How could I get some compile time safety here? It'...

# announcements

[Paul Woitaschek]

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

-.kt

[gildor]

Why do you need internal when? Why not just have AnalysisType.ARM -> BodyValueType.ARM_CIRCUMFERENCE?

[Paul Woitaschek]

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

[gildor]

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

[BMG]

Since these look like 1-1 mapping, can’t you include BodyValueType in AnalysisType itself?

[BMG]

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

[Paul Woitaschek]

If I include it in AnalysisType, I don't have the sealed when safety any more, right?

[Paul Woitaschek]

https://gist.github.com/PaulWoitaschek/50b051cf625c9c2a6848680ff19e9687

[Paul Woitaschek]

This is the whole function

[Paul Woitaschek]

@gildor

[gildor]

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]

Extrat what in a function how?

[gildor]

Common code for those entities

[gildor]

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]

And than just

AnalysisType.ARM -> BodyValueType.ARM_CIRCUMFERENCE.toBodyResult()

[gildor]

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

[gildor]

So in this case you will have 1 level exhaustive when

[gildor]

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]

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]

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

[gildor]

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]

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 😕

[gildor]

What about my approach?

[BMG]

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]

Ah I think I got it

[Paul Woitaschek]

https://gist.github.com/PaulWoitaschek/8a52f04ee7092d0eb14f2b59545745d1

[Paul Woitaschek]

🙂 thanks you two this is better 🙂

[gildor]

caloriesResult and circumferenceResult also may be local, so wouldn’t require mode param

[gildor]

But not sure that it would be clear enough

[Paul Woitaschek]

You mean like this? https://gist.github.com/PaulWoitaschek/83738bb50726d1a010d73fdaded42e07

[gildor]

yes, or with lambda

[Paul Woitaschek]

What do you mean by "with lambda"?

[gildor]

Use local lambda instead of local function