referencing_functions.md

Referencing functions

General idea

Not being able to reference functions by name directly, and instead have to use strings e.g.

$fn = 'strlen';
var_dump($fn('test')); 

// int(4)

is bad is not good, as typos can occur, and are hard for either humans or static analyzers to pickup on.

$fn = 'stlren';
$fn('test');
//  Call to undefined function stlren()

What's needed is some way to refer to a function that is unambiguously intended to be a reference to a function, or method of a class.

A new piece of syntax could allow this:

$fn = $(strlen);
var_dump($fn('test')); 

or maybe refactor how

Hurdles to overcome

Explain the problem more clearly

Currently if you try to use a raw string, it is assumed to be a define:

$fn = strlen;
$fn('test');

We can't we change that to do the right thing?

Figure out all of the requirements

Someone needs to figure out what the correct behaviour is around:

• non-existent functions. Does autoloading occur?
• referencing class methods e.g. and can you reference private methods?

Forecast

PHP 8.2

Implemented!

First-class callable syntax implemented in PHP 8.1.

Notes