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Org Mode

#+title: Notes on Emacs
#+author: Various
#+filetags: NOTE
#+options: toc:t
This is a small collection of Emacs related posts and documentation by other
authors that I find useful.
* Random Notes
** Insert URL from Safari :IRREAL:
:CREATED: [2018-08-04 Sat 17:44]
Responding to [[][yesterday's post]], Sacha asks if I could post the code for
=jcs-insert-url= for others to use. I thought I'd already done that but
apparently not. That's probably because except for the part identical to
=jcs-get-link=, which I /did/ [[][write about]], it's pretty trivial. In any event,
here it is:
#+BEGIN_SRC emacs-lisp
(defun jcs-insert-url ()
"Insert URL of current browser page into Emacs buffer."
(insert (jcs-retrieve-url)))
The =jcs-retrieve-url= function does all the work, of course, and is
just the code that I abstracted out of =jcs-get-link= to actually
retrieve the URL from Safari:
#+BEGIN_SRC emacs-lisp
(defun jcs-retrieve-url ()
"Retrieve the URL of the current Safari page as a string."
(org-trim (shell-command-to-string
"osascript -e 'tell application \"Safari\" to return URL of document 1'")))
One obvious problem with all this is that it works only for macOS. Not to
despair, though, because in the comments to the original post, [[][Brad Collins
suggests a solution]] that uses [[][grab-x-link]] to do the same thing for FireFox and
Chrome on other systems. Be sure to read Brad's comment because there is---or at
least was---an issue with the MELPA version.
Finally, Sacha took the part about looking for ways to make your workflow easier
seriously and came up with a bit of Elisp to [[][insert a function definition at the
point]], regardless of where it's defined. That's very handy and I immediately
stole her code and used it to insert the two functions above. My old method was
to switch to =init.el=, find the function, copy it to the kill ring, switch back
to the original buffer, add the source block fences, and insert the code between
them. Sacha's code did all of that for me and I didn't even have to leave my
current buffer. That's splendid. If you find yourself having to add function
definitions to your text, be sure to read Sacha's post. It will save you a lot
of time.
** Calc for Programmers :IRREAL:
:CREATED: [2018-08-05 Sun 10:04]
After writing about Florian Adamsky's post on [[][acronyms in AUCTeX]], I snooped
around on his site and came across a [[][nice post]] on [[][Emacs Calc]] from a programmer's
and computer scientist's point of view. As regular readers know, I've been
working to increase my calc-fu lately so I read the post with interest.
Adamsky demonstrates some of the Calc functions that are useful to programmers
and computer scientists. This includes such things as entering and displaying
numbers in various radixes and performing the standard logical operations on
(the usually binary representation of) numbers. He even shows how to add a new
“units” representation to Calc---in this case bits/bytes/bits per second.
Calc is a large subsystem and famously hard to master but worth the effort. It's
been described as a “poor man's Mathematica.” It's not nearly as powerful as
Mathematica, of course, but it's surprising how many things it can do. If you're
a programmer/computer scientist and an Emacs user you should spend a little time
investigating Calc. It really can make your life easier. An easy way to get
started is to read Adamsky's post. It covers only a small slice of Calc but will
give you an idea of its power.
** Parsing with ~org-element~ :IRREAL:
:CREATED: [2018-08-10 Fri 17:55]
The other day, I saw [[][this query]] on the reddit Emacs subreddit. I already have
solutions for this type of problem but I'm always interested in the how people
use Org mode to record and report data so I followed the link that primitiveinds
provided for [[][his solution]] to generating time reports.
Even if, like me, you already have your time tracking and reporting needs under
control, primitiveinds' solution is worth looking at for its own sake. It works
by looking for CLOCK entries in an Org buffer and accumulating the relevant
information in the CLOCK line as well data about the associated task. That might
seem like it would require routine but tedious text manipulation but
primitiveinds leverages the org-element functionality to easily handle the task.
He starts by calling =org-element-parse-buffer= to generate a tree
representation of the Org buffer. Then he uses =org-element-map= to examine each
CLOCK element (and only CLOCK elements) to extract the necessary
information. It's a great technique that can easily be adapted for other parsing
of Org data. The code that primitiveinds presents is easy to follow and he
provides a nice explanation of what it's doing.
If you need to programmatically examine Org data for further processing, you
should take a look at primitiveinds' post. It's definitely worth a read.
The relevant code:
#+begin_src emacs-lisp
'(("date" "project" "hours" "task"))
(let ((ast (org-element-parse-buffer 'element)))
(org-element-map ast 'clock
(lambda (x)
(let* ((val (org-element-property :value x))
(task (org-element-property :parent (org-element-property :parent x))))
`(,(let ((year (org-element-property :year-start val))
(month (calendar-month-name
(org-element-property :month-start val)))
(day (org-element-property :day-start val)))
;; (insert (org-element-property :raw-value val))
(format "%s %s, %s" month day year))
,(org-element-property :PROJECT task)
,(org-element-property :duration x)
,(org-element-property :title task)
'(("" "total:" ":=vsum(@2..@-1);T" "")))
** Emacs Lisp Byte-Code :IRREAL:
:CREATED: [2018-08-11 Sat 21:40]
Very few Emacs users---no matter how advanced---ever need to worry about the
specifics of the Elisp bytecode, or even, for that matter, that it
exists. Still, as guys like Chris Wellons [[][have shown]], it can sometimes be useful
to have a basic understanding of the bytecodes.
R Bernstein has put together a comprehensive, book-length [[][documentation on Elisp
bytecodes]]. After a short introduction, the documentation considers the bytecode
environment including the compiler, interpreter, and bytecode optimization. Then
there's a long section on the individual bytecode instructions.
Finally, there are sections on the changes in bytecodes between Emacs versions,
a table of opcodes, and a reference section. There's also a GitHub repository of
the [[][document source]].
As I said, you probably will never need this but if you do, you'll be /very/
glad to have Bernstein's documentation. It's another example of the vibrant
Emacs community.
** Formatting Tables :IRREAL:
:CREATED: [2018-10-28 Sun 09:13]
If you're like me, you automatically think of the Org mode table editor (or
Orgtbl minor mode) when you think of tables in Emacs. It's hard to beat that
functionality and Orgtbl mode makes it available everywhere in Emacs, even if
you're not in an Org buffer. Sometimes, though, you'd like to have special
formatting for some or all of the table. That's where =delim-col= comes in.
=Delim-col= is /built-in/ Emacs functionality that allows you to do things like
adjust what string separates the columns, add a beginning or ending string to
each item, add an ending string for each row, and adjust the padding in the
table. It can be really handy for copying and pasting and then reformatting
tables from an external source.
I didn't know about =delim-col= until I read about it [[][over at Emacs Notes]], where
you'll find a good explanation of the facility and what it can do. The Emacs
Notes post also offers at bit of Elisp to make choosing the strings and
delimiters a bit easier. By default you have to set them using a series of
=setq= statements if you want something different from the built-in choices. The
Emacs Notes codes arranges for you to be prompted for the values.
You probably won't need the =delim-col= functionality very often but when you do
it's much easier than using something like a keyboard macro. Take a look at the
post and see if you don't agree.
** Org Mode Cookbook :IRREAL:
:CREATED: [2018-08-04 Sat 12:51]
Way back in 2014, I [[][posted]] about Eric Neilsen's excellent [[][Emacs org-mode
examples and cookbook]]. I recently came across a reference to it and was reminded
what a great resource it is. It's easy to browse through and just read one or
two entries when you have time. In skimming through it, I learned---or perhaps
relearned---how to [[][insert in-line calculations in a document]].
As I wrote in the original post, Neilsen is a researcher and his cookbook is
oriented at using Org mode to produce documents of various types. Still, that
covers a lot of territory and there are many good examples of powerful Org mode
use cases in it. The Document has moved or, really, taken up a second
residence. It was originally hosted at [[][Fermilab]], where Neilsen works, and it's
still there but it's also available at his own site. The two documents are
identical so it doesn't matter if you use the new link or the original one
pointing to FNAL.
If you're an Org user, especially if you use Org to produce documents,
you should take a look at Neilsen's cookbook and bookmark it for future
** How to paste then copy
:CREATED: [2018-08-11 Sat 21:47]
Question: how to set a mark such that all subsequent copy operations move their
text to that exact mark.
Answer: use ~cua-selection-mode~! See
/Update/: turns out it doesnt work so well, disabled it again.
** Tramp and Telnet over non-standard ports
:CREATED: [2018-12-29 Sat 15:58]
Syntax: ~/telnet:HOST#PORT:~, works also with other protocols.
** Fractals in Emacs
:CREATED: [2018-08-04 Sat 13:01]
#+begin_src emacs-lisp
(defun sierpinski (s)
(pop-to-buffer (get-buffer-create "*sierpinski*"))
(fundamental-mode) (erase-buffer)
(labels ((fill-p (x y)
(cond ((or (zerop x) (zerop y)) "0")
((and (= 1 (mod x 3)) (= 1 (mod y 3))) "1")
(t (fill-p (/ x 3) (/ y 3))))))
(insert (format "P1\n%d %d\n" s s))
(dotimes (y s) (dotimes (x s) (insert (fill-p x y) " "))))
(defun mandelbrot ()
(pop-to-buffer (get-buffer-create "*mandelbrot*"))
(let ((w 400) (h 300) (d 32))
(fundamental-mode) (erase-buffer)
(set-buffer-multibyte nil)
(insert (format "P6\n%d %d\n255\n" w h))
(dotimes (y h)
(dotimes (x w)
(let* ((cx (* 1.5 (/ (- x (/ w 1.45)) w 0.45)))
(cy (* 1.5 (/ (- y (/ h 2.0)) h 0.5)))
(zr 0) (zi 0)
(v (dotimes (i d d)
(if (> (+ (* zr zr) (* zi zi)) 4) (return i)
(psetq zr (+ (* zr zr) (- (* zi zi)) cx)
zi (+ (* (* zr zi) 2) cy))))))
(insert-char (floor (* 256 (/ v 1.0 d))) 3))))
** Presentations with ~org-reveal~
#+title: Foo!
#+author: bar
#+options: author:t toc:t num:nil date:nil timestamp:nil
#+reveal_theme: sky
* Slide 1
* Slide 2
** Subslide 1
** Subslide 2
- Item 1
- Item 2
| a | b | d |
| 1 | 2 | 3 |
* Slide 3
** Writing a PhD thesis with Org Mode
*TLDR*: I started using Emacs about 3 years ago. I couldn't be more grateful to
have seen the light, and to have been rescued from the darkness of Windoze,
Goggle and/or friends. After enlightenment, I've taken upon myself the task of
customising an environment to write my PhD thesis with Org Mode.*
*** Why
Post created in response to the [[][current thread]] in /r/emacs/ on thesis writing
with Org Mode.\\ I see most people's reason to avoid Org mode for scientific
writing is the fact that supervisors or co-authors use Mic. Word. I'll try to
argue that that's not enough reason to accept subpar tools.
*** What I'll talk about
I'll mention a bit of my motivations, and then I'll discuss how to make use of
(mostly) built in Org functionality such as tagging, export, [[][setupfiles]] and
includes, reference management, keyboard shortcuts and advanced searching; all
with the purpose of building a useful thesis writing environment. Readers should
have a minimum knowledge of Org mode, the Org export system and LaTeX.
*** My requirements
Here in the Netherlands, most PhD thesis consist of an introduction, 3 to 4
research chapters (as submitted for publication), a summary, bibliography and
appendices. What this means for me is that my writing environment has to
/necessarily/ satisfy the following *minimum requirements*:
- Inclusion of (parts of) external files
- Keeping track of references
- Include and reference figures
- Version control documents
- Support for sharing with my supervisor in whatever format he wants
Failure to comply with any of these means the editor is unfit for
purpose^{#fn.1”>1}. Unfortunately, this set of requirements are not seamlessly
satisfied by likes of Mic. Word or G. Docs. I reckon they can probably be
configured to satisfy them, but why bother.
Additionally, a PhD thesis writing environment should also provide the following
- Extended searching facilities for both text and references
- Simple syntax for tables and equations
- Support within a proper text editor
- Shortcuts to reach my files and build the thesis
To the best of my knowledge, /only/ Emacs with Org Mode + ox-latex provide all
of these out of the box.
*** Moulding Org Mode for thesis writing
Most of my inspiration comes from reading Kitchin's blogs and code, and reading
the Org Mode documentation, mailing list and Emacs Stack Exchange. Here' I'll go
one by one through all of the requirements listed above, and how to deal with
**** Prelude: File structure
I have a main / document, with latex heading declarations and a
commented setup file. I also have / files, in different
directories, with their own latex heading declarations and commented setup
The first lines of / look like the following:
#+BEGIN_src org
# -*- mode: org; org-latex-title-command: ""; org-latex-toc-command: "" -*-
#+TITLE: Thesis Title
#+LATEX_CLASS: mimosis
# Setupfile with #+LATEX_HEADER, #+OPTIONS and explanations
#+SETUPFILE: thesis.setup
#+LATEX_HEADER: \KOMAoptions{fontsize=12pt,headings=small}
#+LATEX_HEADER: \bibliography{~/Papers/bibtex/Publications}
#+EXCLUDE_TAGS: journal noexport
* Frontmatter :ignore:
#+LATEX: \frontmatter
#+LATEX: \tableofcontents
* Mainmatter :ignore:
#+LATEX: \mainmatter
* Introduction
* Research 1
#+INCLUDE: "../research1/*Abstract" :only-contents t
Some stuff.
#+INCLUDE: "../research1/" :lines "5-"
* Research 2
And the first lines and structure overview of the multiple / files:
#+BEGIN_src org
#+TITLE: Research
#+LATEX_CLASS: elsarticle
#+LATEX_CLASS_OPTIONS: [authoryear,preprint,11pt]
#+SETUPFILE: paper.setup
#+EXCLUDE_TAGS: thesis noexport
* Frontmatter :ignore:journal:
#+LATEX: \begin{frontmatter}
** Author List :ignore: Abstract :ignore: Keywords :ignore:
#+LATEX: \end{frontmatter}
* Introduction
**** Inserting (parts of) external files
I write my research chapters with LaTeX classes targeting the journal's
format. That means that a research chapter may be written with the =elsarticle=
class, whereas the thesis as a whole is written with the =mimosis= [[][class]], a
derivative of KOMA =scrbook=. Here's the class configuration for both:
#+begin_src emacs-lisp
(add-to-list 'org-latex-classes
. "\\section*{%s}") ("\\subsection{%s}"
. "\\subsection*{%s}") ("\\subsubsection{%s}"
. "\\subsubsection*{%s}") ("\\paragraph{%s}"
. "\\paragraph*{%s}") ("\\subparagraph{%s}"
. "\\subparagraph*{%s}")))
(add-to-list 'org-latex-classes
("\\chapter{%s}" . "\\chapter*{%s}")
. "\\section*{%s}") ("\\subsection{%s}"
. "\\subsection*{%s}") ("\\subsubsection{%s}"
. "\\subsubsection*{%s}") ("\\mboxparagraph{%s}"
. "\\mboxparagraph*{%s}") ("\\mboxsubparagraph{%s}"
. "\\mboxsubparagraph*{%s}")))
Research chapters print the bibliography on their own, and they may contain
acknowledgements that shouldn't be present in the middle of the thesis, so they
should be excluded. In other to insert research chapters into my thesis, I use
Org's =#+INCLUDE= derivative:
#+begin_src org
In order to not include the some parts of the file, i.e., to exclude the title,
setupfile and headers, I narrow down the lines:
#+begin_src org
# Include line 5 until the end of the file
#+INCLUDE: :lines 5-
In order to exclude parts of the file, I tag research chapter headings that are
only meant for publication with a =:journal:= tag (such as the bibliography or
acknowledgements). This way they are automatically excluded from the thesis (see
the =#+EXCLUDE_TAGS:= derivative in the / file). Also, I could have
thesis specific content in the / document tagged with =:thesis:=,
and it would be excluded in the / export, but I currently don't
have any.
Now, the most important piece of advice I can give anyone is to *learn how to
use tags*, =EXCLUDE_TAGS= and the org-plus-contributions =ignore= tag. With the
=ignore= tag we separate the structuring of the text as a physical document from
the structuring of the text as a semantic unity. This allows an extremely fine
control over pieces of text to include into another document. For example, in a
research chapter written with the =elsarticle= class, the abstract has to be
included in the Frontmatter. By tagging a headline as follows:
#+begin_src org
** Abstract :ignore:
I can write the research abstract in it's own heading, pretend that the heading
itself does not exist (so it does not trigger =/begin{document}=), only its
contents, and then include the contents in the thesis in an arbitrary location:
#+begin_src org
# in
#+INCLUDE: "*Abstract" :only-contents t
The =:ignore:= tag is one of the best Org mode features, in my opinion. It's
key to my workflow, and a shame to see it's not a part of Org core, but rather a
contribution to be found in /ox-extra.el/. To activate it, add the following to
your /init/:
#+BEGIN_src emacs-lisp
(require 'ox-extra)
(ox-extras-activate '(ignore-headlines))
The realisation that it's possible to have such fine control over where to
include or exclude pieces of text opens the door to all sort of interesting
experiments: putting figures and captions directly into beamer or org-reveal
presentations, creating conference posters, writing blog posts, etc.
**** Keep track of references
For backwards compatibility I still use Mendeley to track literature. I export
bibtex files for each research project individually, and also a master bibtex
for use in the thesis. These documents are saved to =~/Papers/bibtex/=, but for
the research chapters, I keep local copies under
=./ref/Publications-research.bib=.\\ To insert citations, I use [[][org-ref.]] It's
documentation says it all. After setting up local bibliography files with the
derivative =#+BIBLIOGRAPHY=, press =C-c ]= to see a list of publications and
insert them in place. I also prefer to have =parencite= citations instead of
=cite=, because they work nicely with BibLaTeX. My setup for org-ref:
#+begin_src emacs-lisp
(with-eval-after-load 'org-ref ;; see org-ref for use of these variables
(setq org-ref-default-bibliography '("~/Papers/bibtex/Publications.bib")
org-ref-pdf-directory "~/Papers/MendeleyDesktop/"
org-ref-get-pdf-filename-function 'org-ref-get-mendeley-filename
bibtex-completion-pdf-field "file" org-latex-prefer-user-labels t
org-ref-default-citation-link "parencite"
;; bibtex-dialect 'biblatex
(defun org-ref-open-pdf-at-point-in-emacs ()
"Open the pdf for bibtex key under point if it exists."
(let* ((results (org-ref-get-bibtex-key-and-file))
(key (car results))
(pdf-file (funcall org-ref-get-pdf-filename-function key)))
(if (file-exists-p pdf-file)
(find-file-other-window pdf-file)
(message "no pdf found for %s" key))))
(defun org-ref-grep-pdf (&optional _candidate)
"Search pdf files of marked CANDIDATEs."
(let ((keys (helm-marked-candidates))
(get-pdf-function org-ref-get-pdf-filename-function))
(-remove (lambda (pdf) (string= pdf ""))
(mapcar (lambda (key) (funcall get-pdf-function key))
(helm-add-action-to-source "Grep PDF" 'org-ref-grep-pdf helm-source-bibtex 1)
(setq helm-bibtex-map (let ((map (make-sparse-keymap)))
(set-keymap-parent map helm-map)
(define-key map (kbd "C-s") (lambda () (interactive) (helm-run-after-exit 'org-ref-grep-pdf)))
(push `(keymap . ,helm-bibtex-map) helm-source-bibtex)
(setq org-ref-helm-user-candidates
'(("Open in Emacs" . org-ref-open-pdf-at-point-in-emacs))))
**** Include and reference figures
For each research project I keep a =./media= directory, where all my figures
live. You can include figures in Org mode by using the following syntax:
#+begin_src org
#+NAME: figurename
#+CAPTION: This is a figure caption
Currently there is a bug in the ELPA version of Org mode, such that relative
paths to figures in =#+INCLUDE= 'd files aren't adapted with respect to the
including file, so the latex export cannot find them. I've [[][submitted a fix]]
which should land in the next release of Org.
**** Version control documents
[[][Magit]]. I thought about having the research chapters as git submodules in a
thesis git project directory, but I currently don't. This would allow me to
always have the thesis code in a saved state, even if I further work on my
research chapters to answer to reviewers questions.
**** Support for sharing with my supervisor
Unfortunately, my supervisor likes to write comments in Mic. Word. I give in
that sharing your writing with colleagues is a fundamental part of
research.\\ Fortunately, [[][ox-word]] export via Pandoc & LaTeX is capable of
creating nice looking, structured Word files which I send to my supervisor. I
then manually work through each comment step by step, though I'm looking for a
way to improve this part of my workflow. I think the Emacs community is missing
a minor mode to track Word document changes from within Org Mode. There are some
ideas laying around on how to implement it [[][hidden deep in the mailing list]], or
in [[][this Emacs Exchange thread]].
I may update this post with more information later.
**** Extended search facilities
By extended search facilities I mean the ability to quickly search for
information in references, and to keep notes linked to the literature. For
searching I make use of [[][org-ref + pdfgrep]], as shown in my org-ref setup. For
notes linked to documents I've recently started to use [[][Org-noter.]]
**** Simple syntax for tables and equations
Org tables are a pleasure to work with. The following:
| a | b | c |
| 1 | 2 | 3 |
Turns into:
| a | b | c |
| 1 | 2 | 3 |
Equations can be written in LaTeX:
\frac{d \vec{M} (t)}{dt} = \vec{M} (t) \times \gamma \vec{B} (t)
will become /omitted/
**** Support within a proper text editor
No need to talk about the synergy of using Emacs to edit text. I personally
started using Spacemacs without Evil mode, because I find it aesthetically
pleasing and because it offers great support for the languages I use the most,
and excellent integration with Helm and Org.\\ The following configurations make
the Org editing experience a bit nicer, in my opinion:
#+BEGIN_src emacs-lisp
;; Writegood
(add-hook 'org-mode-hook 'writegood-mode)
(use-package org-variable-pitch
:load-path "~/Elisp")
(add-hook 'org-mode-hook 'org-variable-pitch-minor-mode)
(setq visual-fill-column-width 120 visual-fill-column-center-text t)
(add-hook 'org-mode-hook 'visual-line-mode)
(add-hook 'org-mode-hook 'visual-fill-column-mode)
(add-hook 'org-mode-hook 'org-display-inline-images)
;; I have a modified version of the following:
(load-file "~/Projects/rogue/config.el")
(add-hook 'org-mode-hook '(lambda () (setq-local line-spacing 5)))
;; Aesthetical enhancements.
(setq org-fontify-quote-and-verse-blocks t
org-hide-macro-markers t
org-fontify-whole-heading-line t
org-fontify-done-headline t
org-hide-emphasis-markers t)
**** Shortcuts to reach my files and build the thesis
I have a hydra (defined in Spacemacs as a transient-state) to move between my
Thesis files:
#+begin_src emacs-lisp
;; Spacemacs hydra.
:title "Ph.D. Thesis Menu"
:doc "
^Main Files^ ^Chapters^ ^Actions^
_m_: Thesis _1_: Research 1 _o_: Open Thesis.pdf externally
_t_: Title page _2_: Research 2 _c_: Async compile file
_i_: Introduction _3_: Research 3 _a_: things
_s_: thesis.setup _4_: Research 4 ^ ^
("a" things :exit t)
("m" (find-file "~/thesis/") :exit t)
("t" (find-file
"~/thesis/") :exit t)
("s" (find-file
"~/thesis/thesis.setup") :exit t)
("i" (find-file
"~/thesis/intro/") :exit t)
("1" (find-file
"~/thesis/ch1/") :exit t)
("2" (find-file
"~/thesis/ch2/") :exit t)
("3" (find-file
"~/thesis/ch3/") :exit t)
("4" (find-file
"~/thesis/ch4/") :exit t)
("o" (shell-command "open
~/thesis/thesis.pdf" :exit t))
("c" (org-latex-export-to-pdf :async t)
:exit t))
(global-set-key (kbd "H-t") 'spacemacs/thesis-menu-transient-state/body)
** Gnus and notmuch
Currently working: ~notmuch~ for ~nnmaildir~ backend. However, I also have a
local ~nnimap~-backend, which uses Maildir format locally. It would be nice to
have this working with ~notmuch~ as well.
Relevant functions:
- ~nnir-compose-result~ :: Goes over the results of notmuch (stored in the
buffer ~*nnir*~ (with an additional leading space) and decides which lines
to keep;
- ~nnir-notmuch-remove-prefix~ :: a server-local variable to decide what to
remove from the lines in ~*nnir*~.
** Summary of Search and Replace Commands in Emacs
[2016-08-13 Sat 17:50]
** Bookmarks with Org-mode
:CREATED: [2018-07-08 Sun 09:29]
** Inserting a function definition :CHUA:
:CREATED: [2018-08-04 Sat 17:40]
From [[][Sacha Chua]].
While nudging jcs to add a definition of =jcs-insert-url= to the blog post about
[[][Making Things Easier]], I realized it might be handy to have a quick function for
inserting a function definition without thinking about where it's defined. This
tries to use the definition from the source, and it can fall back to using the
stored function definition if necessary. There's probably a better way to do
this, but this was small and fun to write. =)
Naturally, I used it to insert itself:
#+begin_src emacs-lisp
(defun my/org-insert-defun (function)
"Inserts an Org source block with the definition for FUNCTION."
(interactive (find-function-read))
(let* ((buffer-point (condition-case nil
(find-definition-noselect function nil)
(error nil)))
(new-buf (car buffer-point))
(new-point (cdr buffer-point))
(if buffer-point
(with-current-buffer new-buf ;; Try to get original definition
(goto-char new-point)
(setq definition (buffer-substring-no-properties
(save-excursion (end-of-defun) (point))))))
;; Fallback: Print function definition
(setq definition (concat (prin1-to-string
(symbol-function function))
(insert "#+begin_src emacs-lisp\n" definition "#+end_src\n")))
** Tramping into GCloud instances from within emacs :IRREAL:
From via [[][Irreal]].
#+begin_src emacs-lisp
;; make sure you've set your default project with:
;; gcloud config set project <project-name>
(require 'tramp)
(add-to-list 'tramp-methods
(tramp-login-program "gcloud compute ssh")
(tramp-login-args (("%h")))
(tramp-async-args (("-q")))
(tramp-remote-shell "/bin/sh")
(tramp-remote-shell-args ("-c"))
(tramp-gw-args (("-o" "GlobalKnownHostsFile=/dev/null")
("-o" "UserKnownHostsFile=/dev/null")
("-o" "StrictHostKeyChecking=no")))
(tramp-default-port 22)))
;; ... after which it's as easy as:
;; C-x C-f /gcssh:compute-instance:/path/to/filename.clj
** Finding the largest Emacs buffer
I found this somewhere, but forget where …
Approach: sort all buffers by size.
#+begin_src emacs-lisp
(mapcar (lambda (x)
(list x (buffer-size x)))
(cl-sort (buffer-list)
(lambda (x y)
(< (buffer-size y) (buffer-size x)))))
** Emacs reencode buffers with other encoding
- Use the function =revert-buffer-with-coding-system= to re-open a buffer in
another encoding.
- Customize the variable =file-coding-system-alist= to control whether certain
files should always be opened with a specific encoding.