Dev Conventions §

Any time you have to decide (when(...) { }) on something that might get further options if somewhere in the future is extended, e.g.:
atm a model { ... } can only have dto { ... }, dco { ... } and tableFor { ... } as sub nodes, but this might change in the future.

So if at any place in the sourcecode we have to do “something else” depending on the model sub-node,
there should be a whens lambda, e.g. like in WhensDslRef

    fun <R> whenModelSubelement(dslRef: IDslRef,
        isDtoRef: () -> R,
        isTableRef: () -> R,
        isDcoRef: () -> R,
        catching: (DslException) -> Throwable = { Throwable("when on '$dslRef' not exhaustive") }
    ): R {
        when (MODELREFENUM.sentinel) { MODELREFENUM.MODEL, MODELREFENUM.DTO, MODELREFENUM.TABLE, MODELREFENUM.DCO -> {} } // sentinel to check if new MODELREFENUM was added
        return when (dslRef) {
            is DslRef.dto -> isDtoRef()
            is DslRef.table -> isTableRef()
            is DslRef.dco -> isDcoRef()
            else -> throw catching(DslException("no (known) modelSubelement"))
        }
    }

and its usage example:

        intersectPropsData.sourceVarName = WhensDslRef.whenModelSubelement(sourceGenModelFromDsl.modelSubElRef,
            isDtoRef = { "source${intersectPropsData.sourceVarNamePostfix}" },
            isDcoRef = { "source${intersectPropsData.sourceVarNamePostfix}" },
            isTableRef = { "resultRow${intersectPropsData.sourceVarNamePostfix}" },
        )

As you also can see there is a no-op sentinel line of code in fun whenModelSubelement(...):

when (MODELREFENUM.sentinel) { MODELREFENUM.MODEL, MODELREFENUM.DTO, MODELREFENUM.TABLE, MODELREFENUM.DCO -> {} }

As there is also an enum class MODELREFENUM which is “relevant also for any decision on model-sub-node elements”
it is also added here, so that if you change it, you immediately get a compile error also at this code location
(which under other circumstances you might have forgotten to check and realise much more later whilst regression testing)

Using this convention, if a new model-sub-node is introduced and you add it to the fun <R> whenModelSubelement(...)
automagically all code locations show up in intellij with a compile error, that you have to “adjust”.

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