From 6a3452f8cd706a98c24015d6bc831c158f7d1222 Mon Sep 17 00:00:00 2001
From: Neil Brown <neil@twistedsquare.com>
Date: Sat, 23 Feb 2008 18:32:29 +0000
Subject: [PATCH] Added a useful function to Pass for applying a modification
 function to the Only parts of a Structured

---
 common/Pass.hs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/common/Pass.hs b/common/Pass.hs
index 1eea42f..751922c 100644
--- a/common/Pass.hs
+++ b/common/Pass.hs
@@ -34,6 +34,7 @@ import Errors
 import Metadata
 import PrettyShow
 import TreeUtils
+import Utils
 
 -- | The monad in which AST-mangling passes operate.
 type PassM = ErrorT ErrorReport (StateT CompState (WriterT [WarningReport]  IO))
@@ -137,6 +138,13 @@ debugAST p
           veryDebug $ pshow ps
           veryDebug $ "}}}"
 
+applyToOnly :: (Monad m, Data a) => (a -> m a) -> A.Structured a -> m (A.Structured a)
+applyToOnly f (A.Rep m r s) = applyToOnly f s >>* A.Rep m r
+applyToOnly f (A.Spec m sp s) = applyToOnly f s >>* A.Spec m sp
+applyToOnly f (A.ProcThen m p s) = applyToOnly f s >>* A.ProcThen m p
+applyToOnly f (A.Several m ss) = mapM (applyToOnly f) ss >>* A.Several m
+applyToOnly f (A.Only m o) = f o >>* A.Only m
+
 -- | Make a generic rule for a pass.
 makeGeneric :: (Data t) => (forall s. Data s => s -> PassM s) -> t -> PassM t
 makeGeneric top