Emacs Online Feeds
For Twitter users, now all my emacs related tweets will be from @ErgoEmacs. This way, those who just want emacs tips can stay focused.
For Google+ users, you might join g+ emacs page. There, i post one or two short emacs tip a day.
For a complete list of feeds of available topics, please see: Subscribe to XahLee.org Site Feed.
Thank you very much for reading!
Xah's Emacs Tutorial Update 2012-01-20
I have a new version of my emacs tutorial ready.
If you've bought it before, please just email to xah@xahlee.org with subject “emacs tutorial upgrade”. I'll email you the download location. Sorry i don't have a automatic update system. So just send the email please if you would like the updated version.
If you haven't bought it, you can get it for just $10. See: Buy Xah Emacs Tutorial. As far as i know it's more complete and detailed tutorial than any emacs book, printed or not, especially the elisp section.
Thank you for support!
Emacs Page on G+, Today's Tip: Hotkeys
i started a g+ emacs stream at https://plus.google.com/b/113859563190964307534/ . You might want to join. Here's today's post.
in emacs, once you got on the train and know all the basic concepts, there's 1 most important aspect of increasing efficiency. That is, keyboard shorts (keybindings).
emacs has 3k commands out of the box. Everything is a command, including when you type “a” (self-insert-command). For most frequently used commands, there's a key assigned for it.
by default emacs has 1.3k keybindings!
If we take away ancient impractical ones (for obsolete lisp keyboards), there are few hundred keybindings that are actually useful. Most of us probably use around a hundred or 2.
ok. what i want to say is that for daily operation, assiging keys to commands is probably the most useful in creasing your productivity. Emacs is too big. Everyone has different set of commands that each use frequently. So, if you find yourself typing Meta+x to call a particular command often in past weeks, it's time to give it a hotkey! (if it doesn't already have one; or if you find yourself bending your fingers on the default key sequence.)
All your F1…F12 should be used. And some of those 【Ctrl+x Ctrl+…】 and 【Ctrl+c Ctrl+…】 you use often probably should have a shorter key.
if you don't know how to set keys, see:
Emacs: How to Define Keyboard Shortcuts
here's related tips on keys
List Matching Lines in Emacs
learned 2 new commands from a emacs hacker friend Jon Snader (jcs): multi-occur and multi-occur-in-matching-buffers.
See his blog about several ways of listing matching lines:
there, he covered several ways to list matching lines in current buffer or existing buffers.
if you are new to emacs, you might think “i'll just call unix grep; one less thing to learn”. Actually, the emacs commands are much more convenient. I use them several times everyday for past years.
if you want to know the ways to find matching lines in files (as opposed to already opened files), see also: Emacs: Searching for Text in Files (grep, find).
There's a subword-mode that lets you move by camelCase. New in emacs 23, but isn't mentioned in emacs NEWS file. See: Source debbugs.gnu.org bug#6614
Emacs Pinky and RSI
someone on stackoverflow is asking about how to avoid the emacs pinky. See: Source stackoverflow.com
the guy already developed emacs pinky.
Note that this is quite a frequently asked question. People ask about it year round all over. On Reddit, Hacker News, Quara, StackOverflow …, and on lots personal blogs. Many already got RSI. Here's a example of another post about it: Source superuser.com.
On StackOverflow itself, the topics comes up frequently. Sometimes in the name of “what's the best emacs keyboard”.
Here's my take, old article but popular: How to Avoid the Emacs Pinky Problem.
This article is probably one of the top ten most valuable in my ~300 html pages emacs/elisp tutorial: How to Write a Emacs Major Mode for Syntax Coloring.
Updated: Keyboard Ghosting ＆ N-key Rollover: How Many Keys Your Keyboard Can Take?. This is relevant to emacs if you define Hyper and Super. See bottom of the article.
I must offer you emacs coders 2 songs today. The first one is Pulse. Let the tranquil beat accompany you in your hackathon.
Now, the second song i offer is Information High. This is when you are hyper, such as emacs's Hyper key. When you are high. When your thoughts run faster can you can type.
Updated: Emacs Lisp Text Processing: find-file vs with-temp-buffer.
In my previous report, the timing difference is by a factor of 45. That's because i had stuff in my init file. (i have hooks for both find-file and html-mode, and that probably caused the major slowdown.) Now, the factor is actually just about 5.
You should still use with-temp-buffer instead of find-file besides speed, because find-file has quite some side effects.
Big thanks to Trey Jackson.
Updated. The ultimate emacs keyboard: The μTRON Keyboard. Well, one of the ultimate.
This is a frequently confusing point someone just asked again in gnu.emacs.help. How to turn a mode on/off? Is it a function or variable? Is it {1, 0} or {t, nil}? See, updated: Emacs: How to Turn a Minor Mode on/off/toggle?.
Updated: Emacs: Text Pattern Matching (regex) tutorial.
Note: last week's exercise about writing “latitude-longitude-decimalize” will be coming up.
Emacs 24.0.91.1 Crash on linum-mode
Steps to reproduce:
./emacs.exe -QThanks to Jon Snader for discussion.
Spent about 10 hours keyboard geeking again. Several major updates in the following pages. Addition of some 15 glorious photos of keyboards and their layouts.
Updated a function “toggle-line-spacing” for emacs 24, at How to Set Emacs's User Interface to Modern Conventions. Thanks to Ivan Kozik for the tip.
Last week, we discussed how to write a elisp to generat UUID. Christopher Wellons provided a excellent implementation involving random info from emacs, then calling md5. See bottom at: Emacs Lisp Exercise: insert-random-uuid.
For those of you using backward-close-bracket and forward-close-bracket, there's a bug that's been fixed. The bug is this: it misses some brackets because there's some typo in the regex in the code, it contained extra space. Get updated code at: Emacs: Commands and Keys to Navigate Brackets.
Emacs Lisp Example: title-case-string-region-or-line
In english writing, the title follows a particular convention of capitalization. For example, it should be “A Tale of Two Cities”, not “A Tale Of Two Cities”.
I think this is rather a silly convention. For a while, i experimented by simply following a logically simpler style, of capitalizing the first letter of all words. (See: The Writing Style on XahLee.org.) But after a while, i find it rather jarring.
Part of the reason is that it's new, thus it will get some used to. This i expected. However, the other thing that turns out is that, the capitalization has subtle function for emphasis. For example, “Kung Fu versus Karate” seems better than “Kung Fu Versus Karate”.
It's rather cumbersome to manually capitalize words following this convention. So, i wrote a emacs command. Here's the code:
(defun title-case-string-region-or-line (ξstring &optional ξregion-boundary) "Capitalize the current line or text selection, following title conventions. Capitalize first letter of each word, except words like {to, of, the, a, in, or, and, …}. If a word already contains cap letters such as HTTP, URL, they are left as is. When called in a elisp program, if ξREGION-BOUNDARY is nil, returns the changed ξSTRING, else, work on the region. ξREGION-BOUNDARY is a pair [from to], it can be a vector or list." (interactive (let ((bds (get-selection-or-unit 'line))) (list nil (vector (elt bds 1) (elt bds 2)) ) ) ) (let ( replacePairs (workOnStringP (if ξregion-boundary nil t ) ) (p1 (elt ξregion-boundary 0)) (p2 (elt ξregion-boundary 1)) ) (setq replacePairs '( [" A " " a "] [" And " " and "] [" At " " at "] [" As " " as "] [" By " " by "] [" Be " " be "] [" Into " " into "] [" In " " in "] [" Is " " is "] [" It " " it "] [" For " " for "] [" Of " " of "] [" Or " " or "] [" On " " on "] [" The " " the "] [" That " " that "] [" To " " to "] [" Vs " " vs "] [" With " " with "] [" From " " from "] )) (let ((case-fold-search nil)) (if workOnStringP (progn (replace-pairs-in-string-recursive (upcase-initials ξstring) replacePairs) ) (progn (save-restriction (narrow-to-region p1 p2) (upcase-initials-region (point-min) (point-max) ) (replace-regexp-pairs-region (point-min) (point-max) replacePairs t t) ) ) ) ) ) )
I used some elisp utils i wrote. You'll need to get it at: code.google.com xeu_elisp_util.el. This command is also bundled there.
Poll: do you prefer the Home/End keys to:
Vote at http://xahlee.blogspot.com/2011/11/poll-homeend-keys.html, top right.
Two weeks ago, i had a lisp exercise of writing “extract-url”. Here is a solution: Emacs Lisp: Writing a Command to Extract URL.
Updated 2 neglected but very useful articles:
Several updates:
Updated and added a example of “read-from-minibuffer” at Emacs Lisp Idioms (for writing interactive commands).
Major rewrite: Emacs Lisp: Syntax Color Source Code in HTML.
Thanks to Jon Snader (aka jcs)'s solution on last week's problem and some discussion, now updated: Emacs Lisp Exercise: replace-digits-by-subscript.
Famous Emacser, Steve Yegge, wrote a rant on Google that's circulating wildly now. Steve Yegge's Google Platforms Rant.
Anonymous wrote to ask how to write a emacs command to show the decimal value of a hexadecimal string under cursor in source code. Here's answer at bottom: Emacs Lisp: Converting Decimal and Hexadecimal Numbers.
Updated: Emacs and Unicode Tips. Added info about how to insert a unicode character by its decimal code point.
Updated a page that i wrote in 2006. The code was embarrassing. Here's the updated page: Emacs Lisp: Writing a Wrap-URL Function. Elisp level: beginner.
Here's a answer to last week's elisp quiz. Emacs Lisp: Command to Replace HTML Entities with Unicode Characters.
few days ago i posted a article on “string-rectangle”, but it wasn't a finished article and was posted by mistake. Here's a more complete article: Emacs: Manipulate Column Text, string-rectangle, ASCII-Art
Of those who bought my emacs tutorial recently, there's a new free update. (fixing a external link error) Just email to xah@xahlee.org with subject “xah emacs tutorial update”, then i'll email you the download location.
If you haven't bought it, you can buy at Buy Xah Emacs Tutorial.
Thanks to Damon Haley, Lindner Technologies, Shuyang Zhao for donation. Very much appreciated.
Answer to the challenge 2 days ago: Emacs Lisp: Batch Script to Validate Matching Brackets.
Thanks to Xiang Xin Luo for donation.
For those of you who bought my Emacs Tutorial, just send me a email and i'll mail you a update. (xah@xahlee.org) In the subject, put “xah emacs tutorial update”.
Buy at Buy Xah Emacs Tutorial. Thank you for support!
Xah's Emacs Tutorial Poll 2011-06-25
Do you like xah's emacs tutorial writing to be:
Vote at: http://xahlee.blogspot.com/.
Created a dedicated page for buying my tutorial, at: Buy Xah Emacs Tutorial.
For those of you who have bought it before, just email me at xah@xahlee.org with subject “emacs tutorial upgrade” and i'll email it to you.
Thank you for your support!
Major updates on 2 ergonomic keyboards. They are perfect for emacs or ErgoEmacs:
If you are on Mac OS X, this is for you: Mac OS X Keyboard Layout, Keymapping, Keybinding, Tools.
Babolog — Digital Goods Marketplace for the Masses
Recently, 2 guys came up to me on skype. One is Michael K and the other is sabalaba. It turns out, they have something mysterious to sell, and that's their startup company babolog.com.
It's a digital goods marketplace website, where you can sell any of your digital files easily. So, they convinced me to use their service, and here it is, my emacs tutorial sold there, at: http://www.babolog.com/shop/p/471. Go buy it now! Help me out and check them out.
If you have some digital goods, you can sign up with them. Takes about 20 seconds. No upfront fee required. When your item got sold, they charge $0.3 plus 3% of the price. (always check their site for the exact terms.) Their site is quite simple. Check it out at: babolog.com.
David Capello created a new version of “command-frequency.el” now called “keyfreq.el”. See here for detail and download location:Emacs's Command Frequency.
Reminder: you can get all my emacs and elisp tutorial. Close to 300 HTML pages, each HTML page is about 1 to 5 printed pages. It comes in simple HTML+CSS. And is ads free. See: What People Say about Xah's Emacs Tutorial.
Emacs Dired Bug: Delete File List Not Visible
This seems to be a bug. Define this:
(defalias 'yes-or-no-p 'y-or-n-p)
Then, in dired, type ~ to flag backup files. Then, type x to delete them. Dired will prompt you with “Delete D [251 files] (y or n)” with a list of files to be deleted on the top pane. When you have more files to fit in a window, part of the list is not visible, and there's no way to view them. You can't page with 【Alt+PgDn】 or 【Alt+PgUp】, can't use mouse to drag the scrollbar, scroll wheel just produce beeps. I haven't found a way to view it.
(thanks to Eli Zaretskii, Drew Adam for helping track down the cause. Source groups.google.com)
A recent article that should be here: Emacs Keybinding Rant ＆ a Glimpse of Xah Lee's Life 2010 (essay)
New version of Emacs Unicode Math Symbols Input Mode (xmsi-mode) (for math symbol and unicode input). This version added about 102 full width symbols. e.g. “fw&” becomes “＆”. (these chars probably not useful to most, but i use the fullwidth version of ampersand often to avoid encoding complexity in html) happy using.
See: HTML Entities, Ampersand, Unicode, Semantics ◇ Problems of Symbol Congestion in Computer Languages (ASCII Jam; Unicode; Fortress).
Emacs cult scumbag. To spell check a file of 2.6k words, it froze emacs for 10 seconds. While in Mozilla Thunderbird and everywhere else it's 0.3 seconds.
Discovered the command “display-time-world”. These days, when communicating with people around the world (in twitter, Skype, Second Life …), usually i need to know what time it is in their location. This command helps. Faster and more accurate than i can do mental calculation.
Am tired of using dictionary within emacs. See bottom of Emacs Dictionary Lookup for reasons.
Here's the complete solution to the asciify-word-or-selection problem. See bottom of Emacs Lisp: Asciify Unicode String (Zap Gremlins).
Discovered “artist-mode”. It's a mode that let you draw ascii pictures with the mouse.
Open a empty file. (in ErgoEmacs,【Ctrl+n】. In GNU Emacs, 【Alt+x b】 (switch-to-buffer) then give a random name.) Now, you can draw with your mouse. Hold right button to erase. Middle click to switch to rectangle, ellipse, and other tools.
You can see a video of this guy using it at: Source www.cinsk.org.
I should warn that you should not get into a habit of using ascii art in comments, such as drawing boxes. Because, it is a form of hard-formatting. As such, it is not flexible and creates all sorts of problems. See:
For the same reason, i never liked any comment alignment in my source code, and i am annoyed that emacs by default aligns your comment when you call “comment-dwim” 【Alt+;】
Much improved my code for “get-selection-or-unit”. Also, a “unit-at-cursor” function is created. This is separated out because sometimes you want to get the thing at point, without caring whether there's a text selection. For the code, see: Emacs Lisp: Using thing-at-point.
Spent the past 5 hours refactoring elisp code in my .emacs. Not exactly thrilled. it's the kinda work that has no immediate benefit, but potentially disruptive. The software proverb goes: “if it ain't broken, don't fix it.”.
I'd say it's only half complete. But am tired of it at this (point). Actually, about every 4 months in past 4 years i spend several hours refactoring stuff there. (not counting the time adding stuff there) As the functions pile up, more time went into it. As my elisp kungfu increases, more is there to be refactored.
well, today, most work done is to replace “thing-at-point” by get-selection-or-unit. But alone the way, saw old code, and can't help to clean it.
Though, my strategy towards “.emacs” is still basically “don't bother unless you absolutely have to”. Organize Your “dot emacs” Init File in 5 Minutes.
discovered a bug in html-mode. If you have this:
<p>some'</p>
and your cursor is at the beginning of line, then press 【Ctrl+c Ctrl+d】 (sgml-delete-tag), it'll also delete the apostrophe.
I want a command to insert random strings, as a ID. So i wrote one:
(defun insert-random-string () "Insert a random alphanumerics string of length 6." (interactive) (let (mycharset (ii 0) ) (setq mycharset ["1" "2" "3" "4" "5" "6" "7" "8" "9" "0" "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" "t" "u" "v" "w" "x" "y" "z" ] ) (while (< ii 6) (insert (elt mycharset (random (length mycharset)))) (setq ii (1+ ii) ) ) ) )
O, ♥ emacs!
See also: Emacs Lisp Examples (Page 1)
Reminder. If you like this blog, you might also enjoy my other programer related blogs:
Usually i don't repeat a article in more than one place, even if it's related to both.
Find ＆ Replace is a central mechanism in text processing, especially in emacs. I took few hours to edit and re-organize several articles i've written that are all related to find ＆ replace. Here's the re-organized index. It gives a much more clear view on what each article is about and how they relate to each other.
If you like them, please support the site. You can support by buying computer stuff from Amazon links here. USB drives, keyboard ＆ mouse, iPad, mobile phones, laptops, DVDs, …. Or, you get get all my emacs and elisp tutorial. (See bottom of Xah Emacs Tutorial.) Or, you can support the site by a donation. Any amount counts. Thanks!
You can also ask emacs questions here: Ask Emacs.
ErgoEmacs version 1.9.2 binary for Windows is out. Download at ErgoEmacs 1.9.2 Setup.exe.
Thanks to David Capello for the build.
New version: Emacs Math Symbols Input Mode (xmsi-mode)
I'm creating a Ask Emacs page. There, you can ask all sort of questions about emacs or elisp.
There are these unicode symbols
when calling describe-char on them, it doesn't give their names. Is this a bug?
That's because these chars are from Unicode version 6, released in 2010-10.
Unicode 6 added 2088 chars. I don't think there are any fonts that support them yet. However, if you do unicode work, you can add char info to emacs so that “describe-char” will give you all the char's info. You need to download a text file 〔UnicodeData.txt〕. For detail, see: Emacs and Unicode Tips.
(thanks to Jason Rumney and Klaus Straubinger. Source groups.google.com.)
See also: Unicode 6 Emoticons.
If you use org mode, you can set it to not open files in folded view. Put the following in your “.emacs”:
(setq org-startup-folded nil )
I find this useful because when i do interactive find and replace on multiple files, if the org mode files open in folded view, you won't see what's being replaced.
If you prefer to open org mode files in folded view, one solution is to temporarily set the variable org-startup-folded to nil before you do find＆Replace in a dir. Just call “set-variable”.
A great tutorial about eshell. Mastering Eshell @ Source www.masteringemacs.org
See also: Emacs: What's eshell? “eshell” vs “shell” Difference?
Hauke Rehfeld send in this improved version of “fold”.
(defun fold (f x list) "Recursively applies (F i j) to LIST starting with X. For example, (fold F X '(1 2 3)) computes (F (F (F X 1) 2) 3)." (let ((li list) (x2 x)) (while li (setq x2 (funcall f x2 (pop li))) ) x2 ) )
This one improves upon on a primitive one i've written, which has problems if element in the list eval to nil. For some info and a practical example of using “fold”, See: More Elisp Examples. Thanks Hauke.
About 3 months ago, i started to use the Caps Lock key for emacs “M-x”. That's fantastic. If you are on Windows, here's a util that can make it happen.
Download it at this page: System-wide ErgoEmacs Keybinding for Windows, Mac, Bash.
Useful for emacs users on Creating Keyboard Layout in Mac OS X.
Want to learn a new lang in 2011? How about emacs lisp? (See: What is Your Favorite Lisp.)
Instead of a new year's resolution, which often are forgotten after Jan, let's have a resolution just for January.
So, what about setting a short-term goal for learning emacs and elisp? What do you wish to learn in January? Answer these questions. Before you answer, try to have a realistic, low-key goal, that you actually would achieve after Jan. Some of the questions below is about emacs/lisp if you think that's something you'll find helpful.
• Is there a language you wish to learn in Jan?
• What are some things you always wanted to know about emacs/elisp?
• Is it a particular emacs setup that's bugging you for a while?
• Any particular mode, package, you wished to install or know more?
• Do you have a basic understanding of elisp?
• Is it some basic understanding of elisp you always wanted?
• What would be some pratical things that would help in your job?
• How much time you can devote to learning (your choice of new lang or elisp)? (i recommend no more than 30 min a day, but at least every other day. You must stick to this schedule)
• At the end of the month, what would be some things that can concretely measure your effort? (a small set of learning notes? A small program as a project?)
Post your answers below.
