correctly distinguish between fun and data judgements

src/runtime/haskell/PGF2/ByteCode.hs

@@ -0,0 +1,41 @@
+module PGF2.ByteCode(-- * Byte code
+                     CodeLabel, Instr(..), IVal(..), TailInfo(..),
+                    ) where
+
+import PGF2.Expr
+
+type CodeLabel = Int
+
+data Instr
+  = CHECK_ARGS {-# UNPACK #-} !Int
+  | CASE Fun  {-# UNPACK #-} !CodeLabel
+  | CASE_LIT Literal  {-# UNPACK #-} !CodeLabel
+  | SAVE {-# UNPACK #-} !Int
+  | ALLOC  {-# UNPACK #-} !Int
+  | PUT_CONSTR Fun
+  | PUT_CLOSURE   {-# UNPACK #-} !CodeLabel
+  | PUT_LIT Literal
+  | SET IVal
+  | SET_PAD
+  | PUSH_FRAME
+  | PUSH IVal
+  | TUCK IVal {-# UNPACK #-} !Int
+  | EVAL IVal TailInfo
+  | DROP {-# UNPACK #-} !Int
+  | JUMP {-# UNPACK #-} !CodeLabel
+  | FAIL
+  | PUSH_ACCUM Literal
+  | POP_ACCUM
+  | ADD
+
+data IVal
+  = HEAP     {-# UNPACK #-} !Int
+  | ARG_VAR  {-# UNPACK #-} !Int
+  | FREE_VAR {-# UNPACK #-} !Int
+  | GLOBAL   Fun
+  deriving Eq
+
+data TailInfo
+  = RecCall
+  | TailCall {-# UNPACK #-} !Int
+  | UpdateCall