I built a router like this for Rails back in the 2.3 era. It was ridiculously fast for small route sets, but as the sets grew, the standard approach was actually faster. If your route set is small and routing is a bottleneck, though, this approach might work for you. :)

(I don't know how it would stand up against Journey, the Rails 4 router business. I imagine it's only gotten faster so there may be next to no gain)