New Features in PHP 7

https://blog.feryn.eu/php-7-is-now-available-new-features-improvements/

1) Speed

2) Type Declarations:
Since PHP 5, you can use type hinting to specify the expected data type of an argument in a function declaration, but only in the declaration.  Besides only being used in function declarations, we were also limited to basically 2 types. A class name or an array.  When you call the function, PHP will check whether or not the arguments are of the specified type. With PHP 7 we now have added Scalar types. Specifically: int, float, string, and bool.

function stringTest(string $string) {
    echo $string;
 }

Additionally, PHP 7 gives us the opportunity to enable strict mode on a file by file basis. We do this by declare(strict_types=1); at the top of any given file.

PHP 7 also supports Return Type Declarations which support all the same types as arguments. To specify the return type, we add a colon and then the type right before the opening curly bracket.

function getTotal(float $a, float $b) : float {

3) Error Handling :
In PHP 7, an exception will be thrown when a fatal and recoverable error occurs, rather than just stopping the script. Fatal errors still exist for certain conditions, such as running out of memory, and still behave as before by immediately stopping the script. An uncaught exception will also continue to be a fatal error in PHP 7. This means if an exception thrown from an error that was fatal in PHP 5 goes uncaught, it will still be a fatal error in PHP 7.

A big change in PHP 7 is the fact that errors are no longer raised the way they used to be raised. Errors now behave in a similar way as exceptions. This means that errors can now be caught in a try/catch block. You can catch both exceptions and errors as Throwables, but you can also catch errors as Error objects. We point out that other types of errors such as warnings and notices remain unchanged in PHP 7. Only fatal and recoverable errors throw exceptions.

interface Throwable
    |- Exception implements Throwable
        |- ...
    |- Error implements Throwable
        |- TypeError extends Error
        |- ParseError extends Error
        |- ArithmeticError extends Error
            |- DivisionByZeroError extends ArithmeticError
        |- AssertionError extends Error

Throwable may be used in try/catch blocks to catch both Exception and Error objects (or any possible future exception types). Remember that it is better practice to catch more specific exception classes and handle each accordingly. However, some situations warrant catching any exception (such as for logging or framework error handling). In PHP 7, these catch-all blocks should catch Throwable instead of Exception.

4) New Operators (Spaceship Operator, Null Coalesce Operator) :

Spaceship Operator (useful in sort algorithms, etc)

$compare = 2 <=> 1
2 < 1? return -1 2 = 1? return 0 2 > 1? return 1

the Null Coalesce Operator, is effectively the fabled if-set-or.
If $firstName is empty then set it to Guest.

$name = $firstName ??  "Guest";

Can be chained.

$name = $firstName ?? $username ?? $placeholder ?? “Guest”; 

5) Anonymous Classes :

Anonymous classes are useful when simple, one-off objects need to be created.

$util->setLogger(new class {
    public function log($msg)
    {
        echo $msg;
    }
});

http://blog.teamtreehouse.com/5-new-features-php-7

6) Closure:Call() Method:

Closures are anonymous functions that are declared inline and assigned to a variable. It can be used as a callback for later execution. In PHP 5 it was already possible to bind an object to the scope of the closure as if it was a method.

The “call” method is one of the PHP 7 features that was introduced to simplify the process.