lue-bird/elm-linear-direction/9.0.0

linear direction

• -r/-l
  • for example: foldr, foldl
  • does foldr mean fold to the right? unclear and easy to mix up
  • no Array.getr/l, setr/l but foldr, foldl?
• negative indices
  • Array.slice 0 -1 is handy! But you can't do slice 2 -0
  • many operations support negative indices, but others don't
  • not explicit → can have unintended side-effects

How about taking the Direction as an argument!

import Linear exposing (Direction(..))
import List.Linear
import Array exposing (Array)
import Array.Linear

[ 'l', 'i', 'v', 'e' ]
    |> List.Linear.foldFrom "" Up String.cons
--> "evil"

[ 'l', 'i', 'v', 'e' ]
    |> List.Linear.foldFrom "" Down String.cons
--> "live"

Array.fromList [ 'e', 'v', 'i', 'l' ]
    |> Array.Linear.element ( Down, 0 )
--> Just 'l'

• → a less cluttered API, e.g.

  • foldFrom instead of foldr, foldl
  • toChunksOf instead of chunksFromLeft/-Right
  • padToLength instead of resizerRepeat, resizelRepeat, resizerIndexed, resizelIndexed

• → deal with both directions at once

  import Linear exposing (DirectionLinear)
  import Array exposing (Array)
  import Array.Linear
  
  elementAlter :
      ( DirectionLinear, Int )
      -> (element -> element)
      -> (Array element -> Array element)
  elementAlter location alter =
      \array ->
          case array |> Array.Linear.element location of
              Nothing ->
                  array
  
              Just elementAtLocation ->
                  array
                      |> Array.Linear.elementReplace location
                          (\() -> elementAtLocation |> alter)

• → direction is always explicit

where linear direction is already being used

• emptiness-typed
• typesafe-array
• keysset
• rosetree-path

suggestions?

→ contribute