Compgen equivalent?

In OS X’s bash shell, a list of the available commands can be generated using compgen. Is a similar command for BusyBox’s shell?

I’d really like to see the name of the command and its description, displayed as columns:

# foobar -l
Name       Description
acpid      Listen to ACPI events and spawn specific helpers on event arrival
addgroup   Add a group or add a user to a group

No description for ash completion. You can try to use zsh instead (as that seems to be what you are usin on OSX). But I don’t know state of it in OpenWRT and we probably don’t have time to do anything about it if it’s bad.