I have a question about the intent of something that I consider important to determining for YPath:

If a YPath query is applied against a YAML representation graph, has implicit typing been performed or not?

I'm not sure if this has even been considered yet. And I'm not sure if we have to make a decision one way or another. But it's worth discussing.

Consider this example.

- !rational
  numerator: 1
  denominator: 3
- !rational
  numerator: 17
  denominator: 7

This a pair of rational numbers, but they are represented as a mapping of numerator and denominator. So we might want to find numbers greater than 1, or we might want mappings whose numerator is less than 10.

I will assume they YPath queries may wish to be made against a serial YAML stream, or against Native in memory data structures. In the former case we need to compose the representation, and in the latter we need to represent it. Where does type transforming and detransforming happen and how we tell YPath how far to go?