Merge branch '304' into 'master'

YEP-304: has-turret

See merge request !41

yeps/yep-304.md

 ---
 yep: 304
 title: has-turret
-author: Blaise Thompson
-status: draft
+author: Blaise Thompson <blaise@untzag.com>
+status: accepted
 tags: trait
 post-history: 2020-04-22
+              2020-07-14
 ---
 
-This YEP is a stub.
+# Abstract
+
+This YEP defines the has-turret trait.
+
+This trait has been accepted.
+See built documentation at at [yaq.fyi](https://yaq.fyi/traits/has-turret).
+
+# Table of Contents
+
+[TOC]
+
+# Motivation
+
+Certain positional hardware has an additional turret.
+This trait ensures consistant interfaces for such hardware across the yaq ecosystem.
+
+# Proposal
+
+Turret position is represented using an index.
+Daemons should return busy while turret position is changing.
+
+## state: turret
+
+type: int
+
+## message: get_turret
+
+response: int
+
+Get current turret index.
+
+## message: set_turret
+
+parameter: turret: int
+
+Set the turret to a given index.
+
+# Discussion
+
+Discussion can be found on the [gitlab issue](https://gitlab.com/yaq/yeps/-/issues/21) for this YEP.
+
+# Copyright
+
+This document is placed in the public domain or under the CC0-1.0-Universal license, whichever is more permissive.