Strong data typing bug

Question

Is it normal to get the error "Default value for parameters with a class type hint can only be NULL" for a method in an interface defined as

public function nullify(bool $force=FALSE);

?

I need it to be bool, not an object, and FALSE by default.

Answer 1

There is no type hinting for boolean parameters in php (yet). You can only specify a class name or array. Therefore function foo(bool $b) means: "the parameter $b must be an instance of the class 'bool' or null".

http://docs.php.net/language.oop5.typehinting:

Functions are now able to force parameters to be objects (by specifying the name of the class in the function prototype) or arrays (since PHP 5.1).

Answer 2

As already stated, type hinting only works for arrays and object. Your function can be written like this:

public function nullify($force=FALSE){
  $force=(bool)$force;
  //further stuff
}

Answer 3

PHP 5 type hinting is limited to a specific class (or one of its subclasses), or an array. You cannot specify any other scalar types.

Answer 4

You can't force a parameter to be a boolean.

As found in language.oop5.typehinting :

PHP 5 introduces type hinting. Functions are now able to force parameters to be objects [...], interfaces, arrays (since PHP 5.1) or callable (since PHP 5.4).

[...]

Type hints can not be used with scalar types such as int or string. [...]

And as found in language.types.intro, PHP scalar types are :

- boolean
- integer
- float (floating-point number, aka double)
- string

Answer 5

You could try:

public function nullify($force){
  if(is_object($force)) $force = false;
  ...
}

Consider it as a temporary solution until you upgrade PHP.