[Haskell-cafe] Avoid sharing

[Michael Roth]

Hello! A short question, given:


     data Seed = ...
     data Value = ...

     someGenerator :: Seed -> [Value]

     createTwo :: Seed -> ([Value], [Value])
     createTwo s = (as, bs) where
       as = someGenerator s
       bs = drop 1000000000 (someGenerator s)


Is it guaranteed that 'someGenerator s' is created twice and not shared 
between 'as' and 'bs'? Is this by language design? Are there any GHC 
options that change the behaviour?


Thank you,

Michael