1.1 --- a/src/HOL/Library/Code_Natural.thy	Thu Aug 26 12:19:50 2010 +0200
     1.2 +++ b/src/HOL/Library/Code_Natural.thy	Thu Aug 26 13:25:14 2010 +0200
     1.3 @@ -9,7 +9,9 @@
     1.4  section {* Alternative representation of @{typ code_numeral} for @{text Haskell} and @{text Scala} *}
     1.5  
     1.6  code_include Haskell "Natural"
     1.7 -{*newtype Natural = Natural Integer deriving (Eq, Show, Read);
     1.8 +{*import Data.Array.ST;
     1.9 +
    1.10 +newtype Natural = Natural Integer deriving (Eq, Show, Read);
    1.11  
    1.12  instance Num Natural where {
    1.13    fromInteger k = Natural (if k >= 0 then k else 0);