From 60f678f221d05c288dab67b56cff9e06a36086ae Mon Sep 17 00:00:00 2001
From: aarne <aarne@cs.chalmers.se>
Date: Mon, 18 Dec 2006 15:25:00 +0000
Subject: [PATCH] Koji's bug fixed

---
 src/GF/Grammar/AbsCompute.hs | 78 +++++++++++++++++++++++++++++-------
 1 file changed, 64 insertions(+), 14 deletions(-)

diff --git a/src/GF/Grammar/AbsCompute.hs b/src/GF/Grammar/AbsCompute.hs
index 593c6d96f..57e21f1dd 100644
--- a/src/GF/Grammar/AbsCompute.hs
+++ b/src/GF/Grammar/AbsCompute.hs
@@ -26,13 +26,16 @@ import GF.Data.Operations
 import GF.Grammar.Abstract
 import GF.Grammar.PrGrammar
 import GF.Grammar.LookAbs
-import GF.Grammar.PatternMatch
 import GF.Grammar.Compute
 
 import Debug.Trace
-
+import Data.List(intersperse)
 import Control.Monad (liftM, liftM2)
 
+-- for debugging
+tracd m t = t 
+-- tracd = trace
+
 compute :: GFCGrammar -> Exp -> Err Exp
 compute = computeAbsTerm
 
@@ -53,23 +56,24 @@ computeAbsTermIn lookd xs e = errIn ("computing" +++ prt e) $ compt xs e where
       let vv' = yy ++ vv
       aa'    <- mapM (compt vv') aa
       case look f of
-        Just (Eqs eqs) -> ----trace ("matching" +++ prt f) $ 
+        Just (Eqs eqs) -> tracd ("\nmatching" +++ prt f) $ 
                           case findMatch eqs aa' of
           Ok (d,g) -> do
-            let (xs,ts) = unzip g
-            ts' <- alphaFreshAll vv' ts ---
-            let g' = zip xs ts'
+            --- let (xs,ts) = unzip g
+            --- ts' <- alphaFreshAll vv' ts
+            let g' = g --- zip xs ts'
             d' <- compt vv' $ substTerm vv' g' d
-            return $ mkAbs yy $ d'
-          _ -> ---- trace ("no match" +++ prt t') $ 
+            tracd ("by Egs:" +++ prt d') $ return $ mkAbs yy $ d'
+          _ -> tracd ("no match" +++ prt t') $ 
                do
             let v = mkApp f aa'
             return $ mkAbs yy $ v
-        Just d -> do
+        Just d -> tracd ("define" +++ prt t') $ do
           da <- compt vv' $ mkApp d aa' 
           return $ mkAbs yy $ da
         _ -> do
-          return $ mkAbs yy $ mkApp f aa'
+          let t2 = mkAbs yy $ mkApp f aa'
+          tracd ("not defined" +++ prt_ t2) $ return t2
 
   look t = case t of
      (Q m f) -> case lookd m f of
@@ -81,15 +85,61 @@ computeAbsTermIn lookd xs e = errIn ("computing" +++ prt e) $ compt xs e where
 
 beta :: [Ident] -> Exp -> Exp
 beta vv c = case c of
-  Let (x,(_,a)) b -> beta vv $ substTerm vv [xvv] (beta (x:vv) b) 
-                                                    where xvv = (x,beta vv a) 
+  Let (x,(_,a)) b -> beta vv $ substTerm vv [(x,beta vv a)] (beta (x:vv) b) 
   App f         a -> 
     let (a',f') = (beta vv a, beta vv f) in 
     case f' of
-      Abs x b -> beta vv $ substTerm vv [xvv] (beta (x:vv) b) 
-                                                    where xvv = (x,beta vv a) 
+      Abs x b -> beta vv $ substTerm vv [(x,a')] (beta (x:vv) b) 
       _ ->               (if a'==a && f'==f then id else beta vv) $ App f' a'
   Prod x a b      -> Prod x (beta vv a) (beta (x:vv) b)
   Abs x b         -> Abs x (beta (x:vv) b)
   _               -> c
 
+-- special version of pattern matching, to deal with comp under lambda
+
+findMatch :: [([Patt],Term)] -> [Term] -> Err (Term, Substitution)
+findMatch cases terms = case cases of
+  [] -> Bad $"no applicable case for" +++ unwords (intersperse "," (map prt terms))
+  (patts,_):_ | length patts /= length terms -> 
+       Bad ("wrong number of args for patterns :" +++ 
+            unwords (map prt patts) +++ "cannot take" +++ unwords (map prt terms))
+  (patts,val):cc -> case mapM tryMatch (zip patts terms) of
+     Ok substs -> return (tracd ("value" +++ prt_ val) val, concat substs)
+     _         -> findMatch cc terms
+
+tryMatch :: (Patt, Term) -> Err [(Ident, Term)]
+tryMatch (p,t) = do 
+  t' <- termForm t
+  trym p t'
+ where
+
+  trym p t' = err (\s -> tracd s (Bad s)) (\t -> tracd (prtm p t) (return t)) $ ---- 
+              case (p,t') of
+    (PV IW, _) | notMeta t -> return [] -- optimization with wildcard
+    (PV x,  _) | notMeta t -> return [(x,t)]
+    (PString s, ([],K i,[])) | s==i -> return []
+    (PInt s, ([],EInt i,[])) | s==i -> return []
+    (PFloat s,([],EFloat i,[])) | s==i -> return [] --- rounding?
+    (PP q p pp, ([], QC r f, tt)) | 
+       p `eqStrIdent` f && length pp == length tt -> do
+         matches <- mapM tryMatch (zip pp tt)
+         return (concat matches)
+    (PP q p pp, ([], Q r f, tt)) | 
+       p `eqStrIdent` f && length pp == length tt -> do
+         matches <- mapM tryMatch (zip pp tt)
+         return (concat matches)
+    (PT _ p',_) -> trym p' t'
+    (_, ([],Alias _ _ d,[])) -> tryMatch (p,d)
+    (PAs x p',_) -> do
+       subst <- trym p' t'
+       return $ (x,t) : subst
+    _ -> Bad ("no match in pattern" +++ prt p +++ "for" +++ prt t)
+
+  notMeta e = case e of
+    Meta _  -> False
+    App f a -> notMeta f &&  notMeta a  
+    Abs _ b -> notMeta b
+    _ -> True
+
+  prtm p g = 
+    prt p +++ ":" ++++ unwords ["  " ++ prt_ x +++ "=" +++ prt_ y +++ ";" | (x,y) <- g]