[m-dev.] Re: [mercury-users] with_stream

[Fergus Henderson]

On 16-Nov-2000, Michael Day <mikeday at corplink.com.au> wrote:
> 
> > That won't work, since `change_stream' followed by `write' will result
> > in side effects to things other than the state of the original stream.
> > In other words `change_stream' is impure.
> 
> I don't quite follow. I left out extra io__state arguments in the original
> example, is that the problem?

Yes.  That was enough to confuse me ;-)

If you put the io__state arguments back, then I think `change_stream'
would be fine.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
                                    |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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