Export more of MicroLens: (.~), (%~), others?

[akhra]

Discussion. Considering that set and over are exported, I assume (.~) and (%~) were omitted to minimize operator soup in RIO, for newbie-friendliness and/or best practice assertion. But critiques aside, there are quite a few important libraries that provide a lens-based configuration API (e.g. http-client), and their examples tend to lean heavily on (.~). And if that's provided, it seems silly not to toss in (%~).

So:

• Are there strong reasons why we don't want to open this door at all?
• Do we want to provide these operators in the prelude?
• Whether or not anything more goes in the prelude, is it worth adding RIO.Lens with a more complete set of re-exports? Which ones?

[snoyberg]

I'd lean towards a RIO.Lens module, and being very conservative about adding operators or functions the RIO.

[akhra]

I've been leaning that way myself. So the remaining question is, what to re-export and from where? Initial thoughts:

• RIO.Lens.Partial: singular, (^?!)
• RIO.Lens.Unchecked: failing, _1.._5? (due to behavior on undefined)
• RIO.Lens.Pseudo (or just omitted): the not-actually-Iso and Prism functions
• RIO.Lens: Everything else
• RIO.Lens.Operators: All operators except (^?!), as a convenience for getting them all unqualified

I'm not sure about .Operators (does RIO.Lens itself need to be qualified?) or the placement of _1.._5 (frankly I'm not 100% sold on their existence). Thoughts? Did I miss anything that belongs in .Partial or .Unchecked? Should we be more conservative in general, skipping or relocating things like (<>~) and the LensLike operators? I'm not fully fluent in lenses yet, much less the ins and outs of how the different lens libraries interact or conflict, so I don't entirely trust my own judgement on this.

[snoyberg]

I don't think I can weigh in that effectively here, I'm not that familiar with what is commonly used in lens-heavy projects. I still tend to stick to a relatively small subset of lens functionality in my code.

[akhra]

I'm starting to lean in the same direction, to the point that I was lately annoyed to find no prefix synonym for (^.). Leaving this open for others to weigh in, though.