-- `fmt` only supports bare `{}` placeholders. Printf-style format specs
-- inside the braces (`{:06d}`, `{:.3f}`, etc.) used to silently emit the
-- literal template (e.g. `fmt "{:06d}" 42` → `"{:06d}"`), which was a
-- silent-wrong-output footgun. Both verify and runtime now reject them.
--
-- Idiomatic substitutes:
-- precision → fmt "...{}" (fmt2 v 2)
-- padding → padl (str n) 6 (space-pad; today)
-- decimal precision via fmt2 composed inside the {} slot
pct r:n>t;fmt "{}%" (fmt2 (* r 100) 1)
-- width / padding via padl
sort-key n:n>t;padl (str n) 6
-- run: pct 0.12345
-- out: 12.3%
-- run: sort-key 42
-- out: 42