Question

I’m not sure if my brain is worn out or if I’m just thinking about this too hard. The following code is from the about_regular_expressions in the Ruby Koans.

def test_asterisk_means_zero_or_more
   assert_equal "abb", "abbcccddddeeeee"[/ab*/]  
   assert_equal "a", "abbcccddddeeeee"[/az*/]  
   assert_equal "", "abbcccddddeeeee"[/z*/]  

 # THINK ABOUT IT:
 #
 # When would * fail to match?
end  

How do you get * to fail a match?

When I say fail, I’m assuming they mean they want assert_equal to return nil. I know one way would be to throw a \ in front of the * to make the regex explicitly look for the * character but I’m pretty sure this isn’t what they were implying.

Answer 1

Maybe the answer to “when would * fail to match” is “never”.