rfc:batch_use_declarations

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rfc:batch_use_declarations [2015/01/29 16:31] – fix some code samples that had duplicated use statements marciorfc:batch_use_declarations [2015/01/29 23:14] – change feature name to "group use declarations" marcio
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-====== PHP RFC: Batch Use Declarations ======+====== PHP RFC: Group Use Declarations ======
   * Date: 2015-01-28   * Date: 2015-01-28
   * Author: Márcio Almada, marcio.web2@gmail.com   * Author: Márcio Almada, marcio.web2@gmail.com
   * Status: Draft   * Status: Draft
-  * First Published at: http://wiki.php.net/rfc/batch_use_declarations+  * First Published at: http://wiki.php.net/rfc/group_use_declarations
   * Patch: https://github.com/php/php-src/pull/1005   * Patch: https://github.com/php/php-src/pull/1005
  
 ===== Introduction ===== ===== Introduction =====
-This RFC represents an attempt to improve current PHP namespace implementation by introducing the concept of **Batch Use Declarations**:+This RFC represents an attempt to improve current PHP namespace implementation by introducing the concept of **Group Use Declarations**:
  
 <code php> <code php>
-// Proposed batch use syntax:+// Proposed group use syntax:
  
 use FooLibrary\Bar\Baz\Biz { ClassA, ClassB, ClassC as Fizbo, ClassD }; use FooLibrary\Bar\Baz\Biz { ClassA, ClassB, ClassC as Fizbo, ClassD };
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 ===== Proposal ===== ===== Proposal =====
-Batch use declarations, also known as **grouped imports**, are just **syntax sugar** to cut verbosity when importing multiple entities from a common namespace. Using common PHP library examples, the following use declarations are equivalents:+Group use declarations, also known as **grouped imports**, are just **syntax sugar** to cut verbosity when importing multiple entities from a common namespace. Using common PHP library examples, the following use declarations are equivalents:
  
 <code php> <code php>
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 use Doctrine\Common\Collections\Expr\CompositeExpression; use Doctrine\Common\Collections\Expr\CompositeExpression;
  
-// Proposed batch use syntax:+// Proposed group use syntax:
  
 use Doctrine\Common\Collections\Expr { Comparison, Value, CompositeExpression }; use Doctrine\Common\Collections\Expr { Comparison, Value, CompositeExpression };
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 use Symfony\Component\Console\Question\ConfirmationQuestion; use Symfony\Component\Console\Question\ConfirmationQuestion;
  
-// Proposed batch use syntax:+// Proposed group use syntax:
  
 use Symfony\Component\Console { use Symfony\Component\Console {
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 === Non Mixed Use Declarations === === Non Mixed Use Declarations ===
-As expected, non mixed batch use declarations are supported:+As expected, non mixed group use declarations are supported:
  
 <code php> <code php>
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 use function foo\math\sin, foo\math\cos, foo\math\cosh; use function foo\math\sin, foo\math\cos, foo\math\cosh;
-use const    foo\math\PI, foo\math\E, foo\math\GAMMA, foo\math\GOLDEN_RATIO;+use const foo\math\PI, foo\math\E, foo\math\GAMMA, foo\math\GOLDEN_RATIO;
  
-// Proposed non mixed batch use syntax:+// Proposed non mixed group use syntax:
  
 use function foo\math { sin, cos, cosh }; use function foo\math { sin, cos, cosh };
-use const    foo\math { PI, E, GAMMA, GOLDEN_RATIO };+use const foo\math { PI, E, GAMMA, GOLDEN_RATIO };
 </code> </code>
  
 === Mixed Use Declarations === === Mixed Use Declarations ===
-Current namespace implementation does not allow mixed imports of functions, constants and classes. With the approval of this RFC, for completeness, the following hypothetical mixed imports would be possible:+ 
 +The current implementation of namespaces does not allow mixed imports of functions, constants and classes. The proposed implementation would allow mixed imports like this: 
 + 
 +Current namespace implementation does not allow mixed imports of functions, constants and classes. The proposed implementation would allow mixed imports like this:
  
 <code php> <code php>
 // Current use syntax: // Current use syntax:
  
-use          foo\math\Math; +use foo\math\Math; 
-use const    foo\math\PI;+use const foo\math\PI;
 use function foo\math\sin, foo\math\cos, foo\math\cosh; use function foo\math\sin, foo\math\cos, foo\math\cosh;
  
-// Proposed mixed batch use syntax:+// Proposed mixed group use syntax:
  
 use foo\math { Math, const PI, function sin, function cos, function cosh }; use foo\math { Math, const PI, function sin, function cos, function cosh };
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 </code> </code>
  
-===== About The Syntax Choice ===== +===== Justification =====
-The current choice for batch use syntax is basically a small variation from the current trait adaptation syntax:+
  
-<code php> +Group use statements makes it easier to identify that multiple imported entities are from the same module. For the first example in this RFC, instead of having to read 'FooLibrary\Bar\Baz\Biz' four times to see that the namespace is the same for each entry, it is clear by the grouping syntax that the entries all come from the same namespace. 
-use A, B { + 
-    B::smallTalk insteadof A; +Also, group use statements makes it easier to see in patch diffs that a dependency on a new module has been introduced. For instance, a patch that adds a new dependency on "Consolidation" namespace has been introduced: 
-    A::bigTalk insteadof B; + 
-}+<code> 
 +use Symfony\Component\Console\Question\ConfirmationQuestion; 
 +use Symfony\Component\Console\Question\ChoiceQuestion as Choice; 
 ++use Symfony\Component\Console\Question\OptionQuestion; 
 ++use Symfony\Component\Consolidation\Question\OptionQuestion; 
 +use Symfony\Component\Console\Question\Question;
 </code> </code>
  
-Such design choice allows the feature to stay familiar and intuitive to most PHP user base.+With the current use syntax it's necessary to read to the 30th character of the 2nd modified line to realise that the patch adds a new dependency. The proposed syntax is much more readable: 
 + 
 +<code> 
 +use Symfony\Component\Console\Question { 
 +    ConfirmationQuestion, 
 +    ChoiceQuestion as Choice; 
 ++   OptionQuestion, 
 +    Question, 
 +}; 
 ++use Symfony\Component\Consolidation\Question\OptionQuestion; 
 +</code> 
 + 
 + 
 +===== About The Syntax Choice ===== 
 +The syntax chosen is inline with the current trait adaptation syntax to make it look and feel similar to existing PHP standards. Such design choice allows the feature to stay familiar and intuitive to most PHP user base.
  
-===== Optional: Nested Batch Use Declarations =====+===== Optional: Nested Group Use Declarations =====
 **Nesting** would allow the following use case: **Nesting** would allow the following use case:
  
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 ===== Open Issues ===== ===== Open Issues =====
-  * Should nested batch use declarations be allowed?+  * Should nested group use declarations be allowed?
  
 ===== Unaffected PHP Functionality ===== ===== Unaffected PHP Functionality =====
-Original namespace implementation is not affected by the addition of batch use declarations. Current syntax would still be valid.+Original namespace implementation is not affected by the addition of group use declarations. Current syntax would still be valid.
  
 ===== Proposed Voting Choices ===== ===== Proposed Voting Choices =====
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 The implementation aims to be minimal and of easy maintenance. I created a PR so that the patch diff can be viewed easily: https://github.com/php/php-src/pull/1005 The implementation aims to be minimal and of easy maintenance. I created a PR so that the patch diff can be viewed easily: https://github.com/php/php-src/pull/1005
  
-The current initial implementation can be found on my PHP [[https://github.com/marcioAlmada/php-src/tree/batch-use|fork]]. You can also directly contribute to this RFC by sending a pull request to https://github.com/marcioAlmada/RFCs.+The current initial implementation can be found on my PHP [[https://github.com/marcioAlmada/php-src/tree/group-use|fork]]. You can also directly contribute to this RFC by sending a pull request to https://github.com/marcioAlmada/RFCs.
  
 ===== References ===== ===== References =====
-There is no found record related to batch use declarations on mailing lists.+There is no found record related to group use declarations on mailing lists.
  
 ==== Support in other languages ==== ==== Support in other languages ====
rfc/batch_use_declarations.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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