erc-oops

Hi again emacsians.
Maybe you're familiar with this IRC log samples.

  15:54 [rgc] xb
  15:54 [rgc] ooops, C-fail

  12:02 [xyz] ls
  12:02 [xyz] oops

  00:21 [foo] cd
  00:22 [foo] wrong buffer :/

To avoid that, some time ago I wrote some elisp to make erc-buffers read-only, but I just came up with a better solution:

(defun rgrau-erc-oops (txt)
  (when (member txt '("ls" "xb" "cd"))
      (setq erc-send-this nil)))

(add-to-list 'erc-send-pre-hook 'rgrau-erc-oops)

It's too simple to make an erc module out of that(isn't it?), so I just put it in this blog entry.

erc-button fun

Erc is one of multiple irc clients bundled with emacs.  It's probably the most complex one, in fact, in #emacs you read that quite a few people left it in favour of simpler clients like rcirc. But I kind of like its complexity :)

One nice thing about erc that's not very known is erc-button.  Yeah, the thing that allows you to click on nicknames and kick them :).

At work, we use github issues to manage our stuff, and we wrote a super simple extension for our bot that whenever it sees #number it just pastes the url of the issue. I tried to use a more silent approach using erc-button, and here's the result.

It just highlights #123 like strings and make them clickable, linking to the appropiate issue in the appropiate repo.


Neat, no?

Well, if you happen to use other sites for your issues, you can work around that github-centric approach with something else, I just hacked an ugly solution on top of the previous one. Not very clean maybe, but working.

Probably, the most sensitive solution would be writing the whole urls for each one, but well... :D

The nice point here is the tight relation between emacs and all other tools and use case. In really few lines of code we solved a problem, and we did it flexibly enough to be used in multiple scenarios.

Btw, hi to all planet emacsers, that's my first post here since I signed in. I hope to contribute here some of my emacs tricks. Don't hesitate giving feedback and commenting.

Update: There are gists inlined in the post that aren't visible in planet emacsen.  Will try to change approach for the next one.

Lisp debugging, step by step. Step 1

Debugging lisp is not as straightforward as one might think at first.  Being a live environment I thought it would be a joy, like in smalltalk, racket, or elisp, which provides a quite decent tracer and stepper.  Smalltalk is another world, but I'm already getting used to it so it doesn't surprise me that much.

We all heard stories about lisp machines (genera), and eventually read some article or seen some talk about how awesome it's lisp to debug.. but for me it was not so straightforward.

I'm using SBCL for all my experimentation in CL, so the examples here are going to be all sbcl related.  First of all, some reasons on why there's not an easy mapping between your debugger on the language next door and lisp when debugging:

- Lisp normally compiles the source code to native code. Doing so, it runs lots of optimizations on your source, so the code executed has no direct mapping to your written code.
- Lisp is not line oriented, so the order of execution of code is not so easily mappable to the typical next-line, next-line... debugging.
- On the other side, you have 'trace' that lets you track all executions of a function, with params, and so. It's not so live, but with all the instrumentation that sbcl and slime provide, you can track down a fair amount of bugs just with trace.

To instrument a method to be debuggable more easily, my advice is to add this declarations.

  (declare (optimize (speed 0) (space 1) (compilation-speed 0) (debug
3)))

That'll keep sbcl out from doing optimizations that can make variables 'disappear' in runtime.

A little more info in:

http://www.rhinocerus.net/forum/lang-lisp/583943-sbcl-line-line-debugging-tracing.html


and obviously, in your nearest implementation manual http://www.sbcl.org/manual/Debugger.html

CompGuile. Compile guile in ubuntu

Guile is the Gnu Scheme implementation and official extension language for gnu apps. Let alone most gnu apps disregard this rule. I always found guile a good companion because it was easily instalable in all my linux boxes.

 The other day I tried to install a newer version to work with geiser (and because I had been reading some nice things related to new versions on Wingo's blog), but the installing process wasn't as simple as ./configure && make install. Mostly my fault, because I just needed many *-dev packages that were not present in my box. But after installing gmp and some other easy-to-find libs, I got stuck into "No package 'bdw-gc' found". As jao put in a mail in guile maillist,

"You can tell configure where BDW is located by setting the above
mentioned environment variables. With libgc-dev installed from a deb, i
routinely do (in a bash prompt):

  $ BDW_GC_CFLAGS=-L/usr/lib BDW_GC_LIBS=-lgc ./configure
"   

imap for emacs (insert templates on emacs)

You just miss good old :imap for your temporary configuration of your editor (remember vim?).  When you know you'll be going to insert similar strings over and over.

And you love the way vim allowed you to do crazy stuff inside a map.  But now you're in emacs, so let's see how we can scratch your itch.

My concrete case was inserting strings like (?* ?x) where x is a parameter.

•  Skeletons. Skeletons can do that and much more. it's a classical template inserter.  For example, you can setup a skeleton of the desired output and interleave str symbol, that will be replaced for the input you'enter.
   
  Skeleton can do more sophisticated things, like inserting multiple lines while user keeps entering data.  I can imagine myself using this when entering lots of data with some desired format.
  
  
• Yasnippets. Yasnippets are skeletons on steroids. Sad thing is that there's no direct way to bypass the file used to define snippets. I guess you can open a new buffer, put it into yasnippet-mode, and c-c c-c to activate the binding for just this session, but maybe it's too much of a hassle.


• defun+insert.  The dumb way to do it, but the most straightforward if you tend to forget rarely used functionalities like skeletons.  Just define an interactive function that inserts your shit there, and call it at will.  That's the option I go when I don't wanna spend a minute looking for skeleton docs.

Then to call the functions/skeletons, you have different ways, if you want to global-set-key, or even just set the key in insert mode (using evil), reminding of imap style,

I'd love to hear other solutions on that same issue. Any suggestions?

The art of demo programming

Some time ago I met a guy on the internetz that was quite fond of demoscene. I never looked at it before, but since then,, I'm quite amazed by everything related to demos.

BIG BIG respect.

 From programming techniques, to creativity. Raymatching, compressing, and music. Everything pushed to its limits. There's been a recent thread in HN, with a quite a few links to tutorials, videos. 

And here's the freaking amazing demo that started the hn thread. Prepared to shit bricks? All that thing fits in 4096 bytes.

Yeah. 4kb.

 

simple made easy, twice

Here there are a couple of videos of the same talk "Simple, made easy", by Rich Hickey. I love Rich's talks, and I think it's even enlightening seeing the same talk twice, fine tuned for different audiences.

First one is from RailsConf 2012 Keynote. Done with a ruby audience in mind.

Second one is from StrangeLoop 2011. much more hilarious and punchy IMHO, and maybe a little less serious tone, but equally enlightening.

Here it is. bye!