The trio the author decided on 2026-09-20 is now all built: def is CL's
defparameter — its initialiser runs on every daemon re-run, unguarded, so
an edited initialiser repaints the same storage on C-c C-c plus re-run —
defonce (Clojure's name for CL's defvar, per the author) initialises once
behind the .init~once. flag, and defconst stays the image.
One parse arm reads both forms; the difference is Ast.reinit, carried to
Tast.global's grerun. Emit.startup_plan gives a def no guard flag, and
Check.check_global lifts every def initialiser — zero and literal
included — into global/<n>, so the host's startup reaches it through the
function cell and a re-evaluated def swaps it (Session's def_inits;
Emit.redefinition declares the cell for a non-sibling target). The old
defvar spelling is refused with the rename and both compiling spellings,
and every program, test, doc and editor list is swept — except sand.flan,
the author's live WIP, whose seven defvar lines are flagged in FIX.org
and keep its three dependent tests red on this branch.
[flan_merged_park] drained the agent's ring on one of the two flags that
wake it. [program_poll] — which an expression sets, by way of [Program.wake]
— polled and went back to sleep; [program_asked] broke out of the loop and
re-entered [flan_program_main] with the queue untouched. A plain
redefinition sets neither, so a body delivered to a parked program was still
in the ring when the run it was delivered for started, and installed at that
run's first frame boundary instead: everything main did before its first
(agent/poll) ran the body the person had already replaced, and the change
showed up one run late. A redefined main is the whole of a run, so it would
have had to be asked for twice.
Both flags drain now, and the exit drains before it leaves. The re-run is
still tested first and cannot be starved: the flag is latched at the top of
the round and nothing in the round can clear it.
The transcript row in test_dev.ml asserted the old ordering by name — two
lines out of the second run, the first of them the stale body — so it is a
line shorter now, and the absence of that line is the claim. The park-note
fixture grew a print of the redefinable body before its first poll, which is
what makes the new row able to see which body the re-run started with.
This is what the note the delivery is answered with has been promising: a
module queued against a park installs no later than the program's next run.
It now installs before that run's first frame rather than during it.
[merged_serve] waited up to ten seconds for the program to bind agent.sock
before it started [accept_loop]. The listening socket was already up, so an
editor connected fine and then heard nothing: every first request of every
session cost the whole wait when the program calls (agent/start ...) late —
sand.flan starts it after rl/init-window returns — or never.
Nothing the editor asks needs that socket. In one process a delivery is a
call into flan_agent.c, not a connect, and the two-process daemon has already
waited for the bind in [two_process] and fails if it never comes. What the
wait was for is the sentence a program with no agent deserves, and a sentence
does not have to be in front of the loop to be said. So it is a deadline the
session passes ([agent_check]) rather than a wait it does: read from the
accept loop between connections and from [serve] before each request, because
an editor holds one connection for a whole session and the loop is not
cycling while it is attached. No thread, for the reason lib/dune gives about
what the merged link does to this library's dependencies.
Delivery stays honest either way. A program that links no agent at all
refuses through [over_socket]'s ENOENT, as before. One that has the agent but
has not started it takes the module into the ring and is answered with a note
that promises the poll and not a frame: a program with no (agent/poll) in it
never installs this, and "at its next frame boundary" would be the reply that
makes a redefinition look applied when it is not. C-x C-e's five-second
timeout gets the same distinction instead of asking whether a program that
has not got to its loop yet is calling the poll in it.
And the note a parked program's delivery carries is now said once per park.
A finished program is parked, so re-evaluating while a run's output is on the
screen repeated a paragraph on every C-c C-c. The first delivery of each park
explains itself; the rest say the one line that is the claim. [rerun] clears
the flag as well as [eval] does, so a new park is a new reader.
