On Fri, Jun 01, 2007 at 07:28:07PM +0100, Andrew Coppin wrote: > David Roundy wrote: > >Note also that you can use unsafePerformIO to safely get pure functions > >doing both these operations. > > > > I've always been puzzled by this one... how does unsafePerformIO > circumvent the type system? I don't understand.
It's a primitive. You couldn't implement it unless you're the compiler-writer. But it's a necesary primitive, if you wish to build efficient data types. You just need to carefully audit everywhere that unsafePerformIO is used. -- David Roundy Department of Physics Oregon State University _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
