Writing A First Emacs Elisp Function
So today I tried to write my first fully custom Emacs Lisp code. Here are some
things I learned (along with the code for a
Here is my final product, uploaded straight from Emacs.
The final script looks like this at the bottom of my
;;; Region to Gist(defun region-to-gist ()"Sends region to Gist"(interactive)(if (region-active-p)(gist-req (buffer-substring-no-properties (region-beginning) (region-end))))nil)(defun gist-test (buf)(message "%S" `(:content ,buf)))(defun gist-req (buf)(request"https://api.github.com/gists":type "POST":data (json-encode `(:description "Created with Christopher Biscardi's region-to-gist":public t:files (:example.el (:content ,buf))));; :data "key=value&key2=value2" ; this is equivalent:parser 'json-read:success (function*(lambda (&key data &allow-other-keys)(message "I sent: %S" (assoc-default 'html_url data)))))nil)
It is used by setting a mark
C-SPC, selecting a region (arrow keys work to
expand the region) then typing
M-x region-to-gist. The Function then runs and
outputs either an error message (hopefully not) or this to the message buffer:
I sent: "https://gist.github.com/8812412"
The most important part here is the
(interactive) which allows you to use
M-x region-to-gist to execute the function. There are a couple different modes you
can enable with this.
region-active-p basically returns true if there’s a region selection (The
C-SPC and arrows stuff).
gist-test is a function I used to replace the
gist-req call so I could test
whether or not the region was actually being sent and resolve some formatting
issues. This function can be wholly deleted with no ramifications.
buffer-substring-no-properties returns undecorated strings from your buffers.
Use this is you’re trying to handle a string (such as in JSON) and use
buffer-substring if you’re trying to put something in the kill-ring, etc.
I’m using request.el to make my request.
It tries to use
curl if available.
The biggest part of the request code is the
:success function. In this case we
grab the key
html_url from the Gist API
The backtick here:
`(:description "Created with Christopher Biscardi'sregion-to-gist" :public t :files (:example.el (:content ,buf)))
means we have to use the
,buf to get the value of
Oh, and also, this function should probably be called
gist-region as per other
region functions. oops.