3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = 'foo bar baz'; $b = 'a'; var_dump( $$b[0] ); $$b[0] = ''; var_dump( $$b[0] );
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/DknNV
function name:  (null)
number of ops:  16
compiled vars:  !0 = $a, !1 = $b
line      #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
    2     0  E >   ASSIGN                                                   !0, 'foo+bar+baz'
    3     1        ASSIGN                                                   !1, 'a'
    4     2        INIT_FCALL                                               'var_dump'
          3        FETCH_R                      local               ~4      !1
          4        FETCH_DIM_R                                      ~5      ~4, 0
          5        SEND_VAL                                                 ~5
          6        DO_ICALL                                                 
    5     7        FETCH_W                      local               $7      !1
          8        ASSIGN_DIM                                               $7, 0
          9        OP_DATA                                                  ''
    6    10        INIT_FCALL                                               'var_dump'
         11        FETCH_R                      local               ~9      !1
         12        FETCH_DIM_R                                      ~10     ~9, 0
         13        SEND_VAL                                                 ~10
         14        DO_ICALL                                                 
         15      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 8.0.0


preferences:
153.67 ms | 1394 KiB | 15 Q