Add support for optics

[arybczak]

PR adds support for using optics library instead of lens as an alternative. There are no name clashes because optics supports lenses/prisms as labels.

cc @phadej

EDIT: Travis doesn't pick up insert-ordered-containers from the cabal.project file 🤔

[phadej]

It doesn't pick, because .travis.yml is generated using swagger2.cabal, not cabal.project (see REGENDATA in generated file, or header).

Anyway, https://hackage.haskell.org/package/insert-ordered-containers-0.2.3 is released

[phadej]

Please bump base >=4.9, so it's not forgotten.

[arybczak]

Ok, I pushed the changes and it's green now 👍.

[phadej]

@fizruk what you think?

[arybczak]

For the record, I'm working on a code base that currently uses fclabels for field accessors, but also uses swagger which requires lens at the moment. We're in the process of replacing fclabels with optics and want to use them everywhere, including swagger specific code because having the same operators be optics-specific and lens-specific in different modules would be super confusing.

[arybczak]

I improved haddock documentation and added doctests.

[phadej]

There's a conflict now Not anymore.

[fisx]

If nobody requests any more changes, I will merge this on ~2019-11-08.

[fisx]

Trivial conflict, I've resolved it locally and will try to push to master once the tests have passed.

[fisx]

hum...

$ stack test --fast
[...]
[ 7 of 17] Compiling Data.Swagger.Optics
                        
/home/mf/src/swagger2/src/Data/Swagger/Optics.hs:119:10: error:
    • Couldn't match type ‘Join
                             A_Lens
                             (IxKind
                                (Data.HashMap.Strict.InsOrd.InsOrdHashMap
                                   HttpStatusCode (Referenced Response)))’
                     with ‘An_AffineTraversal’
        arising from a use of ‘%’
    • In the expression: #responses % ix n
      In an equation for ‘ix’: ix n = #responses % ix n
      In the instance declaration for ‘Ixed Responses’
    |                   
119 |   ix n = #responses % ix n
    |          ^^^^^^^^^^^^^^^^^
[...]

my stack.yaml:

resolver: lts-14.3
packages:
- '.'
extra-deps:
- optics-core-0.2
- optics-th-0.2
- indexed-profunctors-0.1

i guess i better don't push... sorry @arybczak, could you take another look?

[arybczak]

lts-14.3 has insert-ordered-containers-0.2.2, this PR needs 0.2.3 (as is in .cabal file). Does stack override bound checks from the cabal file?

[fisx]

lts-14.3 has insert-ordered-containers-0.2.2, this PR needs 0.2.3 (as is in .cabal file). Does stack override bound checks from the cabal file?

oops, yes, the way i configured it. it seems allow-newer implies allow-older-too?

(disclaimer: not a proud stack user, just didn't have a lot of time, and couldn't think of a quicker way to test it.)

[fisx]

yes, with the extra stack.yaml tweak the test suite passes. i'll merge this to master manually soon!

[arybczak]

oops, yes, the way i configured it. it seems allow-newer implies allow-older-too?

Yes, that seems to be the case: commercialhaskell/stack#4495 (comment)

I updated the branch, I think you can now merge via github 👍

[fisx]

Thanks!