On 25/09/2024 09:15, Geoff Clare via austin-group-l at The Open Group wrote:
Steffen Nurpmeso wrote, on 24 Sep 2024:
Austin Group Bug Tracker via austin-group-l at The Open Group wrote in
<ea7880ce68ba63cac427845dc4029...@austingroupbugs.net>:
...
|https://austingroupbugs.net/view.php?id=1857
...
| (0006881) geoffclare (manager) - 2024-09-24 10:46
| https://austingroupbugs.net/view.php?id=1857#c6881
...
I have not yet read this completely, but from a glance i see
the ERE "(aaa??)*" matches only the first four characters of the
string "aaaaa", not all five, because in order to match all
five, "a??" would match with length one instead of zero
and that felt not right:
echo 'aaaaa' |
perl -e '$i=<STDIN>;if($i =~ "(aaa??)*"){print "i<$i>; 1<$1> 2<$2>
3<$3>\n"}else{print "no match\n"}'
i<aaaaa
>; 1<aa> 2<> 3<>
It matches only two.
Looks like a bug in perl.
It isn't. It's just that Steffen gave a false representation of what
perl does.
Each repetition of "aaa??" matches "aa"
because the "??" is non-greedy, but the "*" is greedy so should
match the longest string of repeated "aa" as possible.
It does. But the example never shows what it matches. Of course the
output then isn't going to include the match. The match is available in
$&. What's in $1 is the first (the only) capture.
perl does match "aaaa".
Cheers,
Harald van Dijk
