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<?php $v = ""; var_dump(preg_match('/^[a-z]{2}(?:[\-_][A-Z]{2})?$/iu', $v));
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/lWV0N
function name:  (null)
number of ops:  9
compiled vars:  !0 = $v
line      #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
    3     0  E >   ASSIGN                                                   !0, ''
    4     1        INIT_FCALL                                               'var_dump'
          2        INIT_FCALL                                               'preg_match'
          3        SEND_VAL                                                 '%2F%5E%5Ba-z%5D%7B2%7D%28%3F%3A%5B%5C-_%5D%5BA-Z%5D%7B2%7D%29%3F%24%2Fiu'
          4        SEND_VAR                                                 !0
          5        DO_ICALL                                         $2      
          6        SEND_VAR                                                 $2
          7        DO_ICALL                                                 
          8      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 8.0.0


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