PHP/interface - Revision history

Woozle: /* Links */

2024-08-25T13:45:01Z

Links

← Older revision		Revision as of 13:45, 25 August 2024
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	** [https://www.php.net/manual/en/function.interface-exists.php official]		** [https://www.php.net/manual/en/function.interface-exists.php official]
	==Links==		==Links==
	* ~~official:~~ [https://www.php.net/manual/en/language.oop5.interfaces.php interfaces]		===official===
			* [https://www.php.net/manual/en/language.oop5.interfaces.php interfaces]
			** There are some omissions on this page:
			*** "To implement an interface, the {{l/php/keyword\|implements}} operator is used. All methods in the interface must be implemented within a class; failure to do so will result in a fatal error." This is not true if the class is declared {{l/php/keyword\|abstract}}. In this context, an interface can be thought of as equivalent to a class whose methods are all abstract (and public).
			*** There is no mention of whether interfaces can declare member variables. (I ''think'' they cannot, but I haven't tested this yet.)
			**** Note that they ''can'' declare (class) constants.
			===other===
	* '''2018-01-13''' [https://daylerees.com/php-interfaces-explained/ PHP Interfaces Explained]		* '''2018-01-13''' [https://daylerees.com/php-interfaces-explained/ PHP Interfaces Explained]

	==Notes==		==Notes==
	I thought I had derived this rule, but then when I went to test it ''without'' the backslash again, it was working fine:		I thought I had derived this rule, but then when I went to test it ''without'' the backslash again, it was working fine:

Woozle: /* About */

2024-05-19T12:36:54Z

About

← Older revision		Revision as of 12:36, 19 May 2024
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	In [[PHP]], an '''interface''' is a set of public method-functions which can be required in either of two circumstances:		In [[PHP]], an '''interface''' is a set of public method-functions which can be required in either of two circumstances:
	* "'''implements'''" in the declaration of a class		* "'''implements'''" in the declaration of a class
	** This works almost identically to (~~instead~~) declaring the interface's functions as abstract functions in a trait or parent class.		** This works almost identically to (the alternative of) declaring the interface's functions as abstract functions in a trait or parent class.
	* '''as a type''' for a function argument or return value		* '''as a type''' for a function argument or return value
	** Advantages over using a class as a type:		** Advantages over using a class as a type:

Woozle: /* About */

2024-05-19T12:35:17Z

About

← Older revision		Revision as of 12:35, 19 May 2024
Line 1:		Line 1:
	==About==		==About==
	In [[PHP]], an '''interface''' is a set of public method-functions which can be required in either of two circumstances:		In [[PHP]], an '''interface''' is a set of public method-functions which can be required in either of two circumstances:
	* in the declaration of a class		* "'''implements'''" in the declaration of a class
	** This works almost identically to declaring the interface's ~~methods~~ as abstract functions in a trait or parent class.		** This works almost identically to (instead) declaring the interface's functions as abstract functions in a trait or parent class.
	* ~~the~~ type of a function argument or return value		* '''as a type''' for a function argument or return value
	** Advantages over ~~declaring the object~~ as a ~~class~~:		** Advantages over using a class as a type:
	*** narrows down (more closely specifies) the function's expectations of a passed or returned object		*** narrows down (more closely specifies) the function's expectations of a passed or returned object
	*** does not tie the object to a specific class hierarchy		*** does not tie the object to a specific class/implementation hierarchy

			This last point is one of the primary ways in which interfaces are useful: you may have a set of otherwise-unrelated classes with a set of descendants who need to do a set of things that were not part of their parent classes, and other parts of the code need to be able to recognize them as having this functionality. Having those descendants implement a common interface allows other code to require passed arguments to implement that interface, regardless of class-parentage.

	==Predefined==		==Predefined==
	* {{l/sub\|instanceof}} works with both classes and interfaces		* {{l/sub\|instanceof}} works with both classes and interfaces

Woozle at 01:27, 13 January 2020

2020-01-13T01:27:34Z

← Older revision		Revision as of 01:27, 13 January 2020
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	* official: [https://www.php.net/manual/en/language.oop5.interfaces.php interfaces]		* official: [https://www.php.net/manual/en/language.oop5.interfaces.php interfaces]
	* '''2018-01-13''' [https://daylerees.com/php-interfaces-explained/ PHP Interfaces Explained]		* '''2018-01-13''' [https://daylerees.com/php-interfaces-explained/ PHP Interfaces Explained]
			==Notes==
			I thought I had derived this rule, but then when I went to test it ''without'' the backslash again, it was working fine:
			<blockquote>
			If an interface is declared within a namespace but used outside of that namespace in am "implements" clause, the full namespace path must be prefixed with a backslash or it won't match:
			<source lang=php>class fcrUserAcct_admin extends fcrUserAcct implements fiLinkableRecord, \ferreteria\data\ifEditableRecord, fiEventAware {</source>
			...where <code>ifEditableRecord</code> is being declared inside the <code>ferreteria\data</code> namespace.

			For all other uses, the backslash is optional or forbidden.
			</blockquote>
			Perhaps there was some kind of code-caching error? If it happens again, try the backslash.

Woozle at 01:08, 13 January 2020

2020-01-13T01:08:21Z

← Older revision		Revision as of 01:08, 13 January 2020
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	*** narrows down (more closely specifies) the function's expectations of a passed or returned object		*** narrows down (more closely specifies) the function's expectations of a passed or returned object
	*** does not tie the object to a specific class hierarchy		*** does not tie the object to a specific class hierarchy
	==~~Functions~~==		==Predefined==
	* [https://www.php.net/manual/en/~~function~~.~~interface-exists~~.php interface_exists()] returns TRUE if the interface has been declared in code that has executed.		* {{l/sub\|instanceof}} works with both classes and interfaces
			** [https://www.php.net/manual/en/language.operators.type.php official]
			* {{l/sub\|interface_exists()}} returns TRUE if the interface has been declared in code that has executed.
			** [https://www.php.net/manual/en/function.interface-exists.php official]
	==Links==		==Links==
	* official: [https://www.php.net/manual/en/language.oop5.interfaces.php interfaces]		* official: [https://www.php.net/manual/en/language.oop5.interfaces.php interfaces]
			* '''2018-01-13''' [https://daylerees.com/php-interfaces-explained/ PHP Interfaces Explained]

Woozle: Created page with "==About== In PHP, an '''interface''' is a set of public method-functions which can be required in either of two circumstances: * in the declaration of a class ** This work..."

2019-09-29T17:05:53Z

Created page with "==About== In PHP, an '''interface''' is a set of public method-functions which can be required in either of two circumstances: * in the declaration of a class ** This work..."

New page

==About==
In [[PHP]], an '''interface''' is a set of public method-functions which can be required in either of two circumstances:
* in the declaration of a class
** This works almost identically to declaring the interface's methods as abstract functions in a trait or parent class.
* the type of a function argument or return value
** Advantages over declaring the object as a class:
*** narrows down (more closely specifies) the function's expectations of a passed or returned object
*** does not tie the object to a specific class hierarchy
==Functions==
* [https://www.php.net/manual/en/function.interface-exists.php interface_exists()] returns TRUE if the interface has been declared in code that has executed.
==Links==
* official: [https://www.php.net/manual/en/language.oop5.interfaces.php interfaces]