[Haskell-cafe] Fun with the ST monad

[Sterling Clover]

On Feb 24, 2011, at 3:45 PM, Andrew Coppin wrote:

> OK, so I had a function that looks like
> 
>  transform :: [Word8] -> [Word16]
> 
> It works nicely, but I'd like to use mutable state inside. No problem! Use the ST monad. Something like
> 
>  transform :: [Word8] -> [Word16]
>  transform xs = runST (work xs)
>    where
>      work :: [Word8] -> ST s [Word16]
> 
> Ah, yes, well there is one *small* problem... If you do that, the function becomes too strict.

unsafeInterleaveST?

http://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-Monad-ST.html#v:unsafeInterleaveST

--Sterl
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