Posted by Doug
Thu, 08 Nov 2007 02:58:00 GMT
OK, last emacs tip for a while. It’s ironic, but the last two years I’ve written some cool elisp while at RubyConf. I typically run emacs full screen and split buffers both vertically and horizontally to arrange bits of code. It’s not uncommon for me to end up with three, four, five or even six visible windows in emacs. The problem though is navigating between them.
The out-of-the-box solution is to use other-window (bound to C-x o) and just cycle through them. If you’re fancy you can give a prefix argument to other-window and go backwards. This window cycling is tedious to me though and I’d like something faster. Particularly when I’m mostly bouncing back and forth between two windows.
To solve this problem I wrote jump-to-buffer. Of course, right now I’m really enamored with the fuzzy matching in ido-completing-read. That’s what allows you to type non-sequential characters to match the buffer name. It’s very similar to TextMate’s pattern matching. So, jump-to-buffer uses ido-completing-read. The buffers it gives you as options for completion are only the buffers in visible windows. It also sorts those buffers in the order of the buffer-list; which is in the order of most recently accessed.
To make this work, I’ve written two helper functions: rotate-list, and sort-by-other-list. Without further ado:
(defun dka-sort-by-other-list (to-sort-list other-list)
(let* ((index 0)
(other-alist (mapcar (lambda (buffer)
(setq index (+ index 1))
(cons buffer index))
other-list))
(swartz (mapcar (lambda (item)
(cons (cdr (assoc item other-alist)) item))
to-sort-list))
(sorted-list (sort swartz (lambda (a b) (< (car a) (car b))))))
(mapcar 'cdr sorted-list)))
(defun rotate-list (list count)
"Rotate the LIST by COUNT elements"
(cond
((= count 0) list)
((not list) list)
(t
(rotate-list (nconc (cdr list) (list (car list)) '()) (1- count)))))
(defun dka-jump-to-window ()
"Interactively jump to another visible window based on it's `buffer-name' using `ido-completing-read'"
(interactive)
(let* ((visible-buffers (mapcar '(lambda (window) (window-buffer window)) (window-list)))
(sorted-visible-buffers (dka-sort-by-other-list visible-buffers (buffer-list)))
(rotated-buffer-list (rotate-list sorted-visible-buffers 1))
(visible-buffer-names (mapcar (lambda (buffer) (buffer-name buffer)) rotated-buffer-list))
(buffer-name (ido-completing-read "Enter buffer to jump to: "
visible-buffer-names
nil t))
(window-of-buffer
(delq nil
(mapcar '(lambda (window)
(if (equal buffer-name (buffer-name (window-buffer window)))
window nil)) (window-list)))))
(select-window (car window-of-buffer)))
)
I’m definitely interested in feedback on this code. The dka-sort-list-by-other-list method was particularly tricky for me to write. I think it’s both right and fast. I haven’t dove into elunit yet to know for sure if it’s right.
Posted in Emacs, Programming | Tags elisp, elunit, emacs, schwartz, sorting, transform | no comments
Posted by Doug
Thu, 08 Nov 2007 02:09:00 GMT
While I’m sharing emacs hacks, I finally got around to researching this and/or figuring it out. I almost always run emacs inside the terminal in a “no window” mode. It’s pretty natural for me to use M-w to copy something from emacs and then try to Cmd-V it in another Terminal window or likewise Cmd-C something in Terminal and then try paste it into emacs with C-y. Until now, I haven’t known how to share the clipboard with emacs.
(defun copy-from-osx ()
(shell-command-to-string "pbpaste"))
(defun paste-to-osx (text &optional push)
(let ((process-connection-type nil))
(let ((proc (start-process "pbcopy" "*Messages*" "pbcopy")))
(process-send-string proc text)
(process-send-eof proc))))
(setq interprogram-cut-function 'paste-to-osx)
(setq interprogram-paste-function 'copy-from-osx)
This takes advantage of the pbcopy and pbpaste command line programs to access the clipboard and offers them up as elisp method for emacs’ interprogram-*-functions. Easy, peasy, pumkin weasy.
I need to give some props to Mark Aufflick for his post on Automatic Copy from X11 App to Mac OS Clipboard. My paste-to-osx is pretty much a straight rip from him.
Posted in Emacs, Mac OS X | Tags clipboard, emacs, mac, pbcopy, pbpaste | no comments
Posted by Doug
Wed, 07 Nov 2007 16:04:00 GMT
One of the things that’s really nice about TextMate is the Cmd-T navigation of files in your project. It pops up this little dialog with fancy pattern matching input to select one of the files in your project and then jumps to that file. There’s a similar command once your in a file to jump to symbols in that file. I’ve tried a couple things to achieve that behavior in emacs that I’d like to talk about.
The first thing I tried was a method called find-file-in-project. It was originally implemented by Phil Hagelberg as part of his “Another Ruby on Rails Mode” (arorem) and then also ported over to the current Rinari Is Not a Rails IDE. Basically, it indexes all the files in a “project” and then provides a nice interactive completing read to switch between them. It basically works just like Cmd-T in TextMat. I did quite a bit of work optimizing the completing read so that it would behave nicely. The problem is that emacs is slow to index the files in your project.
What I’m using now is the tried and true find-tag method which is part of etags.el. ETags depends on an external TAGS file as an index of all the symbols in your project. When you invoke find-tag (by default bound to M-.) it prompts you with completing read for the symbol to find. It then jumps directly to the file and location where that symbol is defined. It’s basically combining the find-file-in-project with find-symbol-in-buffer. It’s also very, very fast.
As an added bonus, you can use tags-search to search through your project finding places that tag is used. This is similar to TextMate’s slowly grep all the files and render a buffer with those results in it, but much faster.
The bad news is you have to manually build the TAGS file periodically. Emacs is pretty good about continuing to work when you’ve made modifications to the files, but if you add new methods, new files, or refactor significantly where thing are located then it gets confused. When that happens, simply rebuild the TAGS file.
Jim Weirich gave me a nice little rake task to do the job:
module Tags
RUBY_FILES = FileList['**/*.rb'].exclude("pkg")
end
namespace "tags" do
task :emacs => Tags::RUBY_FILES do
puts "Making Emacs TAGS file"
sh "xctags -e #{Tags::RUBY_FILES}", :verbose => false
end
end
task :tags => ["tags:emacs"]
Just put that in lib/tasks/tags.rake and then run rake tags:emacs when you invoke find-tag and it can’t find it. That shouldn’t happen very often. I’ve found it’s also very fast to build the TAGS file. I might consider putting that tags task as part of the normal run tests task, but I’m not sure that’s necessary.
The other catch here is that the rake task above calls out the exuberant ctags rather than the ctags that comes with emacs. The exuberant ctags knows how to parse ruby files whereas the ctags that comes with emacs can’t.
I’ve installed exuberant ctags from MacPorts. It is xctags even though MacPorts doesn’t install it that way. So (for better or worse) I’ve renamed the ctags files installed with ports to xctags. This also gets around the conflict that MacPorts thinks there is between the ctags installed with emacs and the exuberant ctags.
Give this a spin and let me know what you think. I’ve found it to be very accurate and very fast.
Posted in Emacs, Programming, Lisp, Ruby on Rails, Mac OS X | Tags emacs, etags, rinari, Ruby, TextMate, xctags | 4 comments
