Proposal for stand-alone deriving declarations?

Brian Smith brianlsmith at
Wed Nov 1 13:30:31 EST 2006

On 11/1/06, Simon Peyton-Jones <simonpj at> wrote:
> The thread about "stand-alone" deriving is long-ish now, so I have
> summarised the issues here:

I think it is difficult to discuss things via a Wiki. I tried to add my
comments to the page and it took a lot of edits due to a collision with
BrianH's edit. Plus, it is not clear to me how agreement is to be indicated.
For example, I think that Brian H's idea really good. Basically, the syntax
for instances and derived instances would be identical, but derived
instances would just omit the "where" clause, while non-derived instances
would need the "where" clause. For that to work, the rules for when a
context is required need to be the same for derived and non-derived
instances, which I also think is a good idea.

It is a much better idea than my "derive instance" suggestion, and I no
longer support it.

- Brian Smith
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