Florian Gross wrote:
>
> "bab\nbcab".gsub(/^(?<!bc?)ab$/, "cd")
                         ^^^
                         ^^^
           oniguruma doesn't like your questionmark 


Oniguruma only supports fixed width lookbehind.. quantifiers are not possible
however you can use alternation instead.

       (?<!b(?:c|))

-- 
Simon Strandgaard