Hojun-Cho
7f320d3e75
#30 (82be8b9) unblocked tagged-union widen for runtime f64. Add the
f64 arm to fmt's formattable union and dispatch.
`formattable` gains an f64 case (appended last to preserve existing
tag indices). fdprint / fprint mirror their i64-arm shape. formatraw
peels strconv's natural '-' so signof folds neg/+/space uniformly
with i64. formatfield uses the inline widen-per-arm #18 sidestep.
rawlenf64 renders via strconv.f64tos to count bytes for width
alignment (Hare's print.ha:53 uses an io::empty sink for this; ww
has none yet, so we render twice — acceptable v1 trade).
Width / alignment / pad / sign mods honored. prec / base ignored
with inline rationale (no ffmt/fflags in mods yet; Hare aborts on
non-DEC base, ww silently falls through). NaN/Inf deferred — Inf
renders deterministically as "huge"/"-huge" via strconv's `f >= cap`
path; NaN is garbage. Detection waits on f64↔u64 bit-reinterpret in
cgen.
13 test rows at signalled 31-43 cover basic/int-valued/neg/zero/
small-frac/huge/sign±/space/width-right/width-left + fprint
variadic + bsprintf + asprintf sinks. Each pins exact byte output.
Three rows bind negative literal via intermediate `let nv: f64 =
-2.5;` to route around #40 (cstage drops payload on N_UNARY-of-
N_FLOATLIT in tagged-union widen). Comments cite #40 at each row.
Probe at .ai/probe_f64_unary_neg.ww.
Strconv f64tos is fixed-point today; graduate to Ryū (ref/hare/
strconv/ftos.ha:432) when needed.