PHP Language Constructs
PHP has many built-in language constructs and functions. Language constructs can be used with or without parentheses while functions always have parentheses. Here is an example using a language construct. With brackets: require_once('filename.php') Without Brackets: require_once 'filename.php'
Here is a list of several PHP constructs which will be used quite frequently in even the simplest PHP / mySQL applications.
Printing strings and variables
Unsetting a session variable
Check is a variable is set
Check if post variable is empty
Check if post variable is not empty
End the php script
die() or die