rfc:functional-elements

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rfc:functional-elements [2008/03/06 02:00]
lstrojny Initial creation. Introduction, current use cases
rfc:functional-elements [2008/03/17 09:40]
lstrojny
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-====== Functional elements ​for object lists ======+This RFC is still in progress 
 +====== Functional elements ​to work with aggregations ​======
 ==== Abstract ==== ==== Abstract ====
-A common pattern in PHP is iterating through a list of objects and executing certain methods of the function. This is especially common when it comes to 1:​n-relations (e.g. one object, n adapters). This proposal is meant to abstract those iterations in convenient functional constructs.+A common pattern in PHP is iterating through a list of objects and executing certain methods of the objects. This is especially common when it comes to 1:​n-relations (e.g. one object, n adapters). This proposal is meant to abstract those iterations in convenient functional constructs ​by adding method call iterators and iterator functions.
  
-==== Current ​examples ​==== +==== Current ​usage patterns ​==== 
-=== UC-1 ===+=== UC-1: Iterating over an aggregation of objects ​===
 <code php> <code php>
 foreach ($list as $element) { foreach ($list as $element) {
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 </​code>​ </​code>​
  
-=== UC-2 ===+=== UC-2: Iterating over an aggregation of objects and keeping the results ​===
 <code php> <code php>
 $result = array(); $result = array();
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 </​code>​ </​code>​
  
-=== UC-3 ===+=== UC-3: Iterating over an aggregation of objects and conditionally executing a method ​===
 <code php> <code php>
 foreach ($list as $element) { foreach ($list as $element) {
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 </​code>​ </​code>​
  
-=== UC-4 ===+=== UC-4: Iterating over an aggregation of objects and conditionally executing a method while keeping the results ​===
 <code php> <code php>
 $result = array(); $result = array();
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 } }
 </​code>​ </​code>​
 +
 +
 +
 +==== Required functionality ====
 +Extracting the required functionality to leads to the following required additions:
 +  * [[rfc:​functional-elements:​call-iterator|class CallIterator]]:​ a simple iterator which walks over a traversable list (including arrays) and calls a specified method. The CallIterator might optionally gather the results
 +  * [[rfc::​functional-elements:​is-traversable|function is_traversable()]]:​ Returns true if a list is traversable (Iterator/​IteratorAggregate/​array)
 +  * [[rfc:​functional-elements:​iterate|function iterate()]]:​ Walks over a traversable list and does nothing
 +  * function iterator_true():​ Walks over a traversable list and assumes every element to be bool(true)
 +  * function iterator_false():​ Walks over a traversable list and assumes every element to be bool(false)
 +
 +==== Modified use cases ====
 +=== UC-1: Iterating over an aggregation of objects ===
 +<code php>
 +iterate(new CallIterator($list,​ '​method'​));​
 +</​code>​
 +
 +=== UC-2: Iterating over an aggregation of objects and keeping the results ===
 +<code php>
 +$result = iterate(new CallIterator($list,​ '​method'​),​ true);
 +</​code>​
 +
rfc/functional-elements.txt · Last modified: 2017/09/22 13:28 (external edit)