FWIW, please note that  /^"((?:[^"\\]|\\["\\])+)"$/ does not match the empty string:

c:\@Work\Perl\monks>perl -wMstrict -le
"my $emptystring = '\"\"';
 print '+ match' if $emptystring =~ /^\"((?:[^^\"\\]|\\[\"\\])+)\"$/;
 print '* match' if $emptystring =~ /^\"((?:[^^\"\\]|\\[\"\\])*)\"$/;
"
* match
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(Please forgive all the extra backslashes and ignore the extra  ^ in [^^\"\\]. These are Windoze command line artifacts.)