On Fri, Jun 01, 2007 at 07:39:32PM +0100, Andrew Coppin wrote: > David Roundy wrote: > >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. > > > > No, I mean... how could you use unsafePerformIO to perform a typecast? I > don't see a way to do that.
Then I'm confused. What typecast are you talking about? -- David Roundy Department of Physics Oregon State University _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
