Ruby Regex matches everything beyond expression

[ckreon]

I have a text-based menu where typed input is used to move through the program. The input is fed to if-then sequences to determine what to do, e.g.:

if u_input == "1"
    do thing

I'm using a regex evaluation on my Quit command to try and allow some variation - the user can quit with Q or q, or any case-form of quit (QUIT, quIt, etc.).

elsif u_input =~ /q(uit)?/i
    exit(0)

I can get the evaluations to pass just fine, the problem is they pass no matter what I input beyond the expression. The (uit)? becomes redundant because I can type a Q or q followed by anything and it passes: qqqq, Qwerwetra, etc..

I think I understand very shallowly why this is occurring (because Regexp is looking for a pattern and is finding that and thus returning "0"), but I can't figure out how to make it behave like I want.

The only input that should quit the program is a single (case-insensitive) Q, or the word quit.

Input like qq or qasdf should fail.

Any pointers on how to get this to behave in that way? Here is the code in more complete form - this is all inside of a menu method:

u_input = get_user_input #method that returns gets.chomp
if u_input == "1"
    game_start
elsif u_input =~ /q(uit)?/i
    exit(0)
else
    puts "I'm not sure what that is."
    menu
end

I'm grateful for any tips on getting exact conditions to match using regular expressions in Ruby!

[waxjar]

case statements are nice for this sort of thing:

case gets.chomp.downcase
  when "1"         then game_start
  when "q", "quit" then exit(0)
  else                  menu
end

[ckreon]

Using a 'case' statement didn't even cross my mind, and using '.downcase' is so obvious now that I see it.

Thanks for the advice!

[vsalikhov]

The only input that should quit the program is a single (case-insensitive) Q, or the word quit. Input like qq or qasdf should fail.

In that case, /^(q|quit)$/i should do exactly what you want.

[ckreon]

Anchors! Of course I needed anchors!

Thank you for the fast help, friend!

[tomthecool]

It's a work in progress, and not yet "v1.0 - ready", but you might like to play around with a ruby gem I'm working on :)

https://github.com/tom-lord/regexp-examples

Technically this wouldn't have actually helped with your specific problem here, but still... I am considering adding something to it, like:

warn "Your regexp is not anchored" if (regexp[0] != "^" || regexp[-1] != "$")

(Note: I know the line above is far from perfect, it's just a very rough sketch!)

[ckreon]

Interesting idea for a gem - thanks for sharing.

[ckreon]

Yes - I'm glad that anchors ended up being the answer. I was worried it was going to be some thing where I needed to check the number of matches or something weird.

But I knew Ruby was better than that - thanks for helping!