How to make Tagbar work with Objective-C

For the longest time, ctags did not support Objective-C. Without tags, many of the cool programming-related features of Vim simply didn't work. (There are ways to coax other programs to output tags, but this is usually painful)

Recently however, ctags finally gained support for Objective-C! Hurrah!
As of today, Objective-C support is not in the stable branch yet, but thanks to the magic of homebrew, an Obj-C ready ctags is only a brew install ctags --HEAD away!

With that, tag navigation in Vim works for Objective-C. Awesome!
However, Tagbar does not work yet. There used to be a workaround that apparently worked for some people, but it did not work for me.
Things like this drive me nuts. I can see that tags are being generated, but Tagbar won't show them. What is going wrong?

Some investigation proved: There is simply no template in Tagbar for Objective-C! Luckily, that can be fixed quite easily: Simply put this code in your .vimrc:


" add a definition for Objective-C to tagbar
let g:tagbar_type_objc = {
    \ 'ctagstype' : 'ObjectiveC',
    \ 'kinds'     : [
        \ 'i:interface',
        \ 'I:implementation',
        \ 'p:Protocol',
        \ 'm:Object_method',
        \ 'c:Class_method',
        \ 'v:Global_variable',
        \ 'F:Object field',
        \ 'f:function',
        \ 'p:property',
        \ 't:type_alias',
        \ 's:type_structure',
        \ 'e:enumeration',
        \ 'M:preprocessor_macro',
    \ ],
    \ 'sro'        : ' ',
    \ 'kind2scope' : {
        \ 'i' : 'interface',
        \ 'I' : 'implementation',
        \ 'p' : 'Protocol',
        \ 's' : 'type_structure',
        \ 'e' : 'enumeration'
    \ },
    \ 'scope2kind' : {
        \ 'interface'      : 'i',
        \ 'implementation' : 'I',
        \ 'Protocol'       : 'p',
        \ 'type_structure' : 's',
        \ 'enumeration'    : 'e'
    \ }
\ }


With that, Tagbar should work. Admittedly, it won't work perfectly yet. Class definitions will show up in addition to their contents and the contents of all categories will go into the same list. Also, you won't get much more than a flat list of functions with no way to distinguish between class methods and object methods. This can be confusing at times, but by and large, it does the job!


Happy Vimming!

Compiling Scipy and Matplotlib again

Well, it's compile time again. Once again, I need to install scipy and matplotlib using homebrew and pip on Lion.
It seems things have improved since I tried to compile last time! Well, it still does not work out of the box, but at least now it can be done without compiling by hand:
(remember to brew install pkg-config and gfortran first)
pip install -e git+https://github.com/scipy/scipy#egg=scipy-dev
pip install -e git+https://github.com/matplotlib/matplotlib#egg=matplotlib
I must say, this is still a mess. But at least, it is getting less bad.

Adobe AIR Application Crashes

Adobe, oh Adobe. Why?

Your updater pops open. Adobe AIR 2.5, if I remember correctly. It runs, and after that, all AIR applications stop working. They boot, then crash and barf up a crash report.

Turns out, this is a problem with case sensitive file systems. If your file system is not case sensitive, you are experiencing some other problem and this fix is not for you.

See, Adobe has this library called WebKit.dylib. However, their code actually looks for Webkit.dylib (note the capitalisation of the K). Well, spelling is hard, I presume.

At least this is an error that can easily be fixed. Fire up your terminal, type

cd /Library/Frameworks/Adobe\ AIR.framework/Version/Current/Resources/

sudo ln -s WebKit.dylib Webkit.dylib

Then enter your password and your AIR applications should work again.

Dear Adobe, is it too much to ask to pretty please make your software work on a case sensitive file system? Spelling is primary school stuff. It is really not that hard!

Compiling Scipy and Matplotlib using pip on Lion

So I upgraded to Lion. Predictably, some things went wrong. This time, the main thing that bit me was that for some reason, pip stopped working. After a bit of messing around with brew, pip and easy_install, I found out it was almost entirely my own fault. I messed up my PATH.

In the meantime, I had uninstalled all of brew's Python, so I had to reinstall. For me, that entails Python, Numpy, Scipy and Matplotlib. Only this time, Scipy would not build. Some obscure error in some veclib_cabi_c.c would report errors. A quick round of googling reveals:

In order to get Scipy to compile, you need to insert #include <complex.h> in

• ./scipy/lib/blas/fblaswrap_veclib_c.c.src
• ./scipy/linalg/src/fblaswrap_veclib_c.c
• ./scipy/sparse/linalg/eigen/arpack/ARPACK/FWRAPPERS/veclib_cabi_c.c

That done, Scipy compiles perfectly fine.

But, that is not enough yet. As this blogpost outlines, Matplotlib is not currently compatible with libpng 1.5, which ships with Lion. Fortunately, this is already fixed in the most recent source on the Matplotlib repo, so you just have to checkout that:

 pip install -e git+https://github.com/matplotlib/matplotlib.git#egg=matplotlib

By doing that, Matplotlib should install just fine.

Seriously though, these PyPi repos are in a very sorry state. Every time I install one of these packages, I have to jump through hoops and spend hours debugging packages that really should work right out of the box. After all, brew, rvm and gem can do it just fine. Why is pip such a horrible mess?

Installing Pygame using Homebrew

So I want to do audio development on the Mac without using Matlab. An alternative to Matlab is Python, or rather, Numpy, Scipy and Matplotlib. They are awesome for working with audio data. What they don't do however is playing back audio. There are several packages out there that would afford audio playback. If you are serious about this though, you not only want audio playback, you want asynchronous audio playback. That is, you want to send some audio data to the sound card and continue with your program without waiting for the audio to finish playing. This allows continuous audio playback of computer-generated sound.

Pygame is one package that allows this. (I will submit a patch to Pyaudio soon that will enable it there, too). There are pre-built binaries on the Pygame website that you can install easily. But then there would be no easy way to uninstall them, so what I would rather want is to install Pygame using package managers that allow easy updating and uninstallation. My tool of choice on the Mac is of course Homebrew.

Note that although I am mostly interested in audio playback, this post will detail the installation of all modules of Pygame, not just pygame.mixer.

Homebrew won't install Pygame, but it will install all the prerequisites for Pygame. So, let's do that.

brew install sdl, sdl_mixer, sdl_ttf, libpng, jpeg, sdl_image, portmidi

This will install most packages for you. Note that libpng is also available as a system library, so it is installed keg_only, that is, without linking it in your path. We will need to compile against it though, so the next step is

brew link libpng

Now there is still one package missing, smpeg. Sadly, smpeg does not install its headers, so you can't compile against it. To fix that, type

brew edit smpeg

and add the following line just above the two end at the end of the file

include.install Dir["*.h"]

Then save the file. (I submitted a bug to have this fixed, so you might not need to do this when you read this). Now you can install smpeg with the usual

brew install smpeg

and you will get the headers, too. Isn't Homebrew great?

Now that all the prerequisites are met, lets look at Pygame itself. This is rather more difficult, as it will not build properly against Homebrew libraries on its own. First, download the source package of Pygame from the official website. Unpack it to some directory.

Now open a terminal and navigate to that directory. Me, I like iTerm, but Terminal.app will do just fine, too. In there, run python config.py to create an initial setup file.

At this point, the setup file is mostly useless since config.py failed to find any homebrew-installed library. It is also strangely garbled, so there is some manual labor to do. Open the file Setup (no extension) in your favourite text editor. After the first comment block, you will see a line that looks like this

SDL = -I/NEED_INC_PATH_FIX -L/NEED_LIB_PATH_FIX -lSDL

Obviously, this is lacking the paths to the SDL library. If you installed Homebrew to its default directory, this will be in /usr/local…. Hence, change this line to

SDL = -I/usr/local/include/SDL -L/usr/local/lib -lSDL

The next lines are strangely garbled. They say, for example

FONT = -lS -lD -lL -l_ -lt -lt -lf

Where they actually should say

FONT = -lSDL_ttf

Instead of having one -l and then the library name SDL_ttf, they put -l in front of every single letter of the name. This is strange, and certainly wrong. So, correct it for FONT, IMAGE, MIXER and SMPEG.

Note that I did not tell you to do this for PORTTIME, too. Actually, PORTTIME is already correctly linked in PORTMIDI, so you don't need that at all any more. Just delete or comment the PORTTIME line.

Now that all the dependencies are corrected, lets enable the features. A few lines further down, there will be a block of lines, where most lines begin with a # except for the ones beginning with _numericsurfarray… and _camera…, These are the different features of Pygame: The ones with the # are disabled, the other two are enabled.

With all the stuff we installed earlier, you can now enable all features (remove the # in front of imageext…, font…, mixer…, mixer_music…, _minericsndarray…, movie…, scrap… and pypm…).

Remember we disabled PORTTIME a while ago? Right, so we have to remove that dependency: In the line starting with pypm…, delete the part that says $(PORTTIME). Great. That was easy, right? Now save that file and go back to the Terminal.

We are now going to compile and install Pygame. The nice thing is, even though we are installing it manually, it will go in the right directories and it will be registered with pip or easy_install, so you can just invoke them if you want to uninstall it later by typing pip uninstall pygame. This is something I love about Python!

Alright, now without further ado, install Pygame by typing

python setup.py install

Great! That's it! Everything should work now!

Installing Python/Numpy/Scipy/Matplotlib on OSX

For numerical analysis and signal processing prototyping, you would use Matlab. However, Matlab has some downsides that might make it unsuitable for your project. It might be too expensive. You might be a snobbish programmer that can't stand less-than-elegant programming languages. I certainly am.

So, you look for alternatives. You could take Octave, which is free, but that would not solve that ugly-code issue. You could take any scripting language you fancy, but Ruby, Perl and Python are too slow to do serious number crunching.

Then, you stumble upon that Python package called Numpy, which seems to be nearly as fast as Matlab when it comes to matrix processing and linear algebra. You then discover SciPy, which would add all that signal processing prowess of Matlab (do quick transformations, random numbers, statistics) to your toolbox. Last but not least, you need plotting. That would be Matplotlib then, which provides quick plotting facilities in Python.

And the best thing is, these three systems work really well together. They seem to be the perfect replacement for Matlab that could even be superiour to it in many regards.

Next up, you need to install all that stuff. If you are like me, you naturally want to do all that on a Mac. Also, you kind of dislike all these installer-thingies, which install stuff to unknown places and are nigh impossible to uninstall or update cleanly. Even though, you could of course just go to the individual websites, download Python, Numpy, SciPy and Matplotlib, run them installers, and be done. You would save yourself a lot of trouble that way.

But since you allegedly are like me, you instead fire up brew and try to install all that stuff using that. Again, you could use MacPorts or Fink instead, but you probably had some bad experiences with them and you generally love the hackishness of Homebrew, so this is your natural first try.

So you set about this, you believe in packet managers and trust them to take care of every obstacle that might be lying in your way. First of all, install the latest developer tools from developer.apple.com. You might need to register (for free) to get them. Also, you need to install Homebrew.

To cut this short, here is what you need to get that Python running:

brew install python

This one should be obvious. At the time of writing, it will install Python 2.7.1. You could take Python 3, but matplotlib is not compatible to it, so you kind of have to stick with 2.7.1 instead.

You also need to put /usr/local/bin and /usr/local/sbin in the beginning of your path to make sure the new Python gets loaded instead of the pre-installed one. You do that by writing

export PATH=/usr/local/bin:/usr/local/sbin:$PATH

in your ~/.bash_profile. (Create it if its not there--it is just a simple text file).

Now, if you type python --version, you should get Python 2.7.1 as a response.

Alright, next up, install the python package manager:

brew install distribute
brew install pip

This will come preconfigured for your newly installed Python. In an ideal world, this should be all. The world being as it is, the pip package of Matplotlib is severely broken and has one other unstated dependency:

brew install pkg-config

Also, SciPy is using some FORTRAN sources, so you need a fortran compiler:

brew install gfortran

Alright. That was enough. Now on to pip. With all these dependencies cleared, pip should be able to download Numpy and Scipy without trouble:

pip install numpy
pip install scipy

Matplotlib, on the other hand, is more difficult to install. You see, pip is looking at the Python package repository PyPi for each package. PyPi then provides a URL. Pip then scans that website for links to suitable package files. But, Sourceforge changed its links a while ago, so pip gets confused and will download an outdated version. Sourceforge says, its new links are way better and no way we will change them back; Pip says, well, if Sourceforge can't provide proper links, that's not our problem. Oh My. Silly children.

So we have to do this manually:

pip install -f http://sourceforge.net/projects/matplotlib/files/matplotlib/matplotlib-1.0.1/matplotlib-1.0.1.tar.gz matplotlib

That URL comes straight from Sourceforge. Look for the latest version of Matplotlib, search for the download link to the source distribution (*.tar.gz), copy that link and strip any trailing '/download'.

UPDATE:

It seems the matplotlib package was updated in the meantime, so you can just run pip install matplotlib now.

This should now download and install matplotlib.

Thank you for reading.

The strangeness of widescreen displays in modern operating systems

So today, pretty much everyone has widescreen displays. That is, displays that are far more wide than high. This was not always so. In ye olden days, computers were mainly used for displaying text, hence displays tended to have a similar layout as books or magazines. Today, they are more like movies (which might be worrying in itself).

So todays displays are widescreen. To do all that modern stuff, like watch (widesreened) videos or multitask (display two windows side by side). However, this also means that vertical pixels are something of a scarcity. Especially on those small Laptop screens. In fact, the first Netbook screens were so tiny that many of Windows' own windows could not be used at all since the lower parts did not fit on the screen. Raise your hand if Word 2007 leaves barely ten lines of visible text between all its blue-tinted UI-splendour on your laptop screen.

This gets most straining when reading text. On the internet for example. There is practically no website at all that can be displayed in its entirity even on one of those full HD displays. Print-formatted documents are a similar matter. Actually, I find myself craving for pixels regularly. I even disable the bookmark bar in my browser to free those extra two lines of text. And I memorize keyboard shortcuts so I can hide toolbars. And I use Google Chrome instead of Firefox/Safari/Internet Explorer, not least of all since it has the smallest title bar and no bottom bar.

Why, then, do modern operating systems still waste so much vertical space with that Dock/Taskbar? This is something I really don't get. Vertical space is such a scarcity, yet virtually every operating system choses to waste at least three lines of text with something that could easily go on the side of the display. Well, at least on Windows 7 and OSX that is something you can easily change.

So if you are like me and appreciate every added line of text, do yourself a favour and put your Dock/Taskbar on the side. Really, this should be the default.