This is one of the most useful gates of all as it allows you to program within game and make your own gate... this is event driven programming so if you input something you get something out. Anyhow what I was going to say is check out this fully noted guide on wiremod if you are stuck with expression gates as it was a big help to me and (i think) to thingshappen aswell:
http://www.wiremod.com/439-expression-gate-documentation.html
So I hope this is useful on terms of the expression gate but any other problems please feel free to post and someone will reply to you soon!
Enjoy!
