PHP: Commenting standards

问题:

I need to comment massive amounts of information in only a handful of files, and when I look around Google and here at SO, I continue to find results matching coding standards, when I need commenting standards. My coding matches most coding standards except not when it comes to commenting.

Could someone please provide examples for the following?

<?

    // beginning of file comments

    require( 'filename.php' ); // require or include, with filename

    public class Test { } // class without constructor

    public class Test // class with constructor, if different from above
    {
        public function __constructor() { } // constructor, no parameters

        public function __constructor(var1, var2) { } constructor, with parameters

        public function func1() { } // function, no parameters

        public function func2($var1, $var2) { } // function, with parameters

        public function func3( $optional = '' ) { } // function, optional parameters

        private function func4() { } // private function, if different from above

        public static staticfunc1() { } // public static function, if different from above

        public function returnfunc1(var1, var2) // function, with return value
        {
            return var1 + var2; // return statement, dynamic
        }

        public function returnfunc2() // function, with unchanging return value, if different from above
        {
            return 1; // return statement, unchanging, if different from above
        }

        public function fullfunc1() // declaration, calling and assignment, in function
        {
            $var1; // variable declaration

            $arr1 = array(); // array declaration, if different from above

            $var2 = dirname( __FILE__ ) . '/file.ext'; // variable assignment

            $this->var1 = $path . '_'; // class variable assignment

            ob_start(); // function call

            $this->func1(); // class function call

            ob_end_clean();

            foreach($arr as $key => $val) { } // foreach and for loops
        }

        public $var1; // public variable

        private $var2; // private variable, if different from above
    }

    // ending of file comments?

?>

Knowing proper style is important. It helps other individuals understand how your code works, and how to use it in the future if you are not there to explain it.

回答1:

In general, PHP seems to have a lot of different style guides...

1. phpDocumentor style
2. Zend Framework style
3. Pear style

But in general, something to remember about commenting is... you probably don't want to comment every line in your code. Instead, try to make your code readable¹ (as is.) And comment (mostly,) when you really need someone else to understand what your code is doing.

¹ http://www.codinghorror.com/blog/2008/07/coding-without-comments.html

回答2:

Taken from http://www.kevinwilliampang.com/2008/08/28/top-10-things-that-annoy-programmers/

Comments that explain the “how” but not the “why”

Introductory-level programming courses teach students to comment early and comment often. The idea is that it’s better to have too many comments than to have too few. Unfortunately, many programmers seem to take this as a personal challenge to comment every single line of code. This is why you will often see something like this code snippit taken from Jeff Atwood’s post on Coding Without Comments:

r = n / 2; // Set r to n divided by 2
// Loop while r - (n/r) is greater than t
while ( abs( r - (n/r) ) > t ) {
    r = 0.5 * ( r + (n/r) ); // Set r to half of r + (n/r)
}

Do you have any idea what this code does? Me neither. The problem is that while there are plenty of comments describing what the code is doing, there are none describing why it’s doing it.

Now, consider the same code with a different commenting methodology:

// square root of n with Newton-Raphson approximation
r = n / 2;
while ( abs( r - (n/r) ) > t ) {
    r = 0.5 * ( r + (n/r) );
}

Much better! We still might not understand exactly what’s going on here, but at least we have a starting point.

Comments are supposed to help the reader understand the code, not the syntax. It’s a fair assumption that the reader has a basic understanding of how a for loop works; there’s no need to add comments such as “// iterate over a list of customers”. What the reader is not going to be familiar with is why your code works and why you chose to write it the way you did.

also... phpdoc

回答3:

PHP Commenting is more freestyle than you may think. However, the reason why really specific comment standards becomes important is because of how they interact with particular IDE's for speeding up development. In that case, you'd be able to look up how an IDE wants you to comment.

Whats important is usually marking what a functions @param's are and what it @return's

You can see some good information about proper commenting in this stack overflow question and answer: What is the proper PHP function documentation format?