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<?php $string = '--'; $doesNotMatchInPhp7 = '/(?|(---)|(-))\1/'; $matchesInPhp7 = '/(?|(-)|(---))\1/'; var_dump(preg_match($doesNotMatchInPhp7, $string)); var_dump(preg_match($matchesInPhp7, $string));
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/fr55p
function name:  (null)
number of ops:  18
compiled vars:  !0 = $string, !1 = $doesNotMatchInPhp7, !2 = $matchesInPhp7
line      #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
    3     0  E >   ASSIGN                                                   !0, '--'
    5     1        ASSIGN                                                   !1, '%2F%28%3F%7C%28---%29%7C%28-%29%29%5C1%2F'
    6     2        ASSIGN                                                   !2, '%2F%28%3F%7C%28-%29%7C%28---%29%29%5C1%2F'
    8     3        INIT_FCALL                                               'var_dump'
          4        INIT_FCALL                                               'preg_match'
          5        SEND_VAR                                                 !1
          6        SEND_VAR                                                 !0
          7        DO_ICALL                                         $6      
          8        SEND_VAR                                                 $6
          9        DO_ICALL                                                 
    9    10        INIT_FCALL                                               'var_dump'
         11        INIT_FCALL                                               'preg_match'
         12        SEND_VAR                                                 !2
         13        SEND_VAR                                                 !0
         14        DO_ICALL                                         $8      
         15        SEND_VAR                                                 $8
         16        DO_ICALL                                                 
         17      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 8.0.0


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