Another example of the effect of what you were doing in the OP (i.e., a non-zero-width capture within a zero-width assertion): 

Win8 Strawberry 5.8.9.5 (32)  Wed 11/11/2020 18:02:18
C:\@Work\Perl\monks
>perl -Mstrict -Mwarnings -l
my $s = 'ABCDE';

while ($s =~ m{ (?= (\w+)) }xmsg) { print $1; };

^Z
ABCDE
BCDE
CDE
DE
E

[download]
A useful trick when you want overlapping captures.

Update: This might be a better example of overlapping capture: 

Win8 Strawberry 5.8.9.5 (32)  Wed 11/11/2020 21:41:12
C:\@Work\Perl\monks
>perl -Mstrict -Mwarnings -l
my $s = 'ABCDE X YZ FGHI';

while ($s =~ m{ (?= (\w{3})) }xmsg) { print "'$1'"; };

^Z
'ABC'
'BCD'
'CDE'
'FGH'
'GHI'

[download]

Give a man a fish:  <%-{-{-{-<

In reply to Re: Return value from positive look behind (updated) by AnomalousMonk
in thread Return value from positive look behind by bestresearch2

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.