Hello Andrew,
Thursday, November 29, 2007, 9:43:48 PM, you wrote:
>> Fifth thing: better use an STUArray, don't drag IO in if it's not necessary.
>>
> I don't understand the ST monad.
it's just a subset of IO monad, with renamed operations
the subset is selected in the way that guarantees reference
transparency, i.e. compiler is able to do more checks that your
program is correct. so, instead of writing
main = do a <- newArray
writeArray a 1 3.14
x <- readArray a 1
print x
you can write
main = do x <- runST (do a <- newArray
writeArray a 1 3.14
x <- readArray a 1
return x)
print x
--
Best regards,
Bulat mailto:[EMAIL PROTECTED]
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