Syntax Versus Semantics

Basic Haskell - Splitting Strings by newline "\n" only (not "\r", "\r\n" etc.)

2012-01-02T16:35:00.001+05:30

Based on a quick reply I posted to the Haskell mailing list recently -

On Mon, Jan 2, 2012 at 3:14 PM, max wrote:
> I want to write a function whose behavior is as follows:
>
> foo "string1\nstring2\r\nstring3\nstring4" = ["string1",
> "string2\r\nstring3", "string4"]
>
> Note the sequence "\r\n", which is ignored. How can I do this?

Here's a simple way (may not be the most efficient) -

import Data.List (isSuffixOf)
split = reverse . foldl f [] . lines
where
f [] w = [w]
f (x:xs) w = if "\r" `isSuffixOf` x then ((x++"\n"++w):xs) else (w:x:xs)

Testing -

ghci> split "ab\r\ncd\nefgh\nhijk"
["ab\r\ncd","efgh","hijk"]

Search for a Haskell IDE - Vim blows Leksah out of the water!

2011-12-18T09:24:00.001+05:30

Vim advantages

GHCi integration using shim.vim
Vim font rendering is awesome!!
Source Candy using haskell-unicode.vim

Here's a screenshot of the font rendering (Currently using Monaco as the font) -

More information on my Vim setup coming soon!

Convert multiple JPG files into a single PDF on Linux (Ubuntu)

2010-12-02T12:18:00.002+05:30

It's extremely simple if you have imagemagick installed!

sudo apt-get install imagemagick

Simple pass all the image files to convert with the adjoin parameter -

convert *.jpg -adjoin output.pdf

Done!

Installing Yesod (Haskell web framework) on Webfaction

2010-10-20T15:21:00.002+05:30

Assuming that the latest GHC is installed on webfaction (see my previous posts for that process).

The first step is to install cabal. The best method is to download the cabal-install source package from hackage. In that source package there is a script called "bootstrap.sh". Running this script will download all the necessary packages (including Cabal itself) and install them in ~/.cabal.

Add cabal bin directory (~/.cabal/bin) to your system path.

Installing yesod is then as simple as "cabal install yesod".

The only real problem I faced with installing Yesod is that webfaction mounts /tmp with no-exec. Cabal sometimes requires execution of temporary files from /tmp. This will cause strange errors related to hsc-make or sometimes related to mmap in ghc. The workaround is to manually download the source for each troublesome package from hackage and run "cabal install" inside the source directory.

Otherwise the process is smooth sailing.

Note: The haskell platform is not easy to install on webfaction due to missing GLUT libraries. But if you follow the process above of using cabal install for installing only the libraries you need then things should work out fine without haskell platform.

Simple Linux BASH script to swap two filenames

2010-09-22T23:48:00.002+05:30

#!/bin/bash

if [ $# -lt 2 ]

then

echo "2 arguments needed."

exit

mv $1 tmp

mv $2 $1

mv tmp $2

echo "Done!"

Haskell: Memoise arbitrary functions and monadic values

2010-09-07T02:36:00.002+05:30

I recently got thinking about memoisation in Haskell functions to improve efficiency. Here are my notes -

Pure memoisation

This means adding memoisation to a function transparently (without changing the function signature).

i.e. write a function - memoise :: (a -> r) -> a -> r

so that all we have to do to memoise a function is - memoised_f = memoise f

This seems like an impossible thing to accomplish. Memoisation by definition requires a table/map in memory from argument to return values.

However by exploiting Lazy evaluation, and Compiler optimisations, we can accomplish this in haskell with relative ease. An example from the Haskell wiki -

-- The naive fibonacci function fib :: Int -> Integer fib 0 = 1 fib 1 = 1 fib n = fib (n-1) + fib (n-2)  -- Fast memoised fibonacci function memoised_fib :: Int -> Integer memoised_fib x = (map fib [0..]) !! x

Here we use lazy evaluation to build a map. And then exploit an optimisation of Haskell compilers that arguments to functions are only evaluated once. i.e. in this case that makes sure that (map fib [0..]) is only evaluated once.

It's perhaps clearer this way, which makes it clear that fibs is a constant that is only evaluated once -

-- Mapping from Indices to Fibonacci numbers fibs :: [Integer] fibs = map fib [0..]  -- Fast memoised fibonacci function memoised_fib :: Int -> Integer memoised_fib x = fibs !! x

Impure Memoisation

In general however, it is needed to add some kind of a stateful wrapper over the function to be memoised. IORefs in the IO Monad and State threading in the State Monad can be used for this. I however decided that it would be better to write a function to memoise any "Monadic Value" (m s). I also decided to use StateT Monad Transformer to store the State.

Here's a general solution that can memoise any monadic computation by wrapping it inside a StateT Monad Transformer -

module Main where  import qualified Data.Map as M(Map,empty,insert,lookup) import "monads-fd" Control.Monad.Trans(lift) import Control.Monad.Trans.State.Lazy(StateT(..))  -- Memoise arbitrary monadic computations by wrapping them inside a StateT Monad Transformer memoState :: (Ord k, Monad m) => (k -> m s) -> k -> StateT (M.Map k s) m s memoState f k = StateT $ \s ->         case M.lookup k s of             Nothing -> do                 z <- f k                 return (z, M.insert k z s)             Just z -> return (z, s)

Rather than explain how it works, here's an example of using it -

-- Our base monadic computation (IO) f :: Int -> IO String f x = do     putStr "Get Value #"     putStrLn $ show x     putStr "writesomething>"     s <- getLine     return s  -- Here's the IO monadic value (f) used in a memoised context -- First we wrap f inside StateT using memoState -- Then we chain it together using the usual monadic operations -- Note the use of Lift to perform actions in the IO monad fchain :: StateT (Stat Int String) IO String fchain = do     s <- f' 0     lift $ putStrLn s     s <- f' 1     lift $ putStrLn s     s <- f' 0     lift $ putStrLn s     s <- f' 1     lift $ putStrLn s     s <- f' 2     lift $ putStrLn s     return s         where f' = memoState f  -- The memoised computation fchain can now be run as a whole -- Thanks to memoisation, inspite of us invoking (f' 0) and (f' 1) twice, the user will be asked for their values only once. main :: IO () main = runStateT fchain $ M.empty

Works as advertised I'd say....

Quick multi level mergesort algorithm in javascript

2010-08-31T00:34:00.005+05:30

/* Quick multi level mergesort algorithm in javascript *  * Sort the array first by field1 then by field 2      */

var sort = function(arr) {
               var len = arr.length;
               if (len < 2) return arr;
               var pivot = Math.ceil(len / 2);
               return merge(sort(arr.slice(0, pivot)), sort(arr.slice(pivot)));
};

var merge = function(left, right) {
               var result = [];
               var li = 0;
               var ri = 0;
               var ll = left.length;
               var rl = right.length;
               var le = null;
               var re = null;

               while ((li < ll) && (ri < rl)) {

                               le = left[li];
                               re = right[ri];

                               if (le.field1 > re.field1) {
                                               result.push(le);
                                               li++;
                                               continue;
                               }

                               if (le.field1 < re.field1) {
                                               result.push(re);
                                               ri++;
                                               continue;
                               }

                               if (le.field2 > re.field2) {
                                               result.push(le);
                                               li++;
                                               continue;
                               }

                               result.push(re);
                               ri++;
                               continue;

               }

               result = result.concat(left.slice(li), right.slice(ri));
               return result;
};

Wget as a spider/crawler - Recursively download a webpage and everything it links to

2010-08-12T00:06:00.003+05:30

Here's a handy command line for using the Linux utility wget as a web crawler.

wget -r -np -p -k http://www.example.com

An explanation of the options -

r - enable recursive downloads

np - wget will not follow links up the url. e.g. it will not follow a link from example.com/abcd/page1.html to example.com/page2.html.

p - get all the page requisites. e.g. get all the image/css/js files linked from the page.

k - convert all links to make them suitable for local viewing. Will convert all absolute links to relative links if the file has been downloaded locally.

Some more useful tips:

c - continue a previous download. This option is very handy to resume past aborted download attempts. It compares the local filesize with the remote filesize and downloads only the difference. Beware that if the files have changed on the server, you would end up with a garbled file.

X - Supply a list of directories to exclude from downloading. Is helpful for example when you want to not download a particular section of the site. You can include wildcards in the directory pattern. e.g. -X /ads/* will skip over anything that begins with www.example.com/ads folder.

Linux BASH function to search recursively for a string in all files in the current directory

2010-08-07T00:00:00.003+05:30

If you do any serious coding at all, you would have used a "Search" function in your editor. Some IDEs even allow you to search within the entire project/workspace or a subset of files within that workspace. But when you are using a simple text editor that does not support such features, such functionality is sorely missed.

Fortunately, the Linux shell BASH provides an easy way to search for any string recursively in a directory. Just cd to the desired location and do -

grep -ri "[a phrase]" .

This would give you the results of a recursive (-r), case insensitive match (-i) for the supplied string in all the files in the current directory.

But I find even this small line a pain to type when I have to do this every other minute during a marathon coding session. So I wrote a small wrapper function to make this even easier -


function grepcr() {
if [ $# -gt 0 ]; then
 a=$1
 shift
fi
sp=" "
while [ $# -gt 0 ]; do
 a=$a$sp$1
 shift
done
echo "grep -ri \"$a\" ."
grep -ri "$a" .
}

Just put this function in your ~/.bashrc file and then you can search for "a phrase" using the simple -

grepcr a phrase

As you may have guessed, "grepcr" stands for GREP Contents Recursively.

Installing Leksah IDE for Haskell on Ubuntu 10.04 Lucid Lynx

2010-06-28T19:56:00.003+05:30

From this post -

sudo apt-get install cabal-install libghc6-zlib-dev libgtk2.0-dev libgtksourceview2.0-dev libglade2-dev
sudo cabal update
sudo cabal install cabal-install --global
sudo cabal install alex --global
sudo cabal install happy --global
sudo cabal install gtk2hs-buildtools --global
sudo cabal install glade --global
sudo cabal install leksah --global

Easy!

Converting videos for playback on Blackberry Storm 9530

2010-06-25T13:48:00.003+05:30

Playing decent quality videos on the Blackberry Storm is no walk in the park!

File size is always an issue on a mobile device. You should convert your videos to smaller screen sizes to save space. A more serious issue is compatibility. I tried to play a bunch of my AVI files on the storm but with no cigars. So transcoding video files was a necessity.

There are a bunch of utilities for Windows to convert videos to a variety of formats but nothing equivalently easy exists on Linux. Or so I thought.

Then I discovered that Tablet Encoder (perl script) for the Nokia Maemo platform works equally well for encoding videos for the Storm! Infact I realised that the default options for conversion to MPG give you a decent enough video playback. So you can just do this -

./tablet-encode original_movie.avi converted_for_the_storm.mpg

and you are done.

It squishes a 1.5 GB movie into a 300 MB filesize with very decent audio and video quality. Try it!

Getting Mobireader to work correctly on Blackberry Storm

2010-06-12T17:08:00.003+05:30

MobiPocket Reader is the best solution for reading ebooks on your Blackberry.

Unfortunately, the current Blackberry version of Mobireader available is not tweaked appropriately for the full screen touch enabled Storm experience and is an eyesore. So much so that it can be labeled unusable.

Fortunately, the MobiPocket team has indicated that they are working on a Storm version of their software. Till the time that version is release however, you can get by disabling compatibility mode, using the following steps -

On your blackberry, go to Options -> Advanced Options -> Applications.
Hightlight Mobipocket Reader and click the menu button
Select "Disable Compatibility Mode"
Perform a hard reset by turning off the Blackberry and taking out the battery.
Restart the blackberry.

At this point when you start the Mobipocket Reader application you would see a full screen interface that can be controlled effectively using the touchscreen. Opening any books would open in full screen but sadly cannot be navigated. To navigate you need to click the menu button and "Show keyboard". Then you can navigate using the Space key and the O/P keys on the keyboard.

That simple trick will make Mobipocket Reader pretty usable on the Blackberry Storm.

Pre built Erlang/OTP R13B04 Debian package for Ubuntu 10.04 (Lucid). Includes WX support and all documentation

2010-06-10T09:37:00.001+05:30

While building the latest Erlang distribution from sources (R13B04 at the time of writing) is not too difficult on Ubuntu (see my last post on this blog), it is a royal pain to do so for all of your machines every time you upgrade your distribution. The bundled erlang with Ubuntu is always a few steps behind the latest official release of Erlang so doing "sudo apt-get install erlang" is not an option.

So for all the people who would like to stay up to date and yet not have to bother with configuring and building erlang from sources, I have created a debian package of erlang R13B04 with wx configured and with all the docs included.

Get the erlang deb file for Ubuntu 10.04 from freesoftwarefreeworld.com. The release has wx support (which is difficult to get configured correctly when building from sources) and the PDF docs, HTML docs, and the man pages are also included. This is the first deb package I created so it is admittedly a bit rough (though it should work fine). I will be refining the deb file every once in a while, and keep it up to date with the latest released erlang sources. So keep your eyes peeled for updates on this blog!

I'm thinking of building a deb package for bleeding edge erlang from it's git repository as well. Please let me know if you think it's a good idea.

Compiling Erlang OTPR13B04 with wx support on Ubuntu Lucid

2010-06-05T19:38:00.002+05:30

Erlang R13B04 compiles and installs fairly easily on Ubuntu Lucid. The only tricky bit was installing wx dependencies. Here's how -

Make sure you do this first even before running configure -

sudo apt-get install wx2.8-dev freeglut3-dev libwxgtk2.8-dev

There is some problem with caching so if you have run ./configure before you have installed these dependencies, things will break with weird error messages. In such cases it is better to delete the otp_src_r13b04 directory completely and untar it from the tarball again.

To break the rules, you must first know the rules

2010-05-20T23:29:00.003+05:30

I had to put this down somewhere -

The previous post (with it's small comment on power and responsibility) reminded me of the zen koan where a master taught a pupil to always use structured code with proper design patterns. Then one day the pupil saw the master writing unstructured code. The pupil was furious and disillusioned. He asked his master - "Why do you force me to write structured code, when you yourself don't follow your own guidelines". To which the master replied "But I already know how to write structured code!", and the pupil was enlightened.

"To break the rules, you must first know the rules".

"This world is like any other. It has rules, some can be bent, others, broken."

Javascript performance - closures versus prototypal inheritence

2010-05-20T22:51:00.003+05:30

Another @ work story.

Today while reviewing some code a junior wrote - I saw a 'class' definition that looked like this -


--------------------------------------------
function Foo(x, y) {
 var innerx = x*10;
 var innery = y*50;

 ... some more processing here ...

 var returned = {};
 returned.sum = function () {
   return innerx+innery;
 };
 returned.setx = function (xval) {
   innerx = xval;
 };

 return returned;
}

var newFoo = Foo();
--------------------------------------------

Do you see what is happening here? This code is using closures to mimic object encapsulation in javascript. The returned object is a closure and therefore has access to innerx and innery variables of the enclosing object/function. The piece of code that calls Foo() gets this object but cannot access the inner variables. It can only access the setx() method to set the value of innerx. And innery is completely inaccessible. This is functional paradigm not an object oriented one (notice the distinct absence of new anywhere in the code)!

There isn't a way to do this using plain prototype mechanism provided by javascript. You would write something like -


--------------------------------------------
function Foo(x, y) {
 this.innerx = x*10;
 this.innery = y*50;

 ... some more processing here ...
}
Foo.prototype.sum = function(){
 return innerx+innery;
};
Foo.prototype.setx = function(xval){
 this.innerx = xval;
};

var newFoo = new Foo();
--------------------------------------------

Here the variables innerx and innery are exposed to the world. But that's not such a bad thing in my opinion - power == responsibility.

But the functional style code (using closures) has another problem - For each object that is created, the methods are redefined! This is a great speed and memory overhead if your methods are small. In the prototypal code, the methods are defined once (for the prototype object) and then shared across all instances.

The verdict - I told the coder to rewrite the code using the prototype object. There really wasn't a need to support strict encapsulation in this piece of code (in my experience, there rarely is) and the performance hit wasn't worth it.

Installing CouchDB from latest guthub sources in Ubuntu Lucid

2010-05-19T00:16:00.002+05:30

It's a 3 step process -

1. Install dependencies -

$ sudo apt-get install erlang build-essential libicu-dev libcurl4-openssl-dev xulrunner-dev

Note that libmozjs-dev is no longer provided on Ubuntu starting with Lucid. This is why we need to install xulrunner-dev which includes spidermonkey. We point couchdb to the appropriate directory within xulrunner in step 3.

2. Checkout latest couchdb sources from official git repos -

$ git clone http://github.com/apache/couchdb.git

3. Bootstrap, Configure, Make and Install!

$ cd couchdb
$ ./bootstrap
$ ./configure --with-js-lib=/usr/lib/xulrunner-devel-1.9.2.3/lib --with-js-include=/usr/lib/xulrunner-devel-1.9.2.3/include
$ make
$ make install

Quick profiling script to gather performance metrics in ruby

2010-05-07T14:27:00.003+05:30

So over at work we are using an interpreted language for performing many tasks. The interpreter has a debug mode wherein it prints out START and END messages for every function executed with a timestamp in milliseconds. Here's a sample -

LOG : 1221489714064 : foo() : START
LOG : 1221489714286 : bar1() : START
LOG : 1221489714411 : baz1() : START
LOG : 1221489714676 : baz1() : END
LOG : 1221489714812 : baz2() : START
LOG : 1221489715478 : baz2() : END
LOG : 1221489715574 : bar1() : END
LOG : 1221489715698 : bar2() : START
LOG : 1221489718073 : bar2() : END
LOG : 1221489720092 : foo() : END

You can see what is going on there. The huge number is a milliseconds timestamp, followed by the function name and a START or an END depending on whether it entered or exited the function.

This is pretty useful information when you are trying to squeeze out every bit of performance out of these functions.. Unfortunately looking at the log files and performing mental subtraction between 13-14 digit numbers on the fly is really not something I wanted to do, EVER.

So I wrote this simple ruby script in a jiffy. It converts the previous bit of information into something a lot easier to parse -

foo() == 6028 msec
-->bar1() == 1288 msec
-->-->baz1() == 265 msec
-->-->baz2() == 666 msec
-->bar2() == 2375 msec

As you can see, the script gives you the elapsed times for all the functions. It supports nesting and depicts the function stack graphically. It makes it easy, for example, to see that foo calls two more functions bar1 and bar2 which take more than half of the processing time of foo. Here's the script -


$pat = /LOG : ([\w.]+) : ([\w.()]+) : (START|END)/
$re = Regexp.new($pat)

stk = []
out = [[]]
File.open('log').each do |line|
  if line =~ $re
    if ($3 == 'START')
      out.push []
      stk.push $~
    elsif ($3 == 'END') and not stk.empty?
      # gather all information
      end_msec = $1
      $~ = stk.pop
      elapsed = end_msec.to_i-$1.to_i
      children = out.pop
      out.last.push("#{"-->"*stk.length}#{$2} == #{elapsed} msec\n")
      out[out.length-1] = out.last + children
    end
  end
end
out.each {|ls|ls.each{|l|print l}}

It expects to find the START and END statements in a file called 'log'.

All the manipulation with the stack are needed to support nested functions and still support correct function call order.

The only tricky bits in the code are really the pushing and popping of regular expression results. Hats off to Ruby for allowing us to do that! Really. Lesser languages would have made this task harder than it needs to be, by requiring us to extract and then save the regex match results into our own data structure.

My new preferred style for function header comments

2010-04-29T17:52:00.002+05:30

Very symmetrical!

/**************************************\
* Description goes here
* IN: something
* OUT: something
\**************************************/

Funny Sign in the men's room at the airport

2010-04-29T17:47:00.003+05:30

As I recall, the sequence went like this -

The liquid soap dispenser next to the washbasin -

Press once for hand wash, 3 times for a bath!

Me:

Ha ha!

Debugging a Linux BASH shell script

2010-04-29T17:42:00.002+05:30

Debugging shell scripts is really a PITA. Here's a handy trick that really saved me today -

Use -x and -v switches to get more insight into what BASH is doing.

To display commands and their arguments as they are executed -
bash -x scriptName

To display shell input lines as they are read -
bash -v scriptName

You can put the above two commands in the shell script itself, like so -
# turn on debug mode
set -x
set -v

OR change the shabang line -
#!/bin/bash -xv

Best webcomic ever! - The Dinosaur Comic

2010-04-28T11:17:00.002+05:30

Yep, the static talking dinosaurs at Qwantz deliver the funniest, geekiest, and even surprisingly insightful, madcap comedy routine several times a week, week after week, and I simply can't get enough. Even XKCD gets boring every once in a while but dinosaur comics stay fresh.

And now it gets even better! Look at the "overlay" feature -

http://www.qwantz.com/index.php?butiwouldratherbereading=xkcd

If you'd rather be reading xkcd with the sharp witty banter of dinosaur comics just append - &butiwouldratherbereading=xkcd to the end of the url. Talking dinosaurs replaced by talking stick figures if you find that more "real world".

There are several other overlays available, mostly to convert the dinosaurs into characters from other popular webcomics. Like Penny Arcade for example -

http://www.qwantz.com/index.php?butiwouldratherbereading=pennyarcade

And then there are the "tweak" overlays.. Like if you prefer your prehistoric dinosaurs with just a dash of the future (think Star wars), you can make it happen. Best read with comic 1701-

http://www.qwantz.com/index.php?comic=1701&butiwouldratherbereading=onewheretrexgotassimilated

Are you easily offended by nudity (even in cartoon extinct animals)? Try on this overlay -

http://www.qwantz.com/index.php?butiwouldratherbereading=onewheretrexwearsmore

Oh well, TRex is still not wearing any pants...

Linux BASH tip - How to subtract arrays

2010-04-27T17:22:00.002+05:30

So I needed a BASH code snippet to subtract arrays...

What I mean by "subtracting arrays" is actually set difference like so -

IF
array1="A B C D E F G H"
array2="C B D G"
THEN
array1-array2 = "A E F H"

Note that the arrays (strings with space separated terms really) need not be in any particular order. Also it's not be clear from the example above but in my solution duplicates are automatically removed.

So without further ado here's the code -

$ array1="A B C D E F G H"
$ array2="C B D G"
$ finalResult=`comm -23 <(echo ${array1} | sed 's/ /\n/g' | sort -u) <(echo ${array2} | sed 's/ /\n/g' | sort -u)`
$ echo $finalResult
A E F H

It uses the cool "comm" which comes installed on Linux by default. Comm basically compares two sorted files line by line and can give you lines only in a particular file and not the other; In other words the "difference" between two files. This is basically all we needed. We do need to sort the inputs (which removes duplicates as well) before we pass them to comm, hence the use of 'sort'. And we need to convert 'space' to 'newline' before we can pass the strings to sort, hence the use of 'sed'. Piping it all together, we have a nice little one liner.

Minicom lock file

2010-04-05T20:25:00.001+05:30

Is in this place -

/var/tmp/LCK..ttyUSB0

Or something similar.

The search for a good Linux GUI for SVN ends at RabbitVCS

2010-04-02T12:47:00.002+05:30

SVN may not be the best source control management tool in the world (that title goes to 'git' IMO) but it's certainly the most popular, and you would think that there would be a ton of GUI options for it on Linux. Not so..

While on windows there's the excellent TortoiseSVN, the only options for people working with SVN repositories on Linux were RapidSVN (which is not under development anymore and hasn't been updated in a while) or the commandline. And the commandline is what I used till today, which while fine for most purposes, does leave you pining for an easier way to juggle revision numbers and look at specific log messages without headaches.

Well now I have another option. And what a great option it is! RabbitVCS will leave TortoiseSVN behind in its wake!

Rabbit integrates with Nautilus, Thunar, Gedit etc. to give you that familiar "Shell Extension" ease of use of Tortoise. It makes working with SVN repos a snap.

Go grab it here. It has Ubuntu PPA repos which makes it a snap to install.

This has to be one of the most productive uses of twitter I ever saw!

2010-03-09T14:01:00.001+05:30

http://www.longestpoemintheworld.com/

Sampler - The first page

And now for some time in the new Japanese soaking tub.

Done and done. Liking the new haircut. Now to get some grub ^_^

In the hospital, and going to be a first time dad soon!

Today can stop what it's doing already and chang its tune.

Yet you follow and you'll watch you bitch.

we're beautiful and dirty rich

biting off all my nails, and painting them white.

:O Oh and Life of Ryan ... What a great TV night ???

The more we do here and now, the more it'll matter then and there.

I left without my sock hat and i miss having longer hair!

And of course - Varghese Bush. The world suddenly makes a lot of sense.

And I?m leaning on this broken fence between past and present tense.

Work work work and no play!

its toot and boot it day

Monkeys live in trees, grasslands, mountains, forests and on high plains.

No matter the circumstance God is still good and He reigns!

now im running and screaming.

good night and pleasant dreaming ...

Wrapping my hair, and off to bed! :-)

Bang and you are soo very dead. :)

Installing Haskell Platform (with GHC 6.10.4) in Ubuntu Karmic

2010-03-09T13:30:00.003+05:30

From http://gist.github.com/326372

#!/bin/bash

# Install dependencies
sudo apt-get install ghc6 ghc6-prof ghc6-doc haddock libglut-dev happy alex \
libedit-dev zlib1g-dev checkinstall libghc6-mtl-prof libghc6-network-prof

# Get haskell-platform
wget http://hackage.haskell.org/platform/2009.2.0.2/haskell-platform-2009.2.0.2.tar.gz
tar -xzf haskell-platform-2009.2.0.2.tar.gz
cd haskell-platform-2009.2.0.2

# Build & Install
./configure

# Before doing a make, install this patch from http://trac.haskell.org/haskell-platform/ticket/84
# Patch appended at the end of the post

make
sudo checkinstall -y

cabal update


------------------------>8---------------------------
PATCH FOLLOWS
------------------------>8---------------------------
A quick(-and-dirty) hot fix: -- code copied from build.sh

---
scripts/install.sh |   18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)

Index: haskell-platform-2009.2.0.2/scripts/install.sh
===================================================================
--- haskell-platform-2009.2.0.2.orig/scripts/install.sh
+++ haskell-platform-2009.2.0.2/scripts/install.sh
@@ -34,13 +34,23 @@ install_pkg () {
  fi
}

+# Is this exact version of the package already installed?
+is_pkg_installed () {
+  PKG_VER=$1
+  grep " ${PKG_VER} " installed.packages > /dev/null 2>&1
+}
+
# Actually do something!
cd packages
for pkg in `cat platform.packages`; do
-  cd "${pkg}" || die "The directory for the component ${PKG} is missing"
-  echo "Installing ${pkg}..."
-  install_pkg ${pkg}
-  cd ..
+  if is_pkg_installed "${pkg}"; then
+    echo "Platform package ${pkg} is already installed. Skipping..."
+  else
+    cd "${pkg}" || die "The directory for the component ${PKG} is missing"
+    echo "Installing ${pkg}..."
+    install_pkg ${pkg}
+    cd ..
+  fi
done

echo

------------------------>8---------------------------

Installing GHC 6.10.4 on webfaction

2010-03-09T13:20:00.003+05:30

It was surprisingly easy!

Install the generic Haskell 6.10.4 package from http://haskell.org/ghc/download_ghc_6_10_4.html#x86linux

wget http://haskell.org/ghc/dist/6.10.4/ghc-6.10.4-i386-unknown-linux-n.tar.bz2
bunzip2 ghc-6.10.4-i386-unknown-linux-n.tar.bz2
tar -xvf ghc-6.10.4-i386-unknown-linux-n.tar
cd ghc-6.10.4
./configure --prefix=$HOME/applications
make install

Proceeded smoothly.

Ruby one liner for array splitting

2010-03-08T13:37:00.006+05:30

The expressiveness of Ruby can surprise you sometimes. And unlike something ultra powerful like Haskell where the expressiveness can fry your noodles, in Ruby the expressiveness comes naturally for real world code.

Here's a good example -

I needed a quick function to split an array into sub arrays of fixed sizes. It was very quick and painless and the brevity of the code did surprise me!


class Array
  def chunk(sizen=2, chunks=[])
    (0...self.length).step(sizen) { |n| chunks << self[n,sizen] }
    chunks
  end
end

It's effectively a one liner, if you ignore comments and the cruft for declarations and return values.

Gnome IPMessenger replacement

2010-03-08T13:31:00.002+05:30

Just now saw http://code.google.com/p/iptux/

It supports messages and ultra fast file transfers over LAN. Plus! It comes bundled with Ubuntu (Use Ubuntu Software Manager to install).!

L better than IPMessenger because it supports multiple networks and also behaves much more like a traditional messaging client (chat windows, profile avatars etc.), But the tiny downside is that it doesn't support sealed messages.

Getting Erlang crypto to work on windows

2010-02-05T22:28:00.002+05:30

Had a bit of trouble getting Webmachine to work on a windows box. Kept on running into this error -

=ERROR REPORT==== 5-Feb-2010::22:29:24 ===
Unable to load crypto_drv. Failed with error:
"The specified module could not be found."
OpenSSL might not be installed on this system.
{"init terminating in do_boot",{{case_clause,{error,{shutdown,{crypto_app,start,[normal,[]]}}}},[{webmstn,ensure_started,1},{webmstn,start,0},{init,start_it,1},{init,start_em,1}]}}

And being the smart ass that I am, I went searching on the net instead of simply installing OpenSSL.

Here's a very educational post I found on finding if a specific module is installed and loading its DLLs with erlang. This guy had the same problem as me and he finally solved it by installing OpenSSL for Win32! Surprise!

---- Quoting ----
I have a problem with trying to use the mysql driver available on google code (http://code.google.com/p/erlang-mysql-driver/)

I have the windows installation of erlang (tried both with R12B-5 and R13A) on my PC running on Windows XP.

When try to connect to my database it fails.
I have searched the web for hints and found others with similar problems. It seems that the crypto driver is not compiled or linked properly for my machine.

Somewhere on the web I found the following test to verify if crypto works:

4> crypto:start(),
4> crypto:sha("abc").

=PROGRESS REPORT==== 20-Mar-2009::10:14:01 ===
supervisor: {local,crypto_sup}
started: [{pid,<0.61.0>},
{name,crypto_server},
{mfa,{crypto_server,start_link,[]}},
{restart_type,permanent},
{shutdown,2000},
{child_type,worker}]

=PROGRESS REPORT==== 20-Mar-2009::10:14:01 ===
application: crypto
started_at: nonode@nohost
<<169,153,62,54,71,6,129,106,186,62,37,113,120,80,194,108,
156,208,216,157>>

On my machine I get the following:

13> crypto:start(),
13> crypto:sha("abc").

=INFO REPORT==== 19-Mar-2009::21:38:13 ===
application: crypto
exited: {shutdown,{crypto_app,start,[normal,[]]}}
type: temporary
** exception error: bad argument
in function port_control/3
called as port_control(crypto_drv02,5,"abc")
in call from crypto:control/2
14>

I found some other information on the web on how to check if the crypto_drv.dll was loaded properly.

7> erl_ddll:start(),
7>
7> PrivDir = code:priv_dir(crypto),
7>
7> LibDir1 = filename:join([PrivDir, "lib"]),
7>
7> ls(LibDir1).
crypto_drv.dll
ok
8>
8> Mess = erl_ddll:load_driver(LibDir1, crypto_drv).
{error,{open_error,-136}}
9>
9> {_, Err} = Mess.
{error,{open_error,-136}}
10>
10> erl_ddll:format_error( Err).
"The specified module could not be found."
11>

Looking at this is looks like the file location is correct but the file can not be loaded.

Any suggestions what to do?
Is the crypto_drv.dll not correct linked/compiled for my machine?
If so where can I find a new?
---- End Quoting ----

Well at least it was educational...

Bash! You are killing me! How to escape spaces in filenames being passed to tar

2010-02-05T13:14:00.002+05:30

Bash can be really frustrating!

I'm trying to take all the files that match a pattern and put them in a tar.gz file. Sounds simple?

aj@aj-laptop:/home/aj$ find . -name "*tips*"
./data/DRAFT/tips and tricks.doc
./data/DRAFT/tips new.doc

Looks okay till here. But -

aj@aj-laptop:/home/aj$ find . -name "*tips*" | xargs tar czvvf tips.tar.gz
tar: ./data/DRAFT/tips: Cannot stat: No such file or directory
tar: and: Cannot stat: No such file or directory
tar: tricks.doc: Cannot stat: No such file or directory
tar: ./data/DRAFT/tips: Cannot stat: No such file or directory
tar: new.doc: Cannot stat: No such file or directory
tar: Error exit delayed from previous errors
aj@aj-laptop:/home/aj$

Apparently it would not work fine when your filenames have spaces in them because then it would tokenise them with spaces and hence break up the file names.

So I search around on the web and find a bunch of things to try on a stackoverflow thread.

And here's the solution that worked -

aj@aj-laptop:/home/aj$ find . -name "*tips*" -print0 | xargs -0 tar czvvf tips.tar.gz
-rwx------ aj/aj 31232 2010-01-12 19:23 ./data/DRAFT/tips and tricks.doc
-rwx------ aj/aj 30208 2008-10-08 16:57 ./data/DRAFT/tips new.doc
aj@aj-laptop:/home/aj$

Basically adding -print0 to the find command makes it separate strings by NULLs (\0s) which can never be a part of the filenames and can never cause problems.Note that you also need to tell xargs to separate strings by NULLs by passing the -0 flag.

But now since I couldn't find any such flags for other standard linux commands like grep, this solution is only useful when I need to pass the output from find straight into tar. For example I cannot do find . -name "*tips*" -print0 | grep 'tricks' | xargs -0 tar czvvf tips_and_tricks.tar.gz !

Sad! But I am done for the day with this problem. Please let me know in the comments if there is a general solution to this.

How to escape the Matrix (a.k.a. Escaping the '#' hash character in a wget commandline)

2010-02-03T12:54:00.003+05:30

I have a file "ftp://ftpserver/applicationdocs/detail#1" which I need to retrieve using wget but the # character is proving impossible!

Wget tries to retrieve a file with the name "detail" instead of "detail#1". I get the same results with all of the following -

wget ftp://ftpserver/applicationdocs/detail#1
wget ftp://ftpserver/applicationdocs/detail\#1
wget 'ftp://ftpserver/applicationdocs/detail#1'
wget "ftp://ftpserver/applicationdocs/detail#1"

I noticed that echo 'ftp://ftpserver/applicationdocs/detail#1' gives the expected output so I also tried the following -

echo 'ftp://ftpserver/applicationdocs/detail#1' | wget -i -

but to no avail. Sucks.

But then! Inspiration strikes!

%23 is hex code of #. And very surprisingly, this works -

wget ftp://ftpserver/applicationdocs/detail%231

A quick post to the ILUGD list verifies that this is the only quick solution commonly known.

Tips for Avidemux - "Trouble initialising audio device", "Encoder not initialised" etc.

2009-10-23T00:05:00.004+05:30

Tips for converting videos for DVD player playback using Avidemux -

1. A very simple fix for avidemux "Trouble initialising audio device" -

Go to "tools->preferences->audio->alsa device" and change it to "default" instead of "dmix"

Wonder why "default" is not the default for that setting!

2. Best encoding settings for playback on a DVD player -

Video - MPEG-4 ASP (Xvid4)
Audio - MP3 (LAME)

3. If you get an error "Encoder not initialised" then most probably the input audio frequency is non standard. Turn on "Audio->Filters->Resampling (Hz)" and that should fix the problem.

Dazed out english language modification #2

2009-10-08T03:57:00.004+05:30

The previous post got me thinking...

Is ,... a valid punctuation mark?

If it isn't then it should be! It indicates a "pregnant" semi-pause (as opposed to an empty one)...

Ever felt like the range of punctuation marks available is simply not enough to convey even the most basic of emotions?? (Well I can use words yeah, but that went out of fashion decades ago!)

:) ;) !!!)

Random silliness

2009-10-08T03:53:00.002+05:30

It popped up in my head while doodling randomly

I'm a bit insane
as in,... I continuously think outside the box
well that's insanity isn't it...
in this conformant world
where differences can lead to bloodshed

What silliness...

Javascript handleEvent function

2009-10-05T16:23:00.002+05:30

I just discovered this nifty little function!

handleEvent(evt) is basically the internal function which gets called when an event is raised on an object.

For example - when you attach a listener like so (jquery syntax ahoy) $('#divid').click(function(){blah blah}), what really happens is that the anonymous function is added to the event listeners list and the functions in that list are iterated over and called by the handleEvent function defined for DIVs. The anonymous function itself is not called directly when an event is raised.

Seems fairly useless until you realise that you can call this function yourself!

i.e. if you want some other div to handle the click event - use div.handleEvent(evt), passing it the event object!

I am sure it can be used for all sorts of nifty things, I just can't think of any practical examples right now.

TODO: Think of some practical examples.

Also, there is probably a way to attach events to custom objects which define the handleEvent function. Brainfreeze. Gotta try it out soon as I get out of this meeting.

TODO: Attach events to normal objects which define the handleEvent function.

200th Post! (1st Oct) Happy Birthday to me! :)

2009-10-05T14:04:00.006+05:30

This blog is now 200 posts old! Yay! I am now 27 years old! Sigh!

Using an external 1920x1080 LCD monitor with Ubuntu/Kubuntu (intel cards)

2009-10-02T01:25:00.002+05:30

I got a 23 inch 1920x1080 LCD screen for my laptop... AND... I got it working under Ubuntu (and Kubuntu)!

Here are the steps -

1) Edit your xorg.conf to change the virtual mode line

sudo kate /etc/X11/xorg.conf
change
Virtual 2560 1024
to
Virtual 1920 1880

2) Add appropriate mode lines to your ~/.bashrc

sudo kate ~/.bashrc
Add the following lines at the end -
# Mode lines for external LCD 1920x1080
xrandr --newmode "1920x1080" 172.80 1920 2040 2248 2576 10801081 1084 1118 -HSync +Vsync
xrandr --addmode VGA 1920x1080
xrandr --output VGA --mode 1920x1080

3) Reboot the system (Somehow logout and login did not work for me). Or if you have had it enabled, press Ctrl-Alt-Backspace to restart the x.org server.

Rant: WHY OH WHY does KDE not have an option to extend your desktop across multiple screens?? I can do it easily in Gnome, but all KDE can do is mirror your desktop which sucks when the screens differ greatly in reolution.

Using ruby on rails routes in javascript (jquery)

2009-09-17T22:15:00.002+05:30

I am working on a shiny new ajax app using rails and like many before me, I felt the need to use the rails route generation facility in javascript. I found this plugin on the web and it had some ajax abilities but it used prototype instead of jquery so I forked it and added jquery support - go get it here to get all the jquery ajax goodness in your routes. In a later post I will blog about how to create a sample app using it.

Why I love my wife - and other everyday funny stories

2009-08-28T02:43:00.003+05:30

Heh, some blog posts out there are mighty funny in an everyday sort of way (unlike mine which has nothing funny or everyday about it). Consider this quote from a post at ultramicroscopic -

Wife stood in the Barnes and Noble music section wearing the headphones and listening to nothing. A few yards away Son Three (four years old) was also wearing headphones but grooving to cds with brightly colored covers. After a minute or two of fidgeting with the kiosk, she asked Son Three how to make the music play. He waved a cd under the upc scanner and continued to rock out. Wife told him he was silly. She asked him again and he showed her again, she dismissed his naivety. Frustrated she called over a clerk. The clerk took the cd and did exactly what Son Three had demonstrated. The music played but she was too confused to enjoy it.
When she got home she asked me how the device sucks the music off the cd through the packaging.

Ha ha ha ha!

Reminds me of the time when this friend of mine asked a shopkeeper for a "CD" (this was when floppy disks were the norm) and the shopkeeper replied with "Of course! Wooden or Aluminium"!

Note :- If you don't speak Hindi, this anecdote will not make any sense to you. But I won't explain it because it's really not that funny when narrated (it is funny when it actually happens to you).

Using Aptana for Ruby on Rails development on (K)Ubuntu 9.04 - "Rails not found"

2009-08-27T00:22:00.003+05:30

Try using Aptana IDE on (K)Ubuntu 9.04 for developing rails apps and you would run into this problem pretty quickly. Somehow on Ubuntu, the executable "rails" is not installed in the standard /usr/bin or /usr/local/bin. Instead it is only present in /var/lib/gems/1.8/bin/. This means that Aptana cannot find rails even though it was installed using the standard distribution specific package manager.

The fix though is simple - Either create a symlink to rails by doing

sudo ln -s /var/lib/gems/1.8/bin/rails /usr/bin/rails
sudo ln -s /var/lib/gems/1.8/bin/rake /usr/bin/rake

Or even better - do what this post suggests -

cd /usr/local/bin
sudo ln -s /usr/bin/ruby ruby
sudo ln -s /usr/bin/ri ri
sudo ln -s /usr/bin/rdoc rdoc
sudo ln -s /var/lib/gems/1.8/bin/rails rails
sudo ln -s /var/lib/gems/1.8/bin/rake rake

I broke the translation party!

2009-08-25T19:02:00.004+05:30

Translation party is a fun little tool based on Google translate. Ever played "Chinese whispers"? Think of this as playing it with a schizophrenic Chinese guy halfway across the world! It really is quite a time killer! Google translation is quite good so not all results will be funny, but keep at it, and you will hit upon translation gems quite easily.

For example, "You can't teach an old woman to suck eggs." (A variation of a saying I heard recently on a UK trip) is translated as "Eggs can not teach a woman to smoke." and then to "Egg women smoke, please do not tell." and then to the really bizzarre "Please tell us the city regiment of women Purizupurizumi eggs.", "Purizupurizumi Please tell me, please send a regiment of women in urban eggs.", and "Please send Purizupurizumi. Please educate the women of the regiment. Eggs please contact me.", before finally settling on "Please. Please Purizupurizumi please. Women's education, please contact me. Send a regiment of the egg."!!!!

God knows what a Purizupurizumi is. My guess is it's Chinese for either a type of chicken, or some high ranking military designation. Either way, it seems highly revered. :)

I found it intriguing that every sentence seemed to have an equilibrium point, until I chanced upon the simple 2 word sentence, pictured above, that seems to throw Google translate into a tizzy! Since then I have found many more such examples (there are really a lot of them so they are easy to find).

Fun!

http://translationparty.com

Pirate Party wins a seat on the European Parliament!

2009-06-08T13:19:00.002+05:30

http://torrentfreak.com/pirate-party-wins-and-enters-the-european-parliament-090607/

Dazed out English language modification #1 - Many Few

2009-06-01T20:55:00.004+05:30

I get crazy ideas when I'm half asleep. So here's what my sleep deprived mind thought should be valid English -

"This is one of the many few reasons why [noun] rocks"

That's right, MANY FEW.

It somehow sounds better than either "many" or "few" by itself. More rhythmic, balanced.

Plus it's handy when you want to emphasise the "few" good reasons but in a positive sense. Like when you want to point out the best feature of your product but make sure that the customer knows that there are other features that are just as good too but not trivialise the very important feature you are explaining right now but... Forget it.. I did warn you that it was a hair brained idea..

Better looking tabs in jQuery UI 'cupertino' theme

2009-05-08T17:06:00.004+05:30

Cupertino is, arguably, the best theme in the jQuery UI theme set. But it has a fatal flaw. The tabs have an ugly blue background to them which IMHO looks ugly.

So here's the fix.

Basically we are trying to convert this -
into this -
To accomplish this add the following CSS to your web pages -


         #tabs, #tabs .ui-tabs-nav {
             border: none;
             background: none;
         }
         #tabs .ui-widget-content {
             border: 1px solid #DDDDDD;
             background: #F9F9F9 url(images/ui-bg_highlight-hard_100_f9f9f9_1x100.png) repeat-x scroll 50% top;
         }

Now isn't that much nicer. More Mac-ish but still nicer :)

PS: No this cannot be done using Theme Roller (unless you want to break other ui widgets), but you are welcome to try!

MySQL Workbench Lua scripting is awesome!

2009-05-08T13:37:00.002+05:30

So I needed to change the MYSQL engine for all tables to MyISAM. No problems! -

foreach_table(sc, function (ts) ts.tableEngine = 'MyISAM'; end);

And I needed to reset autoincrement values in all tables. No problems again!

foreach_table(sc, function (ts) ts.nextAutoInc = ''; end);

Of course you would need to include the lua utility library script I mentioned in my previous post.

Ruby on Rails helper scripts for MySQL workbench!

2009-05-08T02:30:00.002+05:30

I've been using DB Designer 4 for quite a while now and while it produced very pretty ER diagrams, it was a bit limited in functionality.

In particular it did not behave well with Rails style databases because of the following -

Table names are plural
Foreign keys are singular! E.g. a foreign key to table "Products" will be called "product_id"!
Primary keys are always "id", regardless of the table name.

These pecularities with the Rails db schemas made it impossible for DBDesigner to infer table relationships, and I simply made peace with that fact and used DBDesigner anyways (the lure of the pretty ER diagrams was too much!)

Well I recently discovered the "successor" to DBDesigner called MySQL Workbench. And amongst all the cool things it brings, the most important is its support for LUA scripting! Surely that can do some nifty things like add support for rails schemas! Alas a quick search on the net revealed no prior scripts I could use.

Now I'm knew zero percent Lua before today but a few minutes with the Lua cheat sheet got me up to speed! It is kind of like a mix between Python and C. I also found some handy prebuilt functions for Lua scripting here which really helped me understand the MySQL Workbench API (which is sadly enough mostly undocumented).

A few hours of hacking later I had the solution ready in the form of a script! Here are the steps to import a rails schema with all the relationships -

Download the script here.
Then run it by pressing Ctrl+Shift+R and selecting wb_library.lua from the location where you saved it.
Make sure there are no errors in the output window.
Reverse engineer your DB schema to get all the tables into an ER diagram. None of the tables will be related to each other die to the problems mentioned above. We'll fix that in a minute!
Select "view > advanced > GRT shell" to open the shell which will allow you to invoke functions from the script.
Now the semi-hard part. You need to get an object of your schema so that you can pass it to the script. Type the following in the shell - print(get_schema(1).name);. If this matches your database name then great! otherwise try print(get_schema(2).name); then print(get_schema(3).name); and so on till you find the index of your schema. (Remember that Lua is NOT zero indexed like usual programming languages. This means that there is no index 0). I'll assume that the correct index is 2.
Type the following in the shell - sc = get_schema(2). Where 2 is the number you got in the previous step. Now the variable sc points to the correct schema.
Now the final magic step! Type connect_all_rails_fk_relationships (sc); in the shell! Watch the magic happen!

It really does work! Maybe someday I will convert this to a plugin with a user friendly GUI!

PS: The script also includes a Lua port of the RoR inflectors (pluralise and singularise). Maybe those are useful independent of MySQL workbench. Check them out.

My current non-work-related interests

2009-05-06T20:15:00.003+05:30

A brief list off the top of my head -

FOSS document sharing and publishing. Especially an alternative to PDF.
Any web dev topics PHP/RoR/Python, AJAX, anything.
FOSS platforms suitable for embedded systems. OpenMoko, Android, Embedded Forth/Erlang/Scheme/Python.
FOSS Functional programming. Haskell, Erlang, Scheme.
Foss alternatives for shared Calendars, shared code development, shared todo lists, milestone and task management.
What's up in Ubuntu/Debian. Ubuntu 9.04.
Gnome roadmap. Gnome translations into local languages. Getting a better user experience in Gnome (install Thunar, AWN, and global menu bar!)
What's up with Firefox? What's up with Chrome? What's up with Epiphany and Dillo?
New advances in Javascript engines. V8. Tracemonkey.
FOSS based massive information management. Search engines.

Set Thunar as the default file manager in Gnome

2009-05-06T20:06:00.002+05:30

Here's a simple trick for a leaner Gnome desktop -

Install Thunar as the default file manager on Gnome!

Install thunar - sudo apt-get install thunar
Change the following Exec lines -
in /usr/share/applications/nautilus.desktop to Exec=thunar %U
in /usr/share/applications/nautilus-folder-handler.desktop to Exec=thunar %U
in /usr/share/applications/nautilus-home.desktop to Exec=thunar

That's it! Thunar will open automatically instead of Nautilus in most places. Some locations like Computer and Network are "pseudo" locations which can only be opened by Nautilus.

India needs a pirate party!

2009-05-06T02:35:00.002+05:30

From Wikipedia - The Pirate Party -

The Pirate Party (Swedish: Piratpartiet) is a political party in Sweden as well as the fourth largest party counted in registered members[1] in Sweden which has given rise to parties with the same name and similar goals in Europe and worldwide. The Party strives to reform laws regarding copyright and patents. The agenda also includes support for a strengthening of the right to privacy, both on the Internet and in everyday life, and the transparency of state administration. The Party has intentionally chosen to be bloc independent on the traditional left-right scale[2] to pursue their political agenda with all mainstream parties.

India needs one!

Getting Real Synopsis - Very very rough cut

2009-05-06T01:33:00.003+05:30

I made notes as I stormed my way through the Getting Real book freely available online -

1. Fix time and budget. Cut back on the scope if needed. Cutting back on the scope has the added bonus of keeping you focussed on the most important bits of your application.
2. Pick a worthy adversary and then undercut them. Do not fight on their "home turf". Change the rules of the game. Force them to fight you on your own terms. Having an existing competitors makes your promoters understand the market and the business model more easily. BUT do not overanalyse the competition! Don't follow, lead.
3. Be passionate. It shouldn't be a chore. The app should excite you! Be your best salesman!
4. Be thrifty. Be lean. Embrace agility, change, and openness. The heavier you are the harder it is to adapt when a paradigm shift comes along.
5. Look for creative emergent solutions. Keep it simple. Let it happen.
6. For version 1.0 three's company. A developer, designer and sweeper (someone who can roam both worlds). That's the developer staff. One more guy for logistics. Basss.
7. Stay close to your customers. Be truthful. Be yourself. i.e. don't be evil.
8. One point app. What's the big deal? The cutting insight, the vision? If you need more than a sentence, it's not as great as you think it is.

Examples -

Campfire - group chat over IM sucks.
Basecamp - Project management is communication.
FedEx - Being on time is worth money.

PS: A good side mantra for a future app - Err in favour of the users. Users get the benefit of the doubt.

9. Ignore details for version 1.0
10. Wing it. Ignore problems. Spend more time on short term problems than long term problems.
11. Focus on a small core market segment. Know your customers. Don't try to please everyone. Core group will spread word around faster as well.
12. Don't scale while you still don't need to.
13. Be opiniated. Write software KNOWING what's best for your customers. Have a vision.
14. Half not half assed. Build little but well.
15. Focus on the nuclear plant, not the color of the bike shed.
16. Just say no to feature creep. Listen but don't act until it realy keeps on coming back and then you really need to. Tough Love.
17. Every time you say yes to a feature, you are adopting a child. Be prepared to take good care of it and expend time, money and energy in doing so. Understand the true costs of every new feature.
18. Replace feature requests with conventions. Users will really not mind that much.
19. Ask people what they DON'T want instead of what they want. People really want everything that they don't have.
20. Get something running as soon as possible and get feedback. Real things get real reactions.
21. Work in iterations. Be prepared to throw previous work away. Mockups -> HTML -> Version 1.0. Rinse repeat.
22. Avoid user preferences screens. Make the call on behalf of your users.
23. Decisions are temporary. Don't be afraid to take a call FAST. This isn't brain surgery. Lives aren't at stake. Be prepared to revise your opinion later in face of more clarity. Be prepared to throw previous work away. Execute, build momentum and move on.
24. Ideas a worthless. Execution is gold.

Awful idea = -1
Weak idea = 1
So-so idea = 5
Good idea = 10
Great idea = 15
Brilliant idea = 20

No execution = $1
Weak execution = $1000
So-so execution = $10,000
Good execution = $100,000
Great execution = $1,000,000
Brilliant execution = $10,000,000

To make a business, you need to multiply the two.

25. Test in the wild.
26. Smaller tasks. Smaller timelines.
27. Solve the one problem staring you in the face. Take on a big problem one thing at a time.
28. Hire all rounders, not specialists. Keep them communicating. Outsource to specialists.
29. Keep work timing flexible but get UNINTERRUPTED stretches whenever you get them. Allocate time for fun, don't think about work when having fun. Don't kill yourself.
30. Meetings are toxic. Don't have them. 30 mins max. Lesser people the better. Have a clear singular agenda.
31. Celebrate small victories.
32. Hire temps before permanents. Kick the tires before hiring anyone.
33. Go for open source enthusiasts.
34. Go for quick learners.
35. Go for happy over frustrated. Enthusiastic question askers over silent & stoic.
36. Go for good writers and clear thinkers.
37. Interface before code.
38. Design the "blank" state before the "real" state of the app.
39. Don't ignore the "error" state.
40. Context over consistency.
41. Think about your interface messages. Make them user friendly.
42. Keep admin and regular interfaces combined.
43. Keep code simple.
44. Use tools that keep programmers happy. RoR and Ruby.
45. Choose the easy way instead of the right way. If a feature works slightly differently than what you expected, no problems.
46. Set aside time and money for code mainentance.
47. Keep data flowing. Mashups, RSS feeds, widgets. Let users run wild.
48. Eliminate unnecessary formal documents.
49. Write stories not detail. Strategy not tactics.
50. Use real text instead of Lorem Ipsum.
51. Give your product a personality. Polite? Stern? Forgiving? Strict? Funny? Deadpan? Serious? Loose? Do you want to come off as paranoid or trust-
ing? As a know-it-all? Or modest and likable?
52. Give away freebies. Give away your hit single.
53. Signup and cancellation should be painless. No lock in.
54. fEarn customers money. Don't employ "tricks" like signup fees/long term contracts
55. Give plenty of advance notice for bad news.
56. Hollywood Launch. Teaser -> Preview -> Launch. Reward early adopters.
57. Build an ace community based promotional site. Overview, tour, videos/screenshots, manifesto, case studies, buzz, forum, blog, faq, pricing, signup.
58. Share information / experiences with the community. Good Karma. Pay it forward. Create evangelists.
59. Be an early adopter of "cool" features / technologies. Take advantage of your agility. Generate the buzz. Ride the hype wave. Target the special interest groups.
60. Track your buzz. Pay attention to feedback.
61. Upsell within the app.
62. Pick an easy memorable name. Don't sweat it if you don't get the exact domain name. e.g. backpackit.com or campfirenow.com
63. Development team === Support team. Break down the barriers. Feel the pain. Cut out the middle man.
64. The product should require ZERO training.
65. Quick responses to support questions.
66. Use forums to let users help each other.
67. Be open. Deliver all news, god or bad. Publicise your screwups.
68. Issue a major upgrade 30 days after launch.
69. Keep the heartbeat going. Blog. Newsletters. Buzz. Treat your customer like a friend.
70. No betas. Straight to version 1.0. Betas mean nothing thanks to Google.
71. Prioritise your bugs. Ignore the small ones.
72. Don't panic after a bad decision. It's probably not as bad as you think. Ride out the storm.
73. Keep in touch with your competition.
74. No bloat. No kitchen sink. Mature doesn't mean complicated.
75. Be a surfer. Watch the ocean. Keep looking out for that new big wave on the horizon. Be the first to ride it.
76. Finally. Execution and People! Two things that can make or break. Rest is all gravy.

Check your computer configuration in Linux (Ubuntu)

2009-05-05T01:29:00.002+05:30

Quoting verbatim from this post -

CPU Specification

taufanlubis@zyrex:~$ cat /proc/cpuinfo

processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel(R) Pentium(R) 4 CPU 2.40GHz
stepping : 1
cpu MHz : 2400.238
cache size : 1024 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc up pni monitor ds_cpl cid xtpr
bogomips : 4804.04
clflush size : 64

Memory Usage

taufanlubis@zyrex:~$ cat /proc/meminfo

MemTotal: 481420 kB
MemFree: 5640 kB
Buffers: 72200 kB
Cached: 259676 kB
SwapCached: 7980 kB
Active: 228516 kB
Inactive: 216040 kB
HighTotal: 0 kB
HighFree: 0 kB
LowTotal: 481420 kB
LowFree: 5640 kB
SwapTotal: 979956 kB
SwapFree: 971976 kB
Dirty: 8 kB
Writeback: 0 kB
AnonPages: 104716 kB
Mapped: 94236 kB
Slab: 20624 kB
SReclaimable: 9300 kB
SUnreclaim: 11324 kB
PageTables: 2056 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
CommitLimit: 1220664 kB
Committed_AS: 512424 kB
VmallocTotal: 540664 kB
VmallocUsed: 7500 kB
VmallocChunk: 532700 kB

Harddisk Partition

taufanlubis@zyrex:/proc$ cat partitions

major minor #blocks name
8 0 39121488 sda
8 1 10241406 sda1
8 2 1 sda2
8 3 979965 sda3
8 4 12538732 sda4
8 5 15358108 sda5

Ubuntu Version

taufanlubis@zyrex:~$ cat /proc/version

Linux version 2.6.20-16-generic (root@terranova) (gcc version 4.1.2 (Ubuntu 4.1.2-0ubuntu4)) #2 SMP Sun Sep 23 19:50:39 UTC 2007

taufanlubis@zyrex:~$ cat /proc/version_signature

Ubuntu 2.6.20-16.32-generic

More Mac goodness for Ubuntu - Setup global menu bar on Ubuntu Hardy (8.04)

2009-05-05T01:16:00.002+05:30

Global Menu Bar just a swell idea and It's quite a surprise that the idea hasn't caught up yet with the Gnome developers. Macs have had it forever and it should really be the default behaviour for Gnome, given its obsession with clean user interfaces.

So if you are lucky enough to be running Ubuntu 8.10 (Intrepid) or later, you are in luck. Simply follow the installation steps listed on the installation page and you will be set to go.

For Hardy, there is just one more step that is not very well documented in the installation page. You will need to add the following bit of code in your ~/.gnomerc file - export GTK_MODULES=globalmenu-gnome

For me the .gnomerc file did not exist so I simply created an empty one. Note that adding that line to your ~/.bashrc file or ~/.profile file will NOT work (as opposed to what the installation guide says)! So create a .gnomerc file if needed.

Log out and then log in, and pat yourself on the back, you just made your user interface a little bit better!

Grim Fandango reference in The Curse of Monkey Island

2009-05-05T01:01:00.003+05:30

In The curse of Monkey Island (MI 3) - the "quite patron" in the chicken shop is (a rather poorly drawn) Manny Calavera! Examine his badge and it says "Ask me about Grim Fandango"!

Nice surprise for a Grim Fandango fan!

Linux advice - Use Epiphany instead of Firefox

2009-05-05T00:41:00.003+05:30

I'm running Ubuntu Hardy (8.04) LTS on my not-yet-so-old HP laptop (1.8 GHz Intel Core 2 Duo, 512 MB Ram), and running netbeans+firefox+komodo totally saps out the system! (Don't even ask why I need both Netbeans and Komodo at the same time.) So I did what I should have done a long time back and switched Firefox for Epiphany. It's based on the same Gecko rendering engine which powers Firefox but performs better, doesn't leak as much memory (Firefox easily climbed to over 200 MB of memory usage in a few hours where as Epiphany mostly stays consistantly under 80 MB), and integrates MUCH better into the Gnome desktop (as it uses Gtk instead of XUL stuff). Epiphany needs to be the default Gnome browser.

Added plus which is really a corollory of my last point about Epiphany being based on Gtk - Epiphany behaves well with Gnome Global Menu Bar! Yea! But more about Global Menu Bar in another post.

Open Office won't eat meat, shave, drink or print on Tuesdays!

2009-05-03T15:12:00.003+05:30

https://bugs.launchpad.net/ubuntu/+source/file/+bug/248619
https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/255161

Apparently having a "Tue" at the fourth byte in the postscript files causes them to be incorrectly identified as "Erlang JAM" files! This in turn causes them to not be printed.

Oracle buys Sun. The future of MySQL?

2009-04-22T12:20:00.002+05:30

Oracle buys SUN

MySQL is ostensibly an Oracle competitor and the acquisition casts a shadow over MySQLs future. Will Oracle continue to maintain the Free MySQL earning solely from support, or is MySQL destined to go the Netscape way?

In the meanwhile, the community will do well to start looking at alternatives -

PostgreSQL is of course well known
Less well known is the Community Fork of MySQL known as MariaDB
Firebird is another good but relatively unknown alternative. I had blogged about it some time back

The missing punctuation we all need

2009-04-15T13:17:00.004+05:30

How many times have you expressed the feeling of surprise with a question using the question-mark-exclamation-mark-combo?

The interrobang!

It has a special punctuation symbol of its own?!

Multi Select Bug in Google Chrome

2009-04-15T12:49:00.003+05:30

You can "crash" Google Chrome browser in 3 simple steps -

Visit a page with a multi select.
Click on the empty area within the multi select
Drag up till the text of an entry

i.e. click and drag following the red line in the diagram below -

Voila!

FOSS Physics Software

2009-04-13T12:11:00.001+05:30

FísicaLab is an educational application to solve physics problems. Is made with GNUstep and use the GSL libraries (GNU Scientific Library). The problems are setting adding elements from the palette to chalkboard, and writing the data of each element. The elements are objects as Blocks, Pulleys, Mobiles, Forces, ... . Use the SI and English systems, scientific notation and many conversion factors. The problems that can be solved with FísicaLab 0.1, are:

Kinematics of particles (doesn't include circular motion).
Static of particles in 2D.
Dynamic of particles in 2D (doesn't include dynamic of circular motion).

The static and dynamic problems are entered constructing the free body diagrams of the objects.

http://www.nongnu.org/fisicalab/

Best game I have ever played

2009-04-10T13:26:00.002+05:30

http://en.wikipedia.org/wiki/Grim_Fandango

Vala based DVB-T Guide

2009-04-02T22:40:00.000+05:30

This is cool!

http://live.gnome.org/DVBDaemon/UserGuide

Reading input from stdin within Vala

2009-04-02T22:34:00.004+05:30

Here's how to read stdin input within Vala (a compiler for the GObject type system) -

(This code snippet is based on the one found in Vala Input samples).

// Utility function to read input from stdin

// if single_line is true then returns as soon as the user presses enter

// else waits for end of input (Ctrl+D on Linux, Ctrl+Z Enter on windows)

string read_stdin(bool single_line) {

var input = new StringBuilder ();

var buffer = new char[1024];

while (!stdin.eof()) {

string read_chunk = stdin.gets (buffer);

if (read_chunk != null) {

input.append(read_chunk);

if(single_line) {

break;

}

return input.str;

}

Nice Quote

2009-03-18T13:44:00.002+05:30

Trying to forget someone you love is like trying to remember someone you never met

Fix a broken Linux shell

2009-03-07T19:49:00.005+05:30

When you accidentally cat a binary file, it can leave your shell in a broken state as it can interpret some of the binary sequences as control characters.

You will see gibberish instead of normal letters/digits and the only recourse may seem to close this terminal and start another. But wait! The next time it happens, use the command reset instead!

You can see where I typed reset (second last line) and restored sanity. Note that even the name of the terminal window is back to normal!

DjVu - It's surprising that it has not had widespread acceptance yet.

2009-03-05T20:36:00.004+05:30

http://djvu.sourceforge.net/

"DjVu is a web-centric format and software platform for distributing documents and images. DjVu can advantageously replace PDF, PS, TIFF, JPEG, and GIF for distributing scanned documents, digital documents, or high-resolution pictures. DjVu content downloads faster, displays and renders faster, looks nicer on a screen, and consume less client resources than competing formats. DjVu images display instantly and can be smoothly zoomed and panned with no lengthy re-rendering. DjVu is used by hundreds of academic, commercial, governmental, and non-commercial web sites around the world.

DjVuLibre is an open source (GPL'ed) implementation of DjVu, including viewers, browser plugins, decoders, simple encoders, and utilities."

From my personal experience, PDF's are almost always too slow and cumbersome (I tried a few DjVu files and it was a much smoother experience). More importantly, they are huge - The free document I mentioend in my previous post has a 6MB DjVu file and an equivalent 30 MB PDF File! It's time to bury the PDF behemoth for good.

Quote - Laws of form

2009-03-04T20:49:00.002+05:30

From George Spencer-Brown's controversial book Laws of Form (1969).

"The theme of this book is that a universe comes into being when a space is severed or taken apart. The act is itself already remembered, even if unconsciously, as our first attempt to distinguish different things in a world where, in the first place, the boundaries can be drawn anywhere we please. At this stage the universe cannot be distinguished from how we act upon it, and the world may seem like shifting sand beneath our feet."

To Read => Outliers + The Implementation of Functional Programming Languages

2009-03-04T18:15:00.003+05:30

Free

The Implementation of Functional Programming Languages

Implementing functional languages: a tutorial

Non Free

Outliers: The Story of Success (Hardcover)

"Flexi Arrows" creations - An ink pen

2009-03-01T13:28:00.003+05:30

R2D3 code at a new location

2009-03-01T00:37:00.001+05:30

http://freesoftwarefreeworld.com/public/r2d3.zip

CSS Language Extensions

2009-02-28T02:42:00.005+05:30

CSS is a nice idea gone horribly wrong. It's a major pain in the butt to web content developers worldwide. I've been coding web apps for several years now and it still seems crazy to me! I am not a CSS fan and I am not alone.

So while I sit around and crib, people are coming up with extensions on top of CSS to alleviate the pain somewhat. All of them add support for nesting selectors which is something that should have been a part of CSS spec to being with. In addition -

HSS adds variables, block variables, single line comments and CSS validation. Built on top of Neko.
CSS Dryer adds support for variables. Written in Ruby.
Sass changes the syntax to be a bit more terse (by getting rid of all the braces), and adds variables, namespaces, arithmetic/string/color manipulation operations and a bunch of other things. Written in Ruby.
CleverCSS adds support for variables, property groups, lots of arithmetic/string expression operators and a bunch of other things. Written in Haskell.

Construct your own spaceships using Visio "Flexi Arrows"

2009-02-27T20:45:00.003+05:30

I found out that Visio "Flexi Arrows" are great for creating Spacecraft like shapes!

Check out the proof of concept I threw together in about a minute and half!

Convert an arbitrary Erlang expression to String

2009-02-24T01:48:00.003+05:30

It's the very counter-intuitive -

lists:flatten(io_lib:format("~p", [Term])),

Where Term is the erlang expression.

Simply using io_lib:format should have worked in this case but it returns a deep list for some reason which needs to be flattened before use. Some fun facts -

The deep list returned by io_lib:format still behaves like a normal string within erlang. For example - printing it out to the console using io:format() will work as expected. But when you pass that list to some non-erlang program (Java in my example, using Jinterface) expecting a String, all hell will break loose.
This works too but is more computationally expensive -
binary_to_list(list_to_binary(io_lib:format("~p", [Term])))

Peace Erlang! I don't wanna fight no more..

Painlessly convert code buffers in emacs to HTML

2009-02-23T03:50:00.004+05:30

While looking for a way to convert my Haskell code to HTML, I stumbled upon HTMLize!

Steps -

Download the file at http://fly.srk.fer.hr/~hniksic/emacs/htmlize.el to some location on your hdd (I put mine in ~/emacs.d/htmlize/).
Add the following lines to your init.el file -
(load "~/.emacs.d/htmlize/htmlize.el")
Restart emacs.
From within emacs, invoke - M-x customize-variable htmlize-output-type and set its value to css-inline.
Switch to the code buffer and invoke - M-x htmlize-buffer
Save the newly created buffer with an html extension

Behold! (An excerpt of the code from Yampa) -

--
-- Implementation of Yampa utilities:
--
module YampaUtils where
import AFRP
hold :: a -> SF (Event a) a
hold x0 = loop (arr aux >>> iPre x0 >>> arr dup)
where aux (e,x) = event x id e

PS - A useful little tip: To import HTML into an open office presentation - first open the html file in OOwriter and then copy paste into OOimpress..

It happened to me - IRC Netsplit

2009-02-18T15:25:00.006+05:30

So I'm logged on to #haskell, #erlang, #python on Freenode.

Here's what an IRC Netsplit looks like -

... [690 users on #haskell] ...

... [When suddenly] ...

...

* enascryaptio has quit (kubrick.freenode.net irc.freenode.net)

* Asoasdeir has quit (kubrick.freenode.net irc.freenode.net)

* amaornsfall has quit (kubrick.freenode.net irc.freenode.net)

* reehya has quit (kubrick.freenode.net irc.freenode.net)

* aabosyscsaared has quit (kubrick.freenode.net irc.freenode.net)

* asdfnetcgasat has quit (kubrick.freenode.net irc.freenode.net)

... [etc. etc.] ...

...

... [34 users on #haskell] ...

... [Collective gasp! Holy crap! This is the smallest I've ever seen #haskell]...

...

... [Later. Netburst!] ...

...

* MrSyzsaygy (n=blah@blah.se) has joined #haskell

* Kapsfasdu (i=blah@blah/Japsu) has joined #haskell

* Dotjasde (n=blah@blah.be) has joined #haskell

* sbosk (n=blah@blah/kobs) has joined #haskell

* alesaator_ (i=blah@blah.fi) has joined #haskell

* SAhurique (n=blah@blah.fi) has joined #haskell

* SssimonsRsC (n=blah@blah.org) has joined #haskell

* Raiastraasdh (n=blah@blah.net) has joined #haskell

... [etc. etc.] ...

...

... [Life back to normal] ...

And then moments later - an apology -

[Global Notice] Hi all, it would appear we've discovered yet another bug in hyperion, the ircd we run -- how we've managed to use it successfully for so long is now but a great mystery. The network is back up, for now, but in light of this we will be looking at bringing our ircd-change forward, details shall be forthcoming. Please accept my sincere apologies for the instability as of late and thank you for your patience.

And a retraction!

[Global Notice] Hi all, It appears I may have been too harsh on hyperion -- this crash wasn't a segfault after all, but some of hardened gentoo's 'security' measures deciding that our ircd is a threat. More information will be provided on the blog when we have a better picture and know what actions will be taken to prevent this from occuring again. Thank you for using freenode and have a good day!

The Byzantine Generals Problem

2009-02-16T20:27:00.003+05:30

The problem was described by Leslie Lamport in a 1982 paper written after observing what he felt was an inordinate amount of attention received by Dijkstra’s Dining Philosophers problem.

Interested in understanding concurrent programming algorithms? Writing a program to solve this problem will make you a much better programmer..

Debian Lenny released as Stable!

2009-02-16T01:27:00.002+05:30

Or more accurately..

Debian GNU/Linux 5.0 released!

The next version currently in testing is called "Squeeze"..

Recipe for the "perfect paper plane"

2009-02-16T00:38:00.003+05:30

While on the topic of paper planes.

From here -

The "perfect paper plane"..

Have to try it out tomorrow!

MIA Paper Planes

2009-02-16T00:22:00.002+05:30

MIA - Mathangi "Maya" Arulpragasam is a British songwriter and vocalist of Srilankan descent. Her 2007 album Kala includes this gem with an infectious beat to it - Paper Planes. I don't particularly care about the message she's trying to convey but the Song is awesome! Watch/Listen to it on you tube. (See the fan made video here if you have extra time) :)

This track was very well used in Slumdog Millionaire which is where I heard it first..

It's alternative hip hop.. And that's your "totally useless fact of the day"..

Graphics Solutions for Embedded Linux

2009-02-13T14:44:00.001+05:30

http://www.linuxdevices.com/articles/AT9202043619.html lists some graphics toolkits/libraries for folks deploying Linux on embedded devices.

Here's the list of Free solutions -

Dillo -- Dillo is a very small (less than 300KB), fast, Open Source multi-platform web browser that's written completely in C and built on GTK+ libraries. Dillo's high efficiency and minimal library dependencies make it quite suitable for embedded apps. Dillo can be teamed up with an embedded webserver to completely eliminate the need for a window manager in an embedded device.

DirectFB -- DirectFB is a thin library that provides developers with hardware graphics acceleration, input device handling and abstraction, integrated windowing system with support for translucent windows and multiple display layers on top of the Linux Framebuffer Device. It is a complete hardware abstraction layer with software fallbacks for every graphics operation that is not supported by the underlying hardware.

The Familiar Project -- this open source PDA Linux project, which is an offshoot of the activities at handhelds.org, has collected together all of the key components of a complete Linux-based PDA computing platform. The Familiar distribution currently includes a Blackbox-based window manager, Agenda Computing's Fltk+ based PIM applications, an embedded Python implementation, system configuration and settings backup utilities, OpenSSH client and server, and a Debian-based ARM kernel.

FBUI -- FBUI is a tiny GUI that resides inside the Linux kernel. The key concepts of FBUI are that firstly it is small; secondly that it is spartan, which is good; thirdly that it is just another driver; and fourthly that drivers belong in the kernel, not in userspace.

GGI project -- the "General Graphics Interface" project is dedicated to development of fast, stable, open-source cross-platform multimedia API systems. Designed from the ground up with environments such as embedded systems in mind, GGI is fast, clean, abstract, dynamically modular and highly optimizeable.

GPE Palmtop Environment -- this project aims to provide a Free Software GUI environment for palmtop/handheld computers running the GNU/Linux operating system. GPE uses the X Window System, and the GTK+ widget toolkit.

GtkFB -- beginning with version 2.0, GTK+ will support rendering directly to the Linux framebuffer instead of using the X Window System. This is good for embedded systems and devices with limited resources, because it eliminates the overhead of an X server, while still taking advantage of the power of GTK+ and the large base of existing programs.

handhelds.org PDA support -- want to create your own unique Linux PDA implementation? handhelds.org is for you! Early this year, Compaq created the Open Handheld Program, an initiative designed to stimulate innovation and research on handheld devices that resulted from the company's "Itsy" pocket computer project. To support this initiative, Compaq created handhelds.org -- a vendor neutral website dedicated to open source handheld development. Not surprisingly, Compaq's iPAQ PDA is used as the base platform for all these activities and, consequently, a iPAQ Linux port is available as freely available open source software.

Matchbox -- a small foot-print window manager and associated applications, designed specifically for resource-constrained X11-enabled devices such as handheld computers, PDA's, set-top boxes, and consumer devices where display size, storage, CPU bandwidth, and input mechanisms are limited. Matchbox includes a window manager, a panel, a desktop, a shared utility library, and a number of small panel applications.

Microwindows -- an Open Source project aimed at bringing the features of modern graphical windowing environments to smaller devices and platforms. Microwindows applications can be built and tested on the Linux desktop, as well as cross-compiled for the target device.

NxZilla (formerly nanozilla) -- a set of libraries that allow Mozilla to be used with a NanoX server from the Microwindows project.

OpenGL ES -- a light-weight, royalty-free embedded graphics standard that provides graphics API profiles for a broad range of embedded systems and devices, including handheld wireless devices, automotive and avionics displays, and multimedia consumer devices such as advanced digital TVs, set-top boxes, and game consoles.

OpenGUI -- a fast, 32-bit, high-Level C/C++ graphics & windowing library/GUI built upon a fast, low-level x86 asm graphics kernel. It is under LGPL license. OpenGUI provides 2D drawing primitives and an event-driven windowing API for easy application development.

PicoGUI -- small, portable client/server GUI designed to work on many types of hardware including handheld computers. Like the X Window System, it has a flexible client-server architecture. Unlike X, however, fonts, bitmaps, widgets, and anything else the application needs are built directly into the server. This sacrifices a small decrease in flexibility for an increase in speed and a large decrease in size.

Qt/Embedded -- provides a full graphics stack, from the hardware interface to a full GUI tookkit. Although the API is identical to the popular Qt/X11 and Qt/Windows products, Qt/Embedded is not based on X11 and therefore it has substantially reduced memory requirements. Memory demands can be tuned to the range of 800 KB to 3 MB in ROM (Intel x86). Qt/Embedded is available as open source software, under the GNU General Public License (GPL), or can be licensed on other terms from its originator, Trolltech.

Simple DirectMedia Layer -- an open source cross-platform multimedia development API/library designed to provide fast access to the graphics framebuffer and audio device. SDL is currently being applied to a number of Embedded Linux implementations such as Microwindows.

Tiny-X -- a small footprint X Window server implementation for embedded systems. It was developed by Keith Packard of the XFree86 Core Team, sponsored by SuSE. The goal was to create something that would work well in a small memory footprint and, importantly, be robust in near out-of-memory situations. Typical X servers based on Tiny-X can fit in less than 1MB on x86 CPUs. The project has since forked into several projects, including KDrive, SmallX, and Integrated Tiny-X.

ViewML -- a freely available, open source web browser targeted specifically at the embedded Linux platform. Currently, ViewML along with it's interface requires 2.1 MB of RAM, with a disk image of only 760K.

WML Browser -- a project, sponsored by 5NINE to develop a browser which will allow any wireless device to have WAP functionality. It must support multiple protocol stacks (WAP 1.2.1, http), in differing environments, using differing input devices. The browser will work with framebuffer graphics.

Xynth Windowing System -- a free software project to build a portable, embedded client-server windowing system. The Xynth Windowing System, released under the GPL, offers a lightweight GUI-capable windowing system usable in Linux-based embedded systems and devices, such as handhelds and set-top boxes.

I found Serenity

2009-02-13T00:52:00.002+05:30

I went through a marathon run of 14 episodes of Firefly followed by Serenity the movie, in a span of 3 days. Head rush! Wow!

I can't get over the shock that the series got cancelled..

Image and Color handling in Java2D

2009-02-13T00:35:00.002+05:30

Here are two handy snippets -

1. Color from String -

...

Color c = Color.decode("0x87CEFA");

g.setColor(c);

...

(The hex value is for a serene "lighter" sky blue colour, which I find better than the official "sky blue" of 0x87CEEB)

2. Painting background images -

@Override

public void paint(Graphics g) {

...

URL imgURL = getClass().getResource("foo.jpg");

ImageIcon icon = new ImageIcon(imgURL, "image description");

icon.paintIcon(this, g, 0, 0);

...

}

(Where "foo.jpg" should be in the same folder as the compiled class.)

I hate complications

2009-02-12T00:26:00.001+05:30

But they seem to love me for some reason..

Languages based on the Erlang VM

2009-02-11T14:23:00.004+05:30

Sadly there don't seem to be many of them -

Venture capitalists don't back technologies they back people

2009-02-10T19:34:00.000+05:30

"Give me a grade 1 person with a grade 2 idea rather than a grade 2 person with a grade 1 idea"

Naming distributed nodes in Erlang

2009-02-07T18:31:00.005+05:30

I was trying to setup communication between Erlang and Java, following the example code here - http://www.theserverside.com/tt/articles/article.tss?l=IntegratingJavaandErlang.

Problem -

Server code

C:\Projects\mips>erl -name servernode -setcookie cookie

Eshell V5.6.5 (abort with ^G)

(servernode@ANUPAMDELLAPTOP.Belkin)1> delme:start().

true

(servernode@ANUPAMDELLAPTOP.Belkin)2>

Client Code

C:\>erl -name clientnode -setcookie cookie

Eshell V5.6.5 (abort with ^G)

(clientnode@ANUPAMDELLAPTOP.Belkin)1> rpc:call(servernode@ANUPAMDELLLAPTOP, delme, add, [1,6]).

=ERROR REPORT==== 7-Feb-2009::18:36:16 ===

** System running to use fully qualified hostnames **

** Hostname ANUPAMDELLLAPTOP is illegal **

{badrpc,nodedown}

(clientnode@ANUPAMDELLAPTOP.Belkin)2> rpc:call(servernode@ANUPAMDELLLAPTOP.Belkin, delme, add, [1,6]).

* 1: syntax error before: Belkin

(clientnode@ANUPAMDELLAPTOP.Belkin)2> rpc:call('servernode@ANUPAMDELLLAPTOP.Belkin', delme, add, [1,6]).

{badrpc,nodedown}

(clientnode@ANUPAMDELLAPTOP.Belkin)3> rpc:call(servernode, delme, add, [1,6]).

{badrpc,nodedown}

(clientnode@ANUPAMDELLAPTOP.Belkin)4> rpc:call(servernode@localhost, delme, add

[1,6]).

{badrpc,nodedown}

=ERROR REPORT==== 7-Feb-2009::18:37:56 ===

** System running to use fully qualified hostnames **

** Hostname localhost is illegal **

(clientnode@ANUPAMDELLAPTOP.Belkin)5>

Solution -

Server code

C:\Projects\mips>erl -sname servernode@localhost -setcookie cookie

Eshell V5.6.5 (abort with ^G)

(servernode@localhost)1> delme:start().

true

(servernode@localhost)2>

Client Code

C:\>erl -sname clientnode@localhost -setcookie cookie

Eshell V5.6.5 (abort with ^G)

(clientnode@localhost)1> rpc:call(servernode@localhost, delme, add, [1,6]).

(clientnode@localhost)2>

To Read - On Intelligence by Jeff Hawkins

2009-02-05T17:19:00.002+05:30

http://www.onintelligence.org/

This book is written by Jeff Hawkins, the founder of Palm and Handspring!

New features in Javascript 1.8 (Firefox 3.0)

2009-02-05T16:50:00.004+05:30

While on the subject of Firefox 3.0, check out the new features in Javascript 1.8. Some of these like generators (pythonesque constructs, introduced in Javascript 1.7, souped up to support expression syntax in 1.8) are nice!

Global variables in Javascript - Across JS files!

2009-02-05T16:46:00.003+05:30

Check out Javascript Code Modules!

JavaScript code modules are a concept introduced in Firefox 3 (Gecko 1.9) and can be used for sharing code between different privileged scopes. Modules can also be used to create global JavaScript singletons that previously required using JavaScript XPCOM objects. A JavaScript code module is simply some JavaScript code located in registered location. The module is loaded into a specific JavaScript scope, such as XUL script or JavaScript XPCOM script, using Components.utils.import.

This is only available on Firefox 3.0 or better, and then also only to extension developers. But sweet!

Oni - Concurrent Javascript

2009-02-05T16:00:00.003+05:30

Oni is an an embedded structured concurrency language

It's a framework which allows the programmer to implement concurrent applications without having to explicitely manage the control flow. It does this by "composing" together concurrent actions using operators such as Par which performs actions in parallel, and Alt which performs actions in parallel and returns the result of whichever action finishes first (very useful in implementing timeouts).

Oni can be implemented in any host language, and an implentation exists for Javascript! Currently the implementation only works in Firefox 3.0 or better.

Greenspun's Tenth Rule

2009-02-05T15:28:00.003+05:30

From Wikipedia - http://en.wikipedia.org/wiki/Greenspun's_Tenth_Rule

Greenspun's Tenth Rule of Programming is a common aphorism in computer programming and especially programming language circles. It states: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.

The rule was written sometime around 1993 by Philip Greenspun. Although it is known as his tenth rule, there are in fact no preceding rules, only the tenth. The reason for this according to Greenspun: "Sorry, Han-Wen, but there aren't 9 preceding laws. I was just trying to give the rule a memorable name."

...

The rule is often modified by replacing "Common Lisp" with the speaker's functional language of choice, such as Scheme or Haskell. It can also be generalized as: Any sufficiently complicated platform contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of a functional programming language.

Heh!

It can also be applied to Erlang: Any sufficiently advanced CONCURRENT program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of ERLANG

Double Heh!

To Read - Yahoo Pipes

2009-02-03T16:35:00.001+05:30

Read up!

http://pipes.yahoo.com/pipes/

Java Layout Manager Showdown

2009-02-03T15:42:00.002+05:30

Very interesting "showdown" of the various layout managers in Java Swing.

Seems like there are quite some options for good looking GUI's in Java apart from the haloed GroupLayout manager.

WOTD - Word Of The Day - Segue

2009-02-02T14:20:00.004+05:30

Yes, the title continues the acronyms theme. Let's move on.

http://en.wikipedia.org/wiki/Segue

Segue (pronounced /ˈsɛgweɪ/) - In music, "segue" is a direction to the performer. It means continue (the next section) without a pause. It comes from the Italian "it follows".

...

In journalism, a segue is a method of smoothly transitioning from one topic to another. A segue allows the host or writer to naturally proceed to another topic without jarring the audience. A good segue makes the subject change seem like a natural extension of the discussion.

Example real-world usage - http://www.oreillygmt.co.uk/2008/07/karthik-ramacha.html

Karthik Ramachandra - Erlang eXchange and ThoughtWorks

Video - Karthik Ramachandra is an Extreme Programmer for ThoughtWorks. He is based in Bangalore, India, and was in London recently to speak at Skillsmatter's Erlang eXchange.

He was good enough to talk to me about Erlang, Thoughtworks and the tech scene in India.

And as a slick segue, Pragmatic Programmers have recently released The ThoughtWorks Anthology.

QS: Would the seamless transitions from one sketch to the next on the Monty Python TV Series be called Segue? Stream of consciousness is what they are popularly known as.

What is JAIN?

2009-02-02T14:14:00.002+05:30

While on the topic of acronyms -

From the Wikipedia page for JSLEE

JAIN - Java APIs for Integrated Networks

What does COB stand for?

2009-02-02T13:12:00.001+05:30

Here is the context (from an email I received recently) -

"I will be unavailable from 9:00 AM - COB"

Close Of Business

XUL Development using Komod IDE/Editor

2009-01-30T15:11:00.005+05:30

XUL Explorer is an XULRunner application that aims to provide an IDE for XUL development.

It provides some useful features -

A variety of XUL "templates" a.k.a. "snippets", which allow you to quickly insert commonly used XUL into your code.
A preview pane which shows you a live preview of what the finished application will look like.

Neat idea! Except that the project is in its infancy and bundles a barely usable editor which renders the whole contraption impractical.

I have a license for Komodo IDE and find it very usable and intuitive. Komodo IDE/Editor is also based on the Mozilla platform and therefore has native support for XUL. What's more, it already includes a live preview option for quickly testing out your changes. So to fill in the missing piece, I set out to port the XUL snippets to Komodo format.

A lot of manual copy paste later - Voila!

It's in the Komodo KPZ format. Downoad, Drag drop into the IDE, Enjoy.

PS: Use the Trigger Macro to enable Textmate style macro functionality for more hacking bliss!

Resending meeting invites from Mozilla Lightning

2009-01-28T14:34:00.004+05:30

Scenario -

You use Mozilla Thunderbird with the Lightning extension. Someone sends you an email with a meeting invite which you accept and it's added to the lightning calendar. Then you delete that email.

Problem -

You need to invite a third person to that same meeting. You cannot forward the mail (since you deleted it) and there seems to be no way to forward an event from your Lightning calendar.

Solution -

Right click on the event in Lightning and select "copy".
Open a blank text file and "paste".
Save that file as event.ics or anything else with a .ics extension.
Forward the newly created ICS file as an attachment.

Problem solved!

Note: The ICS file is in the iCalendar format which is supported by a wide variety of software including thunderbird, iCal, and outlook.

Hardware virtualisation

2009-01-28T00:25:00.004+05:30

1. Use VMWare Player - Excellent, extremely easy to use and free (as in beer). i386 only.

Use the Ubuntu 8.04 image from - http://jars.de/english/ubuntu-804-vmware-image-download-english

2. Use QEmu - Excellent, Free (as in speech) and supports a variety of targets.

Use these steps for a MIPS installation

Use these steps for QEmu installation under Ubuntu (ignore the stuff about Windows, and use the QEmu images available here). Follow the directions for KQEmu to speed up i386 emulation (Alas it does not seem to speed up MIPS emulation).

Use Sourcery G++ for cross compilation with a MIPS target. (Supports Linux and Windows both).

NOTE: QEmu for Windows does not work fine. Ignore!

Syntax Versus Semantics

Basic Haskell - Splitting Strings by newline "\n" *only* (not "\r", "\r\n" etc.)

Search for a Haskell IDE - Vim blows Leksah out of the water!

Convert multiple JPG files into a single PDF on Linux (Ubuntu)

Installing Yesod (Haskell web framework) on Webfaction

Simple Linux BASH script to swap two filenames

Haskell: Memoise arbitrary functions and monadic values

Quick multi level mergesort algorithm in javascript

Wget as a spider/crawler - Recursively download a webpage and everything it links to

Linux BASH function to search recursively for a string in all files in the current directory

Installing Leksah IDE for Haskell on Ubuntu 10.04 Lucid Lynx

Converting videos for playback on Blackberry Storm 9530

Getting Mobireader to work correctly on Blackberry Storm

Pre built Erlang/OTP R13B04 Debian package for Ubuntu 10.04 (Lucid). Includes WX support and all documentation

Compiling Erlang OTPR13B04 with wx support on Ubuntu Lucid

To break the rules, you must first know the rules

Javascript performance - closures versus prototypal inheritence

Installing CouchDB from latest guthub sources in Ubuntu Lucid

Quick profiling script to gather performance metrics in ruby

My new preferred style for function header comments

Funny Sign in the men's room at the airport

Debugging a Linux BASH shell script

Best webcomic ever! - The Dinosaur Comic

Linux BASH tip - How to subtract arrays

Minicom lock file

The search for a good Linux GUI for SVN ends at RabbitVCS

This has to be one of the most productive uses of twitter I ever saw!

Installing Haskell Platform (with GHC 6.10.4) in Ubuntu Karmic

Installing GHC 6.10.4 on webfaction

Ruby one liner for array splitting

Gnome IPMessenger replacement

Getting Erlang crypto to work on windows

Bash! You are killing me! How to escape spaces in filenames being passed to tar

How to escape the Matrix (a.k.a. Escaping the '#' hash character in a wget commandline)

Tips for Avidemux - "Trouble initialising audio device", "Encoder not initialised" etc.

Dazed out english language modification #2

Random silliness

Javascript handleEvent function

200th Post! (1st Oct) Happy Birthday to me! :)

Using an external 1920x1080 LCD monitor with Ubuntu/Kubuntu (intel cards)

Using ruby on rails routes in javascript (jquery)

Why I love my wife - and other everyday funny stories

Using Aptana for Ruby on Rails development on (K)Ubuntu 9.04 - "Rails not found"

I broke the translation party!

Pirate Party wins a seat on the European Parliament!

Dazed out English language modification #1 - Many Few

Better looking tabs in jQuery UI 'cupertino' theme

MySQL Workbench Lua scripting is awesome!

Ruby on Rails helper scripts for MySQL workbench!

My current non-work-related interests

Set Thunar as the default file manager in Gnome

India needs a pirate party!

Getting Real Synopsis - Very very rough cut

Check your computer configuration in Linux (Ubuntu)

More Mac goodness for Ubuntu - Setup global menu bar on Ubuntu Hardy (8.04)

Grim Fandango reference in The Curse of Monkey Island

Linux advice - Use Epiphany instead of Firefox

Open Office won't eat meat, shave, drink or print on Tuesdays!

Oracle buys Sun. The future of MySQL?

The missing punctuation we all need

Multi Select Bug in Google Chrome

FOSS Physics Software

Best game I have ever played

Vala based DVB-T Guide

Reading input from stdin within Vala

Nice Quote

Fix a broken Linux shell

DjVu - It's surprising that it has not had widespread acceptance yet.

Quote - Laws of form

To Read => Outliers + The Implementation of Functional Programming Languages

"Flexi Arrows" creations - An ink pen

R2D3 code at a new location

CSS Language Extensions

Construct your own spaceships using Visio "Flexi Arrows"

Convert an arbitrary Erlang expression to String

Painlessly convert code buffers in emacs to HTML

It happened to me - IRC Netsplit

The Byzantine Generals Problem

Debian Lenny released as Stable!

Recipe for the "perfect paper plane"

Basic Haskell - Splitting Strings by newline "\n" only (not "\r", "\r\n" etc.)