[Haskell-cafe] Referential Transparency and Monads
miguelimo38 at yandex.ru
Thu Apr 9 23:29:33 EDT 2009
On 10 Apr 2009, at 06:30, Jonathan Cast wrote:
> s <- readFile "/my_file"
> writeFile "/my_file" "Hello, world!\n"
> threadDelay 10000 -- If you don't like threadDelay, just
> substitute forcing
> -- an expensive thunk here
> writeFile "/my_file" s
> As a function from initial state to final state, this program is just
> the identity;
No, since world state includes the user state itself, not just files
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