Re: Eclipse-style control-click on Elisp function name to visit source

[Ted Zlatanov]

On Fri, 6 May 2011 17:20:28 +0000 (UTC) Alan Mackenzie <acm@muc.de> wrote: 

AM> Ted Zlatanov <tzz@lifelogs.com> wrote:
>> Right now, if I want to see the definition of a function, I do `C-h f'
>> to see the docstring, then RET on the link to the definition.

>> I'd like to bind that visit directly to `C-mouse-1' click on any
>> function name in any ELisp buffer, similar to how Eclipse does it for
>> Java code for instance.  I couldn't find a way to do it in Emacs.  Any
>> ideas?  Or should I write it myself?

AM> I think you should write it yourself.  Shouldn't be too difficult.  The
AM> difficult bit is chosing a key binding (or a "mouse binding").

On Fri, 06 May 2011 14:28:51 -0300 Stefan Monnier <monnier@iro.umontreal.ca> 
wrote: 

SM> M-x find-function is pretty close.

The code below seems to do the job (I don't use the regular C-Mouse-1
binding that selects among the buffers).  

I'd like to highlight valid symbols *only* (which would respond to one
of the handled conditions in `tzz-find-symbol-at-point') when the mouse
hovers over them but haven't done it.  Otherwise this seems like a nice
feature for people who are used to the Eclipse style of finding
functions and variables, and could even be enabled by default in Emacs
or made into a package.  I'm happy with it as it is, but if you find it
useful let me know and I'll make it fit for general consumption.

Thanks
Ted

#+begin_src lisp
(defun tzz-find-symbol-at-point ()
  "Find the function, face, or variable definition for the symbol at point
in the other window."
  (interactive)
  (let ((symb (symbol-at-point)))
    (cond
     ((and (or (functionp symb)
               (fboundp symb))
           (find-definition-noselect symb nil))
      (find-function-other-window symb))
     ((and (facep symb) (find-definition-noselect symb 'defface))
      (find-face-definition symb))
     ((and (boundp symb) (find-definition-noselect symb 'defvar))
      (find-variable-other-window symb))
     (t (message "No symbol at point")))))

(global-set-key [(control mouse-1)]
                (lambda (click)
                  (interactive "e")
                  (mouse-minibuffer-check click)
                  (let* ((window (posn-window (event-start click)))
                         (buf (window-buffer window)))
                    (with-current-buffer buf
                      (save-excursion
                        (goto-char (posn-point (event-start click)))
                        (tzz-find-symbol-at-point))))))

#+end_src