Yogsototh's last blogs entries

Learn Haskell Fast and Hard

2012-02-08T13:17:53Z

tl;dr: A very short and dense tutorial for learning Haskell.

Table of Content

Introduction

Install

Don’t be afraid

Very basic Haskell
...

Typography and the Web

2012-02-02T09:53:00Z

;

tl;dr: Web typography sucks and we’ll have to wait forever before it will be fixed.

I stumbled upon open typography. Their main message is:

«There is no reason to wait for browser development to catch up. We can all create better web typography ourselves, today.»

As somebody who tried to make my website using some nice typography features and in particular ligatures, I believe this is wrong.

I already made an autom...

Haskell web programming

2012-01-15T17:14:40Z

update: updated for yesod 0.10

tl;dr: A simple yesod tutorial. Yesod is a Haskell web framework. You shouldn’t need to know Haskell.

Table of content

Before the real start

Install

Initialize

Configure git

Some last minute words

...

Increase the power of deficient languages.

2011-10-20T09:39:36Z

tl;dr: How to use m4 to increase the power of deficient languages. Two examples: improve xslt syntax and make fractal with svg.

xml was a very nice idea about structuring data. Some people where so enthusiastic about xml they saw it everywhere. The idea was: the future is xml. Then some believed it would be a good idea to invent many xml compatible format and even programming languages with xml syntax.

Yesod excellent ideas

2011-10-04T08:18:59Z

tl;dr:

Yesod is a web framework which recently reached the maturity for which you should consider to use it. Before telling you why you should learn Haskell and use yesod, I will talk about ideas yesod introduced and I didn’t saw in other frameworks before.

Type safety

Let’s start by an obligatory link from xkcd:

When you create a web application, a lot of time is spent...

Higher order function in zsh

2011-09-28T13:15:23Z

tl;dr: some simple implementation of higher order function for zsh.

Why is it important to have these functions? Simply because, the more I programmed with zsh the more I tended to work using functional programming style.

The minimal to have better code are the functions map, filter and fold.

Let’s compare. First a program which convert all gif to png in many different directories of different projects.

Before ⇒

# for each directory in projects dir
for toProject in /path/to/projects/*(...

Programming Language Experience

2011-09-28T10:21:41Z

tl;dr: My short and higly subjective feelings about programming languages I used.

`BASIC`

The language of my firsts programs! I was about 10, with an MO5 and Amstrad CPC 6128 and even with my Atari STe. This is the language of GOTOs. Ô nostalgia. Unfortunately this might be the only interesting part of this language.

Today this language is obsolescent. It is not even good to learn pr...

Learn Vim Progressively

2011-08-25T17:28:20Z

tl;dr: You want to teach yourself vim (the best text editor known to human kind) in the fastest way possible. This my way of doing it. You start by learning the minimal to survive, then you integrate all the tricks slowly.

Vim the Six Billion Dollar editor

Better, Stronger, Faster.

Learn vim and it will be your last text editor. There isn’t any better text editor that I know of. It is hard to learn, but incredible to use.

I suggest you teach yo...

A more convenient diff

2011-08-17T09:33:30Z

Diff is a very useful tool. But it is not so easy to read for us, simple mortal.

This is why, when you use git it will use a better formatting and colorize it.

Here is the script I use when I want to use human readable diff à la git.

➥ ydiff

#!/usr/bin/env zsh

# Load colors helpers
autoload -U colors && colors

function colorize_diff {
    while read line; do
    case ${line[0]} in
    +) print -n $fg[green];;
    -) print -n $fg[red];;
    @) # Display in cyan the @@ positions @@
       if [[ ${line[1]} = '@' ]]; then
           line=$(print $line | perl -pe 's#(\@\@[^\@]*\@\@)(.*)$#'$fg[cyan]'$1'$reset...

ASCII Haskell Mandelbrot

2011-07-10T10:41:26Z

Here is the obfuscated code:

➥ animandel.hs

a=27;b=79;c=C(-2.0,-1.0);d=C(1.0,1.0);e=C(-2.501,-1.003)
newtype C = C (Double,Double) deriving (Show,Eq)
instance Num C where C(x,y)*C(z,t)=C(z*x-y*t,y*z+x*t);C(x,y)+C(z,t)=C(x+z,y+t);abs(C(x,y))=C(sqrt(x*x+y*y),0.0)
r(C(x,y))=x;i(C(x,y))=y
f c z 0=0;f c z n=if(r(abs(z))>2)then n else f c ((z*z)+c) (n-1)
h j k = map (\z->(f (C z) (C(0,0)) 32,(fst z>l - q/2))) [(x,y)|y<-[p,(p+((o-p)/a))..o],x<-[m,(m + q)..l]] where o=i k;p=i j;m=r j;l=r k;q=(l-m)/b
u j k = concat $ map v $ h j k where v (i,p)=(" .,`'°\":;-+oO0123456789=!%*§&$@#"!!i):rst p;rst True="\n";rst False=""
main = putStrLn $ im ...

40 character's passwords

2011-05-18T11:14:28Z

tl;dr: How I manage safely my password with success for some years now.
sha1( password + domain_name )
I memorize only one password. I use a different password on all website.

Disclamer, this is an unashamed attempt to make you download my iPhone app ;-). You’re always here? Even if you won’t download my app, you should read more. My method doesn’t necessitate my app. It is both safe and easy to use everyday.

If you just want to use the tools without searching to understand why it is safe, just jump at the

Now hosted on github

2011-04-20T15:22:15Z

I am now hosted on github.

Why I won't use CoffeeScript (sadly)

2011-01-03T08:37:26Z

Update: I might change my mind now. Why? I just discovered a js2coffee converter. Furthermore Denis Knauf told me about a CoffeeScript.eval function. And as Denis said: “it is time to use Coffeescript as a javascript with Ruby-like syntax not a Ruby-like programming language”.

tl;dr: I would have loved to program client side using a Ruby-like syntax. But in the end, CoffeScript raised more disavantages than advantages.

Recently I read

Happy New Year

2011-01-01T06:55:54Z

Happy New Year!

I was busy during the last months. But I will revive a bit this blog.

I made a project to write book in markdown syntax and generating HTML and high quality PDF. I am not finished with this.

I had written an efficient & simplistic MVC javascript framework.

Best wishes for 2011!

LaTeX like macro for markdown

2010-10-26T12:30:58Z

tl;dr: I made a simple macro system for my blog. Now I juste have to write %latex and it show as L^aT_eX.

I added a macro system for my blog system. When we are used to L^aT

Fun with wav

2010-10-14T09:04:58Z

tl;dr: Played to process a wav file. C was easier and cleaner than Ruby.

edit: I wanted this program to work only on one specific machine (a x86 on a 32 bit Ubuntu). Therefore I didn’t had any portability consideration. This is only a hack.

I had to compute the sum of the absolute values of data of a .wav file. For efficiency (and fun) reasons, I had chosen C language.

I didn’t programmed in C for a long time. From my memory it was a pain to read and write to files. But in the end I was really impressed by the code I get. It was really clean. This is even more impressive know...

Secure eMail on Mac in few steps

2010-10-10T16:39:00Z

tl;dr: on Mac

Get a certificate signed by a CA: click here for a free one,
open the file,
delete securely the file,
use Mail instead of online gmail.
???
Profit

I’ve (re)discovered how to become S/MIME compliant. I am now suprised how easy it was. Some years ago it was far more difficult. Now I’m able to sign and encrypt my emails.

New Blog Design Constraints

2010-10-06T09:33:03Z

I changed the design of my blog. Now it should be far cleaner. I believe I use no CSS3 feature and far less javascript. Of course before my website was perfectly browsable without javascript. Unfortunately some CSS3 feature are not mature enough on some browser. For more details you can read my older blog entry. But the major problem came from, font-shadow and gradients. Then my new design obey to the following rules:

no CSS element begining by ‘-moz’ or ‘-webkit’, etc…,
no text shadow,
clean (I mean delete) most javascript.

I hope the new design please you.

Use git to calculate trusted mtimes

2010-09-02T13:54:10Z

You can remark at the bottom of each page I provide a last modification date. This label was first calculated using the mtime of the file on the file system. But many times I modify this date just to force some recompilation. Therefore the date wasn’t a date of real modification.

I use git to version my website. And fortunately I can know the last date of real change of a file. This is how I do this with nanoc:

➥ gitmtime.rb

def gitmtime
    filepath=@item.path.sub('/Scratch/','content/html/').sub(/\/$/,'')
 ...

base64 and sha1 on iPhone

2010-09-01T22:02:17Z

Lets be straight: here are two functions to add to your code to have base64 and hexadecimal version of the sha1 hash of an NSString.

To use it, simply copy the code in your class and use as this:

#import <CommonCrypto/CommonDigest.h>
...
NSString *b64_hash = [self b64_sha1:@"some NSString to be sha1'ed"];
...
NSString *hex_hash = [self hex_sha1:@"some NSString to be sha1'ed"];

The base64 algorithm must be programmed by hand on iPhone!

➥ iphone_base64_sha1.c


- (unsigned char *)sha1:(NSString *)baseString result:(...

send mail from command line with attached file

2010-08-31T08:16:04Z

I had to send a mail using only command line. I was surprised it isn’t straightforward at all. I didn’t had pine nor mutt or anything like that. Just mail and mailx.

What Internet say (via google) is

uuencode fic.jpg fic.jpg | mail -s 'Subject'

I tried it. And it works almost each times. But for my file, it didn’t worked. I compressed it to .gz, .bz2 and .zip. Using .bz2 format it worked nicely, but not with other formats. Instead of having an attached file I saw this in my email.

begin 664 fic.jpg
M(R$O=7-R+V)I;B]E;G8@>G-H"GAL<STD,0H*9F]R(&QI;F4@:6X@)"@\("1X
M;',@*0H@("`@9&-R/20H96-H;R`D;...

Now hosted by heroku

2010-08-23T13:05:13Z

Now on Heroku

I now changed my hosting to Heroku. I believe it will be far more reliable.

But as you should know my website is completely static. I use nanoc to generate it. But here is the conf to make it work on heroku.

The root of my files is /output. You only need to create a config.ru¹ file:

➥ config.ru

require 'rubygems'
require 'rack'
require 'rack/contrib'
require 'rack-rewr...

Undecidabilities (part 1)

2010-08-11T08:04:31Z

tl;dr: I pretend to create a world to give examples of different meanings behind the word undecidability:

Undecidability due to measure errors,
Big errors resulting from small initial measure error,
Fractal undecidability ;
Logic Undecidability.

The Undecidabilities

If a demiurge made our world, he certainly had a great sense of humor. After this read, you should be convinced. I’ll pretend to be him. I’ll create a simplified world. A world that obey to simple mathematical rules. And I’ll tell you about one of ...

New style after holidays

2010-07-31T21:59:10Z

Before my holidays many visitors tell me my website was too long to scroll. This is why I completely changed my website design. Now all should scroll smoothly on all platforms. I was inspired by Readability and iBooks© (the iPhone© application).

Tell me what you think of this new design.

Do not use CSS gradient with Chrome

2010-07-07T13:43:43Z

Some Reddit users reported my website was really long to load and to scroll. They thinks it was because of the ‘1px shadow’ I apply on all the text. I was a bit surprised, because I make some test into a really slow virtual machine. And all have always worked fine. In fact, what slow down so much are by order of importance:

Radial gradient on Chrome (not in Safari on Mac)
Box shadows on Firefox and Chrome

Gradient

On Safari on Mac there is absolutely no rendering time problem. But when I use Chrome under Linux it is almost unusable.

Safari and Chrome use webkit, when you access my website with javascript enabled, an additionnal browser specific CSS is loaded....

Cappuccino vs jQuery

2010-07-05T11:49:04Z

tl;dr:

Tried to make YPassword in jQuery and with Cappuccino.
Cappuccino nice in desktop browser but 1.4MB, not compatible with iPhone.
jQuery not as nice as the Cappuccino version but 106KB. iPhone compatible.
I’ll give a try to Dashcode 3.

Before start, I must say I know Cappuccino and jQuery are no more comparable than Cocoa and the C++ standard library. One is oriented for user interface while the other is and helper for low level programming. Nonetheless I used these two to make the same web application. This is why I compare the exp...

jQuery popup the easy way

2010-06-18T22:44:50Z

Here is a fast and easy way to create jQuery popup.

➥ essai.js

// --- code popup ---
function openPopup() {
    $(this).clone(false).appendTo($("#_code"));
    $("#_code").show();
}

function closePopup() {
    $("#_code").html("");
    $("#_code").hide();
}

function initCode() {
    $(".code").click(openPopup);
    $(".code").css({cursor: "pointer"});
    $('body').append('<div id="_code"></div>');
    $('#_code').css( { 'text-align': "justify", position: "fixed", 
                        left:0, top:0, width: "100%", height: "100%", 
                        "background-color": "rgba(0, 0, 0, 0.8)", 'z-index':2000, 'pad...

Hide Yourself to your Analytics

2010-06-17T14:37:22Z

This is a way not to count your own visits to your blog. First you should look on how I handle analytics. All analytics are handled in one javascript file, this make things really convenient.

Then you need to know my method use the jquery-cookie.

I check if the key admin is not set in the cookie before adding the visit.

    var admin = $.cookie('admin');
    if (! admin) {
        // put your analytics code here
    } else {
        console.log("[WARNING] you're HIDDEN to analytics");
    }

then create two html files. One to hide:

Track Events with Google Analytics

2010-06-17T12:41:36Z

Here is how to track all clicks on your website using google analytics asynchronously.

First in your html you need to use jQuery and a javscript file I named yga.js:

    <script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript" src="yga.js"></script>

And here is the yga.js file:

➥ yga.js

$(document).ready( function() {
    // add an event to all link for google analytics
    $('a').click(function () {
        // tell analytics to save ...

Get my blog engine

2010-06-15T08:56:32Z

I published a light version of my blog engine based on nanoc yesterday night. By light, I mean a lighter, more portable CSS (without round border). You can get it on github.com.

What this system provide?

All nanoc advantages,
Easy multi-language handling,
Syntax Coloration for most languages,
intenseDebate comments integration (asynchronous) ;
Portable with and without javascript, XHTML Strict 1.0 / CSS3,
Write in markdown format (no HTML editing needed),
Typographic ameliorations (no ‘:’ ...

multi language choices

2010-06-14T14:14:57Z

I translate most of my blog entries in French and English. Most people advice me to have one file per language. Generally it ends with:

Bonjour, 

voici un exemple de texte en français.
[image](url)

Hello, 

here is an example of english text.
[image](url)

This way of handling translations force you to write completely an article in one language, copy it, and translate it.

However, most of time, there are common parts like images, source code, etc… When I want to correct some mistake on these parts, I have to make twice the work. With sometimes adding another mistake in only one language.

This is why I preferred to handle it differently. I use tags on a single file. Finally my files...

Trees; Pragmatism and Formalism

2010-05-24T18:05:14Z

tl;dr: :

I tried to program a simple filter
Was blocked 2 days
Then stopped working like an engineer monkey
Used a pen and a sheet of paper
Made some math.
Crushed the problem in 10 minutes
Conclusion: The pragmatism shouldn’t mean “never use theory”.

Abstract (longer than tl;dr: )

For my job, I needed to resolve a problem. It first seems not too hard. Then I started working directly on my program. I entered in the...

How to repair a cutted XML?

2010-05-19T20:20:34Z

For my main page, you can see, a list of my latest blog entry. And you have the first part of each article. To accomplish that, I needed to include the begining of the entry and to cut it somewhere. But now, I had to repair this cutted HTML.

Here is an example:

<div class="corps">
    <div class="intro">
        <p>Introduction</p>
    </div>
    <p>The first paragraph</p>
    <img src="/img/img.png" alt="an image"/>
    <p>Another long paragraph</p>
</div>

After the cut, I obtain:

<div class="corps">
    <div class="intro">
        <p>Introduction</p>
    </div>
    <p>The first paragraph</p>
 ...

I live again!

2010-05-17T11:25:51Z

Hi all!

The more you wait to do something, the more difficult it is to start doing it.

I had to write another post for this blog. I had added many article idea in my todolist. But, I made many other things, and I’ve always said (until now), I’ll do this later. What changed my mind is the haunt of this simple remark about how to be productive in programming. > Stop write TODO in your code and make it now!
> You’ll be surprised by the results.

In short: > Just do it! ou Juste fait le comme auraient dit les nuls.

Finally I’ll certainly write blog post more often for a ...

Encapsulate git

2010-03-23T20:37:36Z

Here is a solution to maintain divergent branches in git. Because it is easy to merge by mistake. I give a script that encapsulate git in order to forbid some merge and warn you some merge should be dangerous.

how to protect against your own dumb

I work on a project in which some of my git branches should remain divergent. And divergences should grow.

I also use some branch to contain what is common between projects.

Say I have some branches:

master: common to all branches dev: branch devoted to unstable development client: branch with features for all client but not general enough for master clientA: project adapted for client A clientB: project adapted for client B

Her...

Git Tips

2010-03-22T08:42:27Z

clone from github behind an evil firewall

Standard:

git clone git@github.com:yogsototh/project.git

Using HTTPS port:

git clone git+ssh://git@github.com:443/yogsototh/project.git

clone all branches

git clone can only fetch the master branch.

If you don’t have much branches, you can simply use clone your project and then use the following command:

git branch --track local_branch remote_branch

for example:

$ git clone git@github:yogsototh/examp...

When regexp is not the best solution

2010-02-23T08:09:52Z

Regular expression are really useful. Unfortunately, they are not always the best way of doing things. Particularly when transformations you want to make are easy.

I wanted to know how to get file extension from filename the fastest way possible. There is 3 natural way of doing this:

# regexp
str.match(/[^.]*$/); 
ext=$&

# split
ext=str.split('.')[-1]

# File module
ext=File.extname(str)

At first sight I believed that the regexp should be faster than the split because it could be many . in a filename. But in reality, most of time there is only one dot and I realized the split will be faster. But not the fastest way. There is a function dedicated to this work in the File module.

split a file by keyword

2010-02-18T13:29:14Z

Strangely enough, I didn’t find any built-in tool to split a file by keyword. I made one myself in awk. I put it here mostly for myself. But it could also helps someone else. The following code split a file for each line containing the word UTC.

#!/usr/bin/env awk
BEGIN{i=0;}
/UTC/ { 
    i+=1;
    FIC=sprintf("fic.%03d",i); 
} 
{print $0>>FIC}

In my real world example, I wanted one file per day, each line containing UTC being in the following format:

Mon Dec  7 10:32:30 UTC 2009

I then finished with the following code:

#!/usr/bin/env awk
BEGIN{i=0;}
/UTC/ {
    date=$1$2$3; 
    if ( date != olddate ) {
       ...

Pragmatic Regular Expression Exclude (2)

2010-02-16T08:33:21Z

In my previous post I had given some trick to match all except something. On the same idea, the trick to match the smallest possible string. Say you want to match the string between ‘a’ and ‘b’, for example, you want to match:

a.....a......b..b..a....a....b...

Here are two common errors and a solution:

/a.*b/
a.....a......b..b..a....a....b...

The first error is to use the evil .*. Because you will match from the first to the last.

/a.*?b/
...

Pragmatic Regular Expression Exclude

2010-02-15T09:16:12Z

Sometimes you cannot simply write:

if str.match(regexp) and 
    not str.match(other_regexp)
        do_something

and you have to make this behaviour with only one regular expression. But, there exists a major problem: the complementary of a regular language might not be regular. Then, for some expression it is absolutely impossible to negate a regular expression.

But sometimes with some simple regular expression it should be possible^†. Say you want to match everything containing the some word say bull but don’t want to match bullshit. Here is a nice way to do that:

# match all string containing 'bull' (bullsh...