Implementing autocompletion to zsh aliases

Question

I am using the awesome zsh framework oh-my-zsh . Every day I hit gc which is an alias for git commit I hit <Tab><Tab> and it gives me the correct files to commit. I am really interested to know how that is implemented, so I can implement my own idea of navigating to sub-directories using an alias.

I mean navigating into ~/workspace/a-repo using this alias -w a<Tab><Tab> which completes to a-repo and gives me some suggestions which are folders inside ~/workspace . I made this alias already but I need to know how to add the correct autocompletion/suggestion to it.

Here is my alias:

-w() { cd ~/workspace/"$*" }

Answer 1

In the case of gc (which I assume is defined as alias gc='git commit -v' in the git plugin of oh-my-zsh ) zsh internally substitutes the alias ( gc ) with the actual command ( git commit -v ) before looking for trying for completions. This works for every alias (unless the shell option COMPLETE_ALIASES is set, which would allow to set separate completions for aliases).

As for what you want to do: Seing that -w is actually a function and not an alias, you indeed would have to write your own completion. But there is a much simpler way to go about it: Static named directories .

Named directories are usually just the home directories of the users on the system. The most commonly known is probably ~ for the home directory of the current user. Other users directories are named ~USERNAME . You can also define your own static named directories . There are two ways to do this:

• Use hash -d to explicitly define a name, similar to an alias:

hash -d w=~/workspace

• Implicitly define it by defining a string shell parameter whose value begins with an / (this also means you cannot use ~ as shortcut for your home directory)

w="${HOME}/workspace"

In both cases you now can use ~w to reference your workspace, in the second case you can also use $w (for example for use in quoted strings). Typing cd ~w/a-repo will get you to ~/workspace/a-repo . Tab-completion works like it would with any other path, so pressing ~w/a<Tab> will present you ~w/a-repo as completion.

Additionally, if you set the shell option AUTO_CD ( setopt AUTO_CD ), you can switch into a directory just by typing the path (or directory name) without the need for cd .

% w="/tmp"
% cd ~w
% pwd
/tmp
% mkdir 1 2 3
% setopt AUTO_CD
% ~w/<TAB>
1 2 3
% ~w/1
% pwd
/tmp/1