Getting open for new paradigms

I think that all you five readers (ok, I’m being too generous) of my blog know that I love Ruby. Well, I’ll tell you why I haven’t posted in awhile: I have met someone new, and now Ruby only feels… well, it is still pretty good, it just is hiding even better stuff from me.

Yes, that’s right. I’m learning that old-fashioned, parenthesis-filled, known as crappy language called Common Lisp. And… well, parenthesis is a silly reason for you to not learn it, too.

I tried to make a long post explaining why the language is good, but it would require a book. So, instead, I’ll post a link to Practical Common Lisp and tell some things that may convince you:

Ruby’s internal object system is based on Emacs Lisp’s object system. Emacs Lisp’s object system is based on CLOS (Common Lisp Object System).

So imagine all the power of Ruby’s internal typing and message passing (which in Common Lisp is actually message dispatching, and for good reasons), but exposed to you, everything modifiable.

Code is data. Data is code.

Everything in Lisp is composed by S-Expressions, which is simply a syntax for linked lists. And the language has lots of functions to manipulate linked lists. Yes. Yes, you can manipulate your code with these concepts.

First-class functions and lambdas are more flexible than Ruby’s blocks.

You can easily have more than one function as a parameter on Lisp. You can pass a function as a block more easily. For instance, compare this:

[3, 1, 2].sort { |x,y| y <=> x }

With this:

(sort '(3 1 2) #'>)

In the second case, you’re passing the “>” (higher than) function directly to the sort function. On the case of sort it may not be much, but see how you multiply all the elements on your array:

(reduce #'* '(3 1 2))

What if I need to pass a custom function? Well, use a lambda:

(sort '("a" "def" "bc") (lambda (x y) (< (length x) (length y))))

And if I’m creating a function that receives another function? Ruby has yield, is Common Lisp as easy?

Yes. Funcall:

(funcall <variable storing the function> <arguments>)

It can be interpreted, but it can also be compiled.

You can compile Common Lisp code to native code and run it with a great speed, unlike Ruby, which needs to be interpreted or to run under a virtual machine. And yet, you have the facilities of an interpreted language, as garbage collection, on the fly evaluation, first class functions and closures.

Common Lisp isn’t functional, as some people may seem to think.

As I’ve said before, Common Lisp has a powerful object system. It may give support for imperative style programming and declarative style programming. Most lispers seem to have some preference for functional and declarative programming, because it’s often shorter and more trustful. So, don’t be afraid of Common Lisp because of something like programming paradigm: it will fill your needs.

If you complain about lack of libraries, you shouldn’t have started to use Ruby in the first place.

Using something only because it’s popular leads to average technology, not better technology.

I mean, Ruby is good. But you should try Common Lisp yourself and see if it’s better.

If parenthesis bother you, try a good editor, most of them have great navigation for it.

About Richard Stallman and Ubuntu’s dash

For anybody that follows all the GNU/Linux drama that always happen one day or the other, the Amazon search on Ubuntu’s dash is not news. But for those who aren’t informed, here we have some context:

Ubuntu 12.10 brought us a polemic new feature on Ubuntu’s dash. When you type your search on dash, where previously you had only files and applications, now you also have Amazon’s shopping suggestions. This brought rage and privacy concerns to its users, because the terms were not encrypted before being send to Canonical, and because it was enabled by default.

They solved the encryption concern. But not the default enabling. Nor they warn or inform the user in any way during the installation process.

A lot of users tried to suggest solutions to this issue, but Canonical only made it possible to disable this with an option (but it was still enabled by default).

Now, Richard M. Stallman himself published an article, calling this feature a “spyware”, and also suggesting how to address the problem.

As a response, one of Ubuntu’s contributor made his own article saying that people should stop complaining and should instead help make Ubuntu better.

Also, Ubuntu’s Community Manager, Jono Bacon, made another response saying that RMS is actually spreading FUD.

Now, my personal opinion on this issue:

First, linking to launchpad does not address the issue. As I said before, lots of people tried to propose a solution for this problem on launchpad, but they were ignored. Even some satires appeared (saying that using “find” on the CLI did not return Amazon’s results). If Canonical does not want to accept user’s suggestions, how is it true that WE make Ubuntu better? Canonical must accept patches and valid suggestions if it really wants to be free and open.

Also, the “linking to launchpad” is actually very, very dismissive. It seems that Mr. Randall is trying to say that all this are user’s fault. No. It’s not.

When he said that everybody should try to help, he seemed to ignore that Stallman gave his own suggestion on how to make dash better (a button for “search locally” and another for “search on the web”). What’s so difficult about this?

And also, why should Stallman still worry about coding this? Ubuntu runs on top of his Operating System. There wouldn’t be Ubuntu if there wasn’t Stallman. Mr. Randall shouldn’t have forgotten this.

About Bacon’s response, I’ll only say one thing: this is not FUD (Fear, Uncertainty and Doubt). Stallman is very well informed about dash. Stallman’s readers are also well informed. The group of people that isn’t informed is anybody that didn’t deactivate this feature because they wasn’t informed of its existence, nor how to deactivate that.

This feature is even worse than all the free applications that try to install the Ask toolbar on a Windows machine. At least they ask the user if he wants to install the toolbar. Ubuntu is not even doing this.

Concluding, this is NOT a coding issue, this is NOT a help absence issue, this is an ETHICAL issue, and should be addressed as one. Canonical’s dismisses only make it looks worse.

WebloggerMode apparent bug

I create entries on my blog through “WebloggerMode”, a package for Emacs. Yesterday, when I tried to post my previous entry, I noticed that weblogger was setting the date of my entry to “31 Dez 1999 21:00:00 -0300″. That was really… unpleasant. I don’t want to need to open wordpress.com to make things work. And, besides not having categories, only keywords, WebloggerMode was working just fine to me.

Well, the first thing I done was to send an email to WebloggerMode discussion list. The developer of the mode himself asked me if I tried to track down the bug (I was in a hurry when I detected it, so I didn’t read the code profoundly) and the URL for my blog. I promised to try to track down it.

Today, I started to think about potential solutions. I gave one more look to the code, and didn’t see anything really wrong. Nothing on xml-rpc.el either (which is a dependency for weblogger).

So I remembered that there are some extensions that should be loaded with the “require” function, while other only work with “load-file”. I checked the wiki and… load-file. I checked my .emacs and… require. I corrected it and it worked as usual.

Well, just myself being dumb again. Who would say?

Emacs, Emacs, why not Eclipse?

I’m an android developer, meaning that most of my job involves Java and XML. There is a lot of circle-jerk (I don’t know a better word for it, unfortunately) regarding these two technologies, and in fact I see some problems with Java, indeed. But it is a tool that does a good job at the end of the day, and JVM is a good and mature technology.

With all my “Emacs this, Emacs that”, maybe you’re thinking why I don’t using a “modern” IDE, like eclipse or NetBeans.

Well, since I’m a android developer, I actually use eclipse on my day-to-day work. There are three main reasons for that.

1. Java is a dense language, with lots of classes and methods and types. With Android’s SDK, this is get even bigger. An IDE helps me to find myself out.
2. ADT is really well integrated with Eclipse, providing a lot of features that are easily accessed.
3. I never really got JDEE working on Emacs 24, much less android’s modes.

Since Emacs’ shortcut keys are starting to get hardwired in my brain, I installed the extension called Emacs+ (only available on Eclipse Indigo). There are a few things that I miss (if only it were a ELisp parser…), but I’m mostly happy with it.

Well, mostly. There are a few things that I really dislike about eclipse. When it gets in my way. When it doesn’t recognizes things that are there. When there is no other easy way of doing a task besides going to the mouse.

But how does eclipse gets in my way?

Well, I don’t understand exactly how and why, but sometimes eclipse will “hold” a file and no other program will be able to use the same file, even if it is already saved and I’m not doing anything on it. This is a HUGE problem if you, like me, uses version control on the command line because of the flexibility it provides.

Sometimes eclipse will only let me use the file if I close it inside of eclipse. But sometimes I don’t want to. I want it to remain open, because it’s terrible to reopen it.

Maybe this is my fault. I really don’t know.

And what am I talking about when I say that it doesn’t recognizes things that are there?

Sometimes, eclipse won’t start the main activity because, for it, the activity does not exist. Even if it does. Even if I can open it directly on the device.

Finally, about going to the mouse: I’m an incorrigible keyboard adept. My text editor won’t ask me to use the mouse. My window manager will avoid the mouse. I hardly ever use my file manager because I find more practical to do a lot of tasks on a terminal. When I can’t do that on eclipse because it thinks that mouse is easier, I get pissed.

I know, I know that eclipse has lots of shortcut keys and I can edit them. But it seems that eclipse is not meant to be used this way.

Oh, this reminds me of one last thing: customize eclipse is boring as hell. If it had a scripting language, like Emacs Lisp, vim script, Ruby, Python, or whatever, sometimes it would be just better. Eclipse is a programmer’s tool, why not benefiting from that?

Why I chose Emacs over other editors

Last time I posted, I told everybody to choose a text editor from a rather small list.

Again, the most known text editors are Emacs and vim. But other famous editors are starting to show up, such as Text Mate and Sublime Text.

Again, I don’t intend to say that Emacs is better than those, I’ll only list reasons to why it fulfills MY needs. I will try to analyze what I think it is so cool in Emacs, even knowing that some of there features are also on other editors.

1. Emacs is really, REALLY easy to extend. Since Emacs is actually a eLisp parser which its main functionality is text editing, you can customize it using eLisp. That is: anything that you could do in eLisp, you can do in Emacs. Vim has also a scripting language, but it is not as powerful, nor it has as many extensions, as eLisp.
2. Extensions (cont.). There are a lot of extensions for it. Really. As I said before, I write on my blog through Emacs. I could read and write email through it. I can talk through it on IRC on it. Hell, I can even play Tetris on it!
3. Macros. Macros are among the most awesome things about Emacs. You can store a bunch of commands into a macro for executing it repeatedly later. This saves a lot of repetitive work.
4. Shortcut keys. I really don’t like how modal editing works. It’s not intuitive to me, no matter how fewer keystrokes vim users actually type.
5. AUCTeX (and other LaTeX extensions). LaTeX is awesome, and using it on Emacs is even more awesome. The amount of helpers that Emacs has is amazing.
6. Rectangle manipulation. Yup, you can manipulate regions (how Emacs calls “selection areas”) in rectangle shape. You can insert strings, remove them, among other things. Inserting one-line comments in lots of lines is a pleasure with it.
7. Windows, buffers and other concepts. You can divide your screen into multiple windows. You can open multiple buffers and switch freely between them.
8. Ansi-term. You can access any shell (e. g. bash) inside of Emacs. Need to edit a file and execute a command through ssh? Well, open a new window and use the ansi-term.
9. Daemon mode. You can run Emacs as a daemon (and open it at login, for example), and open clients for it. Every client shares the same buffers. This is great in any kind of environment.
10. Tramp mode. Tramp mode allows you to access files directly through FTP, SSH, or anything like it, on your own computer, without worrying if the target machine has Emacs installed on it. No need for downloading, editing and uploading, nor installing the editor on the target machine.
11. Package management. Since Emacs has a lot of extensions, the internal package manager is useful for quickly installing them.

Probably there are other things that I can’t remember at the moment. But if you use Emacs and can give more examples, please, leave a comment!

Learn to use a serious editor

After some insistence from a friend of mine, I decided to try emacs out. This gone for maybe a month, and… well, how could I say? I loved it!

Understand, vim users, I have nothing against you. Actually, after I started to learn emacs I gave vim a try, too. It’s just not what I expect from an editor. I don’t like modes, I like to type and something happens. If and when I want some command, I use shortcut keys. Emacs fills these needs.

I have been using emacs since last time I made a post in this blog. The amount of things you can do with it is amazing. I’m even writing this blog post on it.

But why should you use a serious text editor?

Well, there are a number of things that emacs/vim/text mate/sublime text can do that simpler editors can’t. The main one are macros.

Everything you type on a serious text editor is a command. Even when you insert a character you’re actually executing some sort of command. Macros stores every command you type, so you can use them again instantly. This is the most useful thing you can imagine, and only this would be worth trying a serious editor.

Serious text editors also handle rectangles manipulation. That is, you can select rectangle areas, insert characters in them, or delete them. This is REALLY useful for commenting big blocks of codes in languages that don’t have multiline comments (as Ruby, for instance).

Text editors are not IDE’s. You won’t compile or debug code directly on them, for this there are other tools, like make or GDB. But this is not what text editors intend to be. They are meant to edit your code, and only this.

Emacs has some IDE features with CEDET, but they are poor documented, confusing and not well abstract enough. I tried to use it, but it was clumsy and confusing.

So, don’t trust me. Take some time and start learning vim, emacs or any other serious editor that suits you best.

What I love about Ruby

I talk about Ruby all the time, even being proficient with other languages (such as C, Java and C# – but not C++). Why is that? Well, Ruby has a lot of incredible features that you may find on other languages, but generally are not on static languages:

1 – Code blocks and lambdas

I talked a little about them in a previous post. While a lot (really, a lot) of languages have support for anonymous functions and closures, the “big ones” don’t*. And the way that Ruby implements that is so elegant that most newbies don’t even know they are using a closure, or what would be that.

Actually, C++ (since C++11) and C# (we could use delegates since C# 1.0, but it evolved until C# 3.0) have anonymous functions, and C can do something similar using pointer to functions. Java, on the other hand, doesn’t have anything similar (but everybody is hoping it to implement that on Java 8). But the way Ruby handles that is just so elegant. For example, I can easily select all the non-null entries of a given Array @array with:

non_nil = @array.select { |x| x != nil }

2 – Metaprogramming

Check this:

class Numeric
  def method_missing(m)
    time_hash = { "seconds" => 1, "minutes" => 60, "hours" => 3600 }
    if(time_hash.has_key? m.to_s)
      return self * time_hash[m.to_s]
    else
      super
    end
  end
end

Now I can use the methods “seconds”, “minutes” and “hours” in any numeric object, and with a really DRY code!

These methods are created at run-time, whenever they are needed. Ruby can do that. And it can do more (Rails uses a lot of metaprogramming on ActiveRecord). It’s a really big subject, and I could spend a lot of time talking about that.

3 – Open classes

Have you seen what I’ve done in the previous code? I changed the behavior of the Numeric class. I can do that with any class, have I created it or not. Even built-in classes can have its behavior subscribed.

Now, a lot of people won’t like that, and they have some reasons. And while they can be right sometimes, it is much better to simply change the behavior of a built-in class than to always use a child class on the whole application.

4 – The object model

Everything in Ruby is an object. And when I say everything, that’s everything. Even classes are objects (of the class Class). That means you can create and manipulate almost everything inside of Ruby in runtime.

There are other reasons for why I love Ruby, but these are the main ones.