Zsh function: forward completion to subfunction - autocomplete

Question

Many times I end up writting wrapper function around existing ones, for instance:
function gl {
some_computed_stuff=...
git --no-pager log --reverse $some_computed_stuff "$#"
}
function m {
make "$#" && notify-send success || notify-send failed
}
I know that aliases keep autocompletion but sometimes functions are required and in that case autocompletion is lost.
For instance here I would like to keep git log completion for my function gl or make completion for m.
I tried to add compctl -K _git gl but no suggestions are made. It won't work anyway since I must somehow find how to provide log argument to _git autocompletion script as well, so my question is:
Is there a way to make ZSH (but also bash) understand that typing gl is the exact equivalent of git log? Something like (for ZSH only):
compctl 'git log' gl
compctl 'make' m

Answer 1

For zsh, you can create a new completion with compdef function.
In its basic form it associates a completion function with a word. Provided that zsh comes with lots of completions already built-in, one can just reuse those. For example, for m function from the question:
$ compdef _make m
As per documentation, you can also define a completion for a specific service, if the one is defined in the completion function. Again, as zsh comes with _git completion and it already defines git-log service, a gl function from the question may be autocompleted with:
$ compdef _git gl=git-log
On Linux, you can see existing completion implementations in /usr/share/zsh/functions/Completion/Unix/. You can read the completion implementations to see what services they define.