Helmify some completion mechanisms

Last year I wrote about making Company completion popup appear on demand. There I also briefly mentioned dabbrev-expand and dabbrev-completion, but I have never mentioned hippie-expand, and that it has been pretty much covering my completion needs.

However, moving to Helm prompted me to give helm-dabbrev a try. helm-dabbrev works similarly to dabbrev-completion, but when you hit helm-dabbrev-cycle-threshold (which defaults to 5), it takes you to a Helm buffer with all the benefits that come with it.

Two settings are necessary to have helm-dabbrev behave like I want to. First, I turned off Helm’s show completion, a feature which displays candidates in the current buffer. I don’t like popups, as you may have noticed, and I prefer Helm to always show candidates in the same position of the screen.

(setq helm-turn-on-show-completion nil)

Then, I made helm-dabbrev look for completions in all the available buffers.

(setq helm-dabbrev-related-buffer-fn nil)

By default, helm-dabbrev scans buffers with the same major mode as the current one, but this doesn’t help when, for instance, I am writing a commit message and I want a symbol to be completed. Binding helm-dabbrev to C-. is all that’s left to do.

Moreover, Helm improves on Company too. With the help of helm-company¹ is possible to narrow down the candidates through Helm smart UI. C-TAB is my go-to key binding for helm-company.

Since Helm has become a great companion during my Emacs sessions, it makes sense to rely on it for everything concerning completion.