Six fixes across the toolchain, surfaced by lib/lisp porting work.
1. f64 compound assigns (`acc += d`, `-=`, `*=`, `/=`). Both stages
load slot → X1, OP X0 into X1, store back (ADDSD/SUBSD/MULSD/
DIVSD are reg-reg only). Previous MOVSD-overwrite dropped the
OP. Locals and top-level lets.
2. Top-level `[N]u8` arrays + `&arr[i]`. let_emit_size grows a
TY_ARRAY branch so zero-init DATAW lands; cgindex / N_INDEX
store / `&base[i]` all detect a global array base and use
LEAQ name(SB) instead of LEAQ (BP). TK_AMP no longer pre-
evaluates the operand as a value-load — `&base[i]` computes
base + i*esz directly. Unblocks Hare's static-buffer pattern:
strconv.{u64,i64,f64}tos graduate to module-level `*_buf`
arrays and return owned views.
3. Cross-module `pkg.Enum.MEMBER`. Nested N_DOT chains that
don't fold to a known shape now emit `MOVQ <leaf>(SB), AX`
(mirrors the bare-IDENT unresolved fallback), so isolation
probes — and the test 990 cgen-match floor — stay consistent
across stages. strconv exposes `base` as a real `enum i32`;
callers updated. The `main` exemption (linker entry-point
keeps bare name even when not exported) mirrors C-side
collectmods into selfhost cgendecl.
4. Sum-typed parameter ABI. lib/bytes.{index,rindex} take
`(u8 | []u8)` needle; lib/strings.byteindex / rbyteindex take
`(str | rune)` needle (Hare-shaped; the byte-wise misnomer
`index` is dropped). tagged_arg_size cap bumps to 48 (6 int
regs), with a new partial-fit branch on the callee: when an
N-word tagged arg overflows remaining regs, fill what fits and
stitch the rest from positive BP offsets. scanlocals MCASE
handles slice binds (24B) and walks each arm with a saved /
restored seenmark set so two arms naming the same local each
get their own slot — matches cstage's per-arm scope reset.
5. 4-reg tagged-return ABI (AX=tag, DX=word0, CX=word1, R8=word2),
up from 3 regs. Slice-payload variants (`([]T | E)`, slot 32B)
round-trip ptr/len/cap end-to-end. Every receive site updates:
let-init via cgwidentaggedstore, match scrutinee spill, cgindex
tagged-element load (both N_IDENT and fallback bases),
pushargsrev tagged-ident arg (reads word count from slot size),
cgreturn slice variant in the shuffle path.
6. `expr: TaggedAlias` is a widening, not a re-interpret. C cgen +
selfhost cgwidentaggedstore peel an N_CAST whose destination IS
the union — so cgexpr's natural shape (str: AX=ptr, BX=len;
slice: AX=ptr, BX=len, CX=cap) is consumed by the matching
concrete-variant branch instead of being misread as a tagged
AX/DX/CX triple. Inner casts to a concrete variant (`7: i32`)
keep their type for proper tag lookup. `[N]Alias` arrays
resolve element size via slotsize + aliaslookup, and aliaslookup
strips a `pkg.` prefix so cross-module references work.
lib/fmt grows `formattable = (i64 | str | bool | rune)` plus
`printv` / `printlnv` taking an explicit `[]formattable` slice (the
receive side of Hare's `args: formattable...`). Call-site variadic
gather isn't wired — callers either hand-build the slice or compose
strconv.i64tos + strings.concat.
700_e2e: 114 → 123 rows (f64 compound, top-level u8 arrays + `&buf[i]`,
pkg.Enum.MEMBER, sum-typed (str|rune) and (u8|[]u8) params, 4-reg
slice-return ABI, formattable array). 26/26 tests, bootstrap stable
through ww4.
i64tos / u64tos / f64tos return a fresh owned str (caller frees via
os.free) instead of writing into a caller-supplied [N]u8. Adds typed
variants (i32tos / i16tos / i8tos and u32 / u16 / u8) and the missing
base parameter on stoi64 / stou64 + typed parse wrappers.
Base values are exported as plain-i32 `def`s (strconv.DEC,
strconv.HEX_UPPER, ...) rather than a `base` enum: cross-module
`strconv.base.DEC` chains miscompile in the cstage cgen — it emits a
memory load through `base(SB)` rather than inlining the constant.
The Sdef path resolves correctly, so callers say `strconv.DEC` and
both cgens lower to an immediate.
Also renames strings.byteindex / rbyteindex to strings.indexbyte /
rindexbyte, matching bytes.indexbyte and reserving the Hare name
`byteindex` for the future `(str | rune)`-needle shape.
fmt drops printint / printlnint / fprintint — those were stand-ins
for variadic `fmt::println(42)`; with the owned-str graduation the
substitute is one call: `fmt.println(strconv.i64tos(42, strconv.DEC))`.
strerror is sketched in a comment but not shipped — match arms over
the wider `error = !(invalid | overflow)` union still expose a
cstage-vs-wwstage spill divergence.
Makefile sets WW_W6C=$(BIN)/w6c_ww so `make`, `make test`, and
`make demo` all use the ww-built backend. With the wwstage cgen
fixes in selfhost/cmd/wcc/ the demo no longer needs to dodge:
- bug #1+#2 (global addressing): symbol interner indexes
sym_off / sym_len / sym_blob directly. No `let blob = sym_blob;`
aliasing.
- bug #3 (chained non-pointer sub-struct field): not retired here
(lexer.cur is still flattened) but the cgen now handles the
shape; un-flattening is cosmetic.
- bug #4 (f64 through every boundary): vfloat writes p.fval = v
directly; promote_v's FLOAT branch is one assign; to_f64 reads
v.ival as f64 / v.fval directly. Drops fbuf, FVAL_OFF, copybytes.
- bug #7 (xs[i].field): builtins write xs[0].kind / xs[0].car
directly; no `let p = xs[0];` first.
lisp_test still 101/101.
CLAUDE.md marks each historical bug as retired or still load-
bearing; #6 (slice-len in tagged-union return) and #8 (f64
compound assign) are the remaining shapes to avoid.
vstr now copies the input bytes into the trans arena and promote_v
does the same into perm at the top-level boundary. STR cells used
to borrow the lexer's input slice; the REPL's buf-shift between
forms overwrote those bytes, so a top-level (define x "...") would
print garbage after the next read. Mirror of Hare's strings::dup,
arena-routed so the bytes share the cell's lifetime.
Parser learns dotted-pair literals: '(a b . c) splices the tail
into the cdr of the last cons. A bare '.' inside a list lexes as
tkind.DOT; outside a list it's still a parser error. Pre-fix the
'.' lexed as a one-byte SYM, producing a 3-element proper list.
Drop the unused args_to_slice — eval inlines on purpose (the
wwstage cgen drops slice.len through a tagged-union return).
Tests: 18 new probes (str-survives-3-defines, str-from-lambda,
dotted-pair walk + error edges) + a check_str helper. 101/101.
Two bump arenas. arena_reset_trans() runs between top-level forms;
top-level define / set! deep-copy the bound value graph into perm
via Cheney-style forwarding (pin = -1 + stashed fwd pointer in
.car/.val) so no perm cell ever points into trans. Args slice in
eval's apply path also gets explicit os.free per dispatch — without
that the rt_ensure page-per-call leak dominated and masked the
reset. test_huge peaks at ~2.6 MB under massif --pages-as-heap=yes,
down from ~525 MB pre-arena (~200x).
Replaces rt_alloc-per-cell (one 4 KiB mmap each) with arena_alloc
over 64 KiB chunks. test_huge peak under massif --pages-as-heap=yes
drops from ~525 MB to ~253 MB. Same lifetime semantics; remaining
bulk is per-call append() in eval's arg slice (rt_ensure still
mmaps page-per-call).
Demo program that lives entirely on lib/* and libwwrt.a — no @symbol
FFI of its own. The interpreter sits in lispcore.ww (exports for the
test driver); lisp.ww is a 3-line entry that calls lispcore.repl().
Language surface: integers, floats, symbols, strings, lists, lambdas
with closures, define / set! / if / quote / let / begin, recursion
(fact / fib / ackermann / gcd), map / filter / reduce as user code.
REPL is line-buffered: each read tries to parse one top-level form,
asks for more on "unterminated list", evaluates and prints, then
shifts consumed bytes off the front of the buffer. Lookahead-aware —
the parser primes one extra token so we shift to L.curstart, not
L.pos, otherwise the first byte of the next form gets eaten.
lisp_test.ww exec'd as a regular binary (ww test drops -I in single-
file mode); 66 probes cover arithmetic, lists, closures, recursion,
errors. test_*.lisp drive the live REPL through `make demo`.
The wwstage cgen still mis-lowers a handful of patterns at this
shape of program — top-level array indexing, global-ptr deref,
two-level field stores, f64 routing through *T, alloc(structlit{})
for f64/str fields, (slice | E) returns, xs[i].kind chains, f64
compound assigns. Each workaround is annotated at its use site;
the full taxonomy is in examples/lisp/CLAUDE.md.
