I am developing a music score editor in Python

In January 2014 I started a formidable project: I am writing sheet music editing software. I feel I am very qualified to do so because I am a musician, a composer who knows a lot about music notation, a good software developer, I always put myself in the user’s shoes and I have been using music software for 24 years, having accumulated a little list of wishes that have never been granted by Finale, Encore, Overture, Sibelius, Notion etc.

In fact, the project grew out of my dissatisfaction with all these existing programs. As a composer, I feel using their software is frequently uncomfortable. Even Sibelius, the most user-friendly of them all. Maybe the result of my efforts will be a little more comfortable to use.

Each of these programs has their own set of problems...

• Finale is powerful but unfriendly, it couldn’t be used for composition.
• Encore had the best GUI during the 90s but today it is seriously outdated; its (re)positioning bugs have never been fixed and the user interface is still based on toolbars.
• Overture, which was once the successor of Encore (same author), hasn’t seen a release in years.
• Sibelius is powerful and user-friendly but in July 2012 Avid fired the original development team, so it might be dying too.
• Notion is the new kid on the block, it has the best playback features but also the worst notation abilities, you can’t change the keyboard shortcuts and anything you do requires a mouse click.
• The only open source solution worth mentioning, MuseScore, has quite a few bugs, very basic playback features and bad spacing problems (collisions happen between staves and the user is required to insert a “spacer” item, this is such a bad idea)...

All these programs were written in C++. I am creating mine in the Python language, such that the result will be hackable by its users. They will be more able to scratch their itches.

But the problem is that the scope of the project is so daunting. I have a huge backlog of features I need to implement before my solution can compete. I estimate the entire project will take 2 man-years before it can be useful to anyone. It is July already and I have been able to work on this project for only 2 man-months, so there are 22 to go. When I think about this, I feel I am a little crazy for even having started it. If I give up, I will have wasted X months of my life and nobody will ever have had any use for any of it.

After 2 man-months of work, what do I have? My program reads scores created in other programs in the MusicXML interchange format and puts the score in memory. (Representing music in the computer memory poses intimidating problems by itself.) It also shows a subset of the music symbols on the screen. You can zoom in and out, you can cycle through a few color themes and you can change the title of the piece. Undo and redo have been implemented and there’s a neat framework that will be used for every user command. Many keyboard shortcuts have been planned and placed in a configuration file so the user can change any of them if she wishes to. A music cursor already exists that travels through all notes in the piece. But you still cannot add, change or delete a single note. And there is so much still not shown on the screen... There are no beams, no slurs, no articulations, no dynamic markings etc.

Screenshot of an alpha version of my music editor showing a test of clusters

This is because music notation is very complex. Simply displaying it on screen is very hard. If you are a musician, can you articulate the rules to display clusters of notes? Questions of spacing have to be faced... In my software, from day zero, the collisions (between music signs) that plagued this kind of software for years and years, making users drag symbols all the time... these placement problems are considered bugs with the greatest priority. Nobody wants to be fixing these manually, the program must get this right without any human help!

If this project is so hard even today, I can imagine what the Finale developers accomplished back in 1988 ― such software did not yet exist. Respect goes out to them, deep respect. Today I have open music fonts that I can use, the Python language and the Qt framework which do so much of the work for me, especially concerning graphics. Even creating PDF files probably won’t be much different than showing the stuff on the screen, thanks to Qt.

Obviously I should not be doing this alone. This post is a sort of call for help, as there are some kinds of help I could use:

• Help making the project financially viable. I haven’t found an investor. Here in Brazil, crowdfunding websites such as catarse.me exist but are less successful than in, say, the U. S. Kickstarter itself is not available here. Also, I am a very technical person, I don’t like my business abilities.
• Help programming. The software is being written in the high-level Python 3.4 language, which is proving to be a very good choice because it is so expressive and easy to read. Performance is fine so far even without any optimization. For the GUI I am using Qt through Pyside. Playback features are deferred to the end of the backlog, but it wouldn’t hurt to have someone get started on them. I have ideas (to do things differently from the competition) in many subjects, including playback.
• When the time comes, help testing the application will be very appreciated.

I have dreamed of writing this software for decades. In my dreams it would always be open source. But right now I don’t see how open source could ever repay such an effort. I need to be adequately compensated for this work. This will probably be cheap software, but not (immediately) open source ― even though I like free software so much.

Can you help? Any messages about the project are very welcome!

Why I sort of dislike Django

Here is my opinion on Python web frameworks.

Pyramid is currently the best choice because:

• It is full-featured, with a very well-defined scope as a web framework and a really careful implementation of all the right choices, organized by this little genius called Chris McDonough over literally years of dedicated development.
• Routes are decoupled from request handlers, while offering both URL dispatch and tree traversal.
• Because template rendering is a separate step, view handlers can be easily unit tested. The test case can see the dictionary that a view handler returns. In other frameworks you have to inspect the returned HTML :(
• You can use whatever templating languages you want, including Genshi, Kajiki, Chameleon, Mako, Jinja2 etc.
• You can use whatever you want as a database, including SQLAlchemy, the most powerful Python ORM.
• It has a great authentication and authorization framework which is independent of your choices for data persistence.
• It makes your project an independent Python package, teaching you to use standard Python packaging tools for your benefit.
• It has the best scheme for reusing existing projects, since you can overload templates and views as you integrate another Pyramid site into yours. For an example, see horus, a Pyramid pluggable authentication app using SQLAlchemy.
• It avoids the global variables and threadlocal variables that other web frameworks, such as Flask, like to use, thinking they will be convenient, until they make some things impossible.
• It is thoroughly documented and has a great community with a great IRC channel and a great mailing list.

The only drawbacks of Pyramid might be:

• Because you can choose everything (templating language, ORM etc.), it might take longer to get a project started than if you pick, say, Django. (But the advantages of choosing your libraries, such as deform, compensate for this.)
• Pyramid takes time to learn properly. You have to read the documentation and practise for a while.

Let’s compare this to Django. The advantages of using Django today might be:

• It is old and well-established.
• It has by far the largest community of all web frameworks in Python.
• Very quick to get started because everything has been chosen for you, including templating language and an ORM (even if you don’t want or need an ORM).
• Therefore, there are many existing reusable applications developed in it. These apps tend to work well together because they use the same stack.
• Its web form stuff is really good. (Although not so powerful as deform.)
• Great documentation.

The disadvantages of Django are:

• It is old and needs to maintain backwards compatibility, so it evolves slowly.
• Its daft templating language is severely and deliberately handicapped. It goes to great lengths to prevent you, the developer, from putting logic in a template ― it even forbids you from calling a Python function from the template. Then, in order to remedy this, it allows you to implement a filter, which is nothing more than a way to call a function. What could be more retarded? The syntax of this templating language is also too verbose. On the plus side, many people use Jinja2 instead, which has the same bad syntax, but lets you call functions and works very well.
• People are impressed by the admin, but it really isn’t important at all for development. Other frameworks, being less tightly integrated, cannot offer an admin that would work for everybody. Again, this is of no consequence for real world development.
• Its ORM, created before SQLAlchemy existed, is now much inferior to SQLAlchemy. It is less flexible, its API is less well thought out, and it is based on the Active Record pattern which is worse than the Unit of Work pattern adopted by SQLAlchemy. This means, in Django, models can “save” themselves and transactions are off by default, they are an afterthought. In SQLAlchemy, one thinks in transactional terms from the start. This talk explains this better.
• Model relationships have ON DELETE CASCADE by default, which is a poor choice because it is not safe ― one might lose data because of this. The default should be safe, and the programmer would declare the cascade when applicable. To avoid cascading, one needs to write on_delete=models.PROTECT in each ForeignKey.
• Models can have no mixins ― only simple inheritance. Less powerful than SQLAlchemy.
• Many projects don’t access a database, but there is no way to turn off the ORM, you even have to configure it.
• Django enthusiasts sometimes boast that Django is a single package. Don’t they realize this is actually a bad thing? Django is a tangled monolithic piece of software. The fewer dependencies you have, the more code you have to write yourself. Django is in fact a bad case of Not Invented Here syndrome. Django by itself does not encourage anyone to learn and use standard Python packaging tools.
• Django solved the problem of route definition by using regular expressions; now they have 2 problems. This is jurassic next to the sophisticated dispatch in Pyramid...
• Class-based views. Oh, Django devs have really shot themselves in the foot here, soon they are going to be very sorry. Why? Well, please read Pylons creator Ben Bangert’s blog post titled Why Extending Through Subclassing (a framework’s classes) is a Bad Idea. Looks like Django devs weren’t paying attention to Pylons’ mistakes when they came up with their own class-based views! These are extended through inheritance, which will make everyone’s life complicated in subsequent versions. No separation between the framework’s API and implementation has been indicated. (This separation, by the way, is always in the mind of the Pyramid developers.)
• Class-based views, again, for a different reason. If you ever want to subclass one of them, to change their behaviour slightly, you will be in pain. This is because they themselves are a deep hierarchy of subclasses. Too deep. So you read about 10 classes trying to figure out where you should interfere. This is such a big problem for every Django user who likes class-based views, that an entire website was created to help understand them: http://ccbv.co.uk ― the very existence of which should be seen as a red flag.

Advantages of Flask:

• Gets you started quickly, if the job is simple.

Disadvantages of Flask:

• Suffers from thread local variables everywhere.
• Severely incomplete documentation that seems to only explain something to someone who already knows it.
• Blueprints are simple overengineering.
• Plugin greed: Flask enthusiasts may want everything in the system to be a Flask plugin, which is just plain bad software architecture.

What advantages do I see in Google App Engine?

• Only one: Auto-scaling.

Disadvantages?

• First off, the web framework of Google App Engine is very poorly organized. Some libraries are offered by default, you turn them on via configuration. Then you have to provide other libraries alongside your own project. There is no clean separation, no safe place to put them. You cannot use standand Python packaging tools. Let’s just say this: Guido, I expected more of you...
• The documentation is laughable. Very unhelpful.
• Google folks don’t seem to value an appengine-enabled Python interpreter for the developer to try things out. In order to obtain an ipython shell you have to resort to a tremendous hack that includes adding several directories to sys.path.
• Often, interesting subprojects appear, then their bugs are never ironed out and the projects are discontinued by Google because nobody uses them.
• Lock-in. Develop for the Google App Engine and you can only deploy there.

What advantages do I see in web2py?

• Not one.

Disadvantages?

• Its pypi description starts thus: “Everything in one package with no dependencies.” An even more extreme case of Not Invented Here than Django! At least Django was one of the very first web frameworks developed in Python. web2py is much newer. When it was created, SQLAlchemy already existed, along with many libraries that could have been reused...
• web2py does not offer an ORM (object-relational mapper), only a DAL (data access layer). It boasts this as a great advantage (it’s not a bug, it’s a feature?). By the way, SQLAlchemy has 2 layers: its ORM is based on its DAL, and you can use the one you prefer.
• I didn’t familiarize myself with web2py after seeing this, but I don’t suppose I am missing much.

Large web apps in Python: A good architecture

If you are setting out to write a large application in Python using a relational database, this long post is for you. Herein I share some experience acquired over 6 months while writing large applications that use SQLAlchemy (the most advanced ORM available for the Python language) in a large team.

To be honest, I think this post might be too convoluted, trying to teach too many things at once. But it is really trying to show how multiple aspects converge to fail together.

py.test -s --tb=native -x --durations 2

from functools import wraps

def transaction(fn):
    '''Decorator that encloses the decorated function in a DB transaction.
    The decorated function does not need to session.commit(). Usage::

        @transaction
        def my_function():  # (...)

    If any exception is raised from this function, the session is rewinded.

    But if you pass ``persist=None`` when calling your decorated function,
    the session is neither committed nor rewinded. This is great for tests
    because you are still in the transaction when asserting the result.

    If you pass ``persist=False``, the session is always rewinded.

    The default is ``persist=True``, meaning yes, commit the transaction.
    '''
    @wraps(fn)
    def wrapper(*a, **kw):
        persist = kw.pop('persist', True)
        try:
            fn(*a, **kw)
        except:
            db.session.rollback()
            raise
        else:
            if persist is False:
                db.session.rollback()
            elif persist is True:
                db.session.commit()
    return wrapper

O Monstro

― Acho que hoje ele não vem. Já está tarde ― disse vovô, esperançoso.

Olhei para trás: os olhinhos castanhos de meu priminho Vit ostentavam sua diversão. Como gostávamos de brincar de espião! Fiz sinal de silêncio com a maior veemência.

― Ele sempre vem no início do mês. Pode tardar, mas não tem misericórdia ― soluçou vovó.

― Arre, mulher! É por isso que nada de bom acontece nesta casa! ― bufou vovô roucamente.

Estiquei a cabeça para além da quina do armário. Suas feições graves não me encontraram.

Titia surgiu do quintal limpando as mãos. Escondi-me de novo. ― Mas ela tem razão ― contemporizou. ― Ficando aqui, estamos sujeitos a essa desgraça!

― O que não tem remédio... ― grunhiu vovô, aproximando-se. ― Isso não tem remédio!

Disparamos na direção da entrada da casa com estardalhaço. Vit continuou brincando como se não tivesse escutado nada. Eu era maior e não sei se entendia mais, mas a conversa me deixara um pouco preocupado.

― Crianças, não saiam! ― gritou vovó, lá da cozinha.

Esgueirando-nos pelos cantos, chegamos à janela da frente. Olhamos para fora com cuidado para não sermos detectados, pois restava uma pitada de crepúsculo. Ventava muito: a árvore do outro lado da rua parecia tentar desprender-se do chão. Meus pensamentos foram interrompidos por um estalo medonho, seguido de um trovão, que arregalou os olhinhos do meu primo de susto ― e eu mesmo tive um arrepio, que o raio deve ter caído bem ao lado da casa. Em seguida desabou uma chuva de granizo, a qual assistimos da janela.

Um carro ― lembro que era grande e escuro ― parou em frente à nossa casa. Um minuto depois, desceu uma enorme figura oculta numa capa de chuva bege. Enquanto fechava a porta, pensei ter avistado... o quê? Pelo?

Vit riu baixinho e me puxou para baixo. Empurrei-o ― tinha que olhar ― algo não estava certo.

O vulto dirigiu-se à casa da frente. Segundos depois, abriram e ele entrou.

― É um mon ― começou Vit, mas tapei sua boca, pois nesse momento pude discernir gritos vindo da casa da frente, mesmo sob a chuva. O alarido durou alguns segundos, o que era? Consternação? Pavor? Meu mal-estar só aumentava.

A chuva agora estava mais fraca. A porta se abriu e o vulto veio direto para a nossa casa. A cada passo, um pesado estalido. Vit apertou meu braço com aflição. Arrependi-me de fitá-lo, pois ele detectou o medo nos meus olhos. A campainha soou dura: de um pulo, puxei meu primo para trás da cortina, de onde assistimos o resto da hedionda cena.

Vovô veio da cozinha com um olhar de profundo desgosto. ― Não abra ― instou vovó, mas ele a ignorou e escancarou a porta de uma vez só. E junto com a chuva, aquela voz odiosa entrou na casa:

― O aluguel atrasado, senhores.

Organizing a classical music collection: the Composer tag

If you are into classical music, you know how hard it is to organize your audio files.

The most important problem is lack of support for the “Composer” tag in music player software. For a while, this led me to the idea of reusing the mainstream “artist” tag to contain composer information. But then performer information must go into other tags such as “Album” or “Comment”.

The advantage of this approach is that it works with any and all music players.

But it has many disadvantages. First of all, tagging your music becomes an endless nightmare: no tagging software I have encountered out there does it this way, so basically you would have to make corrections manually. Forever. Remember that your are files always coming from many different sources, so you would have to keep track of which files have already been converted to your system.

Also, this kind of reasoning is just conceptually wrong. Though the idea of the “artist” in music is a wrong concept by itself, what it really means in practice is “performer”. If you start abusing concepts you end up with nightmares as repulsive as this system:

http://musicbrainz.org/doc/ClassicalStyleGuide

No solution could be less correct in data normalization terms...

Finally I found it easier to just use the correct tags. Use the “Composer” tag for the composer. The disadvantage is, you have to work harder to find software that supports it. But it is not impossible. Apple products support the “composer” tag. On a PC (Windows or Linux) one can use powerful music players such as Amarok which fully supports the “composer” tag. (On Ubuntu Linux, you just type sudo apt-get install amarok.)

What about my phone? I’ve been unable to find an Android music player with support for the “composer” field. I did find hints on the web and tried a few players, but the tips were written years ago and apparently the newer versions do not support the “composer” tag anymore.

Since phones are unable to carry that much music anyway, I intend to just use any directory-based player. What’s important is that my collection will be correct and give me less of a headache.

Summing up, I have 2 pieces of advice:

• Use the “composer” field: use the correct tags and spend some time to find software that supports them. Such software deserves to be preferred.
• Regardless of tagging, keep your collection well organized in terms of directories.

So you are going to watch “War Horse”

So you are going to watch War Horse, Spielberg’s movie of 2011. Here is what you need to know. (No spoilers here, this is safe to read.)

This is a traditional movie in many ways. But which traditions? Well, you are going to see a (non-satirical) picaresque fictional story about a horse in First World War times, derived from a book for children.

So the foremost tradition is that of the horse movie. You get everything you would expect: themes of friendship between a youngen and a special horse who is one of the most important characters, stunning visuals that only nature and animals can provide, gallops, adventure etc.

Because the horse is perhaps the main character, he is going to suffer. Be prepared for this. However, it’s all in good taste.

Now remember the story has something of a picaresque quality, without really belonging to this genre. To me this means the hero goes through adventures in different places during his life, and whether characters reappear later is anyone’s guess. These episodes may sometimes seem a bit disconnected from each other, however this is part of the wonder, you would exclaim: “what an interesting life”! And I have to say, this falls quite nicely upon a traditional horse movie character who would like his freedom.

So if the plot is sometimes stretched, well, in my opinion this is just part of the genre. There is no satire though.

The First World War is the circumstance that keeps these episodes together. But this is only a war movie to the extent of old, traditional war movies. I mean, this isn’t a remake of Private Ryan, gore isn’t the focus. This isn’t an ultra-realistic movie in any way and Spielberg has been able to mix these 2 genres (war and horse) in a tasteful way.

I guess I mean to say, there is war in the movie, but it isn’t exactly a war movie, it isn’t focused in showing the raw horrors of war, and if it were, you might care that much less about the horse. You gotta like the horse, otherwise the movie won’t make sense! And I understand this is true, that horses did indeed suffer in that war.

The fact that the Germans speak English put some people off; they wanted to see subtitles. I guess they were expecting a contemporary war movie. But remember that children are to be included in this audience... I, for one, felt it refreshing to see raw realism – which would be pointless here anyway – give way to a more direct way to tell the story. This looks back to old war movies, in which foreign characters might speak their own languages a bit for effect, but not when you really had to understand what they were saying. In many ways, that was a better way to just tell a story.

Some people complain that the first part was slow. Another complaint is that there wasn’t enough friendship established between the horse and the boy. I thought the balance was perfect between these two opposing forces.

Finally, you get traditional John Williams music, not so memorable but perfectly adequate. And Spielberg is the perfect director to manipulate your heart, which makes many people mad at him. How dare he?!

Now you are prepared to be entertained by a pretty good film, knowing that it won’t change your life.

Reasons not to use Windows

When people buy a new computer, it tends to come with Windows preinstalled. Because of this, most people just use it – unaware that it would be much better for them to install Linux instead. Further, Linux is free.

Here is my list of the most important reasons to avoid Windows:

Como se comportar em um teste de elenco sem cachê teste

http://vimeo.com/38818639

Inventing on principle

If you are at all interested in computing or invention or creativity, you shall now watch this talk by Bret Victor.

I am now tinkering.

In June 2004 I started a blog using a full-featured CMS written in PHP. The first post was titled Nando Florestan’s site is now interactive. I was very excited...

Today I am starting a new blog ― and I am also excited because I can finally get rid of the old thing, using something much simpler: Tinkerer, a static blog generator written in Python.

There is a powerful text markup language that Python developers have traditionally used for documentation. It is called reStructuredText. Nowadays, with everybody using Sphinx, reStructuredText is even more popular. So Python developers needed a blog system that supported reStructuredText. Blogging is easier without mental context switching between markup languages.

So when famous programmer Ben Bangert mentioned Tinkerer in a chat, I immediately knew it would be eagerly adopted by Python developers. Ben has just migrated from Tumblr to Tinkerer.

For common people who want a new blog, I still recommend Tumblr though.

What Oracle should do to MySQL

What is probably going to happen now that Sun and MySQL belong to Oracle is:

1) They are going to get a world-class boring buzzword-compliant website.

2) All this.

Java’s opinion of Python

I read some guy talking about Java, “the greatest language in the world”, just like an ugly American might say “the greatest country in the world”. He has motivated me to become an ugly Pythonista.

A Javer and a Cee-Sharper meet a Pythonista and consider Python for a brief moment.

Oracle Certified Java Programmer: ― I guess writing code in Python is quicker, but it might create maintenance nightmares later. Python is optimized for productivity and Java for maintainability.

Microsoft Certified Professional: ― Actually, the absence of great IDEs for Python, such as Visual Studio, might slow down the production of code.

Oracle Certified Java Programmer: ― “Rigid” languages such as Java make you write more code, but that code stays legible till the end of the project lifecycle.

Python apologist guy: ― You are wrong. I chose Python exactly because it is the most readable language available...

Microsoft Certified Professional: ― Nah, creating properties is very hard without an IDE. Another problem in Python is the lack of Generics. I am proud of writing in a language that has LINQ. Python is also missing a nice Reflection library such as the ones in C# and Java! That shows how much more powerful these languages are.

Oracle Certified Java Programmer: ― Yeah, I like Java because I get to program in XML. Hey, in Python you never know the type of a variable or parameter. Java is more explicit, therefore Java code is more readable.

Python apologist guy realizes the hopelessness of it: ― You are right, of course, but you can always use Hungarian Notation: s_name = ‘Nando’; i_age = 33;

Microsoft Certified Professional: ― I don’t like Python or Java. I prefer the C family of languages, invented by Microsoft, that includes C, C++ and C#.

Python apologist guy: ― Wait, in Python you can continue to type a semicolon at the end of every line.

Oracle Certified Java Programmer: ― Hmm, it must have copied Groovy. But that makes Python better than I figured...

Python apologist guy tries to ignore him: ― You can have strongly typed variables too. And braces. See this example:

# MyClass.py
# Proud author: nosklo (Clovis Fabricio)
class MyClass(object):#{
    def __init__(self, s_name, i_age):#{
        assert isinstance(s_name, str);
        assert isinstance(i_age, int);
        if (i_age > 20):#{
            print s_name;
        #}
    #}
#}

Microsoft Certified Professional: ― Hmm, the eye sees the #{ combination easily. OK, this code is readable. But I like .net because it is extremely multi-language.

Python apologist guy: ― Don’t worry, you can even have goto if you wish. Here is a VB-like alternative:

# MyClass.py. Proud author: nosklo (Clovis Fabricio)
class MyClass(object):
    def __init__(self, s_name, i_age):
        assert isinstance(s_name, str)
        assert isinstance(i_age, int)
        if (i_age > 20):
            print s_name
        #end if
    #end function
#end class

Microsoft Certified Professional: ― You can’t convince me because Python is an interpreted language, and I only like compiled languages, like C#. Furthermore, I like when enterprise libraries are ready so I don’t have to write them myself. ― Goes away.

OCJP waits until MCP is far enough. ― Never mind him, he never even understood the importance of Checked Exceptions. Hey, I see there are 2 classes in this file. This must be a maintenance nightmare! The only true way is one class per file.

Python apologist guy: ― Yeah, namespaces are one honking great idea ― let’s do more of those!

Oracle Certified Java Programmer: ― As much as I might like your language, I could never give up world-class enterprise-ready buzzword compliance and a BIG company backing us up.

Python apologist guy: ― Good for you!

Ruby developer: ― Excuse me, I couldn’t help but hear your conversation. I just wanted to say that if you ever need a dynamic language, consider Ruby ― it is more powerful.

Python apologist guy turns his back to OCJP and attacks Ruby developer: ― Die, heretic scum!

Schemaless Python databases

3 new persistence options for Python

As I struggle to create an object-oriented database for Python on top of Tokyo Cabinet – Pykesto – I have found two other nice persistence mechanisms:

Kineta is a dynamic, schemaless, relational database written in Python on top of Berkeley DB. It is almost done, I have tested it a bit and was impressed. It is full of different ideas, sometimes I felt it was too different from what I am used to, but if you really think about them and try to be fair, you realize these are all good ideas. Really, take a look at Kineta.

The last one – Copycat – is a Prevayler for Python. For those unfamiliar with the Prevayler concept, this is an extremely fast, transparent, ACID persistence mechanism for small databases that fit in memory. In such a case you can be free of all the overhead of traditional databases and just use your objects in the most natural way. Behind the scenes, the framework writes a log of all the operations you do. Every night or so a checkpoint is created, too (allowing the log to be reset). When the system is turned off and on again, the checkpoint is loaded and the log is applied so your objects come back to the state they were before. This might take a lot of RAM, but RAM can be much cheaper than developing with traditional databases.

Copycat is in an alpha state, but is already functional.

EDIT: One more! buzhug is a pure-Python database engine.

And there exists a B-plus Tree implemented in Python.

Corel

Comece devagar a gradualmente aproximar-se de uma situação em que raramente você precise contrariar uma convicção absoluta de NUNCA usar software cujo nome comece com Corel.

― Mas qual a alternativa?

― Inkscape é bem mais barato. Senão, tem sempre o Adobe Illustrator.

Installing Tokyo Cabinet and its Python driver

Tokyo Cabinet is the fastest database available, and it comes in several flavors. Here is how to install it in Ubuntu and use it with Python.

After realizing that CouchDB is not appropriate when you know you will need ad hoc queries (which doesn’t mean CouchDB isn’t very cool), I am trying out Tokyo Cabinet.

Here is a post about it, using Ruby.

Tokyo Cabinet offers several types of database, but the version that comes in Ubuntu 8.10 is missing the fixed-length and the table database, so I had to compile it:

sudo apt-get install checkinstall build-essential libbz2-dev
# Dependencies installed; now compile:
./configure --prefix=/usr
make clean
make
# checkinstall -R    # would create an RPM package
sudo checkinstall -D # creates and installs a Debian package
# Now you have a package that you can install AND uninstall, instead of
# sudo make install

Now the library, programs and headers are available, so we can install the Python driver. The most well-known is the old pytc which also doesn’t offer all kinds of databases. tc is the Python driver we need. Here is the author’s blog.

I download the latest code from github, uncompress it, enter its directory, then:

./setup.py install

That will succeed in Ubuntu 8.10 as long as the header files are found.

Unfortunately this driver is only nearly complete. As of 2008-04-03, the table database lacks a close() method, and the query API is being finished (you cannot execute queries yet).

Anyway, what software are we going to write using Tokyo Cabinet? How about an ambitious object-oriented database for Python apps? Something to replace ZODB? I am talking about pykesto and I wish you would help me write it.

However, it will take time to get there, and we might have to start by creating a higher-level interface to Tokyo Cabinet, because right now instantiating, for instance, the table database involves passing ugly flags like this:

import tc
t = tc.TDB('test.tdb', tc.TDBOWRITER | tc.TDBOCREAT)
# The above means open the file 'test.tdb' for writing and
# create it if it does not exist.
t.put('row id', {'col id':'value'})
t.get('row id')
# Out: {'col id': 'value'}
t.close()

Another reason to create a higher-level API is that the query API for the table database also involves lots of flags. I am sure this can easily be made Pythonic. I will put the code at pykesto as soon as I have it.

Running Kurso de Esperanto on Ubuntu 8.10

Today I decided to learn Esperanto. Best way to start seems to be Kurso, a gratis program. So...

...I downloaded Kurso3.0.deb and installed it. You might have 3 issues running this program in Ubuntu:

1. No way to start the program

Installing the program does not add a menu entry for it. So click the Gnome Panel, pick “Add to panel...”, then “Custom Application Launcher”, then type:

Name: Kurso
Command: kurso

You may also click the button at the left to choose a nice icon. That’s it, now you can easily launch the program.

2. /usr/share/kurso/tradukoj

The second problem that might happen is a message about lacking write access to the directory /usr/share/kurso/tradukoj. Another symptom is, clicking on the Settings button does not display the configuration screen.

A solution would be to type the following in a console:

cd /usr/share/kurso/
ls -l # prints out the contents of the kurso directory
sudo chmod 666 tradukoj
ls -l

This sets write permissions on that directory. Now you can restart the program, the message is gone and you can open the Settings screen.

3. Sounds problem

You might get no sound for playback or recording. The solution is:

1. Install mpg321:

sudo apt-get install mpg321

b) Open the Settings screen, switch to the Sound/Internet tab, and leave it like this:

MP3 player:    mpg321
WAV recorder:  aplay
WAV player:    arecord --duration=3 --rate=44100
Browser:       firefox
e-mail client: thunderbird

If you are really paying attention, you might notice that it doesn’t make sense to pick “aplay” to record and “arecord” to play. This is not my mistake; in this version (3.0) of Kurso, they messed up the 2 labels.

There you go, fully functional Kurso.

Web dev in Python: must read

If you are a Python web developer, here is some stuff you absolutely cannot miss.

• WSGI middleware considered harmful
• WSGI Framework Components
• Restish, a new web framework
• Spawning, a WSGI server which supports multiple processes, multiple threads, non-blocking HTTP IO, and automatic graceful upgrading of code
• CherryPy, an easy HTTP framework
• Webpyte, a reimplementation of TurboGears
• Genshi, a great templating system
• Tutorial: CherryPy + Genshi
• CouchDB with Python. Couchdb is a document-oriented database
• Introduction to Twisted, an asynchronous network framework
• The best e-mail address validation module you are going to find

Easily start the screensaver in Ubuntu Linux

How to start the Gnome screen saver immediately

The command to start the Gnome screensaver is:

gnome-screensaver-command -a

I tried to make this happen using keyboard shortcuts first, but couldn’t find a way. So I went with the next best thing: a launcher in the Gnome panel.

Right click the Gnome panel and click “Add to panel...”. Pick “Custom Application Launcher”. Another window appears. Fill it like this:

Type: Application
Name: Screensaver
Command: gnome-screensaver-command -a
Icon: <pick any icon...>

Hit OK and now you can start the screensaver by clicking the new icon.

Tuples, lists, dicts and objects: how fast?

Comparison of tuple, list, dict and object instantiation performance in Python.

It is well-known that in Python tuples are faster than lists, and dicts are faster than objects. I wondered how much so. After some tests, the conclusions are:

1. Use a tuple when you need a tuple and a list when you need a list. A list can have items appended or removed, while a tuple is immutable. If you won’t be adding or removing items, use a tuple and your code will run a little faster.

On the other hand, if you make a tuple with the intention of being fast, and then some code has to create another tuple out of your tuple, when it could have added or removed an item from a list instead, then you are actually being slower.

2. Dicts can be twice as fast as objects (but they do much less). Object oriented programming is based on the fact that uniting data and behaviour in a single place leads to better factored, more reusable code. So go on and make classes and objects, it is the only civilized thing to do! However, note that dicts are quite faster than objects (to instantiate).

Needless to say, premature optimization is the root of all evil, so keep these facts in mind only when you are optimizing some code, not when you are writing something new.

Here is a little module, and the tests are in its docstring if you want to reproduce them:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

'''speed_test.py

Comparison of tuple, list, dict and object instantiation performance.

Usage: (results are from Python 2.5.2 in Ubuntu)


python -m timeit -s 'from speed_test import *' 'a = {}'
10000000 loops, best of 3: 0.0792 usec per loop

python -m timeit -s 'from speed_test import *' 'a = []'
10000000 loops, best of 3: 0.081 usec per loop

python -m timeit -s 'from speed_test import *' 'a = object()'
1000000 loops, best of 3: 0.231 usec per loop

This object() instantiation is almost useless, done only to get a rough idea.

Conclusion:
For empty containers, lists and dicts are equivalent.


python -m timeit -s 'from speed_test import *' 'a = (x, x)'
10000000 loops, best of 3: 0.184 usec per loop

python -m timeit -s 'from speed_test import *' 'a = [x, x]'
1000000 loops, best of 3: 0.271 usec per loop

python -m timeit -s 'from speed_test import *' 'a = {x:x, y:x}'
1000000 loops, best of 3: 0.474 usec per loop

python -m timeit -s 'from speed_test import *' 'a = TestObj(x, x)'
1000000 loops, best of 3: 1.17 usec per loop

Conclusion:
For storing 2 values, tuples are 50% faster than lists.
Lists are twice as fast as dicts, but not fair: dicts also store keys.
Dicts are 250% faster than objects.


python -m timeit -s 'from speed_test import *' 'a = (x, x, x, x)'
1000000 loops, best of 3: 0.268 usec per loop

python -m timeit -s 'from speed_test import *' 'a = [x, x, x, x]'
1000000 loops, best of 3: 0.357 usec per loop

python -m timeit -s 'from speed_test import *' 'a = {x:x, y:x, z:x, v:x}'
1000000 loops, best of 3: 0.79 usec per loop

python -m timeit -s 'from speed_test import *' 'a = TestFour(x, x, x, x)'
1000000 loops, best of 3: 1.81 usec per loop

Conclusion:
When storing 4 values, tuples are 33% faster than lists.
And dicts are 2 times faster than objects.

The difference diminishes as you store more and more values.
'''

__author__ = 'Nando Florestan'

x = 42 # we use variables because constants would be much faster.
y = 43 # you don't use so many constants in the real world.
z = 44
v = 45


class TestObj(object):
    def __init__(self, a, b):
        self.a = a
        self.b = b


class TestFour(object):
    def __init__(self, a, b, c, d):
        self.a = a
        self.b = b
        self.c = c
        self.d = d

I dream of a db4o for Python

I wish Python would have an object database that wouldn’t eat up all the RAM.

Such a project could also be defined as “Durus with queries that don’t have to first instantiate objects”.

It would need a custom file format, without using Python’s pickles, to be able to query without instantiating. And I wouldn’t mind losing some dynamic-language-like flexibility if I could have this.

I have been using the SQLAlchemy ORM because it uses very little memory, it is very powerful and very fast. It does everything you need and more. However...

For some projects, I feel the difficulties in defining SQLALchemy models (and dealing with the relational database behind it). I want to use Python types, not relational database types. I would switch to an object database, if only it would query and use little RAM.

(In Python, making a tuple is faster than making a list is faster than making a dict is MUCH faster than instantiating an object.)

If I were to start such a db4o-like project (maybe 2010?) I would have to wrap my head around pointers to objects and their activation. So at first I might use SQLAlchemy as a backend. A table of properties... belongs to a table of objects... which know their Python type. This would probably enable one to make those queries without first instantiating.

About this scheme, ronny tells me to take a look at RDF – neat for dealing with not clearly defined object graphs.

(This is not my area of expertise...)

If you are a real good, but real good Python developer, go ahead and do it! But heads up, you’re gonna face DAMN tricky stuff about reference cycles and efficient collections.

This project is for the future. Python 3.0 on it!

Backalaika, an easy backup solution

Here is another open source creation of mine!

Backalaika is not a Russian musical instrument. It is a backup solution for small offices, available at SourceForge.

Written in Python, it lets you define backup profiles, filter filenames, compress to zip, tar.gzip or tar.bz2, perform differential, incremental or full backups etc.

You can download it here.

And here is the Python package.

Conseguindo o reembolso da licença do Windows

Se você comprar um computador que vem com Windows, mas for usar outro sistema operacional, pode se reembolsar da licença do Windows. (Eu ainda não fiz isso, mas achei interessante haver gente fazendo.)

Inventando nomes para as notas “pretas”

Solfejar cantando os nomes das notas tem uma utilidade da qual você não está consciente: Cultivar o ouvido. Mas as notas pretas não têm nome próprio... ou melhor, não tinham.

De onde vêm dó, ré, mi e sua turma

Neste momento é interessante lembrar que esses nomes foram inventados na Idade Média pelo monge Guido d’Arezzo, pai da notação musical tradicional. E originalmente as notas se chamavam ut, re, mi, fa, sol, la, si. De onde vieram? Havia um hino em que o 1º verso começava no dó, o 2º no ré e assim por diante. Então na verdade as notas é que tomaram os seus nomes da 1ª sílaba de cada verso:

Ut queant laxis
    resonare fibris,
Mira gestorum
    famuli tuorum,
Solve polluti
    labii reatum,
Sancte Ioannes.

Essa escala que herdamos tem as seguintes características interessantes:

• Dó substituiu Ut por ser mais fácil de solfejar. Ut tinha duas desvantagens: a vogal U e a consoante no final. As vogais abertas são mais fáceis de cantar. E todos os outros monossílabos têm uma consoante para o ataque e uma vogal.
• Si é substituída por Ti em algumas culturas. Ti tem a vantagem de não repetir a consoante S (já usada na nota Sol) e começar com uma consoante mais curta.
• Assim nenhuma consoante é repetida.
• A vogal “a”, talvez a melhor para soltar a voz, já é representada 2 vezes: fá e lá.
• A vogal “i”, boa para colocar a voz no lugar (cante “ni ni”), é usada em mi e si.
• A vogal aberta “ó” está presente em dó e sol, mas não temos a vogal fechada ô.
• A vogal aberta “é” só existe no ré e não temos a vogal fechada ê.
• A vogal “u” não aparece.

Ao inventar nossos monossílabos, fizemos as seguintes presunções (que não estão cientificamente confirmadas):

• O solfejo resultará mais rico se tivermos a máxima variedade de consoantes e vogais.
• Vogais abertas são mais cantáveis que as fechadas.
• Mesmo assim, é injustiça ainda não termos nenhum U.

Começando a usar ipython

(UPDATE de 2011: Estou gostando mais ainda do bpython...)

Dei umas dicas hoje no canal IRC #python-br do Freenode. Colei a conversa aqui para ajudar outras pessoas também.

<NandoFlorestan> pode abrir o interpretador e testar

<NandoFlorestan> já tens ipython?

<marmadeoli> não

<marmadeoli> tinha baixado o Idle

<NandoFlorestan> easy_install ipython

<NandoFlorestan> o ipython não compete com o idle

<NandoFlorestan> ele é um interpretador

<NandoFlorestan> melhor que o python ;)

<marmadeoli> mas o python já não é o interpretdor?

<NandoFlorestan> sim

<NandoFlorestan> mas no ipython por exemplo tem tab completion

<NandoFlorestan> tem histórico dos comandos (usando as setas)

<NandoFlorestan> e uma pá de outros recursos

<marmadeoli> vou baixá-lo... easy_install -U ipython

<marmadeoli> NandoFlorestan: cara, mil desculpas, desde ontem que te encho o saco. Mas... Como eu rodo esse programa?

<marmadeoli> ele é somente no console?

<NandoFlorestan> sim

<NandoFlorestan> digita ipython

<marmadeoli> tá, mas dai ele é só um interpretador. Ou seja, se eu quiser escrever arquivos não rola nele!

<marmadeoli> é como o interpretador do python no console

<NandoFlorestan> isso mesmo

<NandoFlorestan> mas é muito útil

<NandoFlorestan> pra testar coisas, ler docstrings etc.

<marmadeoli> sim..

<NandoFlorestan> tipo

<NandoFlorestan> import cherrypy

<NandoFlorestan> cherrypy?

<NandoFlorestan> põe o ponto de interrogação

<NandoFlorestan> ...e ele mostra a documentação

<NandoFlorestan> cherrypy.request?

<NandoFlorestan> mais documentação

<NandoFlorestan> E se vc quiser ver os fontes?

<NandoFlorestan> Usa 2 pontos de interrogação:

<NandoFlorestan> cherrypy??

<marmadeoli> ahhh bacana

<marmadeoli> bacana mesmo

<NandoFlorestan> Se precisar rodar um comando do shell, usa ponto de exclamação antes do comando. Por exemplo:

<NandoFlorestan> !top

<NandoFlorestan> Resumindo, quem tem ipython não precisa de nenhuma IDE. Só precisa de um editor de textos que mostre o código colorido.

<NandoFlorestan> Mas eu uso a IDE Geany mesmo assim ;)

<marmadeoli> ninguém usa aqui o python com o Eclipse?

<NandoFlorestan> Eu tento de vez em quando, mas quando trava eu fico furibundo :P

Pablo Francisco is hilarious...

Pablo Francisco is an awesome stand-up comedian. But first, you have to know who Don LaFontaine was.

Well, Pablo Francisco made a carrer out of impressions of Don LaFontaine.

But Pablo has other funny material too.

And of course, imitating Arnold is always their preferred sport.

A couple of music links

• Online ear tests for anyone, not just musicians
• Color and music

Wireless network is down on Ubuntu startup/boot

A quick tip for Hardy users.

After finally finding and buying a PCI wireless card that has a little penguin logo on the package, I found out that it worked, but I had to do “sudo ifdown wlan0; ifup wlan0” on every boot.

The solution for this is:

sudo nano /etc/network/interfaces

...and add a line to your interface definition that reads:

pre-up sleep 7

...this way the network will start 7 seconds later, but with success. (Some systems might need more than 7 seconds, just increase the value.)

Linux on Frankenstein PC hardware still has too many of these annoyances and I don’t see them going away at all. Using free software instead of a Mac that just works does have a cost, we have to admit it.

For more information on the interfaces file:

man interfaces

José Saramago: falsa democracia

http://www.youtube.com/watch?v=m1nePkQAM4w

MuseScore, open source music score editor

MuseScore is the most promising free-software music score editor I have ever seen. It is similar to Sibelius in many ways. And it is probably in your Linux distro’s packages already.

Entendendo mal Debussy

Se a “Pequenas Empresas Grandes Negócios” não sabe o que é software livre (vide post anterior), vejamos então a Folha de São Paulo, será que sabe dizer alguma coisa sobre música?

Acabo de ler a maior sandice que já encontrei num artigo que tenta falar de música séria:

“As obras de Debussy não chegaram a revolucionar a história da música, mas influenciaram muitos artistas renomados como Ravel, Satie e Bartók, marcando o fim da era wagneriana.”

Ocioso reclamar: dizer que Debussy não revolucionou a música é não saber absolutamente nada sobre composição. A anta que escreveu isso na Folha de São Paulo parece achar Debussy inferior (e “menos renomado”) a Ravel, Satie e Bartók. Estamos falando do pai da música moderna... Até o ponto em que essas coisas podem ser “medidas” (foi a Folha quem começou, hein?), a obra de Debussy é freqüentemente mais complexa, abstrata, original e influente que a dos outros gigantes mencionados — especialmente Satie, que pode ser considerado basicamente um humorista musical.

O erro só é grave para quem ainda acha que jornal e revista são fonte de informação. Mas precisa ser muito inocente para ainda estar nessa fase, a essa altura do campeonato...

Não adianta, quem trabalha para a indústria cultural vai direto para o inferno!

Que Debussy ele mesmo fale, e que depois disso nenhum animal de orelhas grandes zurre.

WYMeditor

WYMeditor: finally a javascript wysiwyg editor that shouldn’t generate buggy XHTML.

Our daily nazism — parents beware

What are our children being prepared for? *Death Note, seen by millions, is nazi. The story was a huge opportunity for moral thought, but only nazi ethos has a chance to appear.*

I am talking about Death Note, anime series. The manga series has been read by millions in Japan alone. There is also a Japanese film and a few other franchises.

I wouldn’t normally lose any of my time with nonsense such as anime series, but my 14-year-old daughter likes it and I decided to accompany her, plus in the first few episodes I was curious myself. Why?

Light is a popular, good-looking student who only gets A grades. A genius, really. One day he finds a weapon, thrown unto this world by a Shinigami (a God of Death) for his amusement. The weapon basically lets Light kill anyone he wants, without even meeting the victim. Light decides that he will use this weapon to kill every criminal that appears on the news. This way, he thinks, he will be the unknown creator of a new world, without crime.

Crime rates drop quickly and crowds thank the mysteryous Kira (“killer”) for it.

Is it nazi enough for you? But there is more.

The premise of the story seems a golden opportunity to talk about ethics. It would have been easy to discuss (and, in the process, teach children) about:

• how wrong it is to take justice in one’s own hands;
• how wrong it is to be accuser and judge at the same time;
• why we need the due process of law;
• how deceiving the news (and the rest of the culture industry) can be;
• how anybody can end up committing a crime (nobody is immune);
• how the law is not always right and may define crimes that shouldn’t be;
• how the law may not define some actions as crimes when they should be;
• the principle that punishment should be proportional to the crime;
• etc. etc.

Instead what happens?

• The mass murderer, who thinks of himself as a god, is indeed called Light;
• He just kills everybody, he is not interested in finding out whether the news are even true;
• He is Japan’s best student (!!!) but somehow has no idea that his concept of justice is barbaric, absolutely uncivilized;
• The series carefully avoids any moral evaluation, except Kira’s own reasoning to do as he does;
• Nobody else has high dreams;
• Kira is the main character, no other character comes close;
• Eventually other people find a way to follow the mass murderer’s example;
• The Gods of Death don’t ever interfere for moral reasons. They interfere either for fun or because they are in love with a female character. They don’t really think there is an enormous mess going on. In the end the plot just forgets about the Shinigami, they almost disappear.
• The whole series becomes just a thriller alla Sherlock Holmes versus Moryarty. Except that the killer is more competent than the cops.
• When the blockbusterish thriller ends, the series ends. There was nothing else to say.
• Due process of law is never mentioned.
• What is a crime? This is never questioned.
• How should punishment be done? This is never asked.
• etc. etc.

Do you think I am exaggerating? Do you think nobody would really identify with Kira? Think again.

Many people already think like Kira and would do the same. I have witnessed bad taste television shows in Brazil in which the angry host talked about a criminal (not a convicted criminal, but one that had just been arrested by the police), showing sensationalist disgust to what the criminal had done, saying things like “when he was doing it, he didn’t think about human rights, so why should he have human rights now?”

This is how many people think. We are surrounded, outnumbered by the stupid.

I was curious enough to go to IMDb. I know most of the posts there are noise; there is no place to find idiots as the IMDb forums. But I have also found extremely intelligent comments there before. Maybe it depends on the film.

In this case, I could find next to nobody interested in any moral issues raised by Death Note. Most people just talked about the cat/mouse game. When they did talk about ethics, they were always examples of what I am saying:

Entendendo mal o software livre

Será que os jornalistas da Globo sabem o que é software livre? Mas é claro que não!

Um amigo me envia esta notícia no portal Globo.com e fica esperando minha reação. Eu sabia que levaria horas para escrever a seguinte diatribe. Mas decepcioná-lo nunca!

O texto tem duas partes. A primeira noticia o resultado de uma pesquisa. A segunda vira ainda mais um artigo do gênero “Quem tem medo do open source?”. Esse trecho final, para começar, me parece desnecessário. Hoje acho que nem Eric S. Raymond evangeliza mais. Além disso, há erros grosseiros nesses últimos parágrafos. Vou tentar não me preocupar com as asneiras de português e falar só do conteúdo.

A besteira mais ululante e que tanta gente comete é a confusão entre software livre e software grátis. Por exemplo: “Marcelo Okano, confere inúmeras vantagens aos softwares livres frente aos aplicativos pagos.” (A vírgula é do original.)

Vamos combinar uma coisa. Software livre não é o mesmo que software grátis. Essas duas questões são ortogonais. “Livre” opõe-se a “proprietário”. O primeiro pode ser modificado e redistribuído sem dar satisfação a ninguém. O outro não.

O artigo diz: A forma de licenciamento dos softwares livres é gratuita. Isso é freqüente, mas nem sempre. Nada impede uma empresa que produz software livre de cobrar por ele e muitas o fazem. Exemplos: Red Hat, Mandriva, MySQL, db4o etc. O licenciamento é uma questão cheia de firulas; existem muitas maneiras de fazê-lo e uma pessoa comum levará semanas para entender o que está acontecendo.

Nessa esteira, o segundo parágrafo sugere que a “crença geral” é a de que software livre é software para pobre. Verdade? Crença de quem, essa? Da Globo? Pergunto porque já faz anos que o open source é a maneira de trabalhar preferida das maiores empresas de tecnologia (com poucas exceções). Por exemplo, as empresas gostam de fazer tudo em Java e neste universo quase todos os componentes são de código aberto.

Quem fala do open source como se ainda fosse minoria o faz por conhecer somente o monopólio do desktop.

Dito isto, na prática o preço do software livre tende a ser muito competitivo porque o cliente pode mudar de fornecedor sem trocar de software. Por exemplo, se uma empresa fornecedora de suporte ao banco de dados Postgres cometer muitos erros ou cobrar caro demais, o cliente pode mudar de fornecedora e continuar usando o mesmo software.

A liberdade de redistribuir o software também reprime preços altos. O argumento da empresa que vende o software acaba sendo o suporte — pois o mesmo software pode geralmente ser obtido de outra fonte.

Os trechos sobre confiabilidade e segurança são mais ou menos verdadeiros. É que são expressos de maneira tão desajeitada que ficam sujeitos à fácil impugnação pelos adversários. “Há um firewall feito para Linux.” Um? UM firewall? Haja paciência com quem ouviu o galo cantar mas não sabe onde...

O parágrafo seguinte sugere que o Samba é um novo avanço. Como se nossos computadores não conversassem com a rede do Windows há mais de uma década.

“O Linux, por exemplo, é um sistema operacional, sendo o único livre.” Quem disse isso esqueceu-se de FreeBSD, OpenBSD, OpenSolaris... Eu estou me esquecendo de outros. Em números absolutos, existem mais sistemas operacionais livres do que proprietários.

“Pessoas que desenvolvem softwares livres não entendem como uma empresa pode cobrar muito mais pelos programas do que gastou para desenvolvê-los. Como eram contra essa filosofia, lançaram os aplicativos gratuitos”, analisa.

Capitalistas bonzinhos? Isso não existe, é uma asneira de proporções mastodônticas. A dominância do open source é um efeito da acirrada competição na área de tecnologia. Produtos proprietários não sobrevivem se houver equivalente de código aberto. Isto só não atingiu ainda uns poucos mercados em que há monopólio (e.g. Windows). O Adobe Photoshop só sobreviverá, custando o quanto custa, enquanto o Gimp continuar sendo muito inferior. Numa situação de equivalência (ou quase), isso mudará.

O último parágrafo da notícia é tão errado que é incompreensível. Confunde software que roda no servidor (Apache) com software que roda no cliente (navegador do Windows). Também chama de desvantagem do “programa gratuito” a incompatibilidade que na realidade é causada pelo outro lado (sites de bancos que exigem o Internet Explorer). Teria sido melhor não dizer nada.

Finalmente, além de falar de software livre versus software pago, o texto deixa de mencionar que o software livre não é só software. É uma filosofia libertária, é uma causa moral. O primeiro passo para suprimir essa causa foi a invenção do “open source” (código aberto), que é o mesmo software livre, porém sem o argumento de que todo software deveria ser livre pois isto é que é ético.

A IBM fez uma campanha milionária de marketing em prol do Linux. Ao mesmo tempo, gosta de ter alguns produtos proprietários sempre que possível. A IBM não se interessa, destarte, em promover a causa ética do software livre. Por isso falam em open source. Sempre os vi falar em open source.

No Brasil, os meios de comunicação não têm a mesma hombridade. Eles causam mesmo a confusão, usando o termo software livre. Quem lê a notícia da Globo pensa que entendeu e já sabe tudo sobre o assunto. Sequer pode imaginar que a questão é bem mais profunda, é uma questão de liberdade individual mesmo, de direito público e privado. Uma questão que deve ser discutida, não apagada.

Conclusão: mesmo quando dá boas notícias, a indústria cultural o faz de maneira repugnante e estúpida. O propósito é cultivar o framework mental do público, excluindo ou confundindo o que não interessa ao sistema. As razões e o como disto tudo são bem explicadas no documentário “Manufacturing Consent: Noam Chomsky and the Media”. A primeira hora desse filme é devagar, mas depois esquenta.

E quem quiser entender corretamente o software livre conheça o homem que o inventou.

Balada legal é da hora

A indústria cultural também é responsável pela idiotice de algumas novas gírias.

A gíria é uma força que leva ao desentendimento entre diversos tempos. Por exemplo, “Erotik” não é o que você pensou, e sim uma bonita peça para piano de Edvard Gried. “Erótico” significava “amoroso” ou “relativo ao amor”. A palavra, faz pouco tempo, especializou-se no sexo, longe do significado que lhe davam os filósofos.

Outro exemplo. Há anos tento tocar (mas é difícil) a terceira balada para piano de Chopin — uma cativante peça de uns 7 minutos de duração, com um incrível equilíbrio dramático e formal. Quando uma amiga pronuncia a palavra “balada”, o que me vem à mente primeiro é o significado original da palavra: obra musical ou poesia narrativa épica, geralmente de caráter folclórico.

O triste é que eles, os estúpidos, nossos inimigos de sempre, pegaram essa palavra e inventaram uma gíria, significando “festa noturna, geralmente em boate”. Esta página sobre gírias data o fato de 1997 e o atribui aos “espertos da mídia dance (novamente eles)”.

Minha amiga replica: Qual o problema da gente usar a palavra balada, se hoje ela tem esse significado?

O problema é que é necessário resistir à estupidez promovida pela indústria cultural (pois cultura não é mercadoria). Vejamos mais algumas gírias a serem evitadas:

• “Da hora”, “do momento” etc.: É justamente o que o capitalismo quer que você pense: o que é bom é a última novidade, alardeada pelos meios de comunicação. Ao contrário, o bom é o que não é efêmero, e sim eterno.
• “Something rocks!”: mesma crítica, cumulada com mau gosto musical. Eu prefiro exclamar: “É cláaassico!”
• “Legal”: quando surgiu, provavelmente significava “é bom porque não é ilegal”. O problema aqui é aceitar passivamente a presunção de que tudo o que é bom é legal e tudo que não é bom é ilegal.
• “Animal”, “irado”...

SQLAlchemy has a new, easy declarative layer

A historic transcript from the #sqlalchemy IRC channel

<zzzeek_> deitarion: we just added a new declarative layer which removes a little of the verbosity, not sure if thats where you saw “too much boilerplate”

<justsomedood> woot, declarative layer part of SA? So not an extension?

<zzzeek_> its in ext/

<zzzeek_> we’ve had activemapper its just terrilby out of date

<justsomedood> way out of date

<zzzeek_> this is way smaller than activemapper

<zzzeek_> its 90 lines

<justsomedood> I ran into a lot of problems with it, and sent some fixes to johnathan but it ended up being too much work

<zzzeek_> i doubt this one has any big problems

<zzzeek_> since it does almost nothing :)

<justsomedood> hehehe

<Gedd> justsomedood: what kind of problems?

<justsomedood> It deferred class loading / table creation to make sure all dependencies were met before it did, that didn’t always work

<justsomedood> I ran into cases where if I didn’t define my classes in the correct order it would never create them, or get stuck in a loop

<justsomedood> I haven’t used it since 3.10-ish I think though

<Gedd> ah ok

<Gedd> that explains it :)

<NandoFlorestan> zzzeek_, the synonym stuff in the declarative layer is sweet!

<NandoFlorestan> I think this may be an Elixir killer

<jek> nah

<Gedd> NandoFlorestan: FWIW, Elixir handles synonyms too

<NandoFlorestan> hmm, didnt know that.

<zzzeek_> NandoFlorestan: elixir has a ton of stuff this does not

<justsomedood> So on this one, when defining “complex” relations(), with a primaryjoin on a table/object that hasn’t been defined yet you’d probably have to make that at the end with a class_mapper()?

<zzzeek_> you can stick it on later, like User.someprop = relation(SomeOtherObject, priamryjoin=foo.c.bar==bat.c.foo)

<zzzeek_> theres no class_mapper() needed here really since the class goes right to the mapper.....its also there as class.__mapper__

<justsomedood> k

<justsomedood> cool

<justsomedood> it would definitly condense my models and make them easier for others to read, and I wouldn’t have to worry about the syntax changing

<justsomedood> me likes

<NandoFlorestan> that is why I like it: I already know the syntax

Pylons without Buffet, and a critique of TurboGears

Ben Bangert has decided to remove Buffet from Pylons. Of course it will still support all those templating languages, just not through Buffet.

The replacement? Just a few basic render functions. They make it much easier to see how you’d modify parts if you needed to tweak options — something you cannot do if Buffet is in the equation.

Here is ltbarcly’s version of the same thing.

ltbarcly agrees. Why do we need one function that knows how to render every possible type of template? Just have a function called “render_genshi”, one called “render_mako” etc., then you can do things like streaming in genshi, or form filling, and use all the caching etc in mako. Buffet doesn’t do anything for you really — except give you the lowest common denominator.

He thinks, as I do, that dot notation for template names is stupid. If you write a common path instead, such as “test/blah.html”, it looks for “test/blah/html”... Who needs the additional text replacement code — who ever needed dot notation for templates?

(Mitsuhiko answers: Kid was the one that needed dot notation, because it compiled the template, then imported it.)

I wish TurboGears 2.0 does without Buffet, too...

Do you really need 21 MB of RAM for a Python website?

I made a little experiment and found that using CherryPy 3.1, plus the packages I need, instead of the whole TurboGears stack, can save a lot of RAM.

How can a TurboGears website use 1/3 less RAM?

(If you host at WebFaction, your account is mainly constrained on memory usage.)

My TurboGears 1.0.4.2 application is using 23,888 KB on startup, then 27,512 KB after many requests for different pages. Pylons is more or less the same, since a Hello World takes up 21 MB.

(Python 2.5, Ubuntu 7.10. I understand this varies a lot based on OS.)

I decided to see what would happen if I rolled my own “framework” on top of CherryPy 3.1, which is vastly superior to CherryPy 2.3 — pity TG hasn’t upgraded!

So I tried a memory consumption test for a CherryPy 3.1 based website.

I started with the CherryPy Hello World, then added import by import, measuring the impact in memory usage. The total memory used is annotated besides the corresponding import.

You can see memory usage with the following Linux shell commands:

ps aux
ps aux | grep python
ps aux | grep hello.py

Don’t confuse virtual memory with resident memory. I am worried about the latter only.

The answer: A CherryPy 3.1 Hello World amounts to mere 7 MB. After I import everything I remember that I need (including Genshi, SQLAlchemy and Routes), I’m using 14 MB.

Here is the (very simple) test for you to reproduce.

A maravilhosa Cantata 95

Não sou um homem religioso mas sei apreciar música, e garanto que é difícil encontrar coisa melhor que as cantatas religiosas de J. S. Bach.

Estou escutando-as todas, na ordem. A Cantata BWV 95 chamou minha atenção. Ao escutá-la seguindo a partitura, fui levado às lágrimas, coisa que nunca acontece. É que só nesse momento vi a letra da música. Não entendo alemão, mas na partitura há uma tradução para o inglês.

Johann Sebastian Bach escreveu mais de 300 cantatas, porém só nos restaram umas 195. Cada Cantata era apresentada num domingo do ano (durante a missa) e seu assunto era determinado pelo calendário religioso luterano.

Cada cantata é um conjunto de peças tais como corais, recitativos, árias etc.

Um famoso relato revela que, ao escutar uma peça de Bach, Mozart exclamou “eis uma coisa com a qual se pode aprender!”, sentou-se com as partituras e não levantou até ter lido todas. Beethoven chamava Bach de “o pai da harmonia”. O compositor de que Chopin provavelmente mais gostava e mais tocava era Bach.

Para o idiota moderno, acostumado a nulidades musicais como as da MTV e da rádio Jovem Pan, pode haver bastante estranhamento no início. Vencida essa barreira, que de resto é culpa de nosso estúpido estilo de vida e não do genial compositor, as cantatas de Bach trazem muita alegria, afinal veiculam um conteúdo humano e divino ao mesmo tempo.

A Cantata BWV 95, intitulada “Christus, der ist mein Leben” (Cristo é minha vida) contém uma famosa ária com pizzicato: “Ach, schlage doch bald”.

http://www.youtube.com/watch?v=_5-mmfof4H8

Página em inglês sobre a Cantata 95

Webpyte, framework web escrito em Python

Publiquei o código-fonte do Webpyte, novo framework para desenvolvimento de sites inspirado no excelente framework web TurboGears, mas usando componentes atualizados. Se você é um desenvolvedor Python, colabore! Aqui está a página do projeto no Google Code.

Typography: Helvetica and Arial

The history of the design of Helvetica and the subsequent scourge of Arial are pretty interesting.

Alucinações Musicais

Os livros do neurologista Oliver Sacks são todos muito bons e este é especial para mim por tratar da audição. Passa por ouvido absoluto, sinestesia, danos ao ouvido, danos ao cérebro etc. O tema principal são as alucinações musicais. Sabe quando alguém perde uma perna e continua a senti-la? Quando alguém perde a audição, pode acontecer coisa parecida: começa a ouvir música, não como ouvimos internamente todos os dias, mas com a ilusão de que a música realmente vem de fora. Para mim esse é só mais um argumento para não suportar a música vagabunda que toca em tantos ambientes por aí. Não dá pra escolher as alucinações musicais, e se forem de má qualidade, serão duplamente detestáveis...

Resources for learning to program in Python

Python is a great language for beginners. (It is also a great language for any application: imperative programming, object-oriented programming and functional programming.)

• How to think like a (Python) programmer, a free e-book, teaches the basics in a very intelligent way.
• Dive into Python is the most famous e-book. It is even an installable package in Ubuntu Linux.
• Style guide for Python code (PEP 8)
• Docstring conventions (PEP 257)
• Idiomatic Python

Here comes another bubble

Here is a funny but perhaps true music clip:

http://www.youtube.com/embed/YuAJHaXKgFk

What’s wrong with CS research

What’s wrong with Computer Science research

Same subject: Hackers and painters

Beautiful short story by Isaac Asimov

http://www.multivax.com/last_question.html

...and since we are in a science fiction mood: Are we living in a computer simulation?

Project management: C²I²

The C2I2 Hypothesis

The Big Rewrite

Interesting talks at Google Video

The Paradox of Choice - Why More Is Less

How Open Source Projects Survive Poisonous People (And You Can Too)

Practical Common Lisp is a great book by Peter Seibel

Advanced Python

Restoring Grub

If you install Ubuntu, then Windows in a different partition, the GRUB boot loader vanishes. But don’t panic and reinstall Ubuntu — you can recover it.

Boot to the Ubuntu Live CD, open up a Console window and type:

# Create a directory called “mounted”:
mkdir mounted
# In there, mount the partition where Ubuntu is installed:
sudo mount /dev/sda2 mounted
# (For the above step you need to find the partition name on your own.)
# However, replace the /dev directory in the mounted partition with the
# current /dev directory:
sudo mount –bind /dev mounted/dev
# Change the root for now
sudo chroot mounted
# Finally, install grub to the first SATA disk:
sudo grub-install –recheck /dev/sda

For more information:

https://help.ubuntu.com/community/RecoveringUbuntuAfterInstallingWindows

https://wiki.ubuntu.com/phbc50/howtos/how-to_reinstall_grub

Os inimigos: esperança, contentamento e oportunismo

O contente não sabe ou não reconhece que está tudo errado.

O esperançoso sabe que está tudo errado, mas aceita temporariamente. Este “temporariamente” tende ao infinito, afinal a paciência é uma virtude. Talvez “comodismo” fosse uma palavra melhor que “esperança”.

O oportunista aproveita que está tudo errado.

O oportunista é pior do que o contente é pior do que o esperançoso:

oportunista < contente < esperançoso

O esperançoso pode ser convencido. O contente só merece ser ignorado, pois é quase impossível convencê-lo. Ao oportunista deve-se reservar somente o insulto:

— Seu seguidor de ambulância!!!

Orchestration by Berlioz

Here is a website that contains excerpts from Berlioz’s Grand Traité d’Instrumentation et d’Orchestration Modernes:

http://www.hberlioz.com/Scores/BerliozTreatise.html

Grip, for ripping CDs

Grip is a great CD ripper/encoder for GNU/Linux. If you have never tried it, give it a go. It rips to wave using cdparanoia or others. It can simultaneously encode the ripped tracks to the format of your choice. Supports cddb too. Easy to use.

I usually encode to the ogg vorbis format (...)

Ogg Vorbis is much better than MP3 (roughly the same audio quality for half the file size) and is free of patents.

On Windows, Winamp has always been able to play ogg files. If you don’t like Winamp there is plenty of other options too – ogg vorbis really is the successor to MP3.

Zero Install: packaging software for multiple distros

Zero Install looks very useful for free software developers.

Listaller is another perspective.

Where to change your MSN / Passport password

If you ever need to change your Passport / MSN password, you might lose half an hour searching for this function. It is buried here.

Feeds: The ultimate opt-in solution

David Sklar wants to receive marketing, billing, and other corporate communications via RSS instead of e-mail. Me too. http://www.oreillynet.com/pub/wlg/5680

By the way, the new version of Mozilla Thunderbird (the great free e-mail client) is also a feed reader.

Anedota sobre pontuação

Um professor meu gostava de dizer que “vírgula não é orégano”. E às vezes umas poucas vírgulas podem assumir importância insuspeita. Eis um exemplo:

Um homem rico estava à beira da morte. Pediu papel e pena e escreveu assim:

Deixo meus bens à minha irmã não a meu sobrinho jamais será paga a conta do alfaiate nada aos pobres.

Morreu antes de fazer a pontuação. A quem deixava ele a fortuna? Eram quatro concorrentes.

1. O sobrinho fez a seguinte pontuação:

   Deixo meus bens à minha irmã? Não! A meu sobrinho. Jamais será paga a conta do alfaiate. Nada aos pobres.

2. A irmã chegou em seguida. Pontuou assim o escrito:

   Deixo meus bens à minha irmã. Não a meu sobrinho. Jamais será paga a conta do alfaiate. Nada aos pobres.

3. O alfaiate pediu cópia do original. Puxou a brasa pra sardinha dele:

   Deixo meus bens à minha irmã? Não! A meu sobrinho? Jamais! Será paga a conta do alfaiate. Nada aos pobres.

4. Aí, chegaram os descamisados da cidade. Um deles, sabido, fez esta interpretação:

   Deixo meus bens à minha irmã? Não! A meu sobrinho? Jamais! Será paga a conta do alfaiate? Nada! Aos pobres.

Assim é a vida. Nós é que colocamos os pontos. E isso faz a diferença.

On Blade Runner

Blade Runner, the cult movie, faced many problems in post-production. People wouldn’t get it, including, it appears, some of its producers. I have recently watched the director’s cut for the tenth time and it is still growing on me. It certainly is one of the more perfect movies I have ever seen.

A very interesting read is the Blade Runner FAQ. It reveals things that certainly didn’t occur to you as you watched, but will intrigue you now...

Spoiler warning: Do not read the Blade Runner FAQ if you haven’t seen the movie yet!

Bulb 2

Back in the year 2000, as a young music composer wannabe, who even had some music published at the mp3.com phenomenal website, I was looking up the internet for some opportunity to create music for animations and I came across the young filmmaker Ryan Foss. He had just posted a very short scene of a work-in-progress of his, featuring a bulb-headed robot in dark surroundings. I watched the few seconds of silent video and felt an atmosphere... eerie... almost religious... but heavy.

I didn’t talk to Ryan. I proceeded to compose some music on my computer, using the sounds of a church organ, a cello and a fake choir. Then I sent the music to him while also introducing myself.

I remember he said he didn’t immediately like the music, but as soon as he heard it with the video, he found they matched. A partnership was born – he did need music – and the result, a very short 3d animation, can be seen at:

http://www.pocketmovies.net/download/bulb

If you are seeing this much later, bear in mind this was the year 2000 and the whole thing was done in our personal computers...

Now we have completed the animation Bulb II, which shows that we both made a lot of progress in one year.

http://www.pocketmovies.net/download/bulb-ii

This time, there was much more work to do, so in addition to the music, I am responsible for part of the story and part of the sound effects.

2A in the first short meant 2 amperes. But now we think of it as a serial number. Thus, 2B. But the real mysteries in the story are to remain unanswered.

Here is something nobody has ever noticed: Near the end of the music, I quote Schumann’s Warum? (“Why?”, third piece from the Fantasiestücke op.12). That is such a beautiful piece of counterpoint!

For the sequel I have been able to use better sounds and equipment. I feel the lack of words makes the music entirely responsible for setting the mood and explaining the feelings. I like that responsibility. Reminds me of old silent film, such as Metropolis. There now exist countless soundtracks to this classic movie, written by different composers. Not many are good, but at least one is: Descent, written by the Australian composer Carl Vine.

I don’t think the 2 videos can change people’s lives, but they were great as creative exercises and they actually got included in 2002 in Volume One of North America’s Best Independent Animated Shorts.

Hell, my name even got into IMDb, the largest website about cinema.

I have never met Ryan in person. Isn’t it amazing what we can do over the internet these days?

Now if you are tired of the heavy atmosphere of these 2 shorts, I have the perfect antidote for you. Another australian artist, Dave Jones, makes wonderful, funny Flash animations. Browse his Transience website, click Animations, then watch The Heist. (No, I didn’t work with him, I just love The Heist.)

I enjoy composing serious music for film and I would like to do it again...

Alexandre Levy, romantic Brazilian composer

I want you to meet romantic Brazilian composer Alexandre Levy, who lived only 27 years but left important works of very good taste.

While you read about this fantastic musician, listen to the Tango Brasileiro, his most famous work, recovered from an old vynil, as played by the wonderful pianist Eudóxia de Barros:

Thanks to pianist Eudóxia de Barros for allowing me to publish here her recordings of compositions by Alexandre Levy!

Little biography of Alexandre Levy

Alexandre Levy was born in November 10th, 1864. He grew up in a very musical environment. His father, Henrique Luis Levy, owned the Casa Levy, a music store that was very important in the cultural life of the city of São Paulo, Brazil’s largest metropolis. The Casa Levy survives today as a piano store.

Alexandre Levy’s first music teacher was his brother Luis Levy, an excellent pianist and a good composer as well. Later Alexandre studied with Gabriel Giraudon, a French teacher who lived in São Paulo.

French culture must have influenced Alexandre Levy. The family probably used to speak French at home: his father was born French and his mother was from the French part of Switzerland. The composer used to name his works in French.

In 1887 Alexandre went to Europe in order to complete his education. In Paris he studied harmony and counterpoint with Emile Durand, who would also teach Claude Debussy.

Back to São Paulo, Levy composed some masterpieces until his mysterious premature death on January 17th, 1892. He did not suffer from any illness that we know of, but suddenly passed away, leaving an amazing production for a 27 year-old. “An announcement of a genius”, said Mario de Andrade.

Allegro appassionato op. 14

This important and difficult piano piece, from 1887, reveals how much Levy admired Robert Schumann. The appassionato (passionate) isn’t in the title gratuitously; this is one of Levy’s most romantic pieces.

This haunting performance is by sensational pianist Belkiss Carneiro de Mendonça, who lived in Goiás and passed away in 2005.

Alexandre Levy, compositor romântico paulistano

Faço questão que você conheça o compositor romântico paulistano Alexandre Levy, que viveu apenas 27 anos mas deixou uma obra importante e de muito bom gosto.

Enquanto você lê sobre este fantástico músico, ouça o Tango Brasileiro, sua obra mais famosa, na interpretação da maravilhosa pianista Eudóxia de Barros, recuperada de um velho vinil:

Agradeço à pianista Eudóxia de Barros pela permissão para publicar aqui as suas gravações das músicas de Alexandre Levy!

Breve biografia de Alexandre Levy

Alexandre Levy nasceu em 10 de novembro de 1864. Cresceu num ambiente muito musical. Seu pai, Henrique Luis Levy, foi o fundador da Casa Levy, uma loja de música muito importante na vida cultural da cidade de São Paulo. Existe ainda hoje como comércio de pianos.

O primeiro professor de música do menino foi seu irmão Luis Levy, excelente pianista e também compositor. Mais tarde, Alexandre estudou com Gabriel Giraudon, professor francês que vivia em São Paulo.

A cultura francesa certamente influenciou Alexandre Levy. A família provavelmente falava francês em casa: seu pai era francês de nascimento e sua mãe vinha da parte francesa da Suíça. O compositor costumava dar títulos em francês às suas obras.

Em 1887 Alexandre foi para a Europa para completar sua educação. Em Paris ele estudou harmonia e contraponto com Emile Durand, que haveria de ser também professor de Claude Debussy.

De volta a São Paulo, Levy compôs algumas obras-primas até sua misteriosa morte prematura, no dia 17 de janeiro de 1892. Ao que se saiba não sofria de nenhum mal, mas subitamente faleceu, deixando já uma produção espantosa para quem teve apenas 27 anos de vida. “Um anúncio de gênio”, disse Mario de Andrade.

Allegro appassionato op. 14

Esta importante e difícil peça para piano, de 1887, revela o quanto Levy admirava Robert Schumann. O appassionato (apaixonado) não está no título por acaso; é uma das peças mais românticas de Levy.

Esta arrebatadora performance é da sensacional pianista goiana Belkiss Carneiro de Mendonça, falecida em 2005.