[Haskell-cafe] better way to do this?
mpm at alumni.caltech.edu
Sun Oct 4 08:11:33 EDT 2009
Duncan Coutts wrote:
> On Sun, 2009-10-04 at 02:52 -0700, Michael Mossey wrote:
>> I'm looking for a hint to write the following code with less redundancy. I
>> have a constructor called BoxBounds, and I want to make one with random
>> randomBox :: IO BoxBounds
>> randomBox = do
>> x <- getStdRandom (randomR (-10,10))
>> y <- getStdRandom (randomR (-70,70))
>> t <- getStdRandom (randomR (5,10))
>> b <- getStdRandom (randomR (5,10))
>> l <- getStdRandom (randomR (5,10))
>> r <- getStdRandom (randomR (5,10))
>> return (BoxBounds x y l r t b)
> Others have already answered but I'd like to suggest that you avoid
> using IO here. There's no need for this to be impure. The getStdRandom
> function is one that should be avoided IMHO (and indeed removed from the
> Random module).
> A much nicer way to do the above is using some random monad, for example
> from the MonadRandom package. The suggestions from Felipe and Eugene
> will work just as well using Rand monad as the IO monad.
Can you point me to a tutorial that covers the basics of randomness in
Hasell? I find it very confusing.
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