- Facet IDs are now lists so arbitrary ancestors can be computed with
repeated application of cdr
- `stop-facet` is new and untested, other than that `stop-when` is
refactored to use `stop-facet`
- *all* matching stop-when instances run now; the limitation that
exactly one instance should match is lifted.
- roughly, (stop-when E X ...) === (on E (stop (current-facet-id) X ...))
Remaining to be done: fix `terminate-facet!` to do the right things in
the right order.
first: run facets/endpoints to determine the new facet tree and any
actions (messages, spawns)
second: use new facet tree to determine assertions and subscriptions
This makes sure that all field updates are visible to
assertions/subscriptions.
Actors in the upside down may communicate with each other, but not the outside
world. However, the outside world can see what actors in the upside-down are
saying. The intention is to use this facility for testing.
[1] (http://strangerthings.wikia.com/wiki/Upside_Down).
A recent change to Racket must have changed the way `for` expands,
because now in conjunction with `local-expand`, we see *effectively* a
`(begin (values) (void))`. This isn't a problem usually, but in
`#lang syndicate`'s `module-begin` context, we split apart `begin`s
and examine their constituents, leading to examination of something
that will ultimately yield 0 values.
The change accepts either 0 or 1 values when collecting actions for
the module's main boot actor to execute. More than 1 value yielded by
such an expression is still considered an error. Currently, it gives
unhelpful error location information; a future refinement might be to
make the error reporting for this (rare) situation more helpful.
Tony Garnock-Jones
Sam Caldwell