ww/lib/CLAUDE.md at 46edb8db4ac8bf335082e3775ede6ffd53e26039

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Hojun-Cho 46edb8db4a w6c+selfhost+lib: cgen quality batch + lib Hare-shape graduation

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.

2026-05-13 08:05:01 +09:00

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lib/ — Hare-shaped standard library.

Scope: every lib/* directory except lib/ww/, which is the compiler frontend port and has its own rules (see lib/ww/CLAUDE.md).

Names mirror Hare. Before adding a function, find its counterpart in ref/hare/<module>/ and copy the name — drop Hare's underscores per plan 9 style (trim_prefix → trimprefix, next_token → nexttoken). Don't invent. Don't shorten further. Don't reorder parameters.

Signatures mirror Hare too, modulo:

Tagged-union returns are spelled with the ww ! error tag where Hare uses !void / !T, and indices use the underlying length type (i32 today, since str.len: i32). Example: strconv.stoi64(s: str, b: strconv.base) (i64 | invalid | overflow) — same shape as Hare's. The base parameter is the named enum strconv.base (Hare uses enum uint; we pick enum i32 to match the index type).
Static-buffer str returns where Hare uses them. strconv.*tos returns a const str view into a module-level buffer that is overwritten on the next call to the same function. Callers that need the bytes to outlive the next call duplicate via strings.dup. Functions that genuinely allocate a fresh buffer (strings.dup, strings.concat) still return an owned str that callers free via os.free(r.ptr, r.len: u64).
Call-site variadic sugar (fmt::println(42)) doesn't land yet. The receive side does — fmt.formattable is a tagged union of the printable scalar types, and fmt.printv / fmt.printlnv take an explicit []formattable slice. Until the call-site gather is implemented, callers either hand-build the slice: let args: [2]fmt.formattable; args[0] = "count: ": fmt.formattable; args[1] = 42i64: fmt.formattable; fmt.printlnv(args[0:2]); or compose to a single str via strconv.i64tos + strings.concat: fmt.println(strconv.i64tos(42, strconv.base.DEC)); lib/fmt is intentionally print-string-only — no printf-family.
(T | U) sum-typed parameters dispatch via match inside the callee. strings.byteindex(haystack: str, needle: (str | rune)), bytes.index(s: []u8, needle: (u8 | []u8)), and rbyteindex/ rindex follow Hare's shape directly. The rune-indexed strings.index (rune-wise position) isn't shipped yet — we don't have UTF-8 rune iteration in the language stack.

Don't ship a richer surface than Hare has. A documented subset is fine; an extension, rename, or convenience-wrapper is not — callers should not bake the current subset shape into themselves.

Modules with intentional divergence:

lib/os and lib/net stay below the Hare abstraction — they are syscall wrappers, not the high-level io::handle / net::socket API. Use them as the foundation that lib/io and the buffered layers build on.
lib/io keeps the ww-specific stream struct (vtable of fn pointers, no closures, no methods). The Hare io::handle family needs language features we don't have yet.
lib/bufio and lib/sort will be redesigned to Hare's scanner / cmpfunc shapes; the present minimal forms are placeholders until then.
lib/time and lib/math ship only what callers need today; they're not aiming for parity yet.

When the compiler can express a Hare signature that's still in the ww-specific shape (e.g., once a module-level *u8 is mutable, the strconv *tos family graduates to static-buffer returns), graduate the module in one go — replace the current shape with the Hare shape and fix the callers. Don't keep both around.

3.5 KiB Raw Blame History

3.5 KiB

Raw Blame History