Is there a difference between flexible quotes in ruby?

Question

I feel I should preemptively apologize because this seems like the type of question that's probably been asked before. I couldn't find an answer so I'm asking here.

I'm going through the RubyKoans and I'm at line:24 of about_strings.rb There's a test:

def test_use_flexible_quoting_to_handle_really_hard_cases
  a = %(flexible quotes can handle both ' and " characters)
  b = %!flexible quotes can handle both ' and " characters!
  c = %{flexible quotes can handle both ' and " characters}
  assert_equal true, a == b
  assert_equal true, a == c
end

So what exactly is the difference between a, b, and c. Why exactly do three ways of doing something exist? This seems illogical. I know Ruby is flexible but I don't think of it as illogical.

Answer 1

There's not three ways, there's... a lot of ways. Any non-alphanumeric character that follows % is a valid delimiter.

%[this is a valid string]
%~this is a valid string~
%+this is a valid string+

etc.

Note that brackets-and-friends are a little special, ruby is smart enough to allow you to use pairs of them - or even nest balanced pairs inside, a la

%[this is a [valid] string]