rfc:proper-range-semantics

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rfc:proper-range-semantics [2023/05/08 14:31] – Fix grammar in several places theodorejbrfc:proper-range-semantics [2023/05/16 12:27] – Version 0.3: Handle string digits in a sensible way girgias
Line 1: Line 1:
 ====== PHP RFC: Define proper semantics for range() function  ====== ====== PHP RFC: Define proper semantics for range() function  ======
  
-  * Version: 0.2+  * Version: 0.3
   * Date: 2023-03-13   * Date: 2023-03-13
   * Author: George Peter Banyard, <girgias@php.net>   * Author: George Peter Banyard, <girgias@php.net>
Line 132: Line 132:
   [4]   [4]
   string(1) "E"   string(1) "E"
 +}
 +
 +
 +var_dump(range('1', '3'));
 +array(3) {
 +  [0]=>
 +  int(1)
 +  [1]=>
 +  int(2)
 +  [2]=>
 +  int(3)
 } }
 </PHP> </PHP>
Line 341: Line 352:
 Where using a NAN value as a step even breaks the expectation that <php>range()</php> will return a non empty list. Where using a NAN value as a step even breaks the expectation that <php>range()</php> will return a non empty list.
  
 +==== Issues surrounding usage of string digits ====
 +
 +If one of the boundary inputs is a string digit (e.g. ''"1"'') both inputs will be interpreted as numbers.
 +This doesn't pose too much of an issue if both inputs are string digits as it will generate a list of integers.
 +
 +However, if the other input is a non-numeric string the expected behaviour of generating a list of ASCII characters is not upheld anymore:
 +<PHP>
 +var_dump( range("9", "A") );
 +array(10) {
 +  [0]=>
 +  int(9)
 +  [1]=>
 +  int(8)
 +  [2]=>
 +  int(7)
 +  [3]=>
 +  int(6)
 +  [4]=>
 +  int(5)
 +  [5]=>
 +  int(4)
 +  [6]=>
 +  int(3)
 +  [7]=>
 +  int(2)
 +  [8]=>
 +  int(1)
 +  [9]=>
 +  int(0)
 +}
 +</PHP>
 +instead of the expected:
 +<PHP>
 +var_dump( range("9", "A") );
 +array(9) {
 +  [0]=>
 +  string(1) "9"
 +  [1]=>
 +  string(1) ":"
 +  [2]=>
 +  string(1) ";"
 +  [3]=>
 +  string(1) "<"
 +  [4]=>
 +  string(1) "="
 +  [5]=>
 +  string(1) ">"
 +  [6]=>
 +  string(1) "?"
 +  [7]=>
 +  string(1) "@"
 +  [8]=>
 +  string(1) "A"
 +}
 +</PHP>
  
 ===== Proposal ===== ===== Proposal =====
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   * Emit an <php>E_WARNING</php> when <php>$start</php> or <php>$end</php> is the empty string, and cast the value to ''0''   * Emit an <php>E_WARNING</php> when <php>$start</php> or <php>$end</php> is the empty string, and cast the value to ''0''
   * Emit an <php>E_WARNING</php> when <php>$start</php> or <php>$end</php> has more than one byte if it is a non-numeric string.   * Emit an <php>E_WARNING</php> when <php>$start</php> or <php>$end</php> has more than one byte if it is a non-numeric string.
-  * Emit an <php>E_WARNING</php> when <php>$start</php> or <php>$end</php> is cast to an integer because the other boundary input is a number or numeric string. (e.g. <php>range('5', 'z');</php> or <php>range(5, 'z');</php>) +  * Emit an <php>E_WARNING</php> when <php>$start</php> or <php>$end</php> is cast to an integer because the other boundary input is a number. (e.g. <php>range(5, 'z');</php>) 
-  * Emit an <php>E_WARNING</php> when <php>$step</php> is a float when trying to generate a range of characters.+  * Produce a list of characters if one of the boundary inputs is a string digit instead of casting the other input to int (e.g. <php>range('5', 'z');</php>) 
 +  * Emit an <php>E_WARNING</php> when <php>$step</php> is a float when trying to generate a range of characters, except if both boundary inputs are numeric strings (e.g. <php>range('5', '9', 0.5);</php> produces not warning).
  
  
Line 375: Line 442:
   [4]=>   [4]=>
   string(1) "E"   string(1) "E"
 +}
 +
 +var_dump( range("9", "A") );
 +array(9) {
 +  [0]=>
 +  string(1) "9"
 +  [1]=>
 +  string(1) ":"
 +  [2]=>
 +  string(1) ";"
 +  [3]=>
 +  string(1) "<"
 +  [4]=>
 +  string(1) "="
 +  [5]=>
 +  string(1) ">"
 +  [6]=>
 +  string(1) "?"
 +  [7]=>
 +  string(1) "@"
 +  [8]=>
 +  string(1) "A"
 } }
  
rfc/proper-range-semantics.txt · Last modified: 2023/06/19 13:41 by girgias

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