What is the purpose of Array and String Dereferencing implemented in PHP 5.5?

Question

In the PHP manual, we can see New Features the functionality of Array and String literal Dereferencing.

Example:

echo 'string'[2]; // r
echo ['stack', 'overflow'][1]; //overflow

Thinking in case you get one index of a string or array, would already work in other versions of PHP, as long as the Array or string is in a variable.

$var = 'string';
echo $var[2]; // 'r'

In PHP 5.4, I know we now have direct access to members of a array which are returned by a function, and which is very useful by the way (Function array Dereferencing).

But in the case of PHP 5.5, I don’t understand what the purpose of getting a value, through an index, directly from a string or a array, since these are not assigned to a variable?

For me, it would make no sense for the programmer to make use of the first example above.

Is there a more robust purpose than the first example?

Answer 1

The example of documentation is unfortunate (what a novelty, right?). In the way it was placed, where everything is constant, there is no advantage at all. The documentation should help understand the purpose of this, but they preferred a bureaucratic approach.

Using

echo ['stack', 'overflow'][$x];

is "better" (or at least the code is simplified) than doing

switch ($x) {
    case 0: 
        echo 'stack';
        break;
    case 1:
        echo 'overflow';
        break;
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

So it’s used primarily for code simplification. Imagine if you have 10, 20, 30 elements in this array, like the switch would be long.

And in a way to maintain a pattern. If other operations can be done directly with literals, why not this one? Operations should be done over values and not over variables. If by chance a value comes from a variable, from a return of a function, an expression or a literal should not make a difference. If this had been conceptualized correctly when the language was created, there would have been this form since version 1.0. Only PHP even to make this mess.