Consistency for Eq a / Ord a functions with suffix "By"

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
30/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Domain
api

Research direction

Read the array API definitions for difference, elem, notElem, elemIndex, and elemLastIndex, then compare their signatures and naming with the existing By variants listed in the issue. Decide whether differenceBy fits the API’s conventions and identify the corresponding functions to address. Done means the API naming and custom equality support are consistent; the issue provides no file or test paths to start from.

Written by the indexing model from the issue text.

Description

type: enhancement

As I look through the API, I see a pretty consistent pattern of "You can rely on a typeclass for Eq/Ord or you can supply your own".

So if a type signature has forall a. Eq a => ..., there's often a version that removes this constraint and adds in a function like forall a. (a -> a -> Boolean) ...

There even seems like a pretty consistent naming pattern:

insert    & insertBy 
sort      & sortBy
group     & groupBy
groupAll  & groupAllBy
nub       & nubBy
nubEq     & nubByEq  <- Sort of a break from the pattern, but still
union     & unionBy
delete    & deleteBy
intersect & intersectBy

But it feels sort of arbitrary when some functions don't follow that pattern

For example: difference

I'd expect to see

difference :: forall a. Eq a => Array a -> Array a -> Array a
differenceBy :: forall a. (a -> a -> Boolean) -> Array a -> Array a -> Array a

The same holds for elem, notElem, elemIndex, and elemLastIndex, but these are covered by find >>> isJust, find >>> isNothing, findIndex, and findLastIndex. I understand a departure in naming pattern here since Eq a is replaced with (a -> Boolean) instead of (a -> a -> Boolean).

Dominant language
PureScript
Stars
58
Forks
70
Avg merge
2d 22h
Merged PRs (30d)
1

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