Hojun-Cho
f3750ae3ce
io.empty (discard+EOF stream, ref/hare/io/empty.ha:4-17) — needed by getopt's two-pass printusage width measurement. Diverges from Hare's `const empty: *stream`: a `let _empty_vt` + `fn empty()` that wires the fn-ptr slots per call, because const-init of a vtable struct with fn-ptr fields is blocked (#118, ruled accept). Co-discovered while making empty() byte-identical across stages: three wwstage-only cgen fixes (cstage was already correct; wwstage aligned down): - #129 sretretsize: consult the same-module pointer-alias before structlookup's any-module struct fallback (io.stream = *vtable was mis-sized as memio's 56B struct -> spurious sret save). - #129 callsretsize: swap curmod to the callee's module before sret-size classification (cross-module callee context). - #130 cgassign global-struct tagged-union field store: add the missing arm (was a 1-word store) mirroring cstage cgen.c:4893-4912. The three are inseparable from io.empty here — splitting them out leaves a divergent-asm intermediate (993/995 red), so they ride one commit per the one-class gate-repair carve-out (#133-expanded precedent). Regenerates the embedded combined.ww; 989_lib_byteid pins bufio + fmt graduated to M_ID. (cgenexpr.ww fix-3 inline comment cites the #129 cluster; narrow to #130 on next touch to avoid a regen for a comment.)
27 lines
1.3 KiB
Plaintext
27 lines
1.3 KiB
Plaintext
// io — stream interface (Plan 9 Bio / Hare io::stream shape).
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//
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// No closures, no methods. A `stream` is a pointer to a `vtable` of
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// function pointers (lib/io/stream.ww); read/write/close dispatch
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// through it. The error channel is the return value — Hare-shaped
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// tagged unions instead of errno-style integer sentinels.
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//
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// This file owns the eof / underread variant tags; lib/io/stream.ww
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// owns the `vtable` + `stream` + read/write/close dispatchers and the
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// [[empty]] singleton, and lib/io/types.ww owns the error union,
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// mode/whence enums, and the reader/writer/closer fn-type aliases.
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// #94 fold-eFinal collapsed the pre-vtable `stream` struct + `closed`
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// tag into the single vtable surface; the dispatchers are read/write/
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// close (over `stream`), final over `handle` at io fold-2 (#5).
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package io;
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// eof — read past the end of the stream. Hare uses the `done`
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// singleton for EOF; ww doesn't have `done` yet so we ship a
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// named-void variant tag. Lifts to `done` with #93.
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export type eof = void;
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// underread — an I/O handle hit eof partway through a fixed-size
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// read. Payload is the byte count actually delivered. Mirrors
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// Hare's `io::underread = !size`; ww uses i32 because the
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// underlying buffer-length type is i32 today.
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export type underread = !i32;
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