[darcs-users] darcs patch: Use index-based diffing in Record. (and 57 more)

Eric Kow kowey at darcs.net
Mon Sep 14 22:28:16 UTC 2009

On Mon, Sep 14, 2009 at 20:39:24 +0200, Petr Rockai wrote:
> There are two options on substituting NoHash -- either provide a class
> function, noHash, and give up pattern matching (or use view patterns), or wrap
> everything in Maybe again. I find the Maybe wrapping to be really ugly though
> -- it complicates a lot of signatures (and you can't even escape with a type
> synonym anymore, now that "h" is of some unknown type), and I had specifically
> refactored hashed-storage to get rid of this Maybe wrapping.

Would a Hash-specific Maybe-style type help in any way?

data Hash h => MaybeHash h = NoHash | JustHash h

Eric Kow <http://www.nltg.brighton.ac.uk/home/Eric.Kow>
PGP Key ID: 08AC04F9
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