On Fri, Aug 22, 2008 at 05:49:22PM +0200, Henning Thielemann wrote:
The Prelude functions drop, take, and splitAt are unfailing (never call error). This patch changes the Data.List generic versions to behave the same way. At present, they call error on negative arguments.
I had always just assumed that take and genericTake did the same thing, so had never even realised this problem existed. I'd call this a bug, that needs fixing.
Maybe the bug is in 'drop', 'take' and 'splitAt' and it was intended to fix it in 'generic' variants. Is there a good reason why to ignore negative number arguments? It may hide bugs.
But is also makes the functions less useful and another source of non-completeness. I certainly always considered accepting negative numbers a feature of those functions and not an infelicity. Sometimes you want 'drop 1 xs' and other times you want 'tail xs' (or equivalent). John -- John Meacham - ⑆repetae.net⑆john⑈