Moved code and comments around in TransformCFG.

src/GF/Speech/TransformCFG.hs

@@ -86,7 +86,14 @@ getStartCatCF opts sgr = getStartCat opts sgr ++ "{}.s"
 stateGFCC :: StateGrammar -> GFCC
 stateGFCC = mkGFCC . mkCanon2gfcc . stateGrammarST
 
--- | Remove productions which use categories which have no productions
+-- * Grammar filtering
+
+-- | Removes all directly cyclic productions.
+removeCycles :: CFRules -> CFRules 
+removeCycles = groupProds . removeCycles_ . ungroupProds
+  where removeCycles_ rs = [r | r@(CFRule c rhs _) <- rs, rhs /= [Cat c]]
+
+-- | Removes productions which use categories which have no productions
 bottomUpFilter :: CFRules -> CFRules
 bottomUpFilter = fix removeEmptyCats'
     where
@@ -98,6 +105,14 @@ bottomUpFilter = fix removeEmptyCats'
 	emptyCats = filter (nothingOrNull . flip lookup rs) allCats
 	k' = map (\ (c,xs) -> (c, filter (not . anyUsedBy emptyCats) xs)) keep
 
+-- | Removes categories which are not reachable from the start category.
+topDownFilter :: Cat_ -> CFRules -> CFRules
+topDownFilter start rules = filter ((`Set.member` keep) . fst) rules
+  where
+    rhsCats = [ (c, c') | (c,rs) <- rules, r <- rs, c' <- filterCats (ruleRhs r) ]
+    uses = reflexiveClosure_ (allCats rules) $ transitiveClosure $ mkRel rhsCats
+    keep = allRelated uses start
+
 -- | Remove rules which have the same rhs. 
 --   FIXME: this messes up probabilities, names and profiles
 removeIdenticalRules :: CFRules -> CFRules
@@ -214,22 +229,6 @@ isDirectLeftRecursive _ = False
 
 -}
 
--- * Removing cycles
-
-removeCycles :: CFRules -> CFRules 
-removeCycles = groupProds . removeCycles_ . ungroupProds
-  where removeCycles_ rs = [r | r@(CFRule c rhs _) <- rs, rhs /= [Cat c]]
-
--- * Top-down filtering
-
--- | Remove categories which are not reachable from the start category.
-topDownFilter :: Cat_ -> CFRules -> CFRules
-topDownFilter start rules = filter ((`Set.member` keep) . fst) rules
-  where
-    rhsCats = [ (c, c') | (c,rs) <- rules, r <- rs, c' <- filterCats (ruleRhs r) ]
-    uses = reflexiveClosure_ (allCats rules) $ transitiveClosure $ mkRel rhsCats
-    keep = allRelated uses start
-
 -- | Get the sets of mutually recursive non-terminals for a grammar.
 mutRecCats :: Bool    -- ^ If true, all categories will be in some set.
                       --   If false, only recursive categories will be included.