... more rigorously correct ... optimization ...

For me, the issue is not rigor or optimization, but correctness. Insofar as I understand it, the OP requires an overall match on more-than-n contiguous identical characters (although an n-character match may be a component of the overall match). The regexes to which I object match equal-to-or-more-than-n such characters overall, and so are incorrect. The incorrectness of the matches is obscured, but not ameliorated, by the subsequent substitutions, which may replace a string S (which may be empty) with an identical string S.

The point can be exemplified by looking at what is matched by the  qr{ (.)\1\1 \K \1* }xms regex (the most elegant, IMHO, in this thread) in a context that does not involve substitution. (Similar examples could be constructed for the other objectionable regexes.) All the empty strings are, in my view, unneeded (and improper) matches. 

>perl -wMstrict -le
"my $s = 'aaa...bbbb...ccccc...dddddd.x..yy';
 print qq{'$2'} while $s =~ m{ (.)\1\1 \K (\1*) }xmsg;
"
''
''
'b'
''
'cc'
''
'ddd'

[download]

Anyway, that's my story and I'm sticking to it.

In reply to Re^2: Supress similar chars in the string by AnomalousMonk
in thread Supress similar chars in the string by Lana

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