regular express : how to exclude multiple character groups?

Question

I have a set of urls :

/products

/categories

/customers

Now say a customers is named john, and I want to help john to reac

Answer 1

This is entirely the wrong way to go about solving the problem, but it is possible to express fixed negative lookaheads without using negative lookaheads. Extra spacing for clarity:

^ (
( $ | [^/] |
  / ( $ | [^pc] |
    p ( $ | [^r] |
      r ( $ | [^o] |
        o ( $ | [^d] |
          d ( $ | [^u] |
            u ( $ | [^c] |
              c ( $ | [^t] |
                t ( $ | [^s] ))))))) |
    c ( $ | [^au] |
      a ( $ | [^t] |
        t ( $ | [^e] |
          e ( $ | [^g] |
            g ( $ | [^o] |
              o ( $ | [^r] |
                r ( $ | [^i] |
                  i ( $ | [^e] |
                    e ( $ | [^s] )))))))) |
      u ( $ | [^s] |
        s ( $ | [^t] |
          t ( $ | [^o] |
            o ( $ | [^m] |
              m ( $ | [^e] |
                e ( $ | [^r] |
                  r ( $ | [^s] ))))))))))
) .* ) $