Named Arguments in PHP

Question

In C#, there is a new feature coming with 4.0 called Named Arguments and get along well with Optional Parameters.

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Answer 1

You can get around that by having an array such as $array= array('arg1'=>'value1'); And then let the function accept the array such as function dostuff($stuff); Then, you can check arguments using if(isset($stuff['arg1')){//do something.} inside the function itself

It's just a work-around but maybe it could help

Answer 2

As you found out, named arguments don't exist in PHP.

But one possible solution would be to use one array as unique parameter -- as array items can be named :

my_function(array(
    'my_param' => 10, 
    'other_param' => 'hello, world!', 
));

And, in your function, you'd read data from that unique array parameter :

function my_function(array $params) {

    // test if $params['my_param'] is set ; and use it if it is
    // test if $params['other_param'] is set ; and use it if it is
    // test if $params['yet_another_param'] is set ; and use it if it is
    // ...

}

Still, there is one major inconvenient with this idea : looking at your function's definition, people will have no idea what parameters it expects / they can pass.

They will have to go read the documentation each time they want to call your function -- which is not something one loves to do, is it ?

Additionnal note : IDEs won't be able to provide hints either ; and phpdoc will be broken too...

Answer 3

You can fake C++-style optional arguments (i.e. all optional arguments are at the end) by checking for set variables:

function foo($a, $b)
{
  $x = isset($a) ? $a : 3;
  $y = isset($b) ? $b : 4;
  print("X = $x, Y = $y\n");
}

@foo(8);
@foo();

It'll trigger a warning, which I'm suppressing with @. Not the most elegant solution, but syntactically close to what you wanted.

---

Edit. That was a silly idea. Use variadic arguments instead:

// faking foo($x = 3, $y = 3)
function foo()
{
  $args = func_get_args();
  $x = isset($args[0]) ? $args[0] : 3;
  $y = isset($args[1]) ? $args[1] : 3;
  print("X = $x, Y = $y\n");
}

foo(12,14);
foo(8);
foo();