[Haskell-cafe] Referential Transparency and Monads
jonathanccast at fastmail.fm
Fri Apr 10 01:00:45 EDT 2009
On Fri, 2009-04-10 at 07:29 +0400, Miguel Mitrofanov wrote:
> On 10 Apr 2009, at 06:30, Jonathan Cast wrote:
> > do
> > 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
My programs are passing me around inside a state token?
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