Three new SX primitives wrapping Unix socket APIs:
- socket-connect host port → "sockN" (TCP client)
- socket-server ?host? port → "sockN" listening socket (SO_REUSEADDR, backlog 8)
- socket-accept server-chan → {:channel :host :port}
Sockets reuse the channel_table from Phase 5, so existing channel-read/
write/close/select all work on them. Host arg supports localhost,
0.0.0.0, IPv4 literal, or gethostbyname lookup.
Tcl `socket` command:
- socket host port → TCP client
- socket -server cb port → listening socket; auto-registers a fileevent
on the server channel that fires `_sock-do-accept SRV CB` per readable
event. _sock-do-accept (internal) accepts the pending client and calls
the user's callback as `cb client-chan host port`.
puts channel detection now also recognizes "sockN" prefix (was only
"fileN") and dispatches to channel-write.
+4 idiom tests: socket-server-fires-callback, socket-client-server-
roundtrip, socket-server-peer-host, socket-multiple-connections.
358/358 green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
New SX primitive io-select-channels(read-list write-list timeout-ms) wrapping
Unix.select on the registered channel table. Returns {:readable :writable}.
Tcl event loop implemented purely in Tcl (no sx_server.ml changes):
- fileevent $chan readable|writable script (or "" to unregister)
- fileevent $chan event (1 arg) returns the registered script
- after ms script — schedule one-shot timer
- after ms (no script) — sleep, driving event loop in the meantime
- vwait varname — block until var is set/changed, handlers run between polls
- update — non-blocking event drain (poll-timeout=0)
State on interp: :fileevents (list of (chan event script)) and :timers
(sorted list of (expiry-ms script)).
tcl-event-step is the inner loop: expire timers, build fd lists from
:fileevents, call io-select-channels with computed timeout, run ready
handlers. vwait polls every 1000ms or until var changes.
Scoped to script mode by design — vwait from inside a server-handled
command does not interact with sx_server's stdin scheduler.
+5 idiom tests: after-vwait-timer, after-multiple-timers-update,
fileevent-readable-fires, fileevent-query-script,
after-cancel-via-vwait-timing. 354/354 green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
11 new SX primitives in sx_primitives.ml wrapping Unix.openfile/read/write/
lseek/set_nonblock: channel-open/close/read/read-line/write/flush/seek/tell/
eof?/blocking?/set-blocking!.
Tcl runtime now uses real channel ops:
- open ?-mode? returns "fileN" handle (modes r/w/a/r+/w+/a+)
- close/read/gets/puts/seek/tell/eof/flush wired through
- new fconfigure command supports -blocking 0|1
- puts dispatches to channel-write when first arg starts with "file"
- gets command registration fixed (was pointing to old stub)
eof-returns-1 coro test updated to match real Tcl semantics (eof flips
only after a read hits EOF).
Test runner timeout bumped 180s→1200s (post-merge JIT is slow).
+7 idiom tests covering write+read, gets-loop, seek/tell, eof-after-read,
append mode, seek-to-end, fconfigure-blocking. 349/349 green.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
