Configuration for rule: add a clause to a case expression in a specified function in a specified module.

Basic config to add a new clause to a case expression. If you just need to add a new clause at the end of the case, you can simply use it with the makeRule function like this:

Install.ClauseInCase.config
    "Backend"
    "updateFromFrontend"
    "ResetCounter"
    "( { model | counter = 0 }, broadcast (CounterNewValue 0 clientId) )"
    |> Install.ClauseInCase.makeRule

If you need additional configuration, check the withInsertAfter and withCustomErrorMessage functions.

Create a rule that adds a clause to a case expression in a specified function. You can use it like this:

Install.ClauseInCase.config
    "Backend"
    "updateFromFrontend"
    "ResetCounter"
    "( { model | counter = 0 }, broadcast (CounterNewValue 0 clientId) )"
    |> Install.ClauseInCase.makeRule

Add a clause after another clause of choice in a case expression. If the clause to insert after is not found, the new clause will be inserted at the end.

Example

Given the following module:

module Philosopher exposing (Philosopher(..), stringToPhilosopher)


type Philosopher
    = Socrates
    | Plato
    | Aristotle


stringToPhilosopher : String -> Maybe Philosopher
stringToPhilosopher str =
    case str of
        "Socrates" ->
            Just Socrates


        "Plato" ->
            Just Plato


        "Aristotle" ->
            Just Aristotle


        _ ->
            Nothing

To add the clause Aspasia after the clause Aristotle, you can use the following configuration:

Install.ClauseInCase.config
    "Philosopher"
    "stringToPhilosopher"
    "Aspasia"
    "Just Aspasia"
    |> Install.ClauseInCase.withInsertAfter "Aristotle"
    |> Install.ClauseInCase.makeRule

This will add the clause Aspasia after the clause Aristotle in the stringToPhilosopher function, resulting in:

stringToPhilosopher : String -> Maybe Philosopher
stringToPhilosopher str =
    case str of
        "Socrates" ->
            Just Socrates


        "Plato" ->
            Just Plato


        "Aristotle" ->
            Just Aristotle


        "Aspasia" ->
            Just Aspasia


        _ ->
            Nothing

Add a clause at the beginning of the case expression.

You also can add the clause after another clause of choice with the withInsertAfter function:

Install.ClauseInCase.config
    "Backend"
    "updateFromFrontend"
    "ResetCounter"
    "( { model | counter = 0 }, broadcast (CounterNewValue 0 clientId) )"
    |> Install.ClauseInCase.withInsertAtBeginning
    |> Install.ClauseInCase.makeRule

In this case we will have

updateFromFrontend : SessionId -> ClientId -> ToBackend -> Model -> ( Model, Cmd BackendMsg )
updateFromFrontend sessionId clientId msg model =
    case msg of
        ResetCounter ->
            ( { model | counter = 0 }, broadcast (CounterNewValue 0 clientId) )


        CounterIncremented ->
        ...


        CounterDecremented ->
        ...

Customize the error message that will be displayed when running elm-review --fix or elm-review --fix-all.

Install.ClauseInCase.config
    "Backend"
    "updateFromFrontend"
    "ResetCounter"
    "( { model | counter = 0 }, broadcast (CounterNewValue 0 clientId) )"
    |> Install.ClauseInCase.withCustomErrorMessage "Add handler for ResetCounter" []
    |> Install.ClauseInCase.makeRule

Custom error message to be displayed when running elm-review --fix or elm-review --fix-all