Make the pulled def stuff more general

fco2/ParseState.hs

@@ -14,9 +14,12 @@ data ParseState = ParseState {
     psNames :: [(String, A.NameDef)],
     psNameCounter :: Int,
     psNonceCounter :: Int,
-    psPulledSpecs :: [(Meta, A.Specification)]
+    psPulledItems :: [A.Process -> A.Process]
   }
-  deriving (Show, Eq, Typeable, Data)
+  deriving (Show, Data, Typeable)
+
+instance Show (A.Process -> A.Process) where
+  show p = "(function on A.Process)"
 
 emptyState :: ParseState
 emptyState = ParseState {
@@ -24,7 +27,7 @@ emptyState = ParseState {
     psNames = [],
     psNameCounter = 0,
     psNonceCounter = 0,
-    psPulledSpecs = []
+    psPulledItems = []
   }
 
 -- | Add the definition of a name.
@@ -43,3 +46,16 @@ makeNonce s
           put ps { psNonceCounter = i + 1 }
           return $ s ++ "_n" ++ show i
 
+-- | Add a pulled item to the collection.
+addPulled :: MonadState ParseState m => (A.Process -> A.Process) -> m ()
+addPulled item
+    =  do ps <- get
+          put $ ps { psPulledItems = item : psPulledItems ps }
+
+-- | Apply pulled items to a Process.
+applyPulled :: MonadState ParseState m => A.Process -> m A.Process
+applyPulled ast
+    =  do ps <- get
+          let ast' = foldl (\p f -> f p) ast (psPulledItems ps)
+          put $ ps { psPulledItems = [] }
+          return ast'

fco2/Unnest.hs

@@ -193,10 +193,7 @@ removeFreeNames = doGeneric `extM` doProcess `extM` doStructured `extM` doValueP
 removeNesting :: A.Process -> PassM A.Process
 removeNesting p
     =  do p' <- pullSpecs p
-          st <- get
-          let pulled = psPulledSpecs st
-          put $ st { psPulledSpecs = [] }
-          return $ foldl (\p (m, spec) -> A.ProcSpec m spec p) p' pulled
+          applyPulled p'
   where
     pullSpecs :: Data t => t -> PassM t
     pullSpecs = doGeneric `extM` doProcess `extM` doStructured `extM` doValueProcess
@@ -220,7 +217,7 @@ removeNesting p
     doSpec orig m spec@(_, st) child
         = if canPull st then
             do spec' <- pullSpecs spec
-               modify $ (\ps -> ps { psPulledSpecs = (m, spec') : psPulledSpecs ps })
+               addPulled $ A.ProcSpec m spec'
                child' <- pullSpecs child
                return child'
           else doGeneric orig