On 21.9. 21:55, Dmitry Goncharov wrote:
On Sat, Sep 21, 2019 at 12:34:39PM +0300, Ilkka Virta wrote:
[[:space:]]*?(a)b isn't a well-defined POSIX ERE:
9.4.6 EREs Matching Multiple Characters
The behavior of multiple adjacent duplication symbols ( '+', '*', '?',
and intervals) produces undefined results.
https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/basedefs/V1_chap09.html
This is unfortunate.
*? and +? are widely used not greedy regexes.
In Perl-compatible regexes. Bash uses POSIX extended regular expressions.
And on a GNU system, while *? and +? don't give errors when used in an
ERE, they still don't make the repetition non-greedy. They just act the
same as a single * (as far as I can tell anyway).
bash$ re='<.+?>'
bash$ [[ "a<b>c<d>e" =~ $re ]] && echo $BASH_REMATCH
<b>c<d>
bash$ [[ "a<>e" =~ $re ]] && echo $BASH_REMATCH
<>
--
Ilkka Virta / itvi...@iki.fi
