Scalafix rules for Monocle 3

[julien-truffaut]

Monocle 3 deprecates lots of methods, it would be great to use scalafix to automatically refactor the ones that have replacements. Here is a list of changes:

• [ ] set to replace
• [ ] setOption to replaceOption

Shortcuts for popular optics

• [ ] composeLens(at(x)) to at(x)
• [ ] composePrism(some) to some
• [ ] composeOptional(index(x)) to index(x)
• [ ] composeTraversal(each) to each
• [ ] composeTraversal(filterIndex(predicate)) to filterIndex(predicate)
• [ ] composeLens(first) or composeLens(_1) to at(1)
• [ ] composeLens(second) or composeLens(_2) to at(2)
• [ ] composeLens(third) or composeLens(_3) to at(3)
• [ ] composeLens(fourth) or composeLens(_4) to at(4)
• [ ] composeLens(fifth) or composeLens(_5) to at(5)
• [ ] composeLens(sixth) or composeLens(_6) to at(6)
• [ ] composeOptional(headOption) to index(0)

Overloaded compose method

• [ ] composeFold(x) to andThen(x)
• [ ] composeGetter(x) to andThen(x)
• [ ] composeIso(x) to andThen(x)
• [ ] composeLens(x) to andThen(x)
• [ ] composePrism(x) to andThen(x)
• [ ] composeOptional(x) to andThen(x)
• [ ] composeTraversal(x) to andThen(x)
• [ ] composeSetter(x) to andThen(x)

Remove symbolic compose operators

• [ ] ^|->> x to andThen(x)
• [ ] ^|-? x to andThen(x)
• [ ] ^<-? x to andThen(x)
• [ ] ^|-> x to andThen(x)
• [ ] ^<-> x to andThen(x)

ApplyOptics

• [ ] applyLens(at(x)) to optics.at(x)
• [ ] applyPrism(some) to optics.some
• [ ] applyOptional(index(x)) to optics.index(x)
• [ ] applyTraversal(each) to optics.each
• [ ] applyTraversal(filterIndex(predicate)) to optics.filterIndex(predicate)
• [ ] applyLens(first) or applyLens(_1) to optics.at(1)
• [ ] applyLens(second) or applyLens(_2) to optics.at(2)
• [ ] applyLens(third) or applyLens(_3) to optics.at(3)
• [ ] applyLens(fourth) or applyLens(_4) to optics.at(4)
• [ ] applyLens(fifth) or applyLens(_5) to optics.at(5)
• [ ] applyLens(sixth) or applyLens(_6) to optics.at(6)
• [ ] applyOptional(headOption) to optics.index(0)
• [ ] applyFold(x) to optics.andThen(x)
• [ ] applyGetter(x) to optics.andThen(x)
• [ ] applyIso(x) to optics.andThen(x)
• [ ] applyLens(x) to optics.andThen(x)
• [ ] applyPrism(x) to optics.andThen(x)
• [ ] applyOptional(x) to optics.andThen(x)
• [ ] applyTraversal(x) to optics.andThen(x)
• [ ] applySetter(x) to optics.andThen(x)

Reference: https://github.com/fthomas/scala-steward/blob/master/docs/scalafix-migrations.md

Originally proposed in https://github.com/optics-dev/Monocle/issues/684

[chaitanyawaikar]

Do we have a list of scalafix migration rules that we need to apply for the project ?

[julien-truffaut]

@chaitanyawaikar no, sorry I am not familiar with scalafix.

[dsebban]

I will take this one