ExploreFields traverses named fields in a map (or equivalently, struct, if traversing on typed/schema nodes) and applies a next selector to the reached nodes.

ExploreIndex traverses a specific index in a list, and applies a next selector to the reached node.

ExploreRange traverses a list, and for each element in the range specified, will apply a next selector to those reached nodes.

ExploreRecursive traverses some structure recursively.

RecursionLimit is a union type that captures all data about the recursion limit (both its type and data specific to the type).

Reifiable provides a feature detection interface on selectors to understand when and if Reification of the datamodel.node should be attempted when performing traversals.