Disallow unchecked record updates with fromNimber

Previously, one could write 0 {fromNimber=-1} to bypass the nonnegative check. Signed-off-by: Anders Kaseorg <[email protected]>
andersk · Jan 2, 2014 · 3e72bce · 3e72bce
1 parent 7f81035
commit 3e72bce
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diff --git a/Data/Nimber.hs b/Data/Nimber.hs
@@ -56,7 +56,7 @@ instance Show NimberException where
 instance Exception NimberException
 
 -- |The type of finite nimbers.
-newtype Nimber = Nimber {fromNimber :: Integer} deriving (Eq, Ord)
+newtype Nimber = Nimber Integer deriving (Eq, Ord)
 
 nimSize :: Nimber -> Int
 nimSize (Nimber a) = bit (intLog2 (integerLog2 a))
@@ -162,3 +162,7 @@ instance Floating Nimber where
   asinh = throw (Innimerable "asinh")
   atanh = throw (Innimerable "atanh")
   acosh = throw (Innimerable "acosh")
+
+-- |Convert a 'Nimber' to the corresponding natural number.
+fromNimber :: Nimber -> Integer
+fromNimber (Nimber a) = a
diff --git a/nimber.cabal b/nimber.cabal
@@ -1,5 +1,5 @@
 name:                nimber
-version:             0.1.2
+version:             0.1.3
 synopsis:            Finite nimber arithmetic
 description:
   The finite nimbers, 'Nimber', are a quadratically closed field of
@@ -28,4 +28,4 @@ source-repository head
 source-repository this
   type:                git
   location:            https://github.com/andersk/haskell-nimber
-  tag:                 0.1.2
+  tag:                 0.1.3