- spec-generic StreamConnection translators, for simple TCP API
- `when` -> `on`, better use for event-expanders
- Removal of special processing of `at`, making `this-target` properly lexically scopeable
- TcpListenError and handling of tcp-listen errors
- SYNDICATE_COLUMNS for pretty-printing of dataspace traces
- Repair driver-support.rkt thread shutdown turn-taking
- Refinements to stream protocols and implementation
- Improvements to syntax location preservation in syntax.rkt
Instead of having restriction-paths as an adjunct to a change, they're
more propertly a part of each assertion itself. The new `skeleton.rkt`
keeps an optional restriction-path with each assertion, treating it as
distinct from its underlying assertion. The idea of not signalling
changes in assertions that have a restriction-path mismatch stays.
This is used when relaying: because we don't have access to the full
term, but only the projection results, we are inserting various
`(discard)`s. This is the cause of the failure in
`test/core/nesting-confusion.rkt`.
By adding `restriction-path`, we allow the inner dataspace to avoid
showing a reconstructed term to endpoints that might be able to
observe the reconstructed parts.
An alternative implementation approach is to generalize patterns in
the inner relay actor, translating all `(discard)`s into captures,
which would give us all the relevant terms that we need. The way I've
chosen to go (or at least, to try out) allows us to potentially keep
the "efficient" idea of just transmitting pattern-bound values across
some network link connecting dataspaces. The alternative would require
transmission of the full assertions, eliding no irrelevant detail.
The `add-endpoint!` call is changed in two ways:
- the old `assertion-fn` has become `update-fn`, yielding both
an assertion *and* an optional handler, because if the handler
depends on a field which changes, previously the handler wasn't
being updated
- a new parameter, `dynamic?`, can be set to #f (it's usually #t)
to ensure that the assertion and skeleton-interest are calculated
only once ever, and are not connected to the dataflow machinery.
The first change makes it possible for the `(later-than (deadline))`
pattern, where `deadline` is a field, to work; the second change makes
`during` and `during/spawn` work correctly in the face of field
updates.
We now explicitly track *committed* assertions of each actor in a new
field, `actor-cleanup-changes`. Each time a patch action is
*performed*, `actor-cleanup-changes` is updated. When an actor quits,
it enqueues a special new kind of action, a `quit` action.
When a `quit` action is performed, any remaining contents of
`actor-cleanup-changes` are processed in order to fully remove any
leftover assertions. (Leftover assertions will only arise in
exceptional cases: when some stop-script or facet boot-script raises
an uncaught exception.)
As part of this commit, we undo the effect of commit 8624047.
This repairs a bug regarding crashes in a new actor's boot-proc.
Previously, if boot-proc raised an exception, the initial assertions
would stick around forever. By changing adhoc-assertions to a bag
rather than a set, and putting the initial assertions in the bag, we
put them somewhere they are guaranteed to be processed during actor
termination, even when an exception is signalled during boot.
This is an API change wrt the previous Syndicate implementation:
assert!/retract! now have bag semantics, not set semantics. We can add
set-semantics APIs if we end up needing them, of course, layered on
top of the bag implementation.