Adds a tabbar button that signals the SAB pause atomic, waits for
the eval to unwind via lisp_error/LispErr("paused"), then drops
into saveCheckpoint so the resulting snapshot lands in the visible
chip strip with a user-chosen name. Workers stay alive so the next
input runs immediately — this is the "I want to inspect/save state
but keep working" path, distinct from autoPauseTab's
"I'm leaving this tab" flow.
The button enables alongside cancel whenever an eval is running and
SAB is available; on plain http.server (no COOP/COEP) it stays
disabled and an alert points at make serve-repl. Asm tier gets a
"not supported on asm tier yet" alert since the WAT interpreter
has no in-eval poll site.
Tabbar grid expanded from 8 to 9 columns; comment updated to track.
Tab switching during a long-running eval used to silently abandon
the calc — output stopped streaming, no snapshot, nothing to come
back to. Now setActiveTab pauses the outgoing tab's eval (and
optionally portal-saves the env), terminates the worker, and on
re-entry hydrates + re-fires the original input.
Pieces:
* serve-coop.py + make serve-repl — dev server that emits
Cross-Origin-Opener-Policy: same-origin and
Cross-Origin-Embedder-Policy: require-corp so SharedArrayBuffer
is constructable in the browser. Same headers production needs.
* C tier eval-loop pause poll — c/eval.c grows lumbda_check_pause(),
guarded by #ifdef LUMBDA_WASM. Called at the top of leval()'s
while(1); masked to every 1024th iteration so the polling cost
stays under noise floor. When the JS-library import
js_lumbda_pause_requested returns 1, lisp_error("paused")
longjmps out so module-global env survives intact for the
portal-snapshot that follows.
* SAB plumbing — main thread allocates new SharedArrayBuffer(4),
hands it through worker config → runner.setPauseFlag →
lumbda-c.loader.setPauseFlag → globalThis._lumbdaCPauseFlag.
Atomics.store / Atomics.load on index 0 is the signalling
channel. Falls back to null when COOP/COEP isn't isolated, in
which case pause degrades to a hard worker.terminate().
* autoPauseTab() — on setActiveTab away, snapshots the tier
(C tier with SAB) or hard-cancels (other tiers / no SAB),
stashes tab.autoPause = {tier, blob, inputSrc, savedAt},
terminates the workers so the heap is reclaimed.
* autoResumeTab() — on setActiveTab into a tab with autoPause,
reboots the tier, hydrates MEMFS, runs (portal-load! ...), then
re-fires the original input via sendInput so the eval restarts
from the saved state. Asm + Python paths re-run from scratch
until their poll sites land.
Also closes two UX papercuts from fox: chip ⇣ export icon bumped
from 0.85em muted to 1em green so it's actually discoverable; the
scope toggle now reads "scope: this tab" / "scope: all tabs" so the
button label describes the state rather than a target.
attachStreaming.finalize() used to nuke every streamed line and
rebuild from the eval's final text whenever the streamed buffer
didn't match — which always happened on cancel (no final text)
and on tier errors fired mid-stream (asm 'index out of bounds'
5000 lines into a sieve, say). The user watched output scroll for
30 seconds, hit cancel, and saw it all disappear replaced by
'error: cancelled'.
New finalize logic:
* success + streamed matches full output → keep DOM
* success + no streaming happened → rebuild from text
* error + prior streaming → KEEP streamed divs,
append the error as a single trailing line
* error + no streaming → show error only
Trailing error line gets an .err-line class so just the error is
tinted with --err, the preserved output stays the original colour.
Three UX gaps on the portal-bar closed in one pass plus a defensive
fix on the C tier's heap probe:
* Overwrite guard — saving with an existing name asks 'overwrite?'
with the existing entry's tier + savedAt. Rename via dbl-click on
the chip label; same overwrite guard applies on rename.
* Export / import — a ⇣ icon on each chip downloads it as
<name>.portal.json (opaque blob for c/python, replay-inputs for
asm). A 📁 import button on the portal-bar accepts a .portal.json
file via hidden <input type="file">; collisions prompt overwrite,
decline auto-suffixes (baseName-2, -3, …) so importing a 2nd copy
always lands somewhere.
* Cross-tab restore — a 📂 this tab / 🌐 all tabs toggle switches
the chip strip between the active tab's checkpoints and every
tab's. Global chips render as 'name · tabName' with a dashed
border; click restores the snapshot into the active tab (the
saved cp is passed through restoreCheckpoint's new sourceCp
argument so the chip doesn't need a checkpoints[name] match on
the active tab). Edit/delete are hidden in global mode — the
user switches to the owning tab to manage chips.
* heapStats defensive — wasm/c/lumbda-c.loader.js now returns null
when module.HEAPU8 isn't live yet (caught by the heap poll firing
during the tiny window between tier reboot and Module init), so a
restore no longer surfaces 'Cannot read properties of undefined
(reading byteLength)' as a TypeError.
Smoke-tested headlessly: overwrite confirm fires with the expected
message; rename via dblclick swaps the label; ⇣ produces a download
named '<name>.portal.json'; toggle shows both tabs' chips with the
'· tabName' annotation; import round-trips back into the receiving
tab. Zero page errors across the full flow.
Previously align-items: center centered the textarea while the sigil
sat top-aligned with padding-top — single-line input rendered the
sigil visibly higher than the input baseline (see screenshots from
07-52-55 and 07-53-20). Now:
* .prompt-bar uses align-items: baseline so the sigil's text
baseline tracks the textarea's first-line baseline in both 1-line
and N-line cases.
* .prompt-sigil shrinks font-size from 0.95em to 0.92em (matching
the textarea) so cap-height differences don't push baselines
apart.
* line-height: 1.4 pinned on both so baseline geometry stays
predictable (browser default for textarea is 'normal' which
varies per-font).
Until now the input was pinned at rows="1" — paste a 40-line program
and you edited it through a one-line keyhole. autosizeInput() now sets
height to scrollHeight on every input event, history navigation, and
post-send clear. CSS min/max-height (1.5em / 30vh) clamp the bounds;
once the textarea hits 30vh it scrolls internally instead of pushing
the prompt-bar off screen.
Prompt sigil top-aligns (align-self: start + matching padding-top) so
the λ> stays on the first line of input instead of drifting to
vertical-center as the textarea grows.
Smoke-tested headless: 1-line stays 22px, 6-line grows to 97px, 40-line
caps at 216px (30vh of 720px) with scrollHeight 608 (internal scroll
engaged), send empties back to 22px. Zero page errors.
Adds a portal-bar to the REPL between tabbar and transcript: a save
button + chip strip showing all saved checkpoints for the active tab.
Click a chip to restore, click × to delete.
Per-tier strategy:
* c, python — call the tier's (portal-snapshot! NAME), then read the
JSON blob out of MEMFS (Emscripten/Pyodide FS) and stash it in the
encrypted vault entry. Restore reverses: hydrate MEMFS, then
(portal-load! NAME) merges the bindings into the live env.
* asm — no portal serializer in the WAT tier yet (would need a
Cheney-aware walk). Falls back to transcript replay: save snapshots
every successful prior input, restore reboots the tier and re-evals
them in order.
Plumbing:
* Worker bridge: new portal-save / portal-load message kinds wire
MEMFS reads/writes to the main thread.
* runner.js exposes portalSave / portalLoad — null when a tier
hasn't implemented portals (asm stays grey).
* C tier: replace EM_JS with extern + --js-library for js_lumbda_bend_call
(EM_JS-generated declaration was unreachable from wasmImports at
instantiate time, browsers threw "import object field ... not a
Function"). FS added to EXPORTED_RUNTIME_METHODS so JS can reach
pyodide.FS / Module.FS for MEMFS I/O.
Smoke-tested all three tiers headlessly: save → chip render → restore
round-trips clean on c / python / asm, zero console errors.
Step 1 of the GC effort. Each tier loader now exposes heapStats():
- asm-wasm — lumbda_heap_used / lumbda_heap_total wat exports
- c-wasm — emscripten linear memory size (no free path right now,
so used = total; documented in the loader)
- python — pyodide module linear memory size; CPython GC cycles
this naturally
Worker handles a "heap" message kind that round-trips the active tab's
loaded tiers; repl tabbar shows a compact "py 12M · c 32M · asm 4M"
strip next to the buttons. Polls every 2s.
Doesn't solve the leak — just makes pressure visible so the user knows
when to use "reboot tier". Real GC (Cheney over the WAT bump allocator,
Boehm-em or custom mark-sweep for c-wasm) coming next.
New: wasm/tests/parity-cross-tier.mjs runs the parity-corpus.mjs (216
test cases tagged by whitepaper section / R7RS concept) against three
tiers — native python (reference), c-wasm, asm-wasm — and fails on any
unknown divergence. Known gaps live in KNOWN_DIVERGE so the table stays
green while the bignum / call/cc / etc. work proceeds.
Wired into `make wasm-test` so a regression against any spec claim gets
caught before merge.
Bugs caught and fixed:
- python remainder: was `signed_a % signed_b * sign(a)`, which double-
applied the sign of a (python's % floors) — gave -3 for (-17, 5)
instead of the R7RS-correct -2. Now uses abs() on both sides.
- asm-wasm modulo: was i32.rem_s (truncated, remainder semantics)
where R7RS modulo wants sign of divisor. Added the "if rem and
divisor disagree on sign, add divisor" branch.
Cross-tier numbers after fix:
216 passing
3 known diverge: expt-2-100, expt-3-50, big-arith — all asm-wasm
(no bignums on the asm tier yet; whitepaper §2.1 claim still open)
0 fail
REPL layout: body is now the scroll container, prompt-bar is
position:fixed at the viewport bottom so it doesn't get pushed off
screen by a long transcript. Empty space above the prompt on a fresh
session reads like a terminal.
All other tests still pass: 20 unit, 8 integration, 11 functional.
Header (logo + tagline) is the only fixed region. Footer removed.
Everything else — tab bar, transcript, prompt — now lives inside one
.repl-stream scroller. A fresh session shows the prompt right under
the tabs near the top; as entries arrive the prompt drifts down with
them. Tabs use a dashed bottom rule instead of a heavy bar so they
read as the start of the stream rather than a separate chrome strip.
Reads as one continuous stream now. Each entry is just:
λ> <input>
<output> ; tier · NNms
No left border, no boxed cards, no side-column tier label. Output
indents under the prompt (3ch) using monospace ch units. Tier+time
render as a Lisp-comment-style suffix in muted color.
Prompt bar: borderless textarea on the code-bg surface so the input
visually joins the transcript above. Placeholder cut to "(+ 1 2)" —
the surrounding text already explains the semantics.
Multi-line inputs keep prompt continuation marks ("..").
- bend URL and vault password now share a single config-bar row, split
via a 2-column grid (1fr 1fr). Vault still hidden when free-form
isn't selected; just collapses its column.
- Every flexbox removed. Every multi-child container uses CSS grid:
.controls, .config-bar, .bend-bar, .vault-bar, .panes, .pane,
.brand, .tabbar, .tabs, .tab, .transcript, .entry, .tier-output,
.prompt-bar, .lock-screen, .lock-card, .lock-row.
- Added `[hidden] { display: none !important; }` so the ephemeral
button on the REPL lock screen actually hides the modal. Without
this, .lock-screen's `display: grid` overrode the hidden attribute's
UA-default display: none.
Interactive REPL at lumbda.com/repl with:
- multi-tab sessions (click + to add, × to close, double-click to rename)
- per-tab tier selector (python/c/asm/all-three race)
- persistent transcripts encrypted in localStorage via Web Crypto
(PBKDF2 + AES-GCM, vault id = SHA-256(password || device-salt) —
same pattern as unsandbox's vault-encryption-design.md, native
crypto.subtle API instead of CryptoJS)
- ephemeral mode (skip vault, transcripts vanish on reload)
- one worker per (tab × tier) — state persists across evals in a tab
- reboot tier button (terminate this tab's worker, fresh state next eval)
- cancel button (kills the running worker in active tab)
Home page now links to both /playground/ and /repl/.
Tier state itself does NOT persist across reloads — the transcript does,
but defines/set!/hash-tables vanish with the worker. Portal save/resume
in WAT (deferred) will let a tier session survive close+reopen.
