#!/usr/bin/perl

# http://perlmonks.org/?node_id=1128703

use Data::Dump qw(pp);
use strict;
use warnings;

pp [ map 

# explanation of regex

s/
  ,      # find a comma
  .*?    # match as little as possible until you find
  (?:    # grouping for either
  (cd)     # cd  :)
  .*?      # which must be followed by as little as possible up to the
+ next
  ,        # comma
  |      # or
  ,        # a comma
  )      # end either grouping
  /      # replace with
  $1     # test for true to avoid "uninitialized" warning
  ?
  "=$1=" # =cd=
  :
  "=="   # no cd because comma was found first
  /exr   # eval, expanded, and return result of replacement(just for t
+est)

# rest of running code

  , ',abcefg,abcdefg,', ',abcdefg,abcdefg,' ];

__END__
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