3 Hierarchical Naming🔗ℹ

A language implemented with the Rhombus expander may have another dimension of name resolution that is orthogonal to different mapping spaces. For example, a language include a hierarchical naming strategy to reach a binding through sequence of identifiers separated by ., and hierarchical references might be used to reach mappings for expressions, bindings, or more. In the initial example in this proposal weather.currently_raining is that kind of access, as is expr.macro and bind.macro.

The example language overloads . for hierarchical namespace use as well as field access, but the Rhombus expander minimizes any assumptions about the form of hierarchical names. A hierarchical reference must start with an identifier or operator that is mapped in the default space to a name root, and that identifier must be followed with the use of a designated name-path operator. A name root is implemented by a transformer that is similar to a prefix macro transformer (as explained in the next section), but it “expands” to a new identifier whose binding is checked in a space that’s suitable to the context—or it expands to a reference to another name root, in which case the new root is expanded recursively.