rfc:cyclic-replace

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rfc:cyclic-replace [2015/01/10 19:36] – francoisrfc:cyclic-replace [2015/02/02 18:00] – francois
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 ====== Add cyclic string replacements ====== ====== Add cyclic string replacements ======
-  * Version: 1.5+  * Version: 1.6
   * Creation date: 2015-01-05   * Creation date: 2015-01-05
-  * Last modification date : 2015-01-10+  * Last modification date : 2015-02-02
   * Author: François Laupretre, francois@tekwire.net   * Author: François Laupretre, francois@tekwire.net
   * Status: Under discussion   * Status: Under discussion
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 This is what we name 'cyclic replace'. Purists will note that it is really 'cyclic' This is what we name 'cyclic replace'. Purists will note that it is really 'cyclic'
-only when we set the option to loop in the replace array but I didn't find a better name.+only when we set the option to loop in the replace array.
  
 Note that replacements are done in array order. Key values are ignored in replace arrays. Note that replacements are done in array order. Key values are ignored in replace arrays.
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 'string search' case, providing exactly the same features. 'string search' case, providing exactly the same features.
  
-Arbitrarily nested subject arrays are now supported, returning exactly the same array structure and preserving keys. Only +Arbitrarily nested subject arrays are now supported, returning exactly the same 
-values are replaced.+array structure and preserving keys. Only values are replaced.
  
 Empty replace arrays are considered as unexpected. When one is provided, an Empty replace arrays are considered as unexpected. When one is provided, an
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 php_char_to_str_ex() and php_str_to_str_ex() (defined in ext/standard/php_string.h) php_char_to_str_ex() and php_str_to_str_ex() (defined in ext/standard/php_string.h)
 take an additional //options// take an additional //options//
-argument. This argument is not used at the moment but, this allows their API+argument. This argument is not used at the moment but it allows their API
 to remain compatible with the new new php_str_to_array_ex() function. to remain compatible with the new new php_str_to_array_ex() function.
  
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 is raised and the subject is returned unchanged. is raised and the subject is returned unchanged.
  
-The support of multi-level arrays as search, replace, and subject brings the same+The support of arbitrarily-nested subject brings the same
 kind of BC because previous implementations supported one array level only. kind of BC because previous implementations supported one array level only.
-So, if provided with multi-level arrays, array to string conversion would have 
-been performed. 
  
 All these BC breaks are similar and deal with array to string conversions in All these BC breaks are similar and deal with array to string conversions in
-previous implementations. I think we can consider them as very low impact because+previous implementations. Can be considered as very low impact because
 relying on an array-to-string conversion (with E_NOTICE) when calling these relying on an array-to-string conversion (with E_NOTICE) when calling these
-functions, while theoritically supported, can be considered as broken and very +functions, while theoritically supported, is very improbable.
-improbable.+
  
 ===== Proposed PHP Version(s) ===== ===== Proposed PHP Version(s) =====
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 are exclusive (they cannot be combined) : are exclusive (they cannot be combined) :
  
- * STR_REPLACE_STOP : Stop replacements (up to count(replace) occurences of needle can be replaced)+ * STR_REPLACE_STOP : Stop replacements (up to count(replace) occurences of needle can be replaced)
  * STR_REPLACE_FIRST : Remaining occurences are replaced with the first element of the replace array.  * STR_REPLACE_FIRST : Remaining occurences are replaced with the first element of the replace array.
  * STR_REPLACE_LAST : Remaining occurences are replaced with the last element of the replace array.  * STR_REPLACE_LAST : Remaining occurences are replaced with the last element of the replace array.
- * STR_REPLACE_LOOP : Loop and restart replacements with the first element of the replace array. Looping occurs as many times as needed.+ * STR_REPLACE_LOOP : Loop and restart replacements with the first element of the replace array. Loop as many times as needed.
  * STR_REPLACE_EMPTY : Remaining occurences are replaced with an empty string.  * STR_REPLACE_EMPTY : Remaining occurences are replaced with an empty string.
  
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 ===== Open Issues ===== ===== Open Issues =====
  
-==== Support of arbitrarily-nested search array ==== +The need for an additional options arg is still under discussion.
- +
-As search array support is now performed using recursion, search can contain +
-any level of nested arrays, provided replace provides the corresponding structure. +
- +
-Note that, in case of multi-level arrays, replace array can be less deep than +
-search array as, as soon as we find a non-array replace value, this value is +
-used as replacement string for the whole corresponding search subtree. The opposite +
-case is very different : If the replace array tree is deeper than the search tree by more +
-than 1 level, array to string conversion will occur (with E_NOTICE and the +
-wonderful 'Array' result). +
- +
-Recursion also extends the behavior of 'non-cyclic' replacements as the previous +
-implementation supported only one-level arrays for search and replace arguments. +
- +
- This feature is currently under discussion. The trend is towards limiting the search array +
- to 1 level (allow array of strings only) and, as a consequence, it would limit replace to +
- one more level than search.+
  
 ===== Unaffected PHP Functionality ===== ===== Unaffected PHP Functionality =====
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 Proposed: Proposed:
  
- * Add (search=null, replace=array) syntax. Would take search from array_keys(replace). An array of (search => replace) elements would be, IMO, a more intuitive way to specify multiple replacements. Compatible with current trend to limit search array to 1 level.+ * Add (search=null, replace=array) syntax. Would take search from array_keys(replace). An array of (search => replace) elements would be, IMO, a more intuitive way to specify multiple replacements.
  
  * Add similar features (cyclic replacement and multi-level array recursion) to preg_replace() and preg_filter().  * Add similar features (cyclic replacement and multi-level array recursion) to preg_replace() and preg_filter().
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 ===== Proposed Voting Choices ===== ===== Proposed Voting Choices =====
  
-Required majority : probably 2/3.+Required majority : 50%+1.
  
 ===== Patches and Tests ===== ===== Patches and Tests =====
  
-Pull request against current PHP7 branch : [[https://github.com/php/php-src/pull/980]] +Pull request against PHP7 branch : [[https://github.com/php/php-src/pull/980]]
- +
-When implementation will be complete, this PR is intended to be the final patch.+
  
 ===== Implementation ===== ===== Implementation =====
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 ===== Rejected Features ===== ===== Rejected Features =====
  
-(Keep this updated with features that were discussed on the mail lists)+Support for arbitrarily-nested search/replace arrays is abandoned.
  
rfc/cyclic-replace.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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