How does Spacemacs allow tab completion in helm?

Question

I am brand new to using Emacs and I love it. I tried Spacemacs to see the functionality it provided out of the box and I want to replicate some of those features in my own Emacs configuration. From what I can see Spacemacs uses Helm and allows tab completion inside Helm. How does it do that? Does it even use Helm? If not what does it use?

Answer 1

The "tab completion" that spacemacs does in helm is actually the helm command helm-execute-persistent-action. By default helm-execute-persistent-action is bound to C-z and TAB is bound to helm-select-action, but in spacemacs these bindings are switched.

You can switch these bindings in your init.el by adding these lines of elisp

(define-key helm-map (kbd "TAB") #'helm-execute-persistent-action)
(define-key helm-map (kbd "<tab>") #'helm-execute-persistent-action)
(define-key helm-map (kbd "C-z") #'helm-select-action)

Answer 2

Tab completion inside of Helm should come pre-loaded with Helm. It shouldn't need to be configured.

Tab completion outside that uses helm sometimes needs to be configured.

Many packages come with their own helm completion modules. For example helm-c-yasnippet aggregrates yasnippets for Helm.

Helm makes it very easy to add more sources as well.

Spacemacs also uses company/autocomplete, which is the in-buffer drop down like menu. It is similar to helm. Maybe take a look at the auto completion layer.

EDIT: My bad this entire post is wrong. I was not aware that tab-completion was a separate function, I thought it was being referred to as justing hitting tab and auto-completion occuring.