mapM /= traverse?

Edward Kmett ekmett at
Tue May 12 14:26:42 UTC 2015

On Tue, May 12, 2015 at 3:58 AM, Simon Marlow <marlowsd at> wrote:

> Yes, I'm not really concerned that mapM is a method of Traversable rather
> than just being an alias for traverse, but I'm wondering why we define it
> in the list instance rather than using the default.

We were pretty paranoid about introducing space or time regressions and
didn't have a proof that we wouldn't introduce them by changing something
there, so we left it alone.

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