Merge pull request #112 from WordPress/increment-decrement-operators

Increment decrement operators

wordpress-coding-standards/php.md

@@ -227,6 +227,17 @@ if ( $foo && ( $bar || $baz ) ) { ...
 my_function( ( $x - 1 ) * 5, $y );
 ```
 
+When using increment (`++`) or decrement (`--`) operators, there should be no spaces between the operator and the variable it applies to.
+
+```php
+// Correct.
+for ( $i = 0; $i < 10; $i++ ) { [...] }
+
+// Incorrect.
+for ( $i = 0; $i < 10; $i ++ ) { [...] }
+++   $b; // Multiple spaces.
+```
+
 ### Indentation
 
 Your indentation should always reflect logical structure. Use **real tabs**, **not spaces**, as this allows the most flexibility across clients.
@@ -602,6 +613,21 @@ While this operator does exist in Core, it is often used lazily instead of doing
 
 > Warning: Prior to PHP 8.0.0, it was possible for the @ operator to disable critical errors that will terminate script execution. For example, prepending @ to a call of a function that did not exist, by being unavailable or mistyped, would cause the script to terminate with no indication as to why.
 
+### Increment/decrement operators
+
+Pre-increment/decrement should be favoured over post-increment/decrement for stand-alone statements.
+
+Pre-increment/decrement will increment/decrement and then return, while post-increment/decrement will return and then increment/decrement.
+Using the "pre" version is slightly more performant and can prevent future bugs when code gets moved around.
+
+```php
+// Correct: Pre-decrement.
+--$a;
+
+// Incorrect: Post-decrement.
+$a--;
+```
+
 ## Database
 
 ### Database Queries