Re: Haskell Platform proposal: Add the vector package

On Thu, Jul 5, 2012 at 4:58 PM, Thomas Schilling wrote:

On 5 July 2012 15:28, Henning Thielemann wrote: fe functionality should be the default.

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I also see a divergence of usages of the term "safe". It is sometimes used where "total (function)" is meant. I prefer the meaning of "safe" in the sense of SafeHaskell and unsafePerformIO.

Where would you classify functions that don't perform bounds checking? They can be used to read (or write!) arbitrary heap locations.

Right. Even if the IO monad can theoretically allow anything, I feel like there's a qualitative difference between putStrLn and readIORef/writeIORef on the one hand, and raw pointer arithmetic (and unchecked array access which is equivalent) on the other, and I wouldn't mind putting the latter in the Unsafe module together with the functions which break referential transparency. Even in C some things are bad times, and you shouldn't be allowed to do those things in Haskell without having the word "unsafe" somewhere. Perhaps the distinction I'm looking for is that IO should be allowed to break referential transparency, but not memory safety? There's a number of languages which have no concept of referential transparency, but still don't allow raw pointering (and are quite proud of it). WRT to Data.Vector.Storable and the Storable class, I wonder if this isn't analogous to Data.Typeable. Data.Typeable is safe (Trustworthy), but it depends on Typeable instances being correct, otherwise it can do any number of bad things. Can we formulate rules which Storable instances are required to obey, which if they do they are safe? Then we put the methods of Storable in a separate module which is Unsafe, which means that any modules declaring instances must also be Trustworthy (if not Unsafe). Data.Vector.Storable can then also be Trustworthy, and the property is preserved that if all Trustworthy things the user trusts are actually safe (which in this case encompasses following the Storable rules), then unsafe things won't happen. See also this thread: https://groups.google.com/d/topic/haskell-cafe/_Qy2Z65H_xA/discussion -- Your ship was caught in a monadic eruption.