J's E. implements Boyer-Moore, which makes it much faster than a standard search. You could implement a standard search using sequential machines (well, if you don't mind a transition table that grows with the size of the label to find), but I'm fairly sure it's impossible to implement Boyer-Moore using sequential machines, so your search would be several times slower and probably not worth the advantage you get from stopping early.
Marshall On Wed, Oct 12, 2011 at 1:41 PM, Alan Stebbens <a...@stebbens.org> wrote: > It seems to me that another possibility for iterative and lazy evaluation > is the finite sequential machine (;:), with a cleverly designed state table, > such that a "stop" (code 6) or an "error" (_1) is thrown and then caught by > logic in the state table, so that parsing all the input is not always > required. > > Alan > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
