Allow users to customize what to jump to with avy

[tuhdo]

It would be useful for user to customize what to jump to. For example, a user can create an avy command to jump to all the if occurrences; similar while, for... so I can bind all of them under some prefix key like C-j and quickly jump to with a few key strokes with minimal screen disruption.

I got the idea from this issue: abo-abo/lispy#77

[PythonNut]

Would this be something that should be built into avy? You could achieve this yourself with a small snippet:

(defun avy-goto-while ()
  (interactive)
  (avy--goto
    (avy--process
      (mapcar
        (lambda (point)
          (cons (cons point point)
            (get-buffer-window)))
        (let ((points))
          (save-excursion
            (goto-char (window-start))
            (while
              (prog1
                (search-forward "while"
                  (min (point-max) (window-end))
                  t)
                ;; adjust target to beginning of match
                (push (- (point) 5) points)))
            points)))
      (avy--style-fn avy-style))))

[abo-abo]

Even simpler:

(avy--generic-jump "while" nil 'pre)

[tuhdo]

@abo-abo Great to know that it's just that simple. Maybe you could provide a macro that wraps around avy--generic-jump: a user can use this macro to define his jump command to a particular regexp. For example, let's name this macro avy-def-jump. A user can use it like this:

(defvar avy-while-object '("while " nil 'pre))
(avy-def-jump global-map (kbd "C-j w") 'avy-while-object)

Then it generates appropriate binding for a particular keymap.

[tuhdo]

It's great that avy already accepts regexp. Now I can jump to any conditional sexp in Lisp with this simple snippet:

(avy--generic-jump "(if\\|(cond\\|(when\\|(unless" nil 'pre)

So now instead of thinking about jump to a character, I can think about jump to semantic units on screen!

I think this is a great feature that should be mentioned on avy homepage. Now we only need a macro for ease customization.

[abo-abo]

Now we only need a macro for ease customization.

A macro unnecessarily restricts the things you can do:

• naming
• documenting
• advising
• re-using
• calling by name

It's only worth it if the abstraction power is high, which it isn't in this case. This is much better in my opinion, and not much longer:

(global-set-key
 (kbd "C-j w")
 (defun avy-goto-while ()
   (interactive)
   (avy--generic-jump "while " nil 'pre)))

[tuhdo]

But then, new users will have to write boilerplate code like that. I am assuming avy users are non-Elisp programmers as well.

But that's look fine to me. I think this could be turned into a feature, and provide a few built-in commands for popular major modes i.e. C/C++, Python, Lisp