Sublime Text 2's "Goto Anything" (or instant search) for Emacs? - emacs

Question

I tried out Sublime Text 2 recently, and I found Goto Anything superbly useful for navigating source code (Ctrl-P file#symbol seems to work really well). Is there something similar for Emacs? Preferably something that just works, without a ton of custom elisp.
What I've tried so far:
I've seen Helm and Anything, but as far as I understand neither of them is capable of actual "instant" search (see edit below).
I've used multi-occur-in-matching-buffers, but it too seems unable to satisfy the "instant" criterion.
imenu / idomenu works well for single files, but doesn't work across files.
I currently use #2 and #3 together, as a poor substitute for Goto Anything.
If not an exact clone of Goto Anything, then I could make do with a naive instant search solution (one that searches for a given string across all open buffers and displays results dynamically). So that's acceptable too.
I use Emacs 24.2, so any v24-only elisp is also fine.
EDIT: I gave Helm another shot, at event_jr's suggestion, and I found that it does support instant searching across all open buffers. helm-multi-occur + helm-follow-mode comes surprisingly close to meeting my needs, the only minor issues being (at the risk of sounding nit-picky):
I haven't found a way to turn on helm-follow-mode automatically when I run helm-multi-occur. I have to invoke it manually with C-c C-f. Anyone care to take a shot at this with a snippet of elisp? (see edit #2 below)
it isn't "intelligent" like ST2's Goto Anything (i.e., it doesn't understand "symbols" in source code, like Goto Anything does).
EDIT #2: Now I've got most of Goto Anything, thanks to event_jr's answer below (and of course, thanks to Helm's creator, Thierry Volpiatto). I recommend it heartily to anyone looking for a similar feature. Below is the elisp I'm currently using:
;; instant recursive grep on a directory with helm
(defun instant-rgrep-using-helm ()
"Recursive grep in a directory."
(interactive)
(let ((helm-after-initialize-hook #'helm-follow-mode))
(helm-do-grep)))
;; instant search across all buffers with helm
(defun instant-search-using-helm ()
"Multi-occur in all buffers backed by files."
(interactive)
(let ((helm-after-initialize-hook #'helm-follow-mode))
(helm-multi-occur
(delq nil
(mapcar (lambda (b)
(when (buffer-file-name b) (buffer-name b)))
(buffer-list))))))
;; set keybindings
(global-set-key (kbd "C-M-s") 'instant-search-using-helm)
(global-set-key (kbd "C-M-S-s") 'helm-resume)
(global-set-key (kbd "C-M-g") 'instant-rgrep-using-helm)

Answer 1

Just use helm.
It is perhaps more configuration than you asked for, but once you get it
configured how you like, it should be quite comfortable. Very much like Emacs
;).
And you should file a bug with Thierry for getting some more newbie friendly
defaults. He is quite responsive with issues.
helm-multi-occur
Primarily multi-buffer interactive "occur" is provided through
helm-multi-occur. If you execute the command, you'll notice that you have
to pick some buffers first (use C-SPC to select from the list,
M-SPC to select all). Then you can enter your query at the next
prompt. It's easy to make your own version that skips the buffer selection
like so:
(eval-after-load "helm-regexp"
'(setq helm-source-moccur
(helm-make-source "Moccur"
'helm-source-multi-occur :follow 1)))
(defun my-helm-multi-all ()
"multi-occur in all buffers backed by files."
(interactive)
(helm-multi-occur
(delq nil
(mapcar (lambda (b)
(when (buffer-file-name b) (buffer-name b)))
(buffer-list)))))
helm-buffers-list
Often you don't care about the exact occurrences of the query string, but want a
list of all buffers that contain it.
helm-buffers-list has some tricks up its sleeve. The first symbol you
specify is filtering by major-mode, and you can use the "#" prefix to narrow
the list to buffers that contain a string.
To wit, "ruby #prompt" will show you a list of buffers whose major-mode
contains "ruby" and whose contents contains "prompt". Or you can just use "#prompt" to show all buffers that contain "prompt".
Powerful and comfortable once you get used to it.
EDIT modified my-helm-multi-all to enable helm-follow-mode.
EDIT 2 update helm-follow-mode code to reflect helm changes.
EDIT 3 updated again to reflect helm changes

Answer 2

Emacs has Projectile satisfy your need:
jump to a file in project
multi-occur in project buffers

Answer 3

Heml is far from the fuzzy searching of ST3.
Fiplr looks promising but doesn't work on my laptop (see first issue on the github)
Simp.el looks like Fiplr but doesn't work either on my end.
Projectile works for me! Here's your solution!
I used also ido-mode and flx-ido for the fuzzy searching,
and for the vertical way of displaying results I use this in my .emacs:
;; Display ido results vertically, rather than horizontally
(setq ido-decorations (quote ("\n-> " "" "\n " "\n ..." "[" "]" " [No match]" " [Matched]" " [Not readable]" " [Too big]" " [Confirm]")))
(defun ido-disable-line-truncation () (set (make-local-variable 'truncate-lines) nil))
(add-hook 'ido-minibuffer-setup-hook 'ido-disable-line-truncation)
(defun ido-define-keys () ;; C-n/p is more intuitive in vertical layout
(define-key ido-completion-map (kbd "C-n") 'ido-next-match)
(define-key ido-completion-map (kbd "C-p") 'ido-prev-match))
(add-hook 'ido-setup-hook 'ido-define-keys)

Answer 4

Icicles offers some features that are similar to what it seems you are looking for.
C-x b and C-x C-f, to choose buffers or files, allow multi-completion: you can type a pattern to match the buffer/file name and/or a pattern to match content in the buffer/file. Candidates are filtered incrementally as you type (what you call "instant" is what Emacs calls "incremental"). You can refine either or both search patterns progressively, narrowing the choices in different ways. You can visit any number of buffers/files that match, at the same time. You can also use the same method to search the marked files in Dired: C-F.
C-c `(icicle-search) incrementally searches across multiple buffers or files. Again, progressive refinement etc.
The main difference between #1 and #2 is this:
For #1, you just want to find matching buffers or files. You don't care immediately about finding particular occurrences --- any match suffices.
For #2, you provide the buffers or files to search, and you want to navigate among search hits.
You can also use #1 to locate the buffers and files you want, then search their contents: The content-matching pattern you last used is available as the search pattern for Isearch (C-s).

Answer 5

for emacs I customize and modify this solution (for use install helm):
(defun helm-occur-from-point (initial-value)
"Invoke `helm-occur' from point."
(interactive)
(let ((input initial-value)
(bufs (list (buffer-name (current-buffer)))))
;; (isearch-exit)
(helm-occur-init-source)
(helm-attrset 'moccur-buffers bufs helm-source-occur)
(helm-set-local-variable 'helm-multi-occur-buffer-list bufs)
(helm-set-local-variable
'helm-multi-occur-buffer-tick
(cl-loop for b in bufs
collect (buffer-chars-modified-tick (get-buffer b))))
(helm :sources 'helm-source-occur
:buffer "*helm occur*"
:history 'helm-grep-history
:input input
:truncate-lines t)))
(defun get-point-text ()
"Get 'interesting' text at point; either word, or region"
(if mark-active
(buffer-substring (mark) (point))
(thing-at-point 'symbol)))
(defun helm-occur-1 (initial-value)
"Preconfigured helm for Occur with initial input."
(helm-occur-from-point initial-value))
(defun bk-helm-occur ()
"Invoke helm-occur with initial input configured from text at point"
(interactive)
(helm-occur-1 (get-point-text)))
(global-set-key (kbd "M-s-o") 'bk-helm-occur)
primary it based on
#see https://news.ycombinator.com/item?id=6872508 but on last helm versions not work but fixed with my changes (just copy/paste from some internal helm modules)