lue-bird / elm-review-missing-record-field-lens Goto Github PK

2 thoughts

1. rename: VariantLens.GenerateUsed -> NoMissingVariantPrism
   a. One because in Optics terms "Lenses" don't operate over Sum types / ADT's only "Product Types" aka records. Prisms operate over Sums/ADTS/Variants...
   b. To match better with NoMissingRecordFieldLens 🤷‍♂️

2. Generate Prisms inline below the definition of the Variant to not force the defining module to expose its constructors.
   EG: I'd like to "expose" some lenses for operating over say pieces of an otherwise opaque record... something like...

module OpaqueThing exposing (Stuff, current)

type Stuff = Stuff Internal
-- generated opaque Prism constructor for composing helpers for accessing pieces of internal state.
onStuff : Lens Stuff Internal reach wrap
onStuff  = -- ...

type alias Internal = 
    { current_ : String
    , toggle : Bool  -- Notice callers have no access to this toggle property.
    } 

current : Lens Stuff String reach wrap
current = onStuff << Lens.current_

elm/compiler#2260

Solution:
Replace . with _ and vice versa.
Remember to document that behavior in import alias config builder and add the linked issue

On second thought, this might be too weird, so I'll revert to Variant.Module.On.name which will make the rule code and config easier at the same time.

In the future, when @erlandsona defines a Prism type from Relations,
update the generated variant prism declaration type annotations accordingly.

Add a default generator for @erlandsona 's named Accessors.
Have a generator like this lying around? → PR

Unfortunately I cannot get this review rule working. It always results in "I found no errors!". Here's my example code:

Main.elm

module Main exposing (Model, main)

import Browser
import Html exposing (Html, div, text)


type alias Model =
    { x : Int
    }


main : Program () Model Msg
main =
    Browser.sandbox { init = { x = 0 }, update = update, view = view }


type Msg
    = Increment
    | Decrement


update : Msg -> Model -> Model
update msg model =
    case msg of
        Increment ->
            { model | x = model.x + 1 }

        Decrement ->
            { model | x = model.x - 1 }


view : Model -> Html Msg
view model =
    div []
        [ text <| String.fromInt model.x
        ]

review/src/ReviewConfig.elm

module ReviewConfig exposing (config)

import RecordFieldHelper.GenerateUsed
import Review.Rule as Rule exposing (Rule)


config : List Rule
config =
    [ RecordFieldHelper.GenerateUsed.rule
        { generator = RecordFieldHelper.GenerateUsed.accessors
        , generateIn = ( "Lense", [] )
        }
    ]

Then I run npx elm-review --debug:

I found no errors!

I had expected that something gets generated in Lense.elm.

I also tried to create Lense.elm as an empty module beforehand, but didn't work either.

Could someone provide a simple self-contained correct example?

Currently, single-variant types are just ignored.

The default VariantPrismGenerator named accessors generates named Accessors by @erlandsona.
The unnamed version is for users of bChiquet/elm-accessors or those should help transition to named erlandsona/elm-accessors.