How could I get some compile time safety here It s an enum a

Question

How could I get some compile time safety here It s an enum and an exhaustive when and I the cases on line 10 and then the when on line 11 feel like a smell

gildor · Answer

Why do you need internal when Why not just have `AnalysisType ARM gt BodyValueType ARM CIRCUMFERENCE`

Paul Woitaschek · Answer

Because I return sth else later al these nulls are supposed to return sth else later

gildor · Answer

Maybe you could provide full example because this one is not really clear for me

BMG · Answer

Since these look like 1 1 mapping can t you include `BodyValueType` in `AnalysisType` itself

BMG · Answer

Like having a `getBodyValueType` and let it return `null` for base class and have interested entities override it and return proper `BodyValueType`

Paul Woitaschek · Answer

If I include it in AnalysisType I don t have the sealed when safety any more right

Paul Woitaschek · Answer

Paul Woitaschek · Answer

This is the whole function

Paul Woitaschek · Answer

< gildor>

gildor · Answer

Still looks a bit strange so you just want to do some common logic for those cases why not just extract it to function

Paul Woitaschek · Answer

Extrat what in a function how

gildor · Answer

Common code for those entities

gildor · Answer

Something like this ``` fun BodyValueType toBodyResult val key = BodyValueSummaryGroupKey range start range endInclusive this val bodyValueSummary = bodyValueSummaryProvider get key awaitFirst val history = History getAnalysisSummary circumference bodyValueSummary mode Result ChartData2 mode history Summary ```

gildor · Answer

And than just ``` AnalysisType ARM gt BodyValueType ARM CIRCUMFERENCE toBodyResult ```

gildor · Answer

it may be local function or local lambda if you want to use closure instead explicit types for things like range

gildor · Answer

So in this case you will have 1 level exhaustive when

gildor · Answer

It s hard to experiment with this code because I don t have self contained example or at least enum maybe I don t see some problem but looks that this approach should work

BMG · Answer

I was mentioning about removing whole `when` clauses and using methods on `AnalysisType` or more appropriate class to build `Result` objects So this will essentially look like ``` suspend fun get mode AnalysisMode type AnalysisType Result return type buildResult ```

BMG · Answer

Not exactly as your method is somewhat complex in nature But I think this can be worked out

gildor · Answer

Yes one more option but it may depends on case looks that Result also contains some additional information depending on case but I agree it would be probably more clear solution separate when for AnalysisType and BodyValueType + Return

Paul Woitaschek · Answer

Hm not sure there is a good sulution for this The problem is also that there are also `BodyValueType`s where I need to perform a different logic By using `type buildResult ` I only move the problem because then I ll just have a `when this ` switch confused

gildor · Answer

What about my approach

BMG · Answer

But still your `BodyValueType` are 1 1 to `AnalysisType` right So `buildResult` in ` AnalysisType ARM` can use `BodyValueType ARM CIRCUMFERENCE` to construct the result object without `when`

Paul Woitaschek · Answer

Paul Woitaschek · Answer

Ah I think I got it

Paul Woitaschek · Answer

slightly smiling face thanks you two this is better slightly smiling face

gildor · Answer

caloriesResult and circumferenceResult also may be local so wouldn t require `mode` param

gildor · Answer

But not sure that it would be clear enough

Paul Woitaschek · Answer

You mean like this <https gist github com PaulWoitaschek 83738bb50726d1a010d73fdaded42e07>

gildor · Answer

yes or with lambda

Paul Woitaschek · Answer

What do you mean by with lambda

gildor · Answer

Use local lambda instead of local function