Apologies, your update function would actually look like this:
update : Msg -> Model -> Model
update message model =
case (message, model) of
(CreateInvoiceMsg msg, CreateInvoiceImpl data) ->
CreateInvoice.update msg data
(SendTextMsg msg, SendTextImpl data) ->
SendText.update msg data
_ ->
model
On Tue, Aug 23, 2016 at 10:15 AM, Nick H <falling.maso...@gmail.com> wrote:
> I am not sure what you mean by routing to an implementation "in a generic
> way".
>
> You can clean up your code a lot by merging your "Model" type with "Impl".
> This is the more idiomatic way of writing in Elm:
>
>
> type alias Model =
> CreateInvoiceImpl CreateInvoice.Model
> | SendTextImpl SendText.Model
>
> update : Msg -> Model -> Model
> update message model =
> case message of
> CreateInvoiceMsg msg ->
> CreateInvoice.update msg data
> SendTextMsg msg ->
> SendText.update msg data
>
> On Tue, Aug 23, 2016 at 9:58 AM, Larry Weya <larryw...@gmail.com> wrote:
>
>> Thank you for the response, routing to the proper implementation in a
>> generic way is my problem. The command implementation should receive the
>> json value and take care of decoding it.
>>
>> I ended up implementing it using case expressions which is ok but means I
>> need to update the module in a number of place anytime I add a new command.
>> I've pushed the code here
>> <https://github.com/larryweya/dynamic-elm-modules/blob/master/CommandImpl.elm>
>> if anyone wants to have a look.
>>
>> The issue is with the module that manages the commands (CommandImpl.elm)
>> and how to defined a "generic" type which would hold a different kind of
>> message and model depending on the command's name
>>
>> On Tuesday, 23 August 2016 18:04:13 UTC+3, Nick H wrote:
>>>
>>> This sounds like exactly the use case for Json.Decode.andThen
>>> <http://package.elm-lang.org/packages/elm-lang/core/4.0.5/Json-Decode#andThen>.
>>> (See that documentation for an example)
>>>
>>> Your could have your main module decode the JSON "params" enough to
>>> figure out which type of message you've received, then route it to the
>>> proper implementation.
>>>
>>> On Mon, Aug 22, 2016 at 4:25 AM, Larry Weya <larr...@gmail.com> wrote:
>>>
>>>> I have a project where I would like to have different implementations
>>>> depending on a provided value.
>>>>
>>>> I have what we are referring to as Commands and we are using elm
>>>> provide a UI used to configure a command's parameters so e.g. we have 2
>>>> Commands, a CreateInvoice command and a SendText command. They are
>>>> persisted in a database as JSON. To edit the command, I load up the JSON
>>>> and depending on the command's name I'd like my Main module to use the
>>>> commands init/view/update functions. The biggest issue is that
>>>> CreateInvoice and SendText models have different types.
>>>>
>>>> Main.elm
>>>>
>>>> -- how do I define a model that can accomodate both types
>>>>
>>>> main =
>>>> Html.programWithFlags{...}
>>>>
>>>> init : String -> Json.Encode.Value -> Model
>>>> init (moduleName, params) =
>>>> -- how to init a command based on the moduleName
>>>>
>>>>
>>>> CreateInvoice.elm
>>>>
>>>> type alias Model = {amount : Int}
>>>>
>>>> init jsonValue =
>>>> -- decode json value into model
>>>>
>>>> SendText.elm
>>>>
>>>> type alias Model = {message : String}
>>>>
>>>> init jsonValue =
>>>> -- decode json value into model
>>>>
>>>>
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>>>
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>
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