tree 4c9a19943cf96fe9866bb34f11bdef1ef2fb8f06
parent 56c994db54246ff62539a862460274fcc347dbdf
author Marcel van Lohuizen <mpvl@golang.org> 1583685579 +0100
committer Marcel van Lohuizen <mpvl@golang.org> 1587626095 +0000

doc/ref/spec: alternative syntax for definitions

This change is prompted by the need to have separate namespaces
for definitions and regular fields. The solution is inspired by
Go's exporting rules and introduces a lexical distinction
between the identifiers of the two field types.

Advantages:

- puts regular fields and definitions are in a different namespace
- this makes much nicer mappings possible for JSON schema
  and even OpenAPI
- makes exporting rules sensible and workable
- clarity what a reference refers to (similar to casing rules in Go)
- removes confusing "::"
- simplifies spec a little bit
- already partly specifies the syntax for associative lists for free
- reintroduces hidden fields as a special kind of definitions.
  This simplifies the transition away from hidden fields, which
  would be quite cumbersome, as it is a frequently used feature.

```
   #C: 3
}

a: #MyDef.#C
```

Issue #339

Change-Id: I98e187219f720ccec6af6fc9808d5545a9595c21
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/5480
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>