[Haskell-cafe] Haskell Propeganda

[Jonathan Cast]

On Wed, 2008-08-27 at 12:23 -0700, Dan Weston wrote:
> Tim Docker wrote:
> >  
> > David Roundy wrote:
> > 
> >> Which illustrates the point that it's not type safety 
> >> that protects us from segfaults, so much as bounds checking,
> >> and that's got a non-trivial runtime cost.  At least, most
> >> segfaults that *I've* caused (in C or C++) have been from
> >> overwriting the bounds of arrays, and that's precisely the problem
> >> that Haskell does *not* solve using its type system. 
> > 
> > That differs from my experience. Most segfaults that *I've* caused (in
> > C or C++) have been due to dereferencing null pointers. Type safety
> > does help you here, in that Maybe lets you distinguish the types of
> > things that are optionally present from those that must be. 
> > 
> > Tim
> 
> Huh? Type safety buys you not having to worry about dereferencing stale 
> nonnull pointers (lifetime of reference exceeding lifetime of referent), 
> but nothing about dereferencing null pointers, which are the moral 
> equivalent of Nothing.

Actually, that's garbage collection.

> Failure to handle a null pointer is just like using fromJust and results 
> in the same program termination (undefined).

jcc