wiz@NetBSD.org wrote:
> The following script works with GNU sed 4.07, but not with sed
> in -current (1.6ZF).
 
> echo "a{b,c{x,y}}" | sed '
> :a
> s%{\([^,]*\)}%\1%g
[...]

IMHO the expressions requires using -E with sed. Also \1 isn't defined
AFAIK i.e., you MUST NOT backslash-quote characters which are not
unsafe e.g., all sorts of parentheses qualify as "unsafe" because they
are part of the syntax.
Still, after removing those backslashes and using -E I don't get the
desired result.

-- 
Christian