That argument doesn't totally fly since non-termination isn't considered an effect in Haskell. Bottom doesn't commute with a IO operations normally either. But not having readIVar return 'IO a' does make me a little quesy. :)
-- Lennart On Dec 4, 2007 8:25 AM, Simon Peyton-Jones <[EMAIL PROTECTED]> wrote: > But since the read may block, it matters **when** you perform it. For > example if you print "Hello" and then read the IVar, you'll block after > printing; but if you read the IVar and then print, the print won't come > out. If the operation was pure (no IO) then you'd have a lot less control > over when it happened. > > > > Simon > > > > *From:* [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] *On > Behalf Of *Lennart Augustsson > *Sent:* 04 December 2007 08:19 > *To:* Conal Elliott > *Cc:* haskell@haskell.org > *Subject:* Re: [Haskell] IVars > > > > Good question. That must be a matter of taste, because as you say the > read will always produce the same result. But it sill is a bit of a strange > operation. > > -- Lennart > > On Dec 4, 2007 6:25 AM, Conal Elliott < [EMAIL PROTECTED]> wrote: > > Oh. Simple enough. Thanks. > > Another question: why the IO in readIVar :: IVar a -> IO a, instead of > just readIVar :: IVar a -> a? After all, won't readIVar iv yield the same > result (eventually) every time it's called? > > > > On Dec 3, 2007 12:29 AM, Lennart Augustsson <[EMAIL PROTECTED]> > wrote: > > You can make them from MVars. > > On Dec 2, 2007 8:03 PM, Conal Elliott <[EMAIL PROTECTED]> wrote: > > what became of (assign-once) IVars? afaict, they were in concurrent > haskell and now aren't. > > _______________________________________________ > Haskell mailing list > Haskell@haskell.org > http://www.haskell.org/mailman/listinfo/haskell > > > > > > > _______________________________________________ > Haskell mailing list > Haskell@haskell.org > http://www.haskell.org/mailman/listinfo/haskell > > > > _______________________________________________ > Haskell mailing list > Haskell@haskell.org > http://www.haskell.org/mailman/listinfo/haskell > >
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