Re: [Haskell-cafe] runST

Not if you want a pure result. The IO monad is one-way, whereas ST has runST to get back a result. - Cale On 07/10/05, Joel Reymont wrote:

Folks,

Why use runST in the following example at

http://www.n-heptane.com/nhlab/repos/NewBinary/Tests/BinDouble.hs ?

doubleToInts d = runST ( do arr <- newDoubleArray (1,2) writeDoubleArray arr 1 d i1 <- readIntArray arr 1 i2 <- readIntArray arr 2 return (i1,i2))

Isn't it possible to do the same within the IO monad?

Thanks, Joel

-- http://wagerlabs.com/idealab

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