GHC support for the new "record" package

[Mark Lentczner]

On Tue, Jan 27, 2015 at 3:47 PM, Edward Kmett <ekmett at gmail.com> wrote:

> We can make up our own combinators for putting these things together, but
> we can't use (.) from the Prelude or even from Control.Category.
>

Is this the only reason *not* to have a data type? (Sorry, I wasn't totally
following the GADT-nastics!) That is, if, for a moment, we just assume a
different operator for composing lenses, then will a data/newtype work?

Now, *if* (as I understand it), under IV (assuming it work), it works for
lens libraries iff they use a data/newtype for the lens (so that their
instance is *the* instance for ->, I'm guessing)...... *then*, I say using
a different operator for compose is a small price to pay. (Well, as I said
before, I'd actually prefer a different compose operator!)

Mind you, I might be totally mis-understanding the arguments and reasoning!
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