Recently, I happened upon a wonderful blog called
The Axis of Eval. I knew that I'd
love it just when I read the name. (or emacs pales in comparison,
but I couldn't just sit on my hands for months or years while thinking
up a perfect blog name. If you think of a blog name as awesome as "The
Axis of Eval" and are willing to let me use it, I'll probably make the
switch.
The blog did not disappoint, featuring gems like this:
In the Lisp world, new languages are built by combining large,
battle-tested building blocks, and polishing or updating them when
needed, instead of starting over from toothpicks and double-sided
duct tape. A large Lisp like Common Lisp is like a toolchain of
decades-old tools that have proven their worth, and have been
codified in standards, folklore, and implementations.
The only thing in the way of extracting information and enjoyment from
this blog was the horrendous theme of black background, white
foreground and magenta links. Plus the RSS was kind of quirky, and I
couldn't just feed all of it into
Elfeed.
Greasemonkey to the rescue!
In the previous post I've mentioned that, in addition to using
the best editor, I'm using
the best browser. Well,
this particular best browser has an extension called
Greasemonkey
that allows you to automatically run your own JavaScript on certain
websites.
I'm not very proficient in JavaScript, the following code I just found
by searching around. The part to note is the @include - the pattern
of website names for which this script should be run automatically.
I can barely stand to look at it. How could you take Scheme and turn
it into this monstrosity? Such a shame. But it works, so I guess
everyone should learn JavaScript. All hail the mighty
HypnoToad JavaScript!
Currently, I'm using two methods for completing Elisp: company-mode
and helm-lisp-completion-at-point. The latter is the cannon, the big
gun: it always gets the job done, but I don't want to shoot at
sparrows with it. So I only bring it out for hairy cases, like for
stuff that starts with LaTeX-. Hence, the company-mode. But too
often have I typed region- only to find 7 candidates staring at me,
4 of them useless. Which prompted me to look for an additional
completion method.
I had the whole abbrev thing in the back of my mind until I saw a link
to the post
Abbrevs for the most frequent elisp symbols.
That's when I decided to act.
That post eventually links to a pastebin, where 1600 abbrevs are defined.
With my handy best extension
for best browser I've opened
the paste in Emacsbest editor by just clicking the edit button
in the RAW Paste Data section.
I had to M-xemacs-lisp-mode, since the file opened in
text-mode. And boy, it's big. In lispy-mode, I usually use
99j to navigate 99 sexps down and therefore to the end of
the list. Well, for this file even 999j wasn't enough.
I quickly tired of deleting one-by-one the each individual useless abbrev.
I mean:
ek -> echo-keystrokes,
when is that ever going to be useful? So I wrote this throw-away code:
After switching to a two-pane window layout, with point in the
pastebin buffer, calling foobar would count the amount of the abbrev
matches in
my most frequent elisp buffer.
If it was less than 5, the abbrev was auto-deleted, otherwise the
decision was up to me, as holding C-. would no longer
delete. In the end, there were only 56 abbrevs left out of 1600.
In one of the earlier posts,
I was discussing the implementation of an Emacs Lisp lexer for
Pygments. Here, I'll show how to install the
update and get nicely highlighted code in a pdf via the
minted LaTeX package.
The install
Assuming that you are on a Debian-related system:
sudo apt-get install mercurial
mkdir ~/git && cd ~/git
hg clone https://bitbucket.org/abo-abo/pygments-main
cd pygments-main
make mapfiles
sudo python setup.py install
And, of course, I'm assuming that you already have TeX Live installed.
I'm not too sophisticated about it, so I just install everything:
sudo apt-get install texlive-full
The result
So here I took some code from
a previous post and
copy-pasted it into minty.org file.
And here's the result of the PDF export (C-c C-e lo):
minty.pdf.
The red tape
org-mode had trouble exporting on my laptop until I did this:
cd /usr/bin/
sudo ln -s /usr/local/texlive/2013/bin/x86_64-linux/pdflatex
Also be mindful of the -shell-escape flag to pdflatex:
It all started with a heated discussion with the author of
yasnippet over some minor
nonsense. In the end, we agreed to disagree, but not before he suggested:
So I hereby challenge you to create this stripped down, no-crap,
version of yasnippet. Dub it " tiny is not yasnippet " after your
grandiose views and in the glorious unix tradition of recursive
acronyms
The Thought Process
Well, doing exactly that would probably be lame, but I really loved
the acronym. Somewhere around that time I saw some post about using
eval-and-replace, i.e. inserting some Elisp in your non-Elisp buffer
and then replacing that code in-place with the result of the eval.
Here's the type of code that I was playing around with:
(mapcar(lambda(x)(*xx))(number-sequence17))
Then I realized that the code should probably produce a string.
Here's a more refined version:
Loops are a useful thing to have, they are a blind spot of
yasnippet, and looping is exactly what the code above does. The
parameters for this loop expansion are:
integer range start: 1
integer range end: 7
separator to join the expressions: ";\n"
Elisp expression to transform the linear range: (* x x)
format expression for the result: "hex: 0x%x"
So ideally, in order to have a package called tiny, I'd like to
keep only the parameters and throw away everything else.
The Result
Here's the final result of the shortening, and what tiny-expand would produce:
As you see, it's pretty compact, with only two characters which are not
actually the parameters of the template:
m signifies the start of the template. I think this way is much
better than something like having to mark the template body with a
region before expanding. tiny-expand should be called from the end
of the snippet, so there's no need to mark the end position.
| signifies the end of the Elisp expression and the start of the format string.
It can be omitted if your format string starts with a %.
Note also the use of shortened Elisp. You can still use the full thing
if you want. Or just use only the closing parens to resolve the
ambiguities.
The Demos
Here are some more snippets, you can click on them to see what they
expand to. You can also find them and more in the comments section of
the source code:
0 1 2 3 4 5 6 7 8 9 10
5 6 7 8 9 10
5,6,7,8,9,10
25 36 49 64 81 100
19 24 31 40 51 64
0x19 0x24 0x31 0x40 0x51 0x64
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
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
0 and 0 and 0
2 and 1 and 1
4 and 4 and 2
6 and 9 and 3
8 and 16 and 4
10 and 25 and 5
12 and 36 and 6
14 and 49 and 7
16 and 64 and 8
18 and 81 and 9
20 and 100 and 10
* TODO http://emacsrocks.com/e01.html
* TODO http://emacsrocks.com/e02.html
* TODO http://emacsrocks.com/e03.html
* TODO http://emacsrocks.com/e04.html
* TODO http://emacsrocks.com/e05.html
* TODO http://emacsrocks.com/e06.html
* TODO http://emacsrocks.com/e07.html
* TODO http://emacsrocks.com/e08.html
* TODO http://emacsrocks.com/e09.html
* TODO http://emacsrocks.com/e10.html
* TODO http://emacsrocks.com/e11.html
* TODO http://emacsrocks.com/e12.html
* TODO http://emacsrocks.com/e13.html
* TODO http://emacsrocks.com/e14.html
* TODO Wash dog 2
DEADLINE: <2015-01-01 Thu>
* TODO Wash dog 3
DEADLINE: <2015-01-06 Tue>
* TODO Wash dog 4
DEADLINE: <2015-01-11 Sun>
* TODO Wash dog 5
DEADLINE: <2015-01-16 Fri>
* TODO Wash dog 6
DEADLINE: <2015-01-21 Wed>
* TODO Wash dog 7
DEADLINE: <2015-01-26 Mon>
* TODO Wash dog 8
DEADLINE: <2015-01-31 Sat>
* TODO Wash dog 9
DEADLINE: <2015-02-05 Thu>
* TODO Wash dog 10
DEADLINE: <2015-02-10 Tue>
You can expand them one-by-one to see what they do. As you can see,
Ruby-style interpolation is available in the format string. There's
also one special function called date that you can use there. It
takes the start date as a string ("Jan 1" in the example) and an
integer shift and prints an org-style date.
Then optional separator that defaults to a single space.
Then mandatory range end.
Then optional Lisp expr, that defaults to identity.
Then optional format-style string, that defaults to %d. You have
to separate it with | if the format string does not start with
%. You can also Ruby-style interpolation here, e.g. %(* x x).
With the point at the end of the snippet, M-xtiny-expand.
The Summary
In the end, tiny lives up to the name,
implementing only one snippet that can be used in a variety of ways.
Man, I just love toggles: the light switches, the
f - full-screen key in vlc, and the clicky pens (ooh, those
are the best). So I try to model some of my Emacs key bindings as
toggles.
Let me just quantify the two features that make a good toggle:
only two states: on and off
the state is visible at a glance
One could argue that with undo most editing commands become toggles.
But they're not, since each time you call undo, you mess with
Emacs's undo state. And the undo state isn't visible at a glance, so
both requirements for a good toggle aren't fulfilled.
I'll demonstrate the two editing commands that I use every day,
capitalize-word-toggle and upcase-word-toggle, that are good
toggles.
I may not have mentioned this before, but you should for the most part
ignore the key bindings mentioned on this blog. I'm actually using
them, they work for me because of my non-standard layout, but you
should assign what works for you.
Anyway, capitalize-word-toggle clearly has a state that's visible at
a glance: the first char of the current symbol. Also, there are only
two possible states: the char can either be upper-case or lower-case.
Hence, I can toggle this state with C-z for fun and profit.
Maybe some background on how this command is useful for me. I write a bunch of C++,
and the code features a lot of lines like this:
Triangulationtriangulation;// duh
So when I'm using auto-complete, it often eagerly expands to
Triangulation when I want triangulation, and the other way around.
So capitalize-word-toggle is super-useful there.
upcase-word-toggle's state becomes binary after you call it once,
since initially the thing at point could have mixed case.
But afterwards, it's either all lowercase or all uppercase.
So again, a clearly visible binary state is a good thing.
This command works either on (bounds-of-thing-at-point 'symbol) or
on the active region. Since region-active-p is deactivated after you
call the command once, there's some machinery to remember the state
and to toggle when called again.
