How to turn on "helm-mode" for a specific function?

Question

The context

I've defined a big set of yasnippet snippets and sometimes I forget the shortcut for those snippets. I've found out recently that the function yas-insert-snippet can be used to insert a snippet by writing its name and the completion list of the function lists all the existing snippets.

I would like to use helm only for selecting an item from the completion list shown by yas-insert-snippet. However, I don't want helm-mode to be enabled because that would change the behavior of all functions that show a completion list (e.g. switch-to-buffer, bookmark-jump, kill-buffer, etc.).

I just want helm-mode to be enabled when executing the function yas-insert-snippet.

I've found that the variable helm-completing-read-handlers-alist can only be used to turn off helm-mode for specific functions but I would need to add all the functions to helm-completing-read-handlers-alist using cons of the form (FUNCTION . nil) if I want helm-mode to be disabled when executing FUNCTION.

The question

How can I toggle helm-mode for an specific function? I assume that helm-mode is disabled by default since helm is not used for all functions.

Additional context

I've tried the following but it doesn't work. I wrote it because I noticed that helm-mode is a variable.

(let ((previous-helm-mode helm-mode))
  (helm-mode 1)
  (call-interactively 'yas-insert-snippet)
  (helm-mode previous-helm-mode))

Answer 1

You can use the following function to accomplish that

(defun execute-with-helm (command)
  (if helm-mode
      (call-interactively command))
  (progn
    (helm-mode 1)
    ;; We call `unwind-protect' to ensure that `helm-mode' is
    ;; disabled even though `command' doesn't complete normally.
    ;;
    ;; Without `unwind-protect', if the user presses =C-g= while
    ;; `command' is being executed, then the entire function would
    ;; be exited and therefore, `helm-mode' wouldn't be disabled'
    (unwind-protect (call-interactively command)
      (helm-mode -1))))

Then, you can use that function as follows

(execute-with-helm 'switch-to-buffer)

(execute-with-helm 'kill-buffer)

(execute-with-helm 'yas-insert-snippet)