Donald Bruce Stewart wrote: > So how do we help out the beginners, other than warning about fromJust, > and providing a useful error message as we can, for when they just go > ahead and use head anyway?
Kill head and tail right now and provide a safe equivalent? Either uncons :: [a] -> Maybe (a,[a]) which is to be used in conjunction with 'maybe' (or with fmap/first/second/unfoldr) or list :: r -> (a -> [a] -> r) -> [a] -> r in analogy with 'maybe' and 'either'. Or combine it with 'foldr' to form the paramorphism (if I got the terminology right). Or even better, don't mention the existence of uncons and encourage people to write list consumers in terms of 'destroy'. -Udo -- Sturgeon's Law: Ninety percent of everything is crud. (Sturgeon was an optimist.)
signature.asc
Description: Digital signature
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
