From 35296a555d26a4721ffabe7994d59809c63ec93c Mon Sep 17 00:00:00 2001
From: "kr.angelov" <kr.angelov@chalmers.se>
Date: Thu, 22 May 2008 14:31:36 +0000
Subject: move GF.Devel.Compute to GF.Compile.Compute

---
 src-3.0/GF/Compile/Compute.hs  | 456 +++++++++++++++++++++++++++++++++++++++++
 src-3.0/GF/Compile/Optimize.hs |   2 +-
 src-3.0/GF/Devel/Compute.hs    | 456 -----------------------------------------
 3 files changed, 457 insertions(+), 457 deletions(-)
 create mode 100644 src-3.0/GF/Compile/Compute.hs
 delete mode 100644 src-3.0/GF/Devel/Compute.hs

(limited to 'src-3.0')

diff --git a/src-3.0/GF/Compile/Compute.hs b/src-3.0/GF/Compile/Compute.hs
new file mode 100644
index 000000000..5e6902203
--- /dev/null
+++ b/src-3.0/GF/Compile/Compute.hs
@@ -0,0 +1,456 @@
+----------------------------------------------------------------------
+-- |
+-- Module      : Compute
+-- Maintainer  : AR
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- > CVS $Date: 2005/11/01 15:39:12 $ 
+-- > CVS $Author: aarne $
+-- > CVS $Revision: 1.19 $
+--
+-- Computation of source terms. Used in compilation and in @cc@ command.
+-----------------------------------------------------------------------------
+
+module GF.Compile.Compute (computeConcrete, computeTerm,computeConcreteRec) where
+
+import GF.Data.Operations
+import GF.Grammar.Grammar
+import GF.Infra.Ident
+import GF.Infra.Option
+import GF.Data.Str
+import GF.Grammar.PrGrammar
+import GF.Infra.Modules
+import GF.Grammar.Predef
+import GF.Grammar.Macros
+import GF.Grammar.Lookup
+import GF.Grammar.Refresh
+import GF.Grammar.PatternMatch
+import GF.Grammar.Lockfield (isLockLabel) ----
+
+import GF.Grammar.AppPredefined
+
+import Data.List (nub,intersperse)
+import Control.Monad (liftM2, liftM)
+
+-- | computation of concrete syntax terms into normal form
+-- used mainly for partial evaluation
+computeConcrete :: SourceGrammar -> Term -> Err Term
+computeConcrete    g t = {- refreshTerm t >>= -} computeTerm g [] t
+computeConcreteRec g t = {- refreshTerm t >>= -} computeTermOpt True g [] t
+
+computeTerm :: SourceGrammar -> Substitution -> Term -> Err Term
+computeTerm = computeTermOpt False
+
+-- rec=True is used if it cannot be assumed that looked-up constants
+-- have already been computed (mainly with -optimize=noexpand in .gfr)
+
+computeTermOpt :: Bool -> SourceGrammar -> Substitution -> Term -> Err Term
+computeTermOpt rec gr = comput True where
+
+   comput full g t = ---- errIn ("subterm" +++ prt t) $ --- for debugging 
+              case t of
+
+     Q p c | p == cPredef -> return t
+           | otherwise    -> look p c 
+
+     -- if computed do nothing
+     Computed t' -> return $ unComputed t'
+
+     Vr x -> do
+       t' <- maybe (prtBad ("no value given to variable") x) return $ lookup x g
+       case t' of 
+         _ | t == t' -> return t
+         _ -> comp g t'
+
+     -- Abs x@(IA _) b -> do 
+     Abs x b | full -> do 
+       let (xs,b1) = termFormCnc t   
+       b' <- comp ([(x,Vr x) | x <- xs] ++ g) b1
+       return $ mkAbs xs b'
+     --  b' <- comp (ext x (Vr x) g) b
+     --  return $ Abs x b'
+     Abs _ _ -> return t -- hnf
+
+     Let (x,(_,a)) b -> do
+       a' <- comp g a
+       comp (ext x a' g) b
+
+     Prod x a b -> do
+       a' <- comp g a
+       b' <- comp (ext x (Vr x) g) b
+       return $ Prod x a' b'
+
+     -- beta-convert
+     App f a -> case appForm t of
+      (h,as) | length as > 1 -> do
+        h' <- hnf g h
+        as' <- mapM (comp g) as
+        case h' of
+          _ | not (null [() | FV _ <- as']) -> compApp g (mkApp h' as')
+          c@(QC _ _) -> do
+            return $ mkApp c as'
+          Q mod f | mod == cPredef -> do     
+            (t',b) <- appPredefined (mkApp h' as')
+            if b then return t' else comp g t'
+
+          Abs _ _ -> do
+            let (xs,b) = termFormCnc h'
+            let g' = (zip xs as') ++ g
+            let as2 = drop (length xs) as'
+            let xs2 = drop (length as') xs
+            b' <- comp g' (mkAbs xs2 b)
+            if null as2 then return b' else comp g (mkApp b' as2)
+
+          _ -> compApp g (mkApp h' as')
+      _ -> compApp g t
+
+     P t l | isLockLabel l -> return $ R [] 
+     ---- a workaround 18/2/2005: take this away and find the reason
+     ---- why earlier compilation destroys the lock field
+
+
+     P t l  -> do
+       t' <- comp g t
+       case t' of
+         FV rs -> mapM (\c -> comp g (P c l)) rs >>= returnC . variants
+         R r   -> maybe (prtBad "no value for label" l) (comp g . snd) $ 
+                    lookup l $ reverse r 
+
+         ExtR a (R b) ->                 
+           case comp g (P (R b) l) of
+             Ok v -> return v
+             _ -> comp g (P a l)
+
+--- { - --- this is incorrect, since b can contain the proper value
+         ExtR (R a) b ->                 -- NOT POSSIBLE both a and b records!
+           case comp g (P (R a) l) of
+             Ok v -> return v
+             _ -> comp g (P b l)
+--- - } ---
+
+         Alias _ _ r -> comp g (P r l)
+
+         S (T i cs) e -> prawitz g i (flip P l) cs e
+         S (V i cs) e -> prawitzV g i (flip P l) cs e
+
+         _   -> returnC $ P t' l
+
+     PI t l i -> comp g $ P t l -----
+
+     S t@(T ti cc) v -> do
+       v'     <- comp g v
+       case v' of
+         FV vs -> do
+           ts' <- mapM (comp g . S t) vs
+           return $ variants ts' 
+         _ -> case ti of
+{-
+           TComp _  -> do
+             case term2patt v' of
+               Ok p' -> case lookup p' cc of
+                 Just u -> comp g u
+                 _ -> do
+                   t' <- comp g t
+                   return $ S t' v' -- if v' is not canonical
+               _ -> do
+                  t' <- comp g t
+                  return $ S t' v'
+-}
+           _ -> case matchPattern cc v' of
+             Ok (c,g') -> comp (g' ++ g) c
+             _ | isCan v' -> prtBad ("missing case" +++ prt v' +++ "in") t 
+             _ -> do
+               t' <- comp g t
+               return $ S t' v' -- if v' is not canonical
+
+
+     S t v -> do
+
+      t'     <- case t of
+--        T _ _ -> return t
+--        V _ _ -> return t
+        _ -> comp g t
+
+      v'     <- comp g v
+
+      case v' of
+       FV vs -> mapM (\c -> comp g (S t' c)) vs >>= returnC . variants        
+       _ -> case t' of
+         FV ccs -> mapM (\c -> comp g (S c v')) ccs >>= returnC . variants
+
+         T _ [(PV IW,c)] -> comp g c           --- an optimization
+         T _ [(PT _ (PV IW),c)] -> comp g c
+
+         T _ [(PV z,c)] -> comp (ext z v' g) c --- another optimization
+         T _ [(PT _ (PV z),c)] -> comp (ext z v' g) c
+
+         -- course-of-values table: look up by index, no pattern matching needed
+         V ptyp ts -> do
+           vs <- allParamValues gr ptyp
+           case lookup v' (zip vs [0 .. length vs - 1]) of
+             Just i -> comp g $ ts !! i
+-----             _ -> prtBad "selection" $ S t' v' -- debug
+             _ -> return $ S t' v' -- if v' is not canonical
+
+         T (TComp _) cs -> do
+           case term2patt v' of
+             Ok p' -> case lookup p' cs of
+               Just u -> comp g u
+               _ -> return $ S t' v' -- if v' is not canonical
+             _ -> return $ S t' v'
+
+         T _ cc -> case matchPattern cc v' of
+             Ok (c,g') -> comp (g' ++ g) c
+             _ | isCan v' -> prtBad ("missing case" +++ prt v' +++ "in") t 
+             _ -> return $ S t' v' -- if v' is not canonical
+
+         Alias _ _ d -> comp g (S d v')
+
+         S (T i cs) e -> prawitz g i (flip S v') cs e
+         S (V i cs) e -> prawitzV g i (flip S v') cs e
+         _    -> returnC $ S t' v'
+
+     -- normalize away empty tokens
+     K "" -> return Empty
+
+     -- glue if you can
+     Glue x0 y0 -> do
+       x <- comp g x0
+       y <- comp g y0
+       case (x,y) of
+         (FV ks,_)         -> do
+           kys <- mapM (comp g . flip Glue y) ks
+           return $ variants kys
+         (_,FV ks)         -> do
+           xks <- mapM (comp g . Glue x) ks
+           return $ variants xks
+
+         (Alias _ _ d, y)  -> comp g $ Glue d y
+         (x, Alias _ _ d)  -> comp g $ Glue x d
+
+         (S (T i cs) e, s) -> prawitz g i (flip Glue s) cs e
+         (s, S (T i cs) e) -> prawitz g i (Glue s) cs e
+         (S (V i cs) e, s) -> prawitzV g i (flip Glue s) cs e
+         (s, S (V i cs) e) -> prawitzV g i (Glue s) cs e
+         (_,Empty)         -> return x
+         (Empty,_)         -> return y
+         (K a, K b)        -> return $ K (a ++ b)
+         (_, Alts (d,vs)) -> do
+----         (K a, Alts (d,vs)) -> do
+            let glx = Glue x
+            comp g $ Alts (glx d, [(glx v,c) | (v,c) <- vs])
+         (Alts _, ka) -> checks [do
+            y' <- strsFromTerm ka
+----         (Alts _, K a) -> checks [do
+            x' <- strsFromTerm x -- this may fail when compiling opers
+            return $ variants [
+              foldr1 C (map K (str2strings (glueStr v u))) | v <- x', u <- y']
+----              foldr1 C (map K (str2strings (glueStr v (str a)))) | v <- x']
+           ,return $ Glue x y
+           ]
+         (C u v,_) -> comp g $ C u (Glue v y)
+
+         _ -> do
+           mapM_ checkNoArgVars [x,y]
+           r <- composOp (comp g) t
+           returnC r
+
+     Alts _ -> do
+       r <- composOp (comp g) t
+       returnC r
+
+     -- remove empty
+     C a b    -> do
+       a' <- comp g a
+       b' <- comp g b
+       case (a',b') of
+         (Alts _, K a) -> checks [do
+            as <- strsFromTerm a' -- this may fail when compiling opers
+            return $ variants [
+              foldr1 C (map K (str2strings (plusStr v (str a)))) | v <- as]
+            ,
+            return $ C a' b'
+           ]
+         (Empty,_) -> returnC b'
+         (_,Empty) -> returnC a'
+         _     -> returnC $ C a' b'
+
+     -- reduce free variation as much as you can
+     FV ts -> mapM (comp g) ts >>= returnC . variants
+
+     -- merge record extensions if you can
+     ExtR r s -> do
+       r' <- comp g r
+       s' <- comp g s
+       case (r',s') of
+         (Alias _ _ d, _)  -> comp g $ ExtR d s'
+         (_, Alias _ _ d)  -> comp g $ Glue r' d
+
+         (R rs, R ss) -> plusRecord r' s'
+         (RecType rs, RecType ss) -> plusRecType r' s'
+         _ -> return $ ExtR r' s'
+
+     -- case-expand tables
+     -- if already expanded, don't expand again
+     T i@(TComp ty) cs -> do
+       -- if there are no variables, don't even go inside
+       cs' <- if (null g) then return cs else mapPairsM (comp g) cs
+----       return $ V ty (map snd cs')
+       return $ T i cs'
+     --- this means some extra work; should implement TSh directly
+     TSh i cs -> comp g $ T i [(p,v) | (ps,v) <- cs, p <- ps]
+
+     T i cs -> do
+       pty0 <- getTableType i
+       ptyp <- comp g pty0
+       case allParamValues gr ptyp of
+         Ok vs -> do
+
+           ps0  <- mapM (compPatternMacro . fst) cs
+           cs'  <- mapM (compBranchOpt g) (zip ps0 (map snd cs))
+           sts  <- mapM (matchPattern cs') vs 
+           ts   <- mapM (\ (c,g') -> comp (g' ++ g) c) sts
+           ps   <- mapM term2patt vs
+           let ps' = ps --- PT ptyp (head ps) : tail ps
+----           return $ V ptyp ts -- to save space, just course of values
+           return $ T (TComp ptyp) (zip ps' ts)
+         _ -> do
+           cs' <- mapM (compBranch g) cs
+           return $ T i cs'  -- happens with variable types
+
+     Alias c a d -> do
+       d' <- comp g d
+       return $ Alias c a d'  -- alias only disappears in certain redexes
+
+     -- otherwise go ahead
+     _ -> composOp (comp g) t >>= returnC
+
+    where
+
+     compApp g (App f a) = do
+       f' <- hnf g f
+       a' <- comp g a
+       case (f',a') of
+         (Abs x b, FV as) -> 
+           mapM (\c -> comp (ext x c g) b) as >>= return . variants
+         (_, FV as)  -> mapM (\c -> comp g (App f' c)) as >>= return . variants
+         (FV fs, _)  -> mapM (\c -> comp g (App c a')) fs >>= return . variants
+         (Abs x b,_) -> comp (ext x a' g) b
+
+         (QC _ _,_)  -> returnC $ App f' a'
+
+         (Alias _ _ d, _) -> comp g (App d a')
+
+         (S (T i cs) e,_) -> prawitz g i (flip App a') cs e
+         (S (V i cs) e,_) -> prawitzV g i (flip App a') cs e
+
+	 _ -> do
+           (t',b) <- appPredefined (App f' a')
+           if b then return t' else comp g t'
+
+     hnf  = comput False
+     comp = comput True
+
+     look p c
+       | rec       = lookupResDef gr p c >>= comp []
+       | otherwise = lookupResDef gr p c
+
+{-
+     look p c = case lookupResDefKind gr p c of
+       Ok (t,_) | noExpand p || rec -> comp [] t
+       Ok (t,_) -> return t
+       Bad s -> raise s
+
+     noExpand p = errVal False $ do
+       mo <- lookupModMod gr p
+       return $ case getOptVal (iOpts (flags mo)) useOptimizer of
+         Just "noexpand" -> True
+         _ -> False
+-}
+
+     ext x a g = (x,a):g
+
+     returnC = return --- . computed
+
+     variants ts = case nub ts of
+       [t] -> t
+       ts  -> FV ts
+
+     isCan v = case v of
+       Con _    -> True
+       QC _ _   -> True
+       App f a  -> isCan f && isCan a
+       R rs     -> all (isCan . snd . snd) rs
+       _        -> False
+
+     compPatternMacro p = case p of
+       PM m c -> case look m c of
+         Ok (EPatt p') -> compPatternMacro p'
+         _ -> prtBad "pattern expected as value of" p ---- should be in CheckGr
+       PAs x p -> do
+         p' <- compPatternMacro p
+         return $ PAs x p'
+       PAlt p q -> do
+         p' <- compPatternMacro p
+         q' <- compPatternMacro q
+         return $ PAlt p' q'
+       PSeq p q -> do
+         p' <- compPatternMacro p
+         q' <- compPatternMacro q
+         return $ PSeq p' q'
+       PRep p -> do
+         p' <- compPatternMacro p
+         return $ PRep p'
+       PNeg p -> do
+         p' <- compPatternMacro p
+         return $ PNeg p'
+       PR rs -> do
+         rs' <- mapPairsM compPatternMacro rs
+         return $ PR rs'
+
+       _ -> return p
+
+     compBranch g (p,v) = do
+       let g' = contP p ++ g
+       v' <- comp g' v
+       return (p,v')
+
+     compBranchOpt g c@(p,v) = case contP p of
+       [] -> return c
+       _ -> err (const (return c)) return $ compBranch g c
+
+     contP p = case p of
+       PV x -> [(x,Vr x)]
+       PC _ ps -> concatMap contP ps
+       PP _ _ ps -> concatMap contP ps
+       PT _ p -> contP p
+       PR rs -> concatMap (contP . snd) rs
+
+       PAs x p -> (x,Vr x) : contP p
+
+       PSeq p q -> concatMap contP [p,q]
+       PAlt p q -> concatMap contP [p,q]
+       PRep p   -> contP p
+       PNeg p   -> contP p
+
+       _ -> []
+
+     prawitz g i f cs e = do
+       cs' <- mapM (compBranch g) [(p, f v) | (p,v) <- cs]
+       return $ S (T i cs') e
+     prawitzV g i f cs e = do
+       cs' <- mapM (comp g) [(f v) | v <- cs]
+       return $ S (V i cs') e
+
+
+-- | argument variables cannot be glued
+checkNoArgVars :: Term -> Err Term
+checkNoArgVars t = case t of
+  Vr (IA _ _)    -> Bad $ glueErrorMsg $ prt t 
+  Vr (IAV _ _ _) -> Bad $ glueErrorMsg $ prt t 
+  _ -> composOp checkNoArgVars t
+
+glueErrorMsg s = 
+  "Cannot glue (+) term with run-time variable" +++ s ++ "." ++++
+  "Use Prelude.bind instead."
diff --git a/src-3.0/GF/Compile/Optimize.hs b/src-3.0/GF/Compile/Optimize.hs
index 863f11d4c..6da561029 100644
--- a/src-3.0/GF/Compile/Optimize.hs
+++ b/src-3.0/GF/Compile/Optimize.hs
@@ -23,7 +23,7 @@ import GF.Grammar.Macros
 import GF.Grammar.Lookup
 import GF.Grammar.Predef
 import GF.Grammar.Refresh
-import GF.Devel.Compute
+import GF.Compile.Compute
 import GF.Compile.BackOpt
 import GF.Compile.CheckGrammar
 import GF.Compile.Update
diff --git a/src-3.0/GF/Devel/Compute.hs b/src-3.0/GF/Devel/Compute.hs
deleted file mode 100644
index a44ee5424..000000000
--- a/src-3.0/GF/Devel/Compute.hs
+++ /dev/null
@@ -1,456 +0,0 @@
-----------------------------------------------------------------------
--- |
--- Module      : Compute
--- Maintainer  : AR
--- Stability   : (stable)
--- Portability : (portable)
---
--- > CVS $Date: 2005/11/01 15:39:12 $ 
--- > CVS $Author: aarne $
--- > CVS $Revision: 1.19 $
---
--- Computation of source terms. Used in compilation and in @cc@ command.
------------------------------------------------------------------------------
-
-module GF.Devel.Compute (computeConcrete, computeTerm,computeConcreteRec) where
-
-import GF.Data.Operations
-import GF.Grammar.Grammar
-import GF.Infra.Ident
-import GF.Infra.Option
-import GF.Data.Str
-import GF.Grammar.PrGrammar
-import GF.Infra.Modules
-import GF.Grammar.Predef
-import GF.Grammar.Macros
-import GF.Grammar.Lookup
-import GF.Grammar.Refresh
-import GF.Grammar.PatternMatch
-import GF.Grammar.Lockfield (isLockLabel) ----
-
-import GF.Grammar.AppPredefined
-
-import Data.List (nub,intersperse)
-import Control.Monad (liftM2, liftM)
-
--- | computation of concrete syntax terms into normal form
--- used mainly for partial evaluation
-computeConcrete :: SourceGrammar -> Term -> Err Term
-computeConcrete    g t = {- refreshTerm t >>= -} computeTerm g [] t
-computeConcreteRec g t = {- refreshTerm t >>= -} computeTermOpt True g [] t
-
-computeTerm :: SourceGrammar -> Substitution -> Term -> Err Term
-computeTerm = computeTermOpt False
-
--- rec=True is used if it cannot be assumed that looked-up constants
--- have already been computed (mainly with -optimize=noexpand in .gfr)
-
-computeTermOpt :: Bool -> SourceGrammar -> Substitution -> Term -> Err Term
-computeTermOpt rec gr = comput True where
-
-   comput full g t = ---- errIn ("subterm" +++ prt t) $ --- for debugging 
-              case t of
-
-     Q p c | p == cPredef -> return t
-           | otherwise    -> look p c 
-
-     -- if computed do nothing
-     Computed t' -> return $ unComputed t'
-
-     Vr x -> do
-       t' <- maybe (prtBad ("no value given to variable") x) return $ lookup x g
-       case t' of 
-         _ | t == t' -> return t
-         _ -> comp g t'
-
-     -- Abs x@(IA _) b -> do 
-     Abs x b | full -> do 
-       let (xs,b1) = termFormCnc t   
-       b' <- comp ([(x,Vr x) | x <- xs] ++ g) b1
-       return $ mkAbs xs b'
-     --  b' <- comp (ext x (Vr x) g) b
-     --  return $ Abs x b'
-     Abs _ _ -> return t -- hnf
-
-     Let (x,(_,a)) b -> do
-       a' <- comp g a
-       comp (ext x a' g) b
-
-     Prod x a b -> do
-       a' <- comp g a
-       b' <- comp (ext x (Vr x) g) b
-       return $ Prod x a' b'
-
-     -- beta-convert
-     App f a -> case appForm t of
-      (h,as) | length as > 1 -> do
-        h' <- hnf g h
-        as' <- mapM (comp g) as
-        case h' of
-          _ | not (null [() | FV _ <- as']) -> compApp g (mkApp h' as')
-          c@(QC _ _) -> do
-            return $ mkApp c as'
-          Q mod f | mod == cPredef -> do     
-            (t',b) <- appPredefined (mkApp h' as')
-            if b then return t' else comp g t'
-
-          Abs _ _ -> do
-            let (xs,b) = termFormCnc h'
-            let g' = (zip xs as') ++ g
-            let as2 = drop (length xs) as'
-            let xs2 = drop (length as') xs
-            b' <- comp g' (mkAbs xs2 b)
-            if null as2 then return b' else comp g (mkApp b' as2)
-
-          _ -> compApp g (mkApp h' as')
-      _ -> compApp g t
-
-     P t l | isLockLabel l -> return $ R [] 
-     ---- a workaround 18/2/2005: take this away and find the reason
-     ---- why earlier compilation destroys the lock field
-
-
-     P t l  -> do
-       t' <- comp g t
-       case t' of
-         FV rs -> mapM (\c -> comp g (P c l)) rs >>= returnC . variants
-         R r   -> maybe (prtBad "no value for label" l) (comp g . snd) $ 
-                    lookup l $ reverse r 
-
-         ExtR a (R b) ->                 
-           case comp g (P (R b) l) of
-             Ok v -> return v
-             _ -> comp g (P a l)
-
---- { - --- this is incorrect, since b can contain the proper value
-         ExtR (R a) b ->                 -- NOT POSSIBLE both a and b records!
-           case comp g (P (R a) l) of
-             Ok v -> return v
-             _ -> comp g (P b l)
---- - } ---
-
-         Alias _ _ r -> comp g (P r l)
-
-         S (T i cs) e -> prawitz g i (flip P l) cs e
-         S (V i cs) e -> prawitzV g i (flip P l) cs e
-
-         _   -> returnC $ P t' l
-
-     PI t l i -> comp g $ P t l -----
-
-     S t@(T ti cc) v -> do
-       v'     <- comp g v
-       case v' of
-         FV vs -> do
-           ts' <- mapM (comp g . S t) vs
-           return $ variants ts' 
-         _ -> case ti of
-{-
-           TComp _  -> do
-             case term2patt v' of
-               Ok p' -> case lookup p' cc of
-                 Just u -> comp g u
-                 _ -> do
-                   t' <- comp g t
-                   return $ S t' v' -- if v' is not canonical
-               _ -> do
-                  t' <- comp g t
-                  return $ S t' v'
--}
-           _ -> case matchPattern cc v' of
-             Ok (c,g') -> comp (g' ++ g) c
-             _ | isCan v' -> prtBad ("missing case" +++ prt v' +++ "in") t 
-             _ -> do
-               t' <- comp g t
-               return $ S t' v' -- if v' is not canonical
-
-
-     S t v -> do
-
-      t'     <- case t of
---        T _ _ -> return t
---        V _ _ -> return t
-        _ -> comp g t
-
-      v'     <- comp g v
-
-      case v' of
-       FV vs -> mapM (\c -> comp g (S t' c)) vs >>= returnC . variants        
-       _ -> case t' of
-         FV ccs -> mapM (\c -> comp g (S c v')) ccs >>= returnC . variants
-
-         T _ [(PV IW,c)] -> comp g c           --- an optimization
-         T _ [(PT _ (PV IW),c)] -> comp g c
-
-         T _ [(PV z,c)] -> comp (ext z v' g) c --- another optimization
-         T _ [(PT _ (PV z),c)] -> comp (ext z v' g) c
-
-         -- course-of-values table: look up by index, no pattern matching needed
-         V ptyp ts -> do
-           vs <- allParamValues gr ptyp
-           case lookup v' (zip vs [0 .. length vs - 1]) of
-             Just i -> comp g $ ts !! i
------             _ -> prtBad "selection" $ S t' v' -- debug
-             _ -> return $ S t' v' -- if v' is not canonical
-
-         T (TComp _) cs -> do
-           case term2patt v' of
-             Ok p' -> case lookup p' cs of
-               Just u -> comp g u
-               _ -> return $ S t' v' -- if v' is not canonical
-             _ -> return $ S t' v'
-
-         T _ cc -> case matchPattern cc v' of
-             Ok (c,g') -> comp (g' ++ g) c
-             _ | isCan v' -> prtBad ("missing case" +++ prt v' +++ "in") t 
-             _ -> return $ S t' v' -- if v' is not canonical
-
-         Alias _ _ d -> comp g (S d v')
-
-         S (T i cs) e -> prawitz g i (flip S v') cs e
-         S (V i cs) e -> prawitzV g i (flip S v') cs e
-         _    -> returnC $ S t' v'
-
-     -- normalize away empty tokens
-     K "" -> return Empty
-
-     -- glue if you can
-     Glue x0 y0 -> do
-       x <- comp g x0
-       y <- comp g y0
-       case (x,y) of
-         (FV ks,_)         -> do
-           kys <- mapM (comp g . flip Glue y) ks
-           return $ variants kys
-         (_,FV ks)         -> do
-           xks <- mapM (comp g . Glue x) ks
-           return $ variants xks
-
-         (Alias _ _ d, y)  -> comp g $ Glue d y
-         (x, Alias _ _ d)  -> comp g $ Glue x d
-
-         (S (T i cs) e, s) -> prawitz g i (flip Glue s) cs e
-         (s, S (T i cs) e) -> prawitz g i (Glue s) cs e
-         (S (V i cs) e, s) -> prawitzV g i (flip Glue s) cs e
-         (s, S (V i cs) e) -> prawitzV g i (Glue s) cs e
-         (_,Empty)         -> return x
-         (Empty,_)         -> return y
-         (K a, K b)        -> return $ K (a ++ b)
-         (_, Alts (d,vs)) -> do
-----         (K a, Alts (d,vs)) -> do
-            let glx = Glue x
-            comp g $ Alts (glx d, [(glx v,c) | (v,c) <- vs])
-         (Alts _, ka) -> checks [do
-            y' <- strsFromTerm ka
-----         (Alts _, K a) -> checks [do
-            x' <- strsFromTerm x -- this may fail when compiling opers
-            return $ variants [
-              foldr1 C (map K (str2strings (glueStr v u))) | v <- x', u <- y']
-----              foldr1 C (map K (str2strings (glueStr v (str a)))) | v <- x']
-           ,return $ Glue x y
-           ]
-         (C u v,_) -> comp g $ C u (Glue v y)
-
-         _ -> do
-           mapM_ checkNoArgVars [x,y]
-           r <- composOp (comp g) t
-           returnC r
-
-     Alts _ -> do
-       r <- composOp (comp g) t
-       returnC r
-
-     -- remove empty
-     C a b    -> do
-       a' <- comp g a
-       b' <- comp g b
-       case (a',b') of
-         (Alts _, K a) -> checks [do
-            as <- strsFromTerm a' -- this may fail when compiling opers
-            return $ variants [
-              foldr1 C (map K (str2strings (plusStr v (str a)))) | v <- as]
-            ,
-            return $ C a' b'
-           ]
-         (Empty,_) -> returnC b'
-         (_,Empty) -> returnC a'
-         _     -> returnC $ C a' b'
-
-     -- reduce free variation as much as you can
-     FV ts -> mapM (comp g) ts >>= returnC . variants
-
-     -- merge record extensions if you can
-     ExtR r s -> do
-       r' <- comp g r
-       s' <- comp g s
-       case (r',s') of
-         (Alias _ _ d, _)  -> comp g $ ExtR d s'
-         (_, Alias _ _ d)  -> comp g $ Glue r' d
-
-         (R rs, R ss) -> plusRecord r' s'
-         (RecType rs, RecType ss) -> plusRecType r' s'
-         _ -> return $ ExtR r' s'
-
-     -- case-expand tables
-     -- if already expanded, don't expand again
-     T i@(TComp ty) cs -> do
-       -- if there are no variables, don't even go inside
-       cs' <- if (null g) then return cs else mapPairsM (comp g) cs
-----       return $ V ty (map snd cs')
-       return $ T i cs'
-     --- this means some extra work; should implement TSh directly
-     TSh i cs -> comp g $ T i [(p,v) | (ps,v) <- cs, p <- ps]
-
-     T i cs -> do
-       pty0 <- getTableType i
-       ptyp <- comp g pty0
-       case allParamValues gr ptyp of
-         Ok vs -> do
-
-           ps0  <- mapM (compPatternMacro . fst) cs
-           cs'  <- mapM (compBranchOpt g) (zip ps0 (map snd cs))
-           sts  <- mapM (matchPattern cs') vs 
-           ts   <- mapM (\ (c,g') -> comp (g' ++ g) c) sts
-           ps   <- mapM term2patt vs
-           let ps' = ps --- PT ptyp (head ps) : tail ps
-----           return $ V ptyp ts -- to save space, just course of values
-           return $ T (TComp ptyp) (zip ps' ts)
-         _ -> do
-           cs' <- mapM (compBranch g) cs
-           return $ T i cs'  -- happens with variable types
-
-     Alias c a d -> do
-       d' <- comp g d
-       return $ Alias c a d'  -- alias only disappears in certain redexes
-
-     -- otherwise go ahead
-     _ -> composOp (comp g) t >>= returnC
-
-    where
-
-     compApp g (App f a) = do
-       f' <- hnf g f
-       a' <- comp g a
-       case (f',a') of
-         (Abs x b, FV as) -> 
-           mapM (\c -> comp (ext x c g) b) as >>= return . variants
-         (_, FV as)  -> mapM (\c -> comp g (App f' c)) as >>= return . variants
-         (FV fs, _)  -> mapM (\c -> comp g (App c a')) fs >>= return . variants
-         (Abs x b,_) -> comp (ext x a' g) b
-
-         (QC _ _,_)  -> returnC $ App f' a'
-
-         (Alias _ _ d, _) -> comp g (App d a')
-
-         (S (T i cs) e,_) -> prawitz g i (flip App a') cs e
-         (S (V i cs) e,_) -> prawitzV g i (flip App a') cs e
-
-	 _ -> do
-           (t',b) <- appPredefined (App f' a')
-           if b then return t' else comp g t'
-
-     hnf  = comput False
-     comp = comput True
-
-     look p c
-       | rec       = lookupResDef gr p c >>= comp []
-       | otherwise = lookupResDef gr p c
-
-{-
-     look p c = case lookupResDefKind gr p c of
-       Ok (t,_) | noExpand p || rec -> comp [] t
-       Ok (t,_) -> return t
-       Bad s -> raise s
-
-     noExpand p = errVal False $ do
-       mo <- lookupModMod gr p
-       return $ case getOptVal (iOpts (flags mo)) useOptimizer of
-         Just "noexpand" -> True
-         _ -> False
--}
-
-     ext x a g = (x,a):g
-
-     returnC = return --- . computed
-
-     variants ts = case nub ts of
-       [t] -> t
-       ts  -> FV ts
-
-     isCan v = case v of
-       Con _    -> True
-       QC _ _   -> True
-       App f a  -> isCan f && isCan a
-       R rs     -> all (isCan . snd . snd) rs
-       _        -> False
-
-     compPatternMacro p = case p of
-       PM m c -> case look m c of
-         Ok (EPatt p') -> compPatternMacro p'
-         _ -> prtBad "pattern expected as value of" p ---- should be in CheckGr
-       PAs x p -> do
-         p' <- compPatternMacro p
-         return $ PAs x p'
-       PAlt p q -> do
-         p' <- compPatternMacro p
-         q' <- compPatternMacro q
-         return $ PAlt p' q'
-       PSeq p q -> do
-         p' <- compPatternMacro p
-         q' <- compPatternMacro q
-         return $ PSeq p' q'
-       PRep p -> do
-         p' <- compPatternMacro p
-         return $ PRep p'
-       PNeg p -> do
-         p' <- compPatternMacro p
-         return $ PNeg p'
-       PR rs -> do
-         rs' <- mapPairsM compPatternMacro rs
-         return $ PR rs'
-
-       _ -> return p
-
-     compBranch g (p,v) = do
-       let g' = contP p ++ g
-       v' <- comp g' v
-       return (p,v')
-
-     compBranchOpt g c@(p,v) = case contP p of
-       [] -> return c
-       _ -> err (const (return c)) return $ compBranch g c
-
-     contP p = case p of
-       PV x -> [(x,Vr x)]
-       PC _ ps -> concatMap contP ps
-       PP _ _ ps -> concatMap contP ps
-       PT _ p -> contP p
-       PR rs -> concatMap (contP . snd) rs
-
-       PAs x p -> (x,Vr x) : contP p
-
-       PSeq p q -> concatMap contP [p,q]
-       PAlt p q -> concatMap contP [p,q]
-       PRep p   -> contP p
-       PNeg p   -> contP p
-
-       _ -> []
-
-     prawitz g i f cs e = do
-       cs' <- mapM (compBranch g) [(p, f v) | (p,v) <- cs]
-       return $ S (T i cs') e
-     prawitzV g i f cs e = do
-       cs' <- mapM (comp g) [(f v) | v <- cs]
-       return $ S (V i cs') e
-
-
--- | argument variables cannot be glued
-checkNoArgVars :: Term -> Err Term
-checkNoArgVars t = case t of
-  Vr (IA _ _)    -> Bad $ glueErrorMsg $ prt t 
-  Vr (IAV _ _ _) -> Bad $ glueErrorMsg $ prt t 
-  _ -> composOp checkNoArgVars t
-
-glueErrorMsg s = 
-  "Cannot glue (+) term with run-time variable" +++ s ++ "." ++++
-  "Use Prelude.bind instead."
-- 
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