rfc:variadic_empty

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rfc:variadic_empty [2015/02/21 03:11] – tpuntrfc:variadic_empty [2015/03/21 12:35] – tpunt
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   * Date: 2015-02-20   * Date: 2015-02-20
   * Author: Thomas Punt, tpunt@hotmail.co.uk   * Author: Thomas Punt, tpunt@hotmail.co.uk
-  * Status: Draft+  * Status: Voting
   * First Published at: http://wiki.php.net/rfc/variadic_empty   * First Published at: http://wiki.php.net/rfc/variadic_empty
  
 ===== Introduction ===== ===== Introduction =====
-This RFC aims to make the ''empty'' language construct accept any number of arguments.+This RFC aims make ''empty()'' have a variable arity.
  
 <code php> <code php>
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 if (!empty($a) && !empty($b) && !empty($c)) {} if (!empty($a) && !empty($b) && !empty($c)) {}
  
-// new example usage #1:+// new proposed usage #1:
 if (empty($a, $b, $c)) {} if (empty($a, $b, $c)) {}
  
-// new example usage #2:+// new proposed usage #2:
 if (!empty($a, $b, $c)) {} if (!empty($a, $b, $c)) {}
 </code> </code>
  
 ===== Proposal ===== ===== Proposal =====
-This RFC proposes to change ''empty()'' to have a variable arity, which will enable developers to write more compact code when checking for the emptiness of multiple expressions.+The proposal is to change ''empty()'' so that it can accept multiple arguments. This will enable developers to write more compact code when checking for the emptiness of multiple expressions.
  
-As the above snippet demonstrates, the semantics of a variadic ''empty()'' should be the equivalent to logically OR'ing multiple ''empty()'' invocations together. This behaviour seems to be the most useful, and given that ''empty()'' performs a reverse check to ''isset()'', it should have reversed semantics in order to make it inline. ...+As the above snippet demonstrates, the semantics of a variadic ''empty()'' should be the equivalent to logically OR'ing together multiple ''empty()'' invocations. Thus, if //any// arguments passed into ''empty()'' are considered falsy, then **true** will be returned; if //no// arguments are considered empty, then **false** is returned. This behaviour is the most logical (given ''empty()'''s falsy semantics) and seems to be the most prevalent usage of multiple empty checks in user-land code (therefore being the most beneficial behaviour).
  
 ===== Justification ===== ===== Justification =====
  
-==== Common ==== 
 In PHP, it is not uncommon to see conditionals consisting of multiple ''empty()'' invocations. This is evident by simply browsing through some popular open source projects: In PHP, it is not uncommon to see conditionals consisting of multiple ''empty()'' invocations. This is evident by simply browsing through some popular open source projects:
  
-  * WordPress (( https://github.com/WordPress/WordPress/blob/master/wp-admin/includes/template.php#L1963 ))+WordPress (( https://github.com/WordPress/WordPress/blob/master/wp-admin/includes/template.php#L2007 )):
 <code php> <code php>
 if ( empty( $pointer_id ) || empty( $selector ) || empty( $args ) || empty( $args['content'] ) ) if ( empty( $pointer_id ) || empty( $selector ) || empty( $args ) || empty( $args['content'] ) )
 </code> </code>
-  * OpenCart (( https://github.com/opencart/opencart/blob/45fc863fa068d82b5280890e6466a198faa54bff/upload/admin/controller/openbay/ebay_profile.php#L128 ))+OpenCart (( https://github.com/opencart/opencart/blob/45fc863fa068d82b5280890e6466a198faa54bff/upload/admin/controller/openbay/ebay_profile.php#L128 )):
 <code php> <code php>
 if (empty($setting['dispatch_times']) || empty($setting['countries']) || empty($setting['returns'])){ if (empty($setting['dispatch_times']) || empty($setting['countries']) || empty($setting['returns'])){
 </code> </code>
-  * phpBB (( https://github.com/phpbb/phpbb/blob/040d451dcca9ae54d8f4b7bdd2f231033765a8f2/phpBB/phpbb/notification/method/jabber.php#L48 ))+phpBB (( https://github.com/phpbb/phpbb/blob/040d451dcca9ae54d8f4b7bdd2f231033765a8f2/phpBB/phpbb/notification/method/jabber.php#L48 )):
 <code php> <code php>
 return !( return !(
- empty($this->config['jab_enable']) || + empty($this->config['jab_enable']) || 
- empty($this->config['jab_host']) || + empty($this->config['jab_host']) || 
- empty($this->config['jab_username']) || + empty($this->config['jab_username']) || 
- empty($this->config['jab_password']) || + empty($this->config['jab_password']) || 
- !@extension_loaded('xml') + !@extension_loaded('xml') 
- );+);
 </code> </code>
-  * And so on... 
  
-So this seems like quite a common need for users.+And so on...
  
-The second justification is that it will make ''empty()'' more inline with the  ''isset()'', which is good for the principle of least surprise+So this seems like quite a common need for users, and one that cannot be emulated in user-land code because of ''empty()'''s behaviour of suppressing undefined variable errors. 
 + 
 +This change will also make ''empty()'' more inline with the not-too-dissimilar ''isset()'', which is good for [[http://en.wikipedia.org/wiki/Principle_of_least_astonishment|POLA]].
  
 ===== Backward Incompatible Changes ===== ===== Backward Incompatible Changes =====
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 ===== Proposed PHP Version(s) ===== ===== Proposed PHP Version(s) =====
 PHP 7.0 PHP 7.0
- 
-===== RFC Impact ===== 
-==== To SAPIs ==== 
-None. 
- 
-==== To Existing Extensions ==== 
-None. 
- 
-==== To Opcache ==== 
-None. 
- 
-==== New Constants ==== 
-None. 
- 
-==== php.ini Defaults ==== 
-None. 
- 
-===== Open Issues ===== 
-None. 
  
 ===== Unaffected PHP Functionality ===== ===== Unaffected PHP Functionality =====
 The current functionality of ''empty()'' will be completely preserved. The current functionality of ''empty()'' will be completely preserved.
  
-===== Future Scope ===== +===== Vote ===== 
-None that I can think of.+Because this is a language change, a 2/3 majority is required. It is a simple yes/no vote on whether ''empty()'' should be made a variadic.
  
-===== Proposed Voting Choices ===== +<doodle title="Make empty() a Variadic" auth="tpunt" voteType="single" closed="true"> 
-Include these so readers know where you are heading and can discuss the proposed voting options.+   * Yes 
 +   * No 
 +</doodle>
  
-State whether this project requires a 2/3 or 50%+1 majority (see [[voting]])+Voting starts on 2015-03-07 and ends on 2015-03-21.
  
 ===== Patches and Tests ===== ===== Patches and Tests =====
-Links to any external patches and tests go here. 
- 
-If there is no patch, make it clear who will create a patch, or whether a volunteer to help with implementation is needed. 
- 
-Make it clear if the patch is intended to be the final patch, or is just a prototype. 
- 
-===== Implementation ===== 
-After the project is implemented, this section should contain  
-  - the version(s) it was merged to 
-  - a link to the git commit(s) 
-  - a link to the PHP manual entry for the feature 
- 
-===== References ===== 
-Links to external references, discussions or RFCs 
  
-===== Rejected Features ===== +PR: https://github.com/php/php-src/pull/1109
-Keep this updated with features that were discussed on the mail lists.+
rfc/variadic_empty.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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