Things Every Programmer Should Know: #4, #5, #6

Here are the 97 Things Every Programmer Should Know project, pearls of wisdom for programmers collected from leading practitioners, published by O'Reilly (license link).

You can go to read the previous very interesting points #1, #2, #3.

4. Automate Your Coding Standard by Filip van Laenen

You've probably been there too. At the beginning of a project, everybody has lots of good intentions — call them "new project's resolutions." Quite often, many of these resolutions are written down in documents. The ones about code end up in the project's coding standard. During the kick-off meeting, the lead developer goes through the document and, in the best case, everybody agrees that they will try to follow them. Once the project gets underway, though, these good intentions are abandoned, one at a time. When the project is finally delivered the code looks like a mess, and nobody seems to know how it came to be this way.
When did things go wrong? Probably already at the kick-off meeting. Some of the project members didn't pay attention. Others didn't understand the point. Worse, some disagreed and were already planning their coding standard rebellion. Finally, some got the point and agreed but, when the pressure in the project got too high, they had to let something go. Well-formatted code doesn't earn you points with a customer that wants more functionality. Furthermore, following a coding standard can be quite a boring task if it isn't automated. Just try to indent a messy class by hand to find out for yourself.
But if it's such a problem, why is that we want to have a coding standard in the first place? One reason to format the code in a uniform way is so that nobody can "own" a piece of code just by formatting it in his or her private way. We may want to prevent developers using certain anti-patterns, in order to avoid some common bugs. In all, a coding standard should make it easier to work in the project, and maintain development speed from the beginning to the end. It follows then that everybody should agree on the coding standard too — it does not help if one developer uses three spaces to indent code, and another one four.
There exists a wealth of tools that can be used to produce code quality reports and to document and maintain the coding standard, but that isn't the whole solution. It should be automated and enforced where possible. Here are a few examples:
  • Make sure code formatting is part of the build process, so that everybody runs it automatically every time they compile the code.
  • Use static code analysis tools to scan the code for unwanted anti-patterns. If any are found, break the build.
  • Learn to configure those tools so that you can scan for your own, project-specific anti-patterns.
  • Do not only measure test coverage, but automatically check the results too. Again, break the build if test coverage is too low.
Try to do this for everything that you consider important. You won't be able to automate everything you really care about. As for the things that you can't automatically flag or fix, consider them to be a set of guidelines supplementary to the coding standard that is automated, but accept that you and your colleagues may not follow them as diligently.
Finally, the coding standard should be dynamic rather than static. As the project evolves, the needs of the project change, and what may have seemed smart in the beginning, isn't necessarily smart a few months later.

5. Beauty Is in Simplicity by Jørn Ølmheim

There is one quote that I think is particularly good for all software developers to know and keep close to their hearts:
Beauty of style and harmony and grace and good rhythm depends on simplicity. — Plato
In one sentence I think this sums up the values that we as software developers should aspire to.
There are a number of things we strive for in our code:
  • Readability
  • Maintainability
  • Speed of development
  • The elusive quality of beauty
Plato is telling us that the enabling factor for all of these qualities is simplicity.
What is beautiful code? This is potentially a very subjective question. Perception of beauty depends heavily on individual background, just as much of our perception of anything depends on our background. People educated in the arts have a different perception of (or at least approach to) beauty than people educated in the sciences. Arts majors tend to approach beauty in software by comparing software to works of art, while science majors tend to talk about symmetry and the golden ratio, trying to reduce things to formulae. In my experience, simplicity is the foundation of most of the arguments from both sides.
Think about source code that you have studied. If you haven't spent time studying other people's code, stop reading this right now and find some open source code to study. Seriously! I mean it! Go search the web for some code in your language of choice, written by some well-known, acknowledged expert.
You're back? Good. Where were we? Ah yes... I have found that code that resonates with me and that I consider beautiful has a number of properties in common. Chief among these is simplicity. I find that no matter how complex the total application or system is, the individual parts have to be kept simple. Simple objects with a single responsibility containing similarly simple, focused methods with descriptive names. Some people think the idea of having short methods of five to ten lines of code is extreme, and some languages make it very hard to do this, but I think that such brevity is a desirable goal nonetheless.
The bottom line is that beautiful code is simple code. Each individual part is kept simple with simple responsibilities and simple relationships with the other parts of the system. This is the way we can keep our systems maintainable over time, with clean, simple, testable code, keeping the speed of development high throughout the lifetime of the system.
Beauty is born of and found in simplicity.

6. Before You Refactor by Rajith Attapattu

At some point every programmer will need to refactor existing code. But before you do so please think about the following, as this could save you and others a great deal of time (and pain):
  • The best approach for restructuring starts by taking stock of the existing codebase and the tests written against that code. This will help you understand the strengths and weaknesses of the code as it currently stands, so you can ensure that you retain the strong points while avoiding the mistakes. We all think we can do better than the existing system... until we end up with something no better — or even worse — than the previous incarnation because we failed to learn from the existing system's mistakes.
  • Avoid the temptation to rewrite everything. It is best to reuse as much code as possible. No matter how ugly the code is, it has already been tested, reviewed, etc. Throwing away the old code — especially if it was in production — means that you are throwing away months (or years) of tested, battle-hardened code that may have had certain workarounds and bug fixes you aren't aware of. If you don't take this into account, the new code you write may end up showing the same mysterious bugs that were fixed in the old code. This will waste a lot of time, effort, and knowledge gained over the years.
  • Many incremental changes are better than one massive change. Incremental changes allows you to gauge the impact on the system more easily through feedback, such as from tests. It is no fun to see a hundred test failures after you make a change. This can lead to frustration and pressure that can in turn result in bad decisions. A couple of test failures is easy to deal with and provides a more manageable approach.
  • After each iteration, it is important to ensure that the existing tests pass. Add new tests if the existing tests are not sufficient to cover the changes you made. Do not throw away the tests from the old code without due consideration. On the surface some of these tests may not appear to be applicable to your new design, but it would be well worth the effort to dig deep down into the reasons why this particular test was added.
  • Personal preferences and ego shouldn't get in the way. If something isn't broken, why fix it? That the style or the structure of the code does not meet your personal preference is not a valid reason for restructuring. Thinking you could do a better job than the previous programmer is not a valid reason either.
  • New technology is insufficient reason to refactor. One of the worst reasons to refactor is because the current code is way behind all the cool technology we have today, and we believe that a new language or framework can do things a lot more elegantly. Unless a cost–benefit analysis shows that a new language or framework will result in significant improvements in functionality, maintainability, or productivity, it is best to leave it as it is.
  • Remember that humans make mistakes. Restructuring will not always guarantee that the new code will be better — or even as good as — the previous attempt. I have seen and been a part of several failed restructuring attempts. It wasn't pretty, but it was human.

The 'episodes' #7, #8, #9 come in the next posting :)


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