use strict;
my $str = '';
my $regex = qr/(\(|,)(\s{0,})([a-zA-Z0-9_?\\]{0,}\s{0,}&{0,}\$[a-zA-Z0-9_]+\s{0,}=\s{0,}[a-zA-Z0-9_'"\[\]]+)(,\s{0,})([a-zA-Z0-9_?\\]{0,}\s{0,}&{0,}\$[a-zA-Z0-9_]+)(\n\s{0,}){0,}(\)|,)/mp;
my $subst = '$1$2$5$4$3$6$7';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html