Without looking at the source: it could either generate a decision tree made of nested ifs and case statements (or the CPS equivalent), or it could just do a naive linear search over each list element. That's probably good enough until you have long lists of alternatives or structural matching against whole trees.

I have a quick hack of a Lua library that does pattern matching with linear search. Whenever I get around to making it actually do analysis and compile search functions, I'll put it on github. (The patterns can have variable captures in them, too.)