From b603b43b57d5c2fd72ab676de0fe55d4f175ecac Mon Sep 17 00:00:00 2001
From: Neil Brown <neil@twistedsquare.com>
Date: Fri, 6 Jun 2008 10:43:30 +0000
Subject: [PATCH] Added a subOne function (the dual of addOne) to the Types
 module

---
 common/Types.hs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/common/Types.hs b/common/Types.hs
index 7d4e2d7..830ee4d 100644
--- a/common/Types.hs
+++ b/common/Types.hs
@@ -25,7 +25,7 @@ module Types
     , returnTypesOfFunction
     , BytesInResult(..), bytesInType, countReplicator, countStructured, computeStructured
 
-    , makeAbbrevAM, makeConstant, makeDimension, addOne, addExprs, subExprs,
+    , makeAbbrevAM, makeConstant, makeDimension, addOne, subOne, addExprs, subExprs,
       mulExprs, divExprs
     , addDimensions, applyDimension, removeFixedDimensions, trivialSubscriptType, subscriptType, unsubscriptType
     , recordFields, protocolItems
@@ -653,6 +653,11 @@ addOne :: A.Expression -> A.Expression
 addOne e = A.Dyadic m A.Add (makeConstant m 1) e
   where m = findMeta e
 
+-- | Subtrace one from an expression.
+subOne :: A.Expression -> A.Expression
+subOne e = A.Dyadic m A.Subtr e (makeConstant m 1)
+  where m = findMeta e
+
 -- | Add two expressions.
 addExprs :: A.Expression -> A.Expression -> A.Expression
 addExprs a b = A.Dyadic m A.Add a b