders for the /current/ pattern, and build an expression
-        -- matching subpatterns
-        (e', myBinds) = mapAccumL f e as
-
-        f :: Expr' -> Tree Alter' -> (Expr', Name)
-        f e (Left n)       = (e, dsNameToName n)
-        f e (Right (n,cs)) = (e', dsNameToName n) where
-            e' = Case (Var $ dsNameToName n) [branchToCore e cs]
-
-runNameSupply :: IdP RlpcPs -> Eff (NameSupply ': es) a -> Eff es a
-runNameSupply n = runLabeled @NameSupplyLabel (evalState ns) where
-    ns = [ "$" <> n <> "_" <> T.pack (show k) | k <- [0..] ]
-
--- | debug helper
-
-nameSupply :: [IdP RlpcPs]
-nameSupply = [ T.pack $ "$x_" <> show n | n <- [0..] ]
-
-uniqueName :: (NameSupply :> es) => Eff es (IdP RlpcPs)
-uniqueName = labeled @NameSupplyLabel @(State [IdP RlpcPs]) $
-    state @[IdP RlpcPs] (fromMaybe err . uncons)
-  where
-    err = error "NameSupply ran out of names! This shound never happen.\
-                \ The caller of runNameSupply is responsible."
-
-constructorToCore :: Type -> Tag -> ConAlt RlpcPs -> Program'
-constructorToCore t tag (ConAlt cn as) =
-    mempty & programTypeSigs . at cn ?~ foldr (:->) t as'
-           & programDataTags . at cn ?~ (tag, length as)
-    where
-        as' = typeToCore <$> as
-
-typeToCore :: RlpType' RlpcPs -> Type
-typeToCore FunConT''    = TyFun
-typeToCore (FunT'' s t) = typeToCore s :-> typeToCore t
-typeToCore (AppT'' s t) = TyApp (typeToCore s) (typeToCore t)
-typeToCore (ConT'' n)   = TyCon (dsNameToName n)
-typeToCore (VarT'' x)   = TyVar (dsNameToName x)
-
--- | Forwards-compatiblity if IdP RlpDs is changed
-dsNameToName :: IdP RlpcPs -> Name
-dsNameToName = id
-
--}
+    bs' = b2b <$> bs
+    b2b (VarB (VarP k) v) = Binding k v
 

tst/Rlp/HindleyMilnerSpec.hs

@@ -0,0 +1,14 @@
+{-# LANGUAGE TemplateHaskell, QuasiQuotes #-}
+module Rlp.HindleyMilnerSpec
+    ( spec
+    )
+    where
+--------------------------------------------------------------------------------
+import Test.Hspec
+import Rlp.TH
+import Rlp.HindleyMilner
+--------------------------------------------------------------------------------
+
+spec :: Spec
+spec = undefined
+