fix: pattern matching on strings should reconstruct the tokens after matching

src/compiler/GF/Grammar/PatternMatch.hs

@@ -73,14 +73,13 @@ tryMatch (p,t) = do
   t' <- termForm t
   trym p t'
  where
-
-  isInConstantFormt = True -- tested already in matchPattern
   trym p t' =
     case (p,t') of
 --    (_,(x,Typed e ty,y)) -> trym p (x,e,y) -- Add this? /TH 2013-09-05
       (_,(x,Empty,y)) -> trym p (x,K [],y)   -- because "" = [""] = []
-      (PW, _) | isInConstantFormt -> return [] -- optimization with wildcard
-      (PV x,  _) | isInConstantFormt -> return [(x,t)]
+      (PW, _) -> return [] -- optimization with wildcard
+      (PV x,([],K s,[])) -> return [(x,words2term (words s))]
+      (PV x,  _) -> 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?
@@ -132,6 +131,11 @@ tryMatch (p,t) = do
 
       _ -> raise (render ("no match in case expr for" <+> t))
 
+  words2term []     = Empty
+  words2term [w]    = K w
+  words2term (w:ws) = C (K w) (words2term ws)
+
+
 matchPMSeq (m1,p1) (m2,p2) s = matchPSeq' m1 p1 m2 p2 s
 --matchPSeq p1 p2 s = matchPSeq' (0,maxBound::Int) p1 (0,maxBound::Int) p2 s
 matchPSeq p1 p2 s = matchPSeq' (lengthBounds p1) p1 (lengthBounds p2) p2 s
@@ -209,4 +213,4 @@ isMatchingForms ps ts = all match (zip ps ts') where
   match _ = True
   ts' = map appForm ts
 
--}
+-}