2)  Empty string matches problem.  Shown below is the example code that illustrate the problem.
    ...
    ok('good=bad' =~ m/^.*?=.*/, 'test');
    ok('test' =~ m//, 'this will failed before the previous regex match with a "?=" regex match. I have no way to reset back the previous regex change the regex engine unless I put it in its scope.');
    ...
If I put it in its scope as shown below, it will not affect the next text.
    ...
    {
       ok('good=bad' =~ m/^.*?=.*/, 'test');
    }
    ok('test' =~ m//, 'this will failed before the previous regex match with a "?=" regex match. I have no way to reset back the previous regex change the regex engine unless I put it in its scope.');
    ...