+ # Search the last occurence of the text `t`.
+ #
+ # assert "bob".search_last("b").from == 2
+ # assert "bob".search_last("bo").from == 0
+ # assert "bob".search_last("ob").from == 1
+ # assert "bobob".search_last("ob").from == 3
+ # assert "bobbob".search_last("bb").from == 2
+ # assert "bobbob".search_last("bob").from == 3
+ # assert "bob".search_last("z") == null
+ # assert "".search_last("b") == null
+ fun search_last(t: Text): nullable Match do
+ return search_last_up_to(t, length)
+ end
+
+ # Search the last occurence of the text `t` before `up_to`.
+ #
+ # assert "bobbob".search_last_up_to("b", 3).from == 2
+ # assert "bobbob".search_last_up_to("b", 6).from == 5
+ # assert "bobbob".search_last_up_to("b", 0) == null
+ fun search_last_up_to(t: Text, up_to: Int): nullable Match do
+ var i = up_to - t.length
+
+ while i >= 0 do
+ if substring(i, t.length) == t then
+ return new Match(self.to_s, i, t.length)
+ end
+ i -= 1
+ end
+ return null
+ end
+