Hojun-Cho
7d39f6d623
The Option-C parallel _v vstream API was scaffolding to bring the io stack up alongside the old surface; carrying both permanently is a rule-9 divergence from ref/hare, which has exactly one io surface. Collapse onto that surface (stream = *vtable, ref/hare/io/stream.ha) and rename the _v symbols to their Hare names (io vstream->stream, fmt vfprint->fprint, bufio/memio/log surfaces, log.new). Deletes the 4 lib/*/vstream.ww scaffold files; regenerates w6c/wwdump combined.ww. cstage and wwstage stay byte-identical and combined_ww_fresh holds; all 220 tests pass.
83 lines
3.1 KiB
Plaintext
83 lines
3.1 KiB
Plaintext
// stream — Hare-shaped vtable surface. Project #94 fold-eFinal.
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//
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// The single io stream surface (the fold-eFinal collapse retired the
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// pre-vtable `stream` struct + `closed` tag). Three exports:
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//
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// vtable a struct of optional fn-pointer slots — reader/writer/
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// closer per ref/hare/io/stream.ha:36-42. Hare spells the
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// nullable as `nullable *T`; ww parser rejects that
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// spelling (#192), so each slot is a `(*T | void)` tagged
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// union (Plan-9-lean per the Nullable kept ruling; opt-in
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// at optionality boundaries only).
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// stream `*vtable` alias matching Hare's `stream = *vtable`
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// (ref/hare/io/stream.ha:33).
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// read /
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// write /
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// close the three dispatchers per ref/hare/io/stream.ha:44-68.
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// Each `match`es the matching vtable slot, returns
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// `errors.unsupported` (widened twice) when the slot is
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// void, otherwise calls through the fn pointer. Hare keeps
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// these private (`st_read` …) behind a `handle`-typed
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// public `read`/`write`/`close`; ww has no `handle` yet
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// (io fold-2, #5), so the dispatchers ARE the public
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// surface and grow the `handle` match when #5 lands.
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//
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// Deferrals (drew-signed): `seeker` lands with io fold-2 (#5) once `off`
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// + `whence` plug into the signature. Hare's `?`-propagating `close`
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// body (`c(s)?;`) collapses to a direct `return (*c)(s);` here because
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// the dispatcher's surface stays Hare-shaped; only the internal
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// try-prop is omitted (#173 history, now closed — kept direct for the
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// void-arm fall-through shape).
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package io;
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// ref/hare/io/stream.ha:36-42. Nullable spelling per #192 (ww parser
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// rejects `nullable *T`); each slot is `(*T | void)`.
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export type vtable = struct {
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reader: (*reader | void),
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writer: (*writer | void),
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closer: (*closer | void),
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};
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// ref/hare/io/stream.ha:33.
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export type stream = *vtable;
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// ref/hare/io/stream.ha:44-50. The void-arm `return e;` chains two
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// direct widens: `errors.unsupported → error` via #199 α, then
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// `error → (size | eof | error)` via #205. The call-arm spells the
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// fn-ptr call explicitly per #193 (ww requires `(*r)(args)` rather
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// than implicit `r(args)`).
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export fn read(s: stream, buf: []u8) (size | eof | error) = {
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match (s.reader) {
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case void => {
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let u: errors.unsupported;
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let e: error = u;
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return e;
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};
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case let r: *reader => return (*r)(s, buf);
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};
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};
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// ref/hare/io/stream.ha:53-59.
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export fn write(s: stream, buf: []u8) (size | error) = {
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match (s.writer) {
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case void => {
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let u: errors.unsupported;
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let e: error = u;
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return e;
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};
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case let w: *writer => return (*w)(s, buf);
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};
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};
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// ref/hare/io/stream.ha:62-68. Hare propagates the close error via
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// `c(s)?;` then falls through to the void arm; ww collapses to a
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// direct return for the void-arm fall-through shape. The surface
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// (void | error) matches.
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export fn close(s: stream) (void | error) = {
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match (s.closer) {
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case void => return void;
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case let c: *closer => return (*c)(s);
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};
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};
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