Coding standards provide a consistent framework for development within a project and across projects in an organization. A dozen programmers can complete a simple project in a dozen different ways by using unique coding methodologies and styles, so I like to think of coding standards as the “rules of the road” for developers.
When you’re driving in a car, traffic is controlled by “standards” such as lanes, stoplights, yield signs and laws that set expectations around how you should drive. When you take a road trip to a different state, the stoplights might be hung horizontally instead of vertically or you’ll see subtle variations in signage, but because you’re familiar with the rules of the road, you’re comfortable with the mechanics of driving in this new place. Coding standards help control development traffic and provide the consistency programmers need to work comfortably with a team across projects. The problem with allowing developers to apply their own unique coding styles to a project is the same as allowing drivers to drive as they wish … Confusion about lane usage, safe passage through intersections and speed would result in collisions and bottlenecks.
Coding standards often seem restrictive or laborious when a development team starts considering their adoption, but they don’t have to be … They can be implemented methodically to improve the team’s efficiency and consistency over time, and they can be as simple as establishing that all instantiations of an object must be referenced with a variable name that begins with a capital letter:
$User = new User();
While that example may seem overly simplistic, it actually makes life a lot easier for all of the developers on a given project. Regardless of who created that variable, every other developer can see the difference between a variable that holds data and one that are instantiates an object. Think about the shapes of signs you encounter while driving … You know what a stop sign looks like without reading the word “STOP” on it, so when you see a red octagon (in the United States, at least), you know what to do when you approach it in your car. Seeing a capitalized variable name would tell us about its function.
The example I gave of capitalizing instantiated objects is just an example. When it comes to coding standards, the most effective rules your team can incorporate are the ones that make the most sense to you. While there are a few best practices in terms of formatting and commenting in code, the most important characteristics of coding standards for a given team is consistency and clarity.
So how do you go about creating a coding standard? Most developers dislike doing unnecessary work, so the easiest way to create a coding standard is to use an already-existing one. Take a look at any libraries or frameworks you are using in your current project. Do they use any coding standards? Are those coding standards something you can live with or use as a starting point? You are free to make any changes to it you wish in order to best facilitate your team’s needs, and you can even set how strict specific coding standards must be adhered to. Take for example left-hand comparisons:
if ( $a == 12 ) { … } // right-hand comparison if ( 12 == $a ) { … } // left-hand comparison
Both of these statements are valid but one may be preferred over the other. Consider the following statements:
if ( $a = 12 ) { … } // supposed to be a right-hand comparison but is now an assignment if ( 12 = $a ) { … } // supposed to be a left-hand comparison but is now an assignment
The first statement will now evaluate to true due to $a being assigned the value of 12 which will then cause the code within the if-statement to execute (which is not the desired result). The second statement will cause an error, therefore making it obvious a mistake in the code has occurred. Because our team couldn’t come to a consensus, we decided to allow both of these standards … Either of these two formats are acceptable and they’ll both pass code review, but they are the only two acceptable variants. Code that deviates from those two formats would fail code review and would not be allowed in the code base.
Coding standards play an important role in efficient development of a project when you have several programmers working on the same code. By adopting coding standards and following them, you’ll avoid a free-for-all in your code base, and you’ll be able to look at every line of code and know more about what that line is telling you than what the literal code is telling you … just like seeing a red octagon posted on the side of the road at an intersection.
-Jeremy
