rfc:binary_string_comparison

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rfc:binary_string_comparison [2014/08/16 08:05] – examples for <, <=, >, >= maberfc:binary_string_comparison [2014/08/17 10:55] – sorting regular mabe
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 The current behavior leads to bugs that are very hard to find/catch and it makes code hard to know what's going on. The current behavior leads to bugs that are very hard to find/catch and it makes code hard to know what's going on.
  
-Using strict string comparison helps to workaround such behavior bit it ends up in using strict comparison all over which makes non-strict comparison useless.+Using strict string comparison helps to workaround such behavior bit it ends up in using strict comparison all over which makes non-strict comparison useless and some structures like the switch statement can't be used as it internally uses non-strict comparison. 
 + 
 +Since PHP 5.2.1 ''binary'' is an alias of the string type and a prefix ''b'' exists to mark a string binary which has no effect.
  
 ===== Proposal ===== ===== Proposal =====
Line 115: Line 117:
     true ('0.99999999999999995' <= '1')     true ('0.99999999999999995' <= '1')
     false ('0.99999999999999995' >= '1')     false ('0.99999999999999995' >= '1')
 +
 +=== binary marked strings (since PHP 5.2.1) ===
 +(http://3v4l.org/bWnUG)
 +
 +    <?php
 +    var_dump((binary)'1e1' == (binary)'10');
 +    var_dump(b'1e1' == b'10');
 +
 +Current Behavior (binary marked strings will be handled numerically):
 +
 +    bool(true)
 +    bool(true)
 +
 +Changed Behavior (all strings will be handled binary without a context):
 +
 +    bool(false)
 +    bool(false)
 +
 +=== sorting of strings ===
 +(http://3v4l.org/mA0Yq)
 +
 +    <?php 
 +    
 +    $arr = array('1', 3, 2, '03', '01', '02');
 +    
 +    echo "Sort regular:\n";
 +    sort($arr);
 +    var_dump($arr);
 +    
 +    echo "Sort numeric:\n"; 
 +    sort($arr, SORT_NUMERIC);
 +    var_dump($arr);
 +    
 +    echo "Sort binary:\n";
 +    sort($arr, SORT_STRING);
 +    var_dump($arr);
 +
 +Current Behavior:
 +
 +    Sort regular:
 +    array(6) {
 +      [0] =>
 +      string(2) "01"
 +      [1] =>
 +      string(1) "1"
 +      [2] =>
 +      string(2) "02"
 +      [3] =>
 +      int(2)
 +      [4] =>
 +      int(3)
 +      [5] =>
 +      string(2) "03"
 +    }
 +    Sort numeric:
 +    array(6) {
 +      [0] =>
 +      string(2) "01"
 +      [1] =>
 +      string(1) "1"
 +      [2] =>
 +      int(2)
 +      [3] =>
 +      string(2) "02"
 +      [4] =>
 +      string(2) "03"
 +      [5] =>
 +      int(3)
 +    }
 +    Sort binary:
 +    array(6) {
 +      [0] =>
 +      string(2) "01"
 +      [1] =>
 +      string(2) "02"
 +      [2] =>
 +      string(2) "03"
 +      [3] =>
 +      string(1) "1"
 +      [4] =>
 +      int(2)
 +      [5] =>
 +      int(3)
 +    }
 +
 +Changed Behavior:
 +
 +    Sort regular:
 +    array(6) {
 +      [0]=>
 +      string(2) "01"
 +      [1]=>
 +      string(2) "02"
 +      [2]=>
 +      string(1) "1"
 +      [3]=>
 +      int(2)
 +      [4]=>
 +      int(3)
 +      [5]=>
 +      string(2) "03"
 +    }
 +    Sort numeric:
 +    array(6) {
 +      [0]=>
 +      string(2) "01"
 +      [1]=>
 +      string(1) "1"
 +      [2]=>
 +      string(2) "02"
 +      [3]=>
 +      int(2)
 +      [4]=>
 +      string(2) "03"
 +      [5]=>
 +      int(3)
 +    }
 +    Sort binary:
 +    array(6) {
 +      [0]=>
 +      string(2) "01"
 +      [1]=>
 +      string(2) "02"
 +      [2]=>
 +      string(2) "03"
 +      [3]=>
 +      string(1) "1"
 +      [4]=>
 +      int(2)
 +      [5]=>
 +      int(3)
 +    }
  
 ===== Backward Incompatible Changes ===== ===== Backward Incompatible Changes =====
rfc/binary_string_comparison.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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