+ # interchar range
+ [ 'q-x' => '[q-x]'],
+ ['qqq-xxx' => '(?:[r-w]|q[r-z]|qq[q-z]|x(?![x-z])|xx(?![x-z])|xxx)'],
+ ['qqq-xqq' => '(?:[r-w]|q[r-z]|qq[q-z]|x(?![q-z])|xq(?![q-z])|xqq)'],
+ # interchar mixed length
+ ['qqq-xq' => '(?:[r-w]|q[r-z]|qq[q-z]|x(?![q-z])|xq)'],
+ [ 'qq-xqq' => '(?:[r-w]|q[q-z]|' . 'x(?![q-z])|xq(?![q-z])|xqq)'],