Proposal: A propertytype(s) function

[Tortar]

Just like propertynames, I think a propertytypes function could exist to be able to work in tandem with propertynames when one wants to provide/align to an interface by overloading when fieldtypes is not suitable. I think it should work as propertynames, namely by accepting an instance instead of type. And by default it could fallback to fieldtypes(typeof(x)).

[mikmoore]

An improvement over this FR might be to only define the singular Base.propertytype(type, property) = typeof(getproperty(type, property)) (fallback featured here) that returns the type of a specific single property. Given that there is no getproperties function that gets all properties, I don't imagine it's very useful to get the type of every property at once. It also seems like a maintenance annoyance to need to keep the property order matched for propertynames and propertytypes. And some types may have a large/indefinite list of dynamic properties, for which the plural propertytypes doesn't even make sense.

That said, I think that the getproperty overloading business is already messy as it is. One should overload propertynames whenever one changes the properties accessible to getproperty/setproperty (and if those disagree, which should be used to define the propertynames?). Adding yet another function to maintain seems annoying. It will take a lot of time and effort to bring existing types in the ecosystem (or even the majority of them) back to spec after such an addition as propertytypes.

In general, I find non-default property management very tedious and it's not something I use in my own code. X.Y just isn't much nicer than Y(X) yet it's much harder to code and maintain. So I can't say I'm the most relevant party to this discussion in the first place.

[Tortar]

Now that I think at what you say, maybe propertytypes could default to Tuple(typeof(getproperty(x, n)) for n in propertynames(x)) which would be okay to many types which already overload propertynames or even to Tuple(propertytype(x, n)) for n in propertynames(x)) if propertytype is implemented.