Pagger

This should not be an article about Pagger, but once mentioned, I'd like to give a short overview on what it does: Pagger runs on the shell and receives a config file and a directory with MP3s as parameters. The config file determines the genres you want to be used, mappings between tags and genres, ignore patterns for tags and some more configuration.

The no-brace approach

In contrast to many other languages, Python does not use braces of any kind for syntactical code structure. Don't be too shocked, when comparing the following two code pieces, that perform equivalent operations in PHP and Python:

In Python one could achieve the same thing like this:

I know that there are more elegant ways to achieve this in both languages, but examples should be simple and stupid.

Cons

I'll start with the cons of such an approach: First, Python code looks simply ugly for programmers that are used to common languages like PHP, Java, C and many others. Braces are the most common approach for structuring source code at all. Therefore, many many coders out there are highly used to that way and are pretty irritated by Python code missing them. It takes quite a while to get used to it, which keeps you from efficient coding at first.

Second, problems occur easily here, when inconsistent indentation is used. Python only looks for the indentation in number of space characters. This might be blanks, but also tabs (and maybe other space chars?). You need to stick carefully to your style of indentation, otherwise your code will break, not only the optical appearance. However, this can also be considered a pro in terms of coding style, as you will see in the next section. And a sensible editor will fix the issues for you automatically.

Braces produce many blank lines in your code. While this might sound senseless at a first glance, this allows you to visually detect mating structures more easily. Python code looks generally more compact, if you do not introduce blank lines by intention. Having to use braces forces a developer to do so, which helps the readability of code.

Pros

No matter in which language you program, sticking to a common coding style throughout a project or maybe even a whole community provides only advantages. Digging into code which looks like it could be your own (from an optical perspective) makes you feel comfortable and therefore eases the process of analyzing the code. Enforcing a common coding style is therefore a goal in many programming communities. Python simply ensures that every code piece at least appears highly similar to every Python programmer.

Typing braces over and over again is cumbersome. Although most developers won't even notice any more, every brace costs a little bit of time. In addition, some keyboard layouts make typing braces hard: For example on a German keyboard, you need to type <Alt-Gr> + <7> to achieve a {. Removing the need to type braces therefore reduces time and non-productive effort while coding. Although both affect you only a very little.

Conclusion

Code without braces looks and feels strange to many programmers, but having the compiler enforce a certain coding style is cool. However, beside the fact that it won't happen, I also would not want PHP to loose its braces. What I would like to see is a common coding standard which can be enforced by PHP using an INI setting.

Naturally, this would be the coding standard I am using, just for clarity. ;)

I will continue this series whenever I find some time to blog and no hot topic is in the pipe. This won't happen before March 1st, since I'm on vacation for a week now. Read you in a bit! :)

Comments

You can skip braces in PHP example too, because blocks consist only of one command. So this is not very good example (-;

Braces save you, if a file is kind of broken. If python file is broken you have no chance to see where indentation goes wrong (very bad)

May be you'll write also about module organization. In php you have usually one (may be more) classes per file. But in python you have variables, constants, functions in one file! That is really cumbersome. You have often a python class and inside of class some other definitions (property) or whatever. IMO very chaotic. They should be at least sort functions and classes in module...

@php6

Python has had module support since forever. PHP just started using namespaces. See the Python documentation or Google for a tutorial if you don't believe me ;)

And: of course you have fields, functions etc. inside your PHP classes as well. That's how you do OOP!

When I first looked into Python, I really welcomed the no braces approach - I think it makes code much more easily readable. And given the legacy codebases I've been subjected to recently, it would be a true blessing if PHP scripts would simply break if someone got the indentation wrong (shudder).

Also, I find when reading books on software development, I can read the Python examples more easily, because it is much clearer which code belongs to which block even when the example spans over more than one page.

Regarding detecting mating structures more easily when using braces, I have to disagree as well... when I was wearing braces as a teenager, I feld that this highly impaired my ability to take part in any kind of mating structures, since braces are mostly not considered very attractive. Imagine how mysterious and interesting I would've been if I actually had a Python instead.... uhm, am I still on-topic here? ;-)

@trond

You've misunderstood me. In PHP you just use classes. In python you don't know if you should/could classes or function inside module. What I mean, that after php it looks like cumbersome, because it is mix of functions and classes in module. In well written php you never see such organization of files. There is strict separation between functions and classes. Usually, you have some script.php which instantiate classes, but you never see functions definitions inside of some Foo.class.php

module.py