Hojun-Cho
bb10ee73a4
Hare-shaped {} / {0} / {n:mods} parser + printf wrappers. APIs:
fprintf, fprintfln, fdprintf, fdprintfln, printf, printfln, errorfln,
fatalf, bsprintf. Parser handles indexed/positional placeholders,
alignment (- / default / =), pad-width, zero-pad (_05), radix (x X o
b), precision (.N for int pad / str trunc), sign markers (+, space),
and {{ / }} escape.
Internals: scandigits + scanmods drive a field-by-field dispatch into
formatfield, which inlines the field→formattable widen per-arm to
sidestep task #18 (24B return-by-value miscompile in for-loop
context). Render through formatraw + formatone over io.stream sinks.
formatone tail-pad uses a separate counter rather than mirroring
Hare's `?`-propagating loop: ww's memio.fixed returns partial-write
0 instead of errors::overflow, so the Hare shape would spin forever
on a full fixed buffer.
Deferred per drew's vet: asprintf/errorf (needs os.alloc, #16),
parametric width/precision dispatch (#16-family), float arm (#17),
log.printfln family wiring (#15).
Tests: 26 scenarios covering every placeholder shape, both arms of
fprintf's variadic dispatch (incl. bool/rune to pin #18 regression),
bsprintf overflow + width-against-full-buffer, closed-stream.