[Haskell-cafe] Prolog-style patterns

[Tom Murphy]

On Mon, Apr 8, 2013 at 7:59 AM, Joachim Breitner
<mail at joachim-breitner.de>wrote:

> Hi,
>
> I believe one problem with non-linear patterns would be that the
> compiler has to figure out what notion of equality you want here. An
> obvious choice is (==), but the Eq instances might not do what you want.
> Using pattern guards or view patterns explicates this choice.
>

What other types of equality would be possibilities?


Also, for some history, this was discussed a while back:
http://www.mail-archive.com/haskell@haskell.org/msg03721.html

Erlang programmers have this feature without shooting themselves in the
foot too often. That said, I'm happy without it.

Tom
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