rfc:variadic_empty

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rfc:variadic_empty [2015/02/21 00:31] – tpuntrfc:variadic_empty [2017/09/22 13:28] (current) – external edit 127.0.0.1
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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: Declined
   * 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 =====
-By changing ''empty()'' to have a variable arity, we can write more compact code when checking for the emptiness of multiple expressions. This seems like a common scenario for web applications...+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.
  
-===== Backward Incompatible Changes ===== +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).
-No BC breakages.+
  
-===== Proposed PHP Version(s) ===== +===== Justification =====
-PHP 7.0+
  
-===== RFC Impact ===== +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:
-==== To SAPIs ==== +
-None.+
  
-==== To Existing Extensions ==== +WordPress (( https://github.com/WordPress/WordPress/blob/master/wp-admin/includes/template.php#L2007 )): 
-None.+<code php> 
 +if ( empty( $pointer_id ) || empty( $selector ) || empty( $args ) || empty( $args['content'] ) ) 
 +</code> 
 +OpenCart (( https://github.com/opencart/opencart/blob/45fc863fa068d82b5280890e6466a198faa54bff/upload/admin/controller/openbay/ebay_profile.php#L128 )): 
 +<code php> 
 +if (empty($setting['dispatch_times']) || empty($setting['countries']) || empty($setting['returns'])){ 
 +</code> 
 +phpBB (( https://github.com/phpbb/phpbb/blob/040d451dcca9ae54d8f4b7bdd2f231033765a8f2/phpBB/phpbb/notification/method/jabber.php#L48 )): 
 +<code php> 
 +return !( 
 + empty($this->config['jab_enable']) || 
 + empty($this->config['jab_host']) || 
 + empty($this->config['jab_username']) || 
 + empty($this->config['jab_password']) || 
 + !@extension_loaded('xml') 
 +); 
 +</code>
  
-==== To Opcache ==== +And so on...
-None.+
  
-==== New Constants ==== +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.
-None.+
  
-==== php.ini Defaults ==== +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]].
-None.+
  
-===== Open Issues ===== +===== Backward Incompatible Changes ===== 
-None.+No BC breakages. 
 + 
 +===== Proposed PHP Version(s) ===== 
 +PHP 7.0
  
 ===== 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 ===== 
-This sections details areas where the feature might be improved in future, but that are not currently proposed in this RFC.+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.1424478700.txt.gz · Last modified: 2017/09/22 13:28 (external edit)

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