#!perl -l
for ('"Boo","Baz","Bar"','",",","') {
	{
		local $_=$_;
		s/(?<!,)"|"(?!,)/""/g;
		print "Or : $_\n";
	}
	{
		local $_=$_;
		s/([^,])"|"(([^,]))/$1 ? $1.'""' : '""'.$2/ge;
		print "Or (class): $_\n";
	}
	{
		local $_=$_;
		s/([^,])"([^,])/$1""$2/g;
		print "And: $_\n";
	}
}
__END__
Or : ""Boo"",""Baz"",""Bar""

Or (class): ""Boo"",""Baz"",""Bar""

And: "Boo","Baz","Bar"

Or : "",",",""

Or (class): ",",","

And: ",",","