Yep. You hit CTRL+SPACE and it'll give you a drop down list of possible completions. It'll also have your previously typed variables in the list.

I'm more of a tab user myself though. So I'll type array_p and hit tab once for array_push. (for example)

it sorta does. If you hit tab while typing a method name, it'll guess at which one you're trying to type and populate the args as well. It's not particularly useful, but it does indicate that there is code in the app that is trying to do this, and could be improved.

This is one drawback ... so far it doesn't (from what I've seen anyway)