I've recently found yeganesh, a wrapper for dmenu that learns with use:
http://dmwit.com/yeganesh/
I am having trouble getting it to work. I've cached a number of entries, so I can correctly select one, but it just gets returned to stdout, what should I do to run the command? Also, it seems like it doesn't work unless you do something like pipe an empty echo to it. I cannot figure out why this is the case. It makes sense that it gets it's initial list from stdin, and it makes sense to every so often pipe dmenu_path to yeganesh, or always, but shouldn't it still work even if I don't echo anything to it?

This is the script I am currently running it with (everything after yeganesh is just formatting for display):

EDIT: Found this: https://bbs.archlinux.org/viewtopic.php?id=68286 but not really sure what they did to fix it there.

EDIT: Found python based clone (yeganesh uses haskell), testing now https://chanux.wordpress.com/tag/yeganesh/

EDIT: exec. exec was what I was looking for.