a small script to explore reducible from F# (run with: dotnet fsi ./script.fsx)

script.fsx

#r "nuget: Reducible, 0.2.0"

open Morris.Reducible

type UserReducer =
    | EmailDelta of string option
    | AgeDelta of int option
    | NameDelta of string option

type User =
    { name: string
      age: int
      email: string option }

module User =
    let private userReducer =
        Reducer
            .Given<User, UserReducer>()
            .Then(fun state delta ->
                match delta with
                | EmailDelta delta ->
                    if state.email = delta then
                        Reducer.Result(false, state)
                    else
                        Reducer.Result(true, { state with email = delta })
                | AgeDelta delta ->
                    match delta with
                    | Some delta when delta <> state.age -> Reducer.Result(true, { state with age = delta })
                    | Some _
                    | None -> Reducer.Result(false, state)
                | NameDelta delta ->
                    match delta with
                    | Some delta when delta <> state.name -> Reducer.Result(true, { state with name = delta })
                    | Some _
                    | None -> Reducer.Result(false, state))
        |> FuncConvert.FromFunc

    let UpdateUser user delta = (userReducer user delta).Deconstruct()

let user = { name = "Max"; age = 20; email = None }


match User.UpdateUser user (Some "[email protected]" |> EmailDelta) with
| (true, updated) -> printfn $"did update %A{updated}"
| (false, _) -> printfn $"did not update :("

match User.UpdateUser user (AgeDelta(Some 20)) with
| (true, updated) -> printfn $"did update %A{updated}"
| (false, _) -> printfn $"did not update :("