Shawn McKenzie wrote:
> Michael A. Peters wrote:
>> Rene Veerman wrote:
>>> On Sat, Feb 13, 2010 at 9:05 AM, Michael A. Peters <>
>>> wrote:
>>>> How do I specify a default null object, or otherwise make the argument
>>>> argument optional?
>>> To my knowledge: can't be done.
>>> But you can check any args through the func_get_arg*() functions, then
>>> per-parameter push 'm through a check function that checks if their
>>> primary properties are set.
>>> It's equivalent to checking for null ( / bad) objects.
>> Thank you to everybody. I think I will see how far I can get with
>> func_get_arg - it may solve the problem.
>> The other hackish solution I thought of is to put the object arguments
>> into a key/value array and pass the array as a single argument to the
>> function. That way I can check for the key and if the key is set, grab
>> the object associated with it.
> Maybe I mis-read your post, but what's wrong with Jochem's method.
> That's what I was going to propose.

This is a problem with php; you can't do the following (since object
isn't a class):
  function test( object $o = null )

so normally you'd do:
  function test( stdClass $o = null )

but this only works for stdClass - (object)"something" and *not*
instances of classes:

  class Foo {}
  $o = new Foo();
  test( $foo );

will fail because Foo is not an instance of stdClass

in short there is no way (in PHP) to type hint that something should be
an object of any class.

thus you have two options to work around this; option 1:

check yourself:
  function test( $o = null ) {
    if( $o !== null && !is_object($o) ) {
       throw new InvalidArgumentException( '$o must be an object' );

ensure you always only use instances of classes and not just
"objects/stdClass" (or make everything extend stdClass <stupid>)

back to the main question - How do I specify a default null object -
like this:

function foo($a='',$b='',$c=false, $o=null) {
  if( $o !== null && !is_object($o) ) {
    throw new InvalidArgumentException( '$o must be an object' );
  // in the same way a you'd do
  if( !is_string($a) ) {
    throw new InvalidArgumentException( '$a must be a string' );

side note: if you're finding you may need an unknown number of arguments
then other than refactoring all your design to handle one argument at a
time to avoid cross cutting concerns, then you're stuck with
func_get_arg and checking each argument as you go; not strict but if it
works and it's fast..

feel like I've just typed "blah blah blah" for the last 10 minutes, ahh
well ho hum!

regards :)

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