Do we need a mode for this? Getting all the matches? Its possible to do with an embedded code block (as I think you know :-) 

perl -le"$_='bbaabb'; /b*(?{print '.' x $-[0],qq<($&)>})(*FAIL)/g"
(bb)
(b)
()
.(b)
.()
..()
...()
....(bb)
....(b)
....()
.....(b)
.....()
......()

[download]

On earlier perls than mine you can spell (*FAIL) as (?!)

---
$world=~s/war/peace/g

In reply to Re^4: zero-length match increments pos() (saner) by demerphq
in thread zero-length match increments pos() by Errto

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