18 Aug
2016
18 Aug
'16
4:46 p.m.
On Thu, 18 Aug 2016, David Feuer wrote:
I am open to the idea of leaving mergeWithKey in, but I'm not yet convinced. Can you give an example of a realistic application of mergeWithKey that cannot easily be rewritten in terms of generalMerge? I would normally agree with you that backwards compatibility should be preserved. However, mergeWithKey has several very serious problems.
In the past, it caused problems to install a new 'containers' on an old GHC. Is this problem solved?
1. It allows the user to produce invalid maps. Unlike other functions that do so, it's not clear that it offers any significant efficiency benefit (once generalMerge is added).
How about adding WARNING or DEPRECATED?