Is an "Electric" YASnippet possible?

Question

I want to emulate (and even replace) some electric modes (eg. cperl-electric, ruby-electric) with my own custom templates using yasnippet, but it doesn't seem to be possible - can someone enlighten me?

So in addition to normal templates triggered by TAB, I'd like to have some snippets triggered simply by a space, eg. typing "forSPACE" should fire a snippet instead of having to type "forTAB".

Is that possible?

Update: I also realise that for some "electric" features I want some patterns to fire without any sort of trigger key - eg. like cperl-mode turns { into a paired {} with the insertion point in the middle, I'd like to do the same for single and double quotes. (Of course in this case what I really want is paren-mode to work with syntax less regular than lisp, but I fought that battle some years ago with only limited success!)

Answer 1

You can change yasnippet's trigger key to SPC, but it's not per snippet.

(define-key yas-minor-mode-map (kbd "<tab>") nil)
(define-key yas-minor-mode-map (kbd "TAB") nil)
(define-key yas-minor-mode-map (kbd "SPC") ; `yas-maybe-expand' new in 0.12
  (or (bound-and-true-p yas-maybe-expand) #'yas-expand))

See trigger key.

---

what I really want is paren-mode to work with syntax less regular than lisp, but I fought that battle some years ago with only limited success!)

You can try to emulate this with keybinding snippets, see # binding: direct keybinding and joaotavora/yasnippet#533.

e.g. this would give you electric parens:

# -*- mode: snippet; require-final-newline: nil -*-
# name: (
# binding: (
# --
($0)

But it's probably better to use something like smartparens, or electric-pair-mode as joaotavora suggested:

If you want to try out a parenthesis and quote matching alternative to smartparens, I suggest, in this order:

• electric-pair-mode built-in emacs 24.4
• autopair-mode available at http://github.com/joaotavora/autopair