Indexing In UCL
I've been thinking a little about how to support indexing in UCL, as in getting elements from a list or keyed values from a map. There already exists an `index` builtin that does this, but I'm wondering if this can be, or even should be, supported in the language itself. I've reserved `.` for this, and it'll be relatively easy to make use of it to get map fields. But I do have some concerns with supporting list element dereferencing using square brackets. The big one being that if I were to use square brackets the same way that many...