Sinatra app running on Heroku has RegexpError

Question

My sinatra app runs fine locally but when I push it to heroku it crashes and I get this error

RegexpError - undefined (?...) sequence: /(?<=(LIST ALL SELECTED ))\w/:

The line of code where the occurs is

match = data.match('(?<=(LIST ALL SELECTED ))\w')[0]

What I am trying to do is capture the next letter directly after 'LIST ALL SELECTED '

Any insite to what this means would be greatly appreciated.

Thanks.

Answer 1

That's what's called a positive lookbehind. Ruby doesn't support them, but if that's the whole regexp, you don't need it.

match = data.match(/LIST ALL SELECTED(\w)/)[0]

Ben (look down, in the comments) says your regexp with the lookbehind does indeed work on Ruby 1.9.2. Heroku must be using 1.8.6 or 1.8.7, which doesn't have lookbehinds.