/^?(one|foo|bar)$?/
/^?(two|oob)$?/
/^?(three|oob)$?/
/^?(four)$?/
-----------------
/^?(two|oob)$?/
/^?(one|foo|bar)$?/
/^?(four)$?/
/^?(three|oob)$?/
-----------------
/^?(two|oob)$?/, 1
/^?(one|foo|bar)$?/, 0
/^?(four)$?/, 3
/^?(three|oob)$?/, 2
-----------------
/^?(three|oob)$?/, 4, 4
/^?(two|oob)$?/, 3, 2
/^?(one|foo|bar)$?/, 2, 0
/^?(four)$?/, 5, 6