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.
Adds tag-9 rational type to the asm tier. Layout [tag=9, num:i32, den:i32].
make_rational normalizes via gcd and collapses to a fixnum when den
reduces to 1, so 14/2 stays as 7.
Arithmetic (+, -, *, /, =, <, >, <=, >=) now promotes to rational when
any argument is rational. Mixed fixnum/rational lifts the fixnum
accumulator into a rational mid-loop so (+ 1 1/2) returns 3/2, not 1/2.
Reader parses "67/7" literals via the existing atom path: after the
numerator's digits, if '/' follows we keep reading the denominator and
hand back a normalized rational. Falls through to symbol if either side
isn't all digits.
Printer renders rationals as "n/d". equal_p compares numbers by value
(1/2 = 2/4, 3 = 6/2). is_number / number? cover both fixnums and
rationals.
eval now treats rationals as self-evaluating — without this, '1/3'
parsed correctly but evaluated to VOID.
Mandelbrot demo: switched from (/ a b) to (quotient a b) for the
fixed-point math. The demo had been relying on integer truncation
that '/' no longer provides on tiers with R7RS-correct rationals.
Bignums still pending: 31-bit num/den overflows with huge denominators.
Real lift comes with the bignum task in the C tier (which has them) or
a new bignum module in the WAT.
Cross-tier check still hangs on the bigger TCO-heavy sections of
functional.lsp — separate from rationals. Will keep grinding.
Tests: unit 20/20, integration 8/8, functional 11/11.
WASM tail-call instruction wired into every tail position:
if branches, eval_begin last expression, all special-form dispatchers
(cond/when/unless/case/let/let*/letrec/begin/and/or), function
application's $apply, and apply's closure-body $eval_begin.
wat2wasm + wasm-validate now use --enable-tail-call.
Reader fixes:
- Dotted pair syntax: (a b . rest) parses as a real dotted list.
Without this, variadic params and other dotted-cdr forms parsed
as 4-element proper lists.
- Stray ) at top level advances source_ptr instead of spinning
forever. Found via bisection of functional.lsp under TCO.
- eval_args guards against non-pair tails so a misplaced dotted
argument (e.g. an unexpanded macro template) can't deref garbage.
Cross-tier numbers (wasm-test-functional-cross):
before: 93/111 reached, stack overflow on (ack 3 4)
now: progresses through the full TCO section, deep let, named-let
to 100k, mutual recursion to 200k. Still climbing.
Bend gpu demo:
6th playground option ("bend (gpu dispatch) ⚡") ships a SHAKE256
fan-out at 1M inputs via (bend!-call ...). Run button is GUARDED:
if no bend URL is configured, refuses with
"set a bend URL first — this demo is GPU-only by design".
Protects customer machines from burning minutes on a workload the
local tiers cannot finish in reasonable time.
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.
bend!-call from the WAT tier
- New WAT import: (import "env" "bend_call"). The host loader supplies
a sync XMLHttpRequest that POSTs the payload to a configured URL
(workers only — sync XHR isn't allowed on main thread).
- New primitive (bend!-call "<payload>") returns the response as a
lumbda string. Works in playground and REPL once the bend URL is
saved in the new top bar.
- bendUrl persists in plain localStorage (not encrypted — it's a
server address, not a secret).
- Tests stub the import with a no-op so unit / integration / functional
suites keep instantiating cleanly.
Playground + REPL zoom 133% by default
- html { zoom: 1.33 } so the styleguide sizes read comfortably without
requiring browser-level zoom.
Free-form default = cross-tier assertion runner in Lisp
- The default editor content for "free form" is now a small assertion
framework matching tests/functional.lsp's PASS/FAIL convention. A
starter the user can extend, runs identically on the three tiers.
C tier + Python tier (bend) are wired through the runner stub; full
bend integration in those tiers comes next once their loaders learn
about setBendUrl.
Adds (write x) and (write-string s) primitives. write quotes strings
and #\-prefixes chars — what tests/functional.lsp's assert-equal
uses to print failures.
New target: make wasm-test-functional-cross (also rolled into wasm-test)
runs the 205-assertion tests/functional.lsp against each WASM tier and
reports pass counts:
c-wasm: 205 / 205 (full parity with native c)
asm-wasm: 93 / 111 reaches mid-suite before stack overflow on
a deeply recursive test; the 84% it reaches
passes. Documented progress toward full parity
with asm/lumbda.s.
The runner exit-soft on the asm tier — it's a measurement, not a gate.
Free-form radio adds a 5th demo slot. When selected, a vault bar appears
under the controls: enter a password, "unlock" derives a per-device
vault and decrypts (or creates fresh). Edits in the editor auto-save
350ms after typing stops. Reload + same password restores the code.
Same Web Crypto stack as /repl/ (PBKDF2 + AES-GCM, vault id =
SHA-256(password || device-salt)).
Layout: one shared vertical scroller — code pane and output pane both
grow with content, the body scrolls. No more independent in-pane
scrollers fighting the page.
Home page split into "Demo" and "REPL" sections with their own CTAs.
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.
WAT prelude (evaluated after primitive binding at init) adds:
map, filter, fold-left, fold-right, for-each, any, every,
count, find, sort (quicksort), vector-map, vector-for-each,
vector-fill!, string-split, string-trim, string->list,
random-state, assert-equal/true/false.
Higher-order ops are now Lisp-defined, not primitive bloat. Eval-time
parse + bind happens once per WASM instance startup.
Playground output: per fox, single append-only column instead of
3-up grid. Tiers still race in parallel workers; whichever finishes
first appears first in the output. Live ms counters move to the status
bar (python 312ms · c 47ms · asm 89ms).
Two new heap tags:
7 = vector [tag, len, elem_0, elem_1, ...] 8 + 4*len bytes
8 = hashtable [tag, count, alist_ptr] 12 bytes
Vector primitives (88-95):
vector, vector?, make-vector, vector-length,
vector-ref, vector-set!, vector->list, list->vector
Hash table primitives (96-106):
make-hash-table, hash-table?, hash-table-set!,
hash-table-ref, hash-table-ref/default,
hash-table-delete!, hash-table-exists?, hash-table-size,
hash-table-keys, hash-table-values, hash-table->alist
Hash table lookup is linear (equal? on each key) — fine for browser-scale
demos. Same linear-scan caveat as the symbol intern; would warrant a real
hash function at scale.
print_value now renders vectors as #(a b c) and hashtables as #<hashtable>.
One Worker per tier (python/c/asm). "All three" mode dispatches
Promise.all so the tiers race on independent threads — a slow Pyodide
no longer blocks C and asm. Each tier-block ticks its own ms counter
until its worker resolves.
Output grid: 3 columns when 3 tier-blocks render, else stacked.
Status bar announces the winner: "ok — c won in 47 ms".
Cancel terminates every active worker.
User-visible changes
- Cancel button — terminates the running worker. Pyodide's slow mandelbrot
no longer freezes the UI; click cancel and the elapsed counter freezes
at "(cancelled @ NNNN ms)".
- Live ms counter ticks per animation frame while a tier is busy, so the
Pyodide tier's ~5-15 s wait is visible instead of looking hung.
- Restyled to match lumbda.com: chunkfive wordmark, --green: #227842
(light) / #5ec07a (dark), lumbda-logo-green.png, lowercase "lumbda"
everywhere. Pulls fonts/chunkfive locally so the playground stays
self-contained.
Architecture
- All tier evaluations now run inside a Web Worker (wasm/app/worker.mjs)
so the main thread stays responsive. Cancel = worker.terminate(); next
eval respawns a fresh worker.
- Loaders use new URL("./...", import.meta.url) so paths resolve against
the loader file's own location — works identically in window and
worker contexts, no baseURL argument needed.
- C tier Emscripten build flipped to EXPORT_ES6=1; loader uses dynamic
`import()` of the factory module. Integration test updated accordingly.
- Python loader uses `import("pyodide.mjs")` (ES module) instead of
document.createElement, which doesn't exist in workers.
Bug fixes
- Asm tier state leak: running the same demo twice on a cached WASM
instance produced corrupted output (every other cell on row 2+ rendered
as " " instead of the expected shade char). Root cause: top-level eval
passed `global_env` as the env, so closures captured stale globals;
fixed by passing NIL — env_lookup falls back to the CURRENT global_env
via its existing two-pass walk. Multi-run regression added to the
functional test suite.
- fib-ack demo: (ack 3 4) was too heavy for Pyodide (minutes). Cut to
(ack 3 3) + (fib 20) max so every tier finishes in seconds.
Test discipline
- Root `make test-all` now includes `wasm-test`. Adding a language
feature without exercising it on all six implementations is no longer
possible by accident.
- Functional suite: 11 assertions (was 10) — adds asm multi-run stability.
- Integration + unit: still 20 + 8.
Adds a parallel build of all three Lumbda implementations to WASM, a
single-page playground at www/playground/, and a verified test suite.
Tiers
- Python: Pyodide (CPython-in-WASM) hosting lumbda.py
- C: Emscripten build of c/ (tree-walker + bytecode VM; jit.c
stubbed, gc.c uses its existing no-Boehm fallback)
- Asm: hand-written asm/lumbda.wat — parallel impl to asm/lumbda.s.
Reader, eval (lambda/define/if/cond/let/and/or/quote/set!),
recursion across mutated top-level env, bump allocator with
memory.grow, 24 primitives. ~1200 lines of raw WAT.
SPA (wasm/app/, deployed to www/playground/)
- CodeMirror 6 editor (Scheme highlighting) on left, output on right
- Radios: 4 demos (Mandelbrot, Fib+Ack, Sieve, self-interp meta-eval)
x 4 tiers (Python | C | Asm | All three)
- All-three mode renders the three tier outputs side by side with
per-tier elapsed timing
Tests (38 verified assertions)
- 20 unit (Node): per-tier module loads, eval smoke
- 8 integration (Node): each demo on c+asm WASM byte-matches the
canonical native Python run
- 10 functional (Playwright headless Chromium): page mounts, every
demo runs on every tier, all-three renders
Makefile
- Root targets: wasm-build, wasm-test, wasm-test-fn, wasm-serve,
wasm-deploy, wasm-clean
- wasm/Makefile orchestrates the three tier builds; deploy copies
dist/ into www/playground/
Asm tier notes
- WAT linear symbol intern + linear env lookup is MOAD-0001 at scale;
documented in the asm/lumbda.wat header and in the SPA footer. The
demos hit ~30 globals so the linear walks are cheap enough.
- Bump allocator never frees (matches asm/lumbda.s heap discipline);
memory.grow expands by 1 MB chunks. Browser tab tears down at unload.
Toolchain (developer prerequisites)
- Emscripten 6.0.0 via emsdk at ~/git/emsdk
- wabt 1.0.36 at ~/git/wabt
- Playwright for functional tests (symlinked from ~/git/agnt)
