On Wednesday 20 Oct 2004 3:46 pm, Simon Marlow wrote: > I liked the original idea. I'm not sure if I agree with the argument > that allowing fully-fledged IO actions in the initialisation of a module > is unsafe. I agree that it is a little opaque, in the sense that one > can't easily tell whether a particular init action is going to run or > not.
I'm not sure who was arguing that (not me anyway :-). I think the argument was about whether or not there should be any such thing as "module initialisation" at all, or at least that's what concerns me most. (I don't think there should be). > In any case, we're not going to rush to implement anything. Discuss it > some more ;-) Good plan :-) FWIW, at the moment the executive summary of MHO is that the laziness and unpredictability of the unsafePerformIO hack is the one thing I like about it and want to keep. What I don't like about it is the unsafety. The unsafety I'm talking about is _not_ that that arises from allowing arbitrary IO operations. I'm talking about the fact that the compiler cannot be relied upon to generate code that accurately reflects the programmers intentions without using NOINLINE pragma and -fno-cse flag (the latter applying to an entire module). There's also the (IMO) secondary issue of whether or not the IO actions allowed during construction should be constrained in any way (e.g. using type system tricks). I suggested a simple (perhaps naive) way to to this (SafeIO monad), but I don't have any particularly strong views on this either way. Just relying on programmers to use some common sense seems fine to me also (this is what's currently done for finalisers for example). Regards -- Adrian Hey _______________________________________________ Glasgow-haskell-users mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
