recursively walking a case class hierarchy

[Mark Kegel]

I am trying to walk a case class type hierarchy at runtime to find if certain fields exist or not -- basically I'm writing a simple query of fields in the type hierarchy. I would prefer not to use reflection given the runtime overhead, but I haven't been able to figure out how to get shapeless to do what I require.

At runtime I start with a dot-separate String query, say "maker.founded". Let's say this query is being executed over these case classes, with Wine as the root type:

case class Maker(address:String, founded:Int)

case class Wine(name:String, maker:Maker)

So the query "maker.founded" should find a field "maker" of type Maker in the Wine class and then a field "founded" of type Int in the Maker class.

I've been able to get the first level of key names by following the pattern here: http://stackoverflow.com/questions/27434302/extract-label-values-from-a-labelledgeneric-instance

However, its not clear to me how I recurse into the next level so that I can enumerate the keys of the queried field dynamically.

[Miles Sabin]

Hi Mark,

This mailing list has been more or less deprecated in favour of the
shapeless gitter channel ... you'll find lots of people there who'll
be able to point you in the right direction,

https://gitter.im/milessabin/shapeless

Cheers,


Miles

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[Mark Kegel]

Oh thank you! I'll my question there.