rfc:class_and_interface_name_types

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rfc:class_and_interface_name_types [2017/04/29 14:47] – expand ajfrfc:class_and_interface_name_types [2017/05/05 16:21] – revert accidental garbage ajf
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   - If the value is not a string, reject it.   - If the value is not a string, reject it.
   - If there is no currently-loaded class, interface, or trait with the name given by the value, attempt to autoload it.   - If there is no currently-loaded class, interface, or trait with the name given by the value, attempt to autoload it.
-  - If there is now no currently-loaded class or interface (as appropriate) with the name given by the value, reject the value.+  - If there is now no currently-loaded class or interface with the name given by the value, reject the value.
   - Otherwise, accept the value.   - Otherwise, accept the value.
 +
 +As a parameter type, it would permit default values of <php>NULL</php> (to make the parameter null) and constant strings (including <php>::class</php> syntax).
  
 A simple example of usage: A simple example of usage:
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 <?php <?php
  
-function accepts_class(class $class) {+function accepts_class(class $class = stdClass::class) {
     var_dump($class);     var_dump($class);
 } }
  
-accepts_class(stdClass::class);    // works +accepts_class();                   // string(8) "stdClass" 
-accepts_class("stdClass");         // also works +accepts_class(stdClass::class);    // string(8) "stdClass" 
-accepts_class(ArrayAccess::class); // interfaces are also accepted+accepts_class("stdClass");         // string(8) "stdClass" 
 +accepts_class(ArrayAccess::class); // string(11) "ArrayAccess"
 accepts_class("nonexistant");      // Fatal error: Uncaught TypeError: Argument 1 passed to accepts_class() must be of the type class, string given… accepts_class("nonexistant");      // Fatal error: Uncaught TypeError: Argument 1 passed to accepts_class() must be of the type class, string given…
 </code> </code>
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   * It resembles the <php>::class</php> syntax for obtaining the name of a class   * It resembles the <php>::class</php> syntax for obtaining the name of a class
   * It avoids the redundancy of saying "name", given PHP does not represent classes as values in any other way (excepting reflection)   * It avoids the redundancy of saying "name", given PHP does not represent classes as values in any other way (excepting reflection)
-  * It aligns with how PHP treats class and its fully-qualified name the same in several places (e.g. <php>new $class</php> and <php>$class::$property</php>)+  * It aligns with how PHP treats a class and its fully-qualified name the same in several places (e.g. <php>new $class</php> and <php>$class::$property</php>)
  
 However, there are also arguments in favour of ''classname'': However, there are also arguments in favour of ''classname'':
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   * It limits the number of new types that are introduced (one versus two or three)   * It limits the number of new types that are introduced (one versus two or three)
   * It aligns with the internal ''zend_parse_parameters()'' type ''"C"'', used by some functions in the PHP standard library, which likewise accepts both class and interface names   * It aligns with the internal ''zend_parse_parameters()'' type ''"C"'', used by some functions in the PHP standard library, which likewise accepts both class and interface names
 +  * It aligns with how <php>::class</php> works for both class and interface names
   * Interfaces are essentially glorified abstract classes   * Interfaces are essentially glorified abstract classes
   * PHP internally represents interfaces as a kind of class   * PHP internally represents interfaces as a kind of class
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   * It might be surprising to see the name of an //interface// be passed as an argument to a parameter typed "<php>class</php>"   * It might be surprising to see the name of an //interface// be passed as an argument to a parameter typed "<php>class</php>"
  
-There is an advantages to a separate <php>interface</php> type, insofar as having PHP distinguish classes and interfaces in type declarations makes for clearer function signatures and avoids potential manual testing of whether a value is class or an interface.+There is an advantage to a separate <php>interface</php> type, insofar as having PHP distinguish classes and interfaces in type declarations makes for clearer function signatures and avoids potential manual testing of whether a value is class or an interface.
  
-If there was a separate <php>interface</php> type, there would be an argument for having the <php>class</php> type still also accept classes, since classes are a superset of interfaces, and classes can subclass (“implement”) interfaces, but not the other way around.+If there was a separate <php>interface</php> type, there would be an argument for having the <php>class</php> type also accept interfaces, since classes are a superset of interfaces, and classes can subclass (“implement”) interfaces, but not the other way around.
  
 If none of these approaches are palatable, there could be a //third// type accepting both classes and interfaces, perhaps named ''classlike''. However, this might be reaching the point of diminishing returns. If none of these approaches are palatable, there could be a //third// type accepting both classes and interfaces, perhaps named ''classlike''. However, this might be reaching the point of diminishing returns.
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 There is a patch here which contains tests: https://github.com/php/php-src/compare/master...hikari-no-yume:class_type_declaration There is a patch here which contains tests: https://github.com/php/php-src/compare/master...hikari-no-yume:class_type_declaration
  
-It does not yet handle inheritance concerns.+The commits for versions with multiple new types do not handle inheritance concerns.
  
 There is not yet a pull request. There is not yet a pull request.
rfc/class_and_interface_name_types.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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