2018-04-20 09:53:00 +0000, Austin Group Bug Tracker:
[...]
> I think { and } should be
> raised separately as it's questionable whether brace expansion is allowed
> by the standard.
Note that I'm not suggesting POSIX specify brace expansion
(there are too many significant differences between shells which
implement it).
Just that leaving { and } unquoted except in contexts where its
use is explicitely specified (like in ${...} or the { and }
keywords) would produce unspecified results.
That would allow {a,b}, {ac-z} (zsh -o braceccl), {2..9}...
types of brace expansion, or zsh's {echo hello} compact form of
command groups (currently disabled when running as "sh", not the
best feature as it's not consistently recognised there and
clashes with brace expansion), or zsh/bash/ksh93 {fd}> file
forms of redirection and allow future extensions like >{...}.
> Requiring ^ to be equivalent to ! would also best be
> raised as a separate bug.
[...]
Agreed.
--
Stephane
